For years, scientists have worried and warned that such a full- or near-full collapse of the Greenland ice sheet could once again happen if global temperatures rose too high. That would push sea levels up worldwide, further impacting coastal communities. Exactly how warm it would have to get to cross that threshold has been fuzzy.

The window of concern hovered about 3.6 degrees Fahrenheit, or 2 degrees Celsius, above pre-industrial levels (Earth has already warmed about 2F, or 1.1C). If the ice sheet started down the path toward destruction, scientists warned, it would probably not return.

A new study published in Nature suggests there may be more wiggle room left for the ice sheet before it sets on an irreversible decline. Even if human-driven climate change pushes global temperatures above that 2C threshold, an increasingly likely possibility, the Greenland ice sheet could avoid full collapse if temperatures come back down relatively quickly, the study says.

"The Greenland ice sheet is more resilient than we thought," says Nils Bochow, a researcher at the Arctic University of Norway and the lead author of the paper.

But, he stresses, that resiliency has clear bounds. The possibility of irreversible ice sheet collapse within a few thousand years is nearly impossible to avoid if temperatures dramatically overshoot the 2C threshold after 2100, or if they stay even slightly past that threshold for more than a few hundred years. But a window to repair the damage exists. "If we reduce temperatures within a certain time, we can prevent this abrupt loss," Bochow says.

A finite window exists to save Greenland's ice sheet

Since 2002, the Greenland ice sheet has contributed about 20% of the extra water that's pushed global sea levels up. "And the proportion is increasing over time," says Helene Seroussi, a glaciologist at Dartmouth University who was not involved in the study. More concerning, she says, is that "over the last few years, we have been seeing that Greenland is responding more rapidly than the models predict."

The ice sheet will continue to dump more and more water into the ocean in the coming decades as temperatures warm. That cold, fresh water pushes coastal oceans higher–and may also contribute to other major planet-influencing climate changes, like slowing down some of the most important ocean currents in the world.

Ice sheets are less forgiving than the atmosphere. If carbon emissions magically stopped tomorrow, Earth's atmospheric temperatures would likely stabilize or even cool down fairly quickly. In contrast, the ice sheet won't stop melting right away.

In other words, the melting witnessed today from the ice sheet was set in motion long ago. Each year of extra warming locks in more future melt.

The bigger concern is about warming-induced changes to the ice sheet that affect it in a way that makes it come apart even faster, what scientists call positive feedbacks.

The 2-mile-high surface of the ice sheet today is high in the atmosphere–it's colder up there, just like it is on a mountaintop. As ice melts, the whole surface gets shorter. That puts it in contact with warmer air–just like the warm air at the bottom of a mountain. That increases warming. After a certain point, that process becomes too powerful to turn around. Such positive feedbacks are what could lead to near-total ice loss.

The science team used two different models of the ice sheet and ran different time and temperature scenarios to see how the ice would react. They warmed up the atmosphere until 2100 by a little, some, and a lot–6.5C or about 12F–above pre-industrial temperatures. When temperatures came back down to about 1.5C above pre-industrial levels within a few centuries or even faster, the ice sheet stayed away from the dangerous positive feedback thresholds.

"One hundred, 200 years for the ice sheet is basically instantaneous," says Bochow, because it responds so slowly. So quick action makes a big difference.

The "overshoot"—where temperatures get much warmer than global targets and then come back down–could be possible if humans figure out how to suck carbon out of the atmosphere and store it somewhere safe. Whether that is possible at a globally meaningful scale is still far from clear, stressed Bochow.

"The larger the overshoot, the less time you have to respond and start removing the CO2" and the bigger the carbon removal challenges, says Seroussi.

But asking the question is important, even absent critical technology to make it happen.

"It's a really interesting question," says Ginny Catania, a glacier expert at the University of Texas, Austin, who wasn't involved in the study. "It seems clear we're not going to meet [the Paris Agreement] target of staying below 1.5C. We're probably not going to meet that 2C target. So how do we get back from there?"

This study raises as many science questions as it answers. What's the exact threshold temperature? What processes in the ice sheet itself could influence its sensitivity? But the question that has the biggest impact is also the least certain.

"What are humans going to do? That's the bigger player in how the climate is going to change in the future," and therefore the ice sheet, says Catania.

Chris Bergh, the South Florida Program Manager with The Nature Conservancy, says the changes in sea level over the past decades have caused pine rockland forests in the Keys, the main habitat for the Key deer, to recede by hundreds of meters.

This shrinkage is raising major ethical and logistical questions for the federal wildlife managers tasked with keeping endangered species like the Key deer alive.

"If you move the Key Deer to the mainland, they'll interbreed with the regular deer and then it's only a matter of generations before you don't have Key Deer anymore," Bergh says. "If you move the Key Deer to a whole series of zoos like people have done with pandas and, you name it, endangered species, you can do that and you can keep them going but at what cost and to what end? Is that really a future for the species, the sub-species?"

Nikki Colangelo, U.S. Fish & Wildlife Service biologist says saving a species requires time, money and community and governmental support.

"The options range from giving up and letting a species go extinct to doing absolutely everything you can and putting animals in zoos or collecting plants and putting them in botanical gardens," Colangelo says. "And I mean, I don't want any species to go extinct on my watch. I don't think any of us do. But like, where is society on that?"

Climate change is posing a threat to thousands of species — especially ones like the Key deer that live in only one place.

Some scientists predict that as society focuses more on the impacts of climate change on humans, animals like the deer will become a second thought.

"You aren't going to be worried about deer when you have to worry about people. That's my concern," says Nova Silvy, a now-retired biologist who spent most of his career studying the Key deer from Texas A&M.

The military government, which came to power in a military coup in 2022, recently signed a declaration of intent aimed at increasing the country's electricity supply. As part of the agreement, Rosatom, a state-owned Russian company, will be responsible for constructing a nuclear power plant. This development could significantly enhance Burkina Faso's electricity capacity within the next few years, but experts are skeptical about the viability of the project.

Ibrahim Traore has ruled the country since the 2022 military coup and, at age 35, is the youngest serving president in the world. He has largely turned his back on France, the former colonial power, as a partner and, instead, has set his sights on Vladimir Putin's Russia.

Solar power as a viable option

For critics like Adrien Poussou, the former Central African Republic minister for national reconciliation, the construction of a nuclear power plant is merely a form of Russian propaganda.

"It is absurd that the African continent, which has sun, can have problems with energy and electricity," the political analyst told DW. 

Solar energy should be the solution, not an agreement to build a nuclear power plant, he stressed.

"It is time to flip this injustice on its head," UN Special Rapporteur on extreme poverty and human rights, Olivier De Schutter, said in a press release.

"Governments should draw up lists of the most socially valuable professions and pay them accordingly, while also listing the professions where pay should be capped to mitigate their harmful side effects."

20% of global workers live in poverty

According to the latest findings, one in five workers in the world is living in poverty.

"Most of the world's poor people work, yet they do not earn a wage sufficient to afford an adequate standard of living for themselves and their families," the introduction to the report reads.

Many of the workers in jobs that society relies on to function, such as food production, transport, cleaning and sanitation, are earning the minimum wage in their country, the report says. This is often not enough to keep these workers out of poverty, especially in the face of soaring inflation and stagnating wage growth.

Global monthly wages fell in real terms by 0.9% in the first half of 2022, the UN found — the first global wage decline this century.

Gig economy weakens bargaining power

Over the past 20 years, workers have seen a weakening of the ability to fight for better wages, De Schutter says. More and more workers have "flexible" or temporary contract conditions, sometimes called being part of the "gig economy." These substandard contracts and worker isolation make it harder for unions to mobilize and fight for better pay.

There is also the constant threat that employers will look to produce elsewhere in low-wage jurisdictions, which cripples employees' ability to bargain.

"There's a global competition, in which governments take part, leading to a race to the bottom in the area of how wages are set," De Schutter told DW in a call. "There is no future for countries who bet their comparative advantage in this global competition on keeping their workers in poverty."03:43

Minimum wage doesn't always equal a living wage

International human rights law guarantees workers the right to pay which provides them, as a minimum, with fair wages and a decent living for themselves and their families.

"The persistence of in-work poverty can be attributed to violations of these guarantees," the UN report notes. 

For example, the minimum wage in many countries is not keeping pace with the true cost of living. In China, a monthly minimum wage can range from $240 (€226) to $380, but estimates show that "a true living wage" for a single Chinese adult would range from $360 to $585.

According to the UN report, a living wage would need to provide a worker and their family with a decent standard of living, or correspond to at least 60% of the median wage in the country, whichever is highest.

"Governments should stop believing in this fiction that wages are set as a result of supply and demand curves meeting on an equilibrium point in the labor markets," said De Schutter.

Harmful sectors should be less lucrative 

Workers tend to be rewarded for the economic value they create rather than what they contribute to society. This is particularly true of care work, which historically was performed by women within households, without pay. This worldview is one factor keeping wages for essential workers down.

"Instead of designing schemes to help people in poverty, economists will become traders; instead of producing food for the community, farmers will produce cash crops for which there is a demand on the high-value markets of rich countries," the report says.

"My call is to governments to remedy this," De Schutter told DW, "and to ensure that teachers, nurses, health care providers are much better paid, and put a cap on the wages paid in the most toxic industries, such as fossil energy trading or advertising."

Although you may be aware of fungal skin infections, you may not be aware of "invasive" fungal infections, which can affect your lungs or spread to your organs through your blood.

These infections are on the rise and can be life-threatening, especially in immunocompromised people. For years, they have fallen under the radar of the general public. It was only last year that the World Health Organization released its first-ever list of health-threatening fungi.

This general lack of awareness has led to misdiagnosis of fungal infections in clinical settings and stymied development of medications to treat the problem.

It also makes it impossible for the WHO to conclusively estimate the burden of disease. Experts suggest invasive fungal infections kill up to 1.5 million people per year — for reference, that's around the number of deaths attributed to tuberculosis per year.

The Candida fungus can cause invasive fungal infectionsImage: La Nacion/ZUMA Press/picture-alliance

How do you "catch" an invasive fungal infection?

We breathe in spores of fungus all the time. This fungus comes from our compost bins, the moldy bread on our kitchen table or the flower bulbs we plant in our gardens (more on that later).

Oliver Cornely, head of the European Center of Excellence for Invasive Fungal Infections, said these spores aren't a problem for the vast majority of healthy people, whose immune systems can easily fight them off.

But for the immunocompromised — those who smoke very heavily or have recently experienced an organ transplant or cellular therapy — inhaling these spores can sometimes cause problems.

Why are invasive fungal infections on the rise?

Cornely said the rise in invasive fungal infections is largely linked to a rising number of life saving operations.

Today, many more people routinely undergo operations and treatments, such as chemotherapy. But such medical interventions can increase a person's susceptibility to invasive fungal infections,

There's also an increasing issue with antifungal resistance.

What is antifungal resistance and why is it a problem?

Antifungal resistance is like antibiotic resistance. Some fungi are resistant to the medications, or antifungals, used to treat them.

Some fungi are intrinsically resistant to certain classes of antifungals, said Cornely.

Others become resistant to antifungals because a smaller dose reaches them, allowing them to become resistant to, rather than annihilated by, the medication.

One way to understand this is to think about peanut allergy treatments. People with a peanut allergy eat a tiny amount over a period of time to build up resistance. Eventually they become immune to the allergens in peanuts.

This is similar to fungi — when fungi are exposed to tiny doses of antifungals, they can build up resistance.

This resistance can be built within the body of a person being treated with antifungals or in nature — antifungals are used in bulk in agriculture. The United Nations Food and Agriculture Organization estimates that if antifungals were to stop being used in farming, we would lose food for 2 billion people.

"It's a dilemma," Cornely said. "We must use them in agriculture. We should not really use them for flower bulbs, though."

How are antifungals used in agriculture?

Antifungals are used on flower bulbs for the same reasons they are used in food production: to prevent you from picking up a daffodil bulb at the florist and finding a big piece of mold on it.

Before flower bulbs are sold at a nursery, they undergo something called "bulb dipping" into a bath of azoles, the same antifungal agent used to treat invasive fungal infections.

Candida auris could have developed in response to global warming, experts sayImage: Kateryna Kon/IMAGO

"That is why when you go to the garden center, you never find a bulb with fungus," Cornely said. "Usually, like your bread, these things should really decay and be destroyed by Aspergillus fumigators … but that does not happen because they are covered with azoles."

That may all be fine and good — no one wants to deal with moldy flowers! But Cornely said that what happens is that when you take the bulbs home and plant them in your garden, the azoles enter the soil. This results in a high concentration of azoles directly next to the bulb, but as you get farther and farther away, the concentration lessens until it is so low that fungi in the soil can tolerate it — just like the tiny portions of peanuts people eat to treat an allergy. Through this exposure, those fungi become resistant to the azoles.

This is the same thing that happens when an antifungal is used to treat an abscess, Cornely said. In the abscess itself and directly near it, the amount of antifungal will be so strong, it will kill all fungi in its path. But the farther and farther away, the lower the concentration of the antifungal, the higher the likelihood the fungi in the body will become resistant to, rather than die from, this exposure.

Which invasive fungal infections are most common?

The most common invasive fungal infections are caused by the Candida and Aspergillus fungi. Aspergillus primarily affects the lung, while Candida can spread through the bloodstream to cause infection in different organs of the body, most commonly the eyes, bones, liver or spleen.

Cornely said this can happen from the gastrointestinal tract. In healthy people, he said, it's normal to have fungus there "hanging around with myriads of bacteria."

But in people who have undergone procedures or health issues affecting the integrity of their mucosa — the soft tissue that lines our organs, protecting them against invasive pathogens — these fungal organisms can become pathogens themselves. 

It’s the haul of volunteers participating in a 10-day competition that draws over 150 people, life-jacketed rivergoers of all ages that pile into dozens of canoes to scour Hungary’s second-largest river for trash that has flowed downstream.

Since its start in 2013, participants in the annual Plastic Cup competition — which offers a prize for those who collect the most trash each year — have gathered more than 330 tons (around 727,000 pounds) of waste from the Tisza and other Hungarian waters.

“The biggest source of global waste pollution is rivers. The waste comes down the rivers, through the seas and into the ocean, where currents form it into big islands,” Tamas said, referring to collections of debris and microplastics that ocean currents gather into giant fields called gyres.

“If we can prevent this global problem on the rivers, then less will enter the oceans,” he said. “Prevention, solving it at the beginning of the pipeline is the best. If it doesn’t get into the Tisza, then we have nothing to pull out."

Volunteers in Hungary have been cleaning up the Tisza River. The event is called the Plastic Cup and is a ten-day competition to remove waste from the waterway. (Aug 1.) (AP Video/Bela Szandelszky)

Calls for addressing the global plastics crisis have become more urgent in recent years as studies conclude that exposure to such pollution can carry grave ecological and human health risks.

Carbon dioxide emissions stemming from plastic manufacturing are known to contribute to climate change, and some studies suggest that plastics, particularly when broken down into tiny pieces, can have an impact on hormones, fertility, and the endocrine, nervous and immune systems, and can carry an increased risk of cancers.

Research cited by a 2023 United Nations Environment Programme report says microplastics, tiny fragments less than five millimeters in length, have been found “in the deepest recesses of the ocean, in pristine mountain glaciers, in breast milk and human bodies.”

According to the U.N., 75% of plastic waste originates in municipal solid waste streams before being carried into the oceans, “significantly contributing to environmental degradation and biodiversity loss” such as marine and coastal wildlife becoming entangled in plastic waste, or ingesting it after mistaking it for food.

On the Tisza, volunteers disembark from their canoes and scale the steep banks of the river with yellow collection bags in hand, entering the dense vegetation and braving the thick mosquitoes, thorns and nettles as they search for waste. Some use an open-source online application as a guide, where any user can mark places they’ve discovered larger deposits of trash throughout the year.

Once their canoes are overloaded with collection bags, they offload them on waiting “mother ships” — makeshift rafts floating on pontoons of baled plastic bottles — where team members collect the bags and begin sorting through the trash.

The volunteers, who camp in a new spot each night as they make their way downriver, collect an average of 70 tons (around 154,000 pounds) of waste from the Tisza each year. The group estimates it has removed nearly 4 million plastic bottles from Hungarian waterways, and all recyclable materials — around 60% of what they collect — is sent to recycling facilities for processing, while the rest is transported to landfills.

But Gergely Hanko, a conservation engineer and project leader for the Plastic Cup, said that while much of the waste can be removed by hand from the floodplain, there is much more that remains inaccessible.

“Part of the waste is built into the sludge of the river bed. It’s obviously not a good place for it, since fish and Tisza mayflies spawn there,” Hanko said. “We know that fragmented plastic ... has harmful effects. It can get into the blood, it can get into the drinking water, it goes everywhere, into the bodies of animals.”

While the quantity of solid waste pollution has been significantly improved on the Tisza in the decade since the Plastic Cup began, the concentration of microplastics remains high, according to a 2021 study by the University of Szeged, a southern Hungarian city straddling the Tisza.

That study found that microplastics in the river are present at 3-4,000 fragments per kilogram of sediment, a figure the study’s authors said is higher than that of India’s Ganges River, often touted as one of the most polluted in the world.

Hanko says a majority of the waste on the Tisza comes from its headwaters in the Transcarpathia region of Ukraine, where a lack of landfill capacities and collection infrastructure has resulted in improper disposal that carries the waste into Hungary following floods.

Tracing the problem to the source, the Plastic Cup last year provided financial support for waste management efforts in Ukraine, which succeeded in collecting 700 tons of waste from Ukraine’s Upper Tisza in 2022.

Yet as long as single-use plastics production remains high, such pollution is certain to persist. According to the Organisation for Economic Co-operation and Development, the world produces 430 million metric tons of plastics each year, a figure that is set to triple by 2060 at current trajectories.

Over two-thirds of those plastics are short-lived or single-use products which soon become waste, and the U.N. estimates that 19 to 23 million tons of plastic leaks into aquatic ecosystems annually.

To tackle the problem, an international forum was held in Paris in May to exchange solutions on how to end plastic pollution. The forum drew on a U.N. study that found an 80% reduction in plastic pollution is possible by 2040 by “rethinking and redesigning products, reusing, recycling, reorienting and diversifying markets and addressing demand for durable plastics.”

Eszter Hosszu, 23, came to volunteer in the Plastic Cup for the first time this year, and said she felt driven to take action by what she sees as a darkening future amid climate change and ecological damage.

“I think environmental protection is everyone’s concern, to make sure that tomorrow will be livable. I think everyone has a responsibility,” she said. “A lot can be done with events like this, if you think about how much garbage we were able to collect in just one day.”

Over the years, the Plastic Cup has expanded to clean-ups on the Tisza Lake, the Bodrog and the Maros rivers. Tamas, the competition director, says that creating similar organizations in other countries could do much to relieve the burden on the oceans.

The Plastic Cup has engaged in international cooperation with others in Serbia, Romania and Bulgaria, hoping to pass on the knowledge and experience they’ve gained to help others fight against pollution in their own rivers.

Hanko, the conservation engineer, said the organization’s hope is to bring the Tisza and other waterways into a condition where, rather than taking to the water to clean them up, their natural treasures can simply be enjoyed.

“The long-term goal is not to collect garbage, but to organize long-distance canoe tours,” Hanko said. ”We want to constantly clean (the Tisza), so that in the end, all we have to do is paddle.”

The above statement rings true for 63% of 18- to 34-year-old respondents to a CVS Health and Harris Poll survey released during Suicide Prevention Month this September. It’s a heartbreaking window into the mental health of today’s young adults, considering more than a third of this age group also said they had moments in the past year when they contemplated suicide.

As parents ourselves, we are extremely concerned about this crisis and its potential causes, such as social media and the identity crisis it can foster within young adults. As this generation moves from their teenage years to adulthood, it can become harder to find a sense of purpose or identity when values, life milestones and even appearances are compared to those of others their age within the digital world.

Parents have experienced this transitional period themselves, but understanding social media's new role in mental health is crucial as we seek to protect our kids and others we love.

Struggling With Life Online

The journey into and through young adulthood is a pivotal and complex period of identity formation. Although this can be a positive time of self-discovery, it often can be marked by uncertainty or self-doubt as well, compounding with academic, financial and relationship stressors to create feelings of desperation and hopelessness. And when this generation watches their peers have an “easier” time online, with celebratory photos of life events and nights out, it can feel as if they are not transitioning into adulthood the “right way.”

This exemplifies how using social media is a double-edged sword, as it provides a platform for self-expression while simultaneously fueling unrealistic standards and a constant desire for validation. Incessant comparisons to peers, celebrities and influencers can intensify a young person’s internal struggle to align their personal identity with societal standards and ideals.

The real world, however, exists outside of any social media platform, which is an important sentiment to remember. Talking to friends in person about their lives will always provide a more satisfying view into their world than their latest Instagram post or TikTok video, because what they’re depicting may not be an honest representation of their reality.

Setting boundaries on social media for teens – and for yourself – can help foster more of this valuable in-person contact and form deeper, more meaningful relationships that can set a foundation for a healthier identity. But while completely unplugging is likely the best course of action to counter the negative effects of social media, it might feel like things can never truly be turned off in today’s digital world. If that’s the case, try to limit the time your family spends on social media. Use phone settings to help create and manage those boundaries, and reach out to family or friends to suggest a group activity that can take the place of swiping, clicking or doomscrolling.

Cyberbullying is another common issue tied to social media, and we’ve seen its effects as parents of young adults. To help stop the cycle, be the change you wish to see, and consider whether the comment or post you’re contemplating would be reflective of your in-person behavior. Encourage your teens to do the same.

Where to Turn With Concerns

If you are worried that social media is affecting your child’s mental health, be on the lookout for signs that can include withdrawal from family and friends, a lack of interest in the future, decreased interest in hobbies, and major changes in behavior, sleep or appetite.

Knowing the signs of suicidal ideation also can be critical. Noticeable indicators that someone might be considering suicide include talking about death or feelings of emptiness, increased alcohol or drug use, and saying goodbye to loved ones. While it might feel intrusive or uncomfortable, acting on your concerns is an act of courage, and can be lifesaving. If you feel your child or someone you know is at risk, follow these five steps as outlined by the 988 Suicide & Crisis Lifeline until you locate additional support systems:

• Ask: Do not be afraid to be blunt and ask your loved one if they are considering suicide, as this can open an honest dialogue. Make sure when you ask that you are able to actively listen, and do not promise to keep suicidal thoughts a secret.

• Be There: Be present, whether that means being with a person physically, talking with them on the phone or any other way you can show you are available. By doing this, you reestablish a sense of connectedness for someone struggling. 

• Help Keep Them Safe: Establish if there are any methods or actions that the individual has considered or already taken. Knowing the plans for a suicide attempt is the most effective way to stop one, and if you are not physically present, connect with someone who can remove access to any potential lethal means. Be sure to remove any firearms from the home or, at minimum, ensure they are properly locked away. 

• Help Them Connect: Establish a safety net by providing resources and support systems to someone you’ve identified as being in crisis. This can involve community resources like a mental health counselor or help available through the 988 lifeline.

• Follow Up: Set up another time to talk in person or via phone call to see how your loved one is doing and if they’ve received support. This is a good opportunity to discuss ways to seek help in case of another crisis, confirm that you are a trusted source for this person and further their sense of connectedness.

It’s not only our children who may be affected by social media and have thoughts of suicide, and it’s important to be familiar with ways to help before we need them for our loved ones or ourselves. Additional resources include depression screenings that can be accessed at more than 1,000 MinuteClinic locations across the U.S. – with some offering virtual services – as well as tools and supports available through The JED Foundation and the American Foundation for Suicide Prevention. 

Suicide Can Be Preventable

Society as a whole is growing increasingly aware of mental health struggles and working to mitigate them. In 2022, 94% of people surveyed believed that at least some instances of suicide can be prevented. But just like physical health, mental health requires preventive care that people should seek before they ever get close to a moment of crisis.

You don’t have to be a medical professional to listen and offer support. Check in on your loved ones regularly to see how they are feeling and show them that they are not alone. Reach out to family members, friends, community leaders or doctors if you feel hopeless or know someone exhibiting signs of suicide. Use social media responsibly, and encourage others to do the same.

Together, we can shift the stigma that social media can bring and change conversations on suicide from taboo to honest discussions. By getting real, we can help others heal – and even save lives.

If you or someone you know is struggling or in crisis, please call or text 988, or chat at 988lifeline.org.

The attorney won. In the end, the board voted to require that eighth grade science students “describe the carbon cycle” instead.

Over the past two years school board meetings around the country have erupted into shout fests over face masks, reading lists and whether to ban education about structural racism in classrooms. In Texas, a quieter political agenda played out during the lightly attended process to set science education standards—guidelines for what students should learn in each subject and grade level. For the first time, the state board considered requiring that students learn something about human-caused climate change. That requirement came under tense dispute between industry representatives interested in encouraging positive goodwill about fossil fuels and education advocates who think students should learn the science underlying the climate crisis unfolding around them.

Standards adoptions are an exercise in bureaucracy, but the results wield great power over what is taught in classrooms. Publishers consult them as they write textbooks. State education officials use them as the basis of standardized tests. School districts call on them as they shape curricula. Teachers refer to them as they devise lesson plans. Every state adopts its own standards, but Texas adoptions have long had influence far beyond the state’s borders.

In 2020 two major education advocacy groups—the National Center for Science Education and the Texas Freedom Network—hired experts to grade the science standards of all 50 states and Washington, D.C., based on how they covered the climate crisis. Thirty states and D.C. made As or Bs. Texas was one of six states that made an F. But because Texas is one of the largest textbook purchasers in the nation—and because its elected 15-member State Board of Education has a history of applying a conservative political lens to those textbooks—publishers pay close attention to Texas standards as they create materials they then sell to schools across America. As a former science textbook editor once told me, “I never heard anyone explicitly say, ‘We can’t talk about environmentalism because of Texas.’ But we all kind of knew. Everybody kind of knows.” In this way, the proceedings in an Austin boardroom influence what millions of children nationwide are taught.

Most Americans favor teaching kids about the climate crisis. A 2019 nationwide poll by NPR/Ipsos found that nearly four in five respondents—including two of three Republicans—thought schoolchildren should be taught about climate change. When the Texas Education Agency surveyed science educators across the state about what should be added to the standards, one in four wrote in asking for climate change or something adjacent, such as alternative energy. No one asked for more content on fossil fuels.

After hours of testimony, Robert Unger appeared to represent the Texas Energy Council, and he had some suggestions.

And yet, as I learned when I watched 40 hours of live and archived board hearings, reviewed scores of public records and interviewed 15 people involved in the standard-setting process, members of the fossil-fuel industry participated in each stage of the Texas science standards adoption process, working to influence what children learn in the industry’s favor. Texas education officials convened teams of volunteers to rewrite the existing standards, and industry members volunteered for those writing teams and shaped the language around energy and climate. Industry members rallied to testify each time proposals to revise standards got a public hearing. When the board considered the rewritten standards for final approval, the industry appealed to members to advance their favored amendments, ensuring that the seemingly local drama in Austin will have outsized consequences.

For at least a decade the fossil-fuel industry has tried to green its public image. The Texas proceedings show that its actions do not always reflect that image. In little-watched venues, the industry continues to downplay the crisis it has wrought, impeding efforts to provide clear science about that crisis to a young generation whose world will be defined by it.

The last time the board overhauled the Texas Essential Knowledge and Skills (TEKS) for Science, in 2009, it was chaired by Don McLeroy, a dentist from east-central Texas. McLeroy made his views on science education clear when he declared at one meeting, “Somebody’s got to stand up to experts!” The board spent much of that adoption cycle clashing over evolution, but it also required that high school environmental science students debate something scientists hadn’t debated for a long time: whether global warming is happening. McLeroy told a reporter he was pleased because “conservatives like me think the evidence is a bunch of hooey.”

At the end of 2019, when it was time to begin another overhaul, McLeroy was gone. The board made it clear to the 85 volunteers recruited by the Texas Education Agency to draft the new standards that it hoped there would not be a fight over evolution again. It soon became clear the group would fight about climate science instead.

To start the process, board members carved the standards into three tranches that they would consider one at a time: first, high school core sciences, then high school elective sciences and finally grades K–8 sciences. The board would give each tranche to writing teams composed of volunteers. Professional content advisers, most nominated by board members, would provide feedback to the board on proposed changes.

Over the summer of 2020 one team took on the first tranche, the high school core subjects: biology, chemistry, physics, and an integrated chemistry and physics class. The core science standards were important for two reasons. The classes had sky-high enrollment; every year nearly half a million students took biology alone. And what happened with these classes would set the tone for the high school electives and for K–8. To the climate education advocates’ dismay, when the Texas Education Agency posted the writing groups’ results on its website in July 2020, the draft standards didn’t contain a single reference to modern-day climate change. But there was still a chance to fix that omission. The state board would present the draft standards for public testimony, hearings and amendments.

The first major hearing took place in September 2020, held in person and virtually on Zoom because of the COVID pandemic. More than 30 teachers, parents and other education advocates showed up to testify that the climate crisis has biological, chemical and physical aspects that make it relevant to all the core classes. Three and a half hours into that meeting, however, someone with a different message appeared on the Zoom screen: Robert Unger, a silver-haired engineer from Dallas who had worked for the oil and gas industry for more than 45 years. He was representing the Texas Energy Council, and he had some suggestions.

The Texas Energy Council is a coalition of about 35 industry organizations, predominantly from the oil and gas sector, collectively made up of more than 5,000 members. Some months earlier the council had begun recruiting volunteers to participate in the standards adoption process. “The earth sciences and the oil/gas industry in particular have suffered significant degradation in the K–12 curriculum over time,” a page on the council’s website said. In hopes of reversing that trend, the council enlisted 17 people—geoscientists, petroleum engineers, professors, attorneys and other fossil-fuel careerists—who, the site said, “shared its vision of ensuring that oil/gas is portrayed in a balanced fashion as a critical contribution to the Texas, U.S. and worldwide energy mix.” Unger had helped organize the volunteers. (Several members of the organization, including Unger, declined to be interviewed for this story. In an e-mail exchange, Michael Cooper, president of the council, took issue with some of this article’s findings but said he would be unable to provide a comprehensive response without reviewing a complete draft.)

“Inactivism” doesn’t deny human-caused climate change but downplays it, deflects blame for it and seeks to delay action on it.

Unger asked the board to remove a line in the introductory material for each of the high school core classes that discussed social justice and ethics, terms he said “do not belong in the course material.” Instead, he said, the standards should include the concept of cost-benefit analysis.

Most board members had expressed little reaction to the many people testifying in favor of climate education, but Unger’s testimony got their attention. Longtime Republican member Barbara Cargill, a former biology teacher from north of Houston serving her last few months on the board, asked Unger how cost-benefit analysis might be incorporated into the science TEKS. He gave an example: The main benefit of fossil fuels is the energy they produce, and the costs are “environmental issues that our industry is already regulating.” But oil and gas aren’t the only fuels with a cost, Unger said. Take solar: “It seems like the benefits are wonderful, but the costs, in fact, are the mining of rare minerals to create batteries,” he said. “Wind equally has cost and benefit to it.” A science teacher could weigh these things with students, he noted, “and not get into the ambiguities of social injustice and social ethics.” Cargill promised to consider Unger’s proposal.

All sources of energy come with costs. But a fixation on “cost-benefit analysis” is a plank in a raft of arguments supporting what climate scientist Michael Mann has called “inactivism”—a tactic that doesn’t deny human-caused climate change but downplays it, deflects blame for it and seeks to delay action on it. Sure, this brand of thinking goes, fossil fuels have their ills. But what form of energy doesn’t? Mann and others have criticized such arguments for their false equivalencies: the environmental and health costs of rare earth minerals for certain renewable energy sources are small compared with those of fossil fuels.

The next day, when the board met to consider amendments to the standards, Cargill delivered. She proposed removing social justice from the standards and adding cost-benefit analysis. Fellow Republican Pat Hardy, a retired history teacher and curriculum developer representing suburbs near Dallas–Fort Worth, eagerly supported the addition. “People talk about electric cars like they’re saving the universe,” Hardy said, captured on a video of the meeting. “And the answer is no, they are not.” The board voted to accept the changes. It was the Texas Energy Council’s first major victory.

The climate education advocates did get a win on the final day of the hearings. Marisa Pérez-Díaz, a Democratic board member from San Antonio and the youngest Latina to ever be elected to any state’s education board, had heard their pleas. She proposed adding the words “and global climate change” to the end of a standard that asked students to examine a variety of human impacts on the environment. Remarkably, the board approved the motion. It wasn’t a big win; the wording applied to just one standard, for the integrated physics and chemistry course, which is taken by a fifth of the students who take biology. But for the advocates it was a hopeful sign—certainly a step up from “a bunch of hooey.”

In the following months, as the board considered the next two tranches—the high school electives and the K–8 standards—Texas Energy Council volunteers showed up at meeting after meeting. Sometimes they pursued changes that the climate education advocates found reasonable, such as requiring that students learn the laws of geology and encouraging the use of resources such as museums and mentors. But they kept a relentless focus on adding cost-benefit analysis to the standards, and they added new petitions. They insisted on removing the terms “renewable” and “nonrenewable” to describe different energy sources; they preferred to describe all the options as “natural resources.” And they frequently brought up energy poverty—the lack of access to affordable electricity. “Energy poverty is one of the gravest but least talked-about dangers facing humanity,” testified Jason Isaac, director of an energy initiative for a conservative think tank, at one meeting. He suggested just one solution: “Right here in Texas the key to ending global energy poverty lies under our feet.”

The climate education advocates on the board expected to lose some of these battles. But they hoped the Texas Energy Council volunteers would stand down when it came to including clear information about the science of the climate crisis. During the next set of deliberations, it became evident that would not be the case.

In January 2021 the board held the first hearings for high school electives: environmental science, aquatic science, earth science and astronomy. Far fewer students take the electives than take biology, chemistry or physics, but the earth science and environmental science course standards were the only ones that already mentioned climate change.

In the months leading up to the hearings, the 23 people on the electives writing teams had met about every two weeks to draft the new standards. The old standards for the earth science course had asked students to “analyze the empirical relationship between the emissions of carbon dioxide, atmospheric carbon dioxide levels, and the average global temperature trends over the past 150 years,” a reference to the period since industrialization, during which atmospheric carbon dioxide levels have soared. That language didn’t sit well with William J. Moulton, a longtime geophysicist for the petroleum industry. Encouraged by the Texas Energy Council, he and several other industry representatives had applied to the Texas Education Agency for a seat on a writing group and had been placed. Moulton was on the team rewriting the earth science and astronomy courses.

Moulton agreed that climate change should be mentioned in some way because students would hear about it anyway. But he felt students should not be led to believe the science is settled. He argued that the phrase “the past 150 years” should be removed. The group agreed to that change and to several of Moulton’s other language tweaks. When those already diluted standards came before the board in January, four other Texas Energy Council volunteers appeared on Zoom, all recommending amendments. One person said the standards should focus on the dangers of rare earth minerals. Another said it was important for children to learn that the inception of the fossil-fuel industry stopped the practice of whaling for blubber that could be turned into fuel. “Oil and gas literally saved the whales,” she said.

The industry also had a new champion on the board: Will Hickman, who had just been elected in November 2020 for a district outside of Houston. Hickman’s experience in education included serving on parent groups at his kids’ schools, coaching community sports and teaching Sunday school. He’d held the same day job since 2004: senior legal counsel at Shell Oil.

“Let’s call this what it is,” Aicha Davis said. “At this point we’re only making votes based on what oil and gas wants us to do.”

In the January hearing, Hickman’s first, his opening question was where in the proposed standards he could find the advantages and disadvantages of various forms of energy. The next day he offered an example that might be raised in class: “Everyone thinks renewable power’s a great idea, and Germany adopted it on a large scale,” he said. “But the cost-benefit—it ended up raising their power prices to about 2.5 times our power prices.”

The writing committees had already included a reference to cost-benefit analysis in the “scientific and engineering practices” section of each of the elective courses, and the standard for the environmental science course had a second mention. But at the next board hearings, in April, Hickman pressed for more. Another member, Rebecca Bell-Metereau, a professor of English and film at Texas State University, who had just been elected to represent Austin, pressed back: “The very phrase ‘costs and benefits’ places the primary emphasis on money, not on society or well-being or human health.” The board nonetheless approved a motion by Hickman to add another mention of costs and benefits, to aquatic sciences.

Moulton began showing up at the board hearings with additional proposed changes. His colleagues on the writing group had accepted some of his suggestions but not all of them, so he wanted the board to consider adding them as amendments. In the final hearing in June, board member Hardy asked Moulton if he’d heard the “newest stuff that’s been coming out on climate,” which, she said, was that the climate crisis was not unfolding as scientists had predicted. Moulton suggested that the consensus about warming had been exaggerated by scientists in pursuit of grant money.

Hardy began proposing amendments word for word from Moulton’s suggestions. This elicited an outcry from Bell-Metereau. “Do you not think that if someone’s area of work is in fossil fuels that they might have some bias on this issue?” she asked Hardy. “It might be that I have a bias for the fossil-fuel industry,” Hardy answered.

Bell-Metereau and others on the board threatened to delay the entire adoption if Hardy insisted on moving the changes forward. Ultimately Hardy dropped the proposals. But Moulton and the council had already succeeded in important ways: The new electives standards had multiple references to cost-benefit analysis. The terms “renewable energy” and “nonrenewable energy” were removed in several places. The single mention of the effects of burning fossil fuels in the old standards was gone, and the strongest description of climate change had been weakened.

The climate education advocates had failed to install a robust presentation of the science surrounding the climate crisis in any of the high school core or elective classes, as they had watched the Texas Energy Council volunteers achieve one goal after another. But they held out hope for the K–8 standards. Nearly every middle schooler takes the same sciences, and the classes cover weather and climate systems, an obvious and effective place to discuss the crisis for a generation of students that would have to live with its consequences.

On a 96-degree day at the end of August 2021, the board held a public hearing on the K–8 standards, in person and virtually. The writing groups had labored over the drafts, adding a single passage mentioning climate change. Eighth grade science students, the draft declared, would be expected to “use scientific evidence to describe how human activities can influence climate, such as the release of greenhouse gases.” One writing group, which included the executive director of a natural gas foundation, had also appended a note stating it had not been able to reach consensus on a proposal to add another line: “Research and describe the costs and benefits of reducing greenhouse gas emissions versus global energy poverty.”

At the hearing, two of the professional content advisers who had reviewed the standards gave the board radically different opinions. Ron Wetherington, a retired anthropology professor from Southern Methodist University nominated by Pérez-Díaz, argued that the climate standards needed significant strengthening. Among other things, he advocated that the word “can” be dropped from the phrase “describe how human activities can influence climate.” “Can” implies that something is a possibility, but an abundance of evidence shows that the influence is already taking place. He also asked the board to add an expectation that students explore efforts to mitigate the crisis. Because students would learn that it’s happening, he posited, they should learn what people are doing to fix it.

Gloria Chatelain, a longtime educator and CEO of her own consulting firm called Simple Science Solutions, who had been nominated by Hardy and Cargill, stood in absolute opposition. She began her testimony by praising the “absolutely amazing job” the Texas Energy Council had already done in improving the standards. She also said human-caused climate change should be treated very lightly in middle school, if at all. “Our goal is not to produce angry children but children who love science. We’re challenging them to go solve some of these exciting problems but not turn them into Gretas,” she said, referring to the teenage climate activist Greta Thunberg of Sweden. Instead, she contended, the board should add an expectation that students “research and describe the role of energy in improving the quality of life in reducing malnutrition and global poverty,” language the council had suggested. “I think it needs to go in, guys. It’s very, very important that we address it,” Chatelain said.

For three days that week the board considered the K–8 language. Over the protests of Democrats, Hardy moved to add “cost-effectiveness” to each middle school class. She and Hickman persuaded the conservative board majority to change multiple references to renewable and nonrenewable energy to “natural resources” in the elementary standards.

On the second day climate education advocates landed two unexpected victories. Pérez-Díaz proposed rewording the climate standard to “describe how human activities over the past 150 years, including the release of greenhouse gases, influence climate.” Then she proposed adding a separate line: “Describe efforts to mitigate climate change, including a reduction in greenhouse gas emissions.” The amendments both carried. But on the third day the board axed the reference to the past 150 years and added the word “can” back in. The details of recent climate change, Hardy argued, would simply be too hard for eighth graders to grasp.

Aicha Davis, a board member from Dallas who spent 11 years teaching science before pursuing her Ph.D. in education leadership and policy, spoke up. “With all respect to my colleague, you’ve never taught eighth grade science,” she said, her voice tinged with forbearance. “We absolutely can’t let the oil and gas industry dictate what our kids need to learn when it comes to science. It shouldn’t be about the Texas Energy Council. It should be about what’s best for our students.” Neither scientists nor educators had voiced concern about teaching climate change to eighth graders, she noted. “So let’s call this what it is. At this point we’re only making votes based on what oil and gas wants us to do.”

Hickman, the Shell attorney, turned on his microphone. “A few thoughts and reactions,” he said. “One is I think our permanent school fund is generally funded by oil and gas,” referring to a major source of education funding maintained in part by proceeds from fossil fuels reaped from public lands. “All of us are probably going to get home using oil and gas…. If all of this is true—greenhouse gases are evil—what do we do? Do we ban gasoline and stop using gasoline-powered cars? Do we ban diesel for trucks? How do we get our Amazon and Walmart purchases?” The board chair suggested they table the issue until the final round of hearings, scheduled for November 2021.

As they waited for the last round, the National Center for Science Education and the Texas Freedom Network organized. They recruited 67 Texan climate scientists to join a letter asking, among other things, that the word “can” be dropped from the climate passage and that the mitigation language stay put not only because it consisted of “basic knowledge” that every citizen should have but because it would provide students with a sense of hope.

Nevertheless, the final round of deliberations in November was a slaughter. Climate change had been added in a limited way to the standards, and the conservative majority supported that. But it rejected a motion to strike the word “can.” It blocked a motion to remove cost-benefit analysis from the middle school sciences. It approved new language about “the critical role of energy resources” to modern life. It inserted a reference to rare earth elements. It introduced the concept of global energy poverty.

Last, Hickman moved to drop the climate mitigation standard that Pérez-Díaz had managed to add in September, arguing that the subject was more appropriate for social studies than for science and that it “just seems above and beyond for an eighth grade student and teacher.” The board Democrats fought the change, but they were outnumbered. The board replaced the mitigation standard with the line “Describe the carbon cycle.”

The Texas Energy Council and two allied organizations issued a press release praising the State Board of Education for adopting standards that “emphasize the critical role of energy in modern life.” The Texas Freedom Network hit a more ambivalent note in its year-end report. “The State Board of Education could have—and should have—done much better. But our campaign resulted in new science standards that for the first time make clear to Texas public school students that climate change is real and that human activity is the cause.”

The fossil-fuel industry, like some others, has worked for decades to get its messages in front of schoolchildren. I have found examples across the U.S. Petroleum companies regularly fund teacher trainings incentivized by free classroom supplies. Industry organizations have spent millions of dollars producing and distributing energy lesson plans. I witnessed an oil and gas industry employee give a PowerPoint presentation radically downplaying the climate crisis to a class of seventh graders.

Even with abundant online educational materials, just 9 percent of high school science teachers say they never use a textbook. The nation’s most popular middle school science textbooks are replete with language that conveys doubt about climate change, subtly or otherwise. In one textbook that, as of 2018, was in a quarter of the nation’s middle schools, students read that “some scientists propose that global warming is due to natural climate cycles.” In fact, the number of climate scientists who support that idea is effectively zero.

Texas isn’t the only major buyer of textbooks. Other large states such as California have adopted standards that embrace the science of climate change, leading to a divide. Textbook publishers create one set of products to sell in Texas and states that lean the same way and a second set of products for states aligned with California. This poses an equity problem: the education a child receives on an issue central to the modern world depends on what state they happen to live in.

In April 2022 the Texas Education Agency issued a call for textbooks based on the new standards. Publishers were given a year to submit materials to the agency. Review panels, made up of educators, will search the textbooks for errors and rate how closely they follow the standards. Then the materials go before the state board for approval or rejection. Texas school districts have the option of establishing their own textbook adoption process but still must choose books that comply with the standards. Most just defer to the board’s choices. The new science textbooks should be on classroom shelves starting in the fall of 2024.

The Texas Energy Council’s Moulton told me he found the standards adoption process energizing, and he hopes to stay involved. As soon as he gets the chance, he said, he’ll start reviewing the new textbooks and will head back to the board to give them his thoughts.

Researchers have been raising general alarms about AI’s hefty energy requirements over the past few months. But a peer-reviewed analysis published this week in Joule is one of the first to quantify the demand that is quickly materializing. A continuation of the current trends in AI capacity and adoption are set to lead to NVIDIA shipping 1.5 million AI server units per year by 2027. These 1.5 million servers, running at full capacity, would consume at least 85.4 terawatt-hours of electricity annually—more than what many small countries use in a year, according to the new assessment.

The analysis was conducted by Alex de Vries, a data scientist at the central bank of the Netherlands and a Ph.D. candidate at Vrije University Amsterdam, where he studies the energy costs of emerging technologies. Earlier de Vries gained prominence for sounding the alarm on the enormous energy costs of cryptocurrency mining and transactions. Now he has turned his attention to the latest tech fad. Scientific American spoke with him about AI’s shocking appetite for electricity.

[An edited and condensed transcript of the interview follows.]

Why do you think it’s important to examine the energy consumption of artificial intelligence?

Because AI is energy-intensive. I put one example of this in my research article: I highlighted that if you were to fully turn Google’s search engine into something like ChatGPT, and everyone used it that way—so you would have nine billion chatbot interactions instead of nine billion regular searches per day—then the energy use of Google would spike. Google would need as much power as Ireland just to run its search engine.

Now, it’s not going to happen like that because Google would also have to invest $100 billion in hardware to make that possible. And even if [the company] had the money to invest, the supply chain couldn’t deliver all those servers right away. But I still think it’s useful to illustrate that if you’re going to be using generative AI in applications [such as a search engine], that has the potential to make every online interaction much more resource-heavy.

I think it’s healthy to at least include sustainability when we talk about the risk of AI. When we talk about the potential risk of errors, the unknowns of the black box, or AI discrimination bias, we should be including sustainability as a risk factor as well. I hope that my article will at least encourage the thought process in that direction. If we’re going to be using AI, is it going to help? Can we do it in a responsible way? Do we really need to be using this technology in the first place? What is it that an end user wants and needs, and how do we best help them? If AI is part of that solution, okay, go ahead. But if it’s not, then don’t put it in.

What parts of AI’s processes are using all that energy?

You generally have two big phases when it comes to AI. One is a training phase, which is where you’re setting up and getting the model to teach itself how to behave. And then you have an inference phase, where you just put the model into a live operation and start feeding it prompts so it can produce original responses. Both phases are very energy-intensive, and we don’t really know what the energy ratio there is. Historically, with Google, the balance was 60 percent inference, 40 percent training. But then with ChatGPT that kind of broke down—because training ChatGPT took comparatively very little energy consumption, compared with applying the model.

It’s dependent on a lot of factors, such as how much data are included in these models. I mean, these large language models that ChatGPT is powered by are notorious for using huge data sets and having billions of parameters. And of course, making these models larger is a factor that contributes to them just needing more power—but it is also how companies make their models more robust.

What are some of the other variables to consider when thinking about AI energy usage?

Cooling is not included in my article, but if there were any data to go on, it would have been. A big unknown is where those servers are going to end up. That matters a whole lot, because if they’re at Google, then the additional cooling energy use is going to be somewhere in the range of a 10 percent increase. But global data centers, on average, will add 50 percent to the energy cost just to keep the machines cool. There are data centers that perform even worse than that.

What type of hardware you’re using also matters. The latest servers are more efficient than older ones. What you’re going to be using the AI technology for matters, too. The more complicated a request, and the longer the servers are working to fulfill it, the more power is consumed.

In your assessment, you outline a few different energy-use scenarios from worst- to best-case. Which is the most likely?

In the worst-case scenario, if we decide we’re going to do everything on AI, then every data center is going to experience effectively a 10-fold increase in energy consumption. That would be a massive explosion in global electricity consumption because data centers, not including cryptocurrency mining, are already responsible for consuming about 1 percent of global electricity. Now, again, that’s not going to happen—that’s not realistic at all. It’s a useful example to illustrate that AI is very energy-intensive.

On the opposite end, you have this idea of no growth—zero. You have people saying that the growth in demand will be completely offset by improving efficiency, but that’s a very optimistic take that doesn’t include what we understand about demand and efficiency. Every time a major new technology makes a process more efficient, it actually leads to more people demanding whatever is being produced. Efficiency boosts demand, so boosting efficiency is not really saving energy in the end.

What do I think is the most likely path going forward? I think the answer is that there’s going to be a growth in AI-related electricity consumption. At least initially, it’s going to be somewhat slow. But there’s the possibility that it accelerates in a couple of years as server production increases. Knowing this gives us some time to think about what we’re doing.

What additional research or other steps might be needed?

We need a higher quality of data. We need to know where these servers are going. We need to know the source of the energy itself. Carbon emissions are the real numbers that we care about when it comes to environmental impact. Energy demand is one thing, but is it coming from renewables? Is it coming from fossil fuels?

Maybe regulators should start requiring energy use disclosures from AI developers because there’s just very little information to go on. It was really hard to do this analysis—anyone who is trying to work on AI at the moment is facing the same challenges, where information is limited. I think it would help if there was more transparency. And if that transparency doesn’t come naturally, which it hasn’t so far, then we should think about giving it a little bit of a push.

The balloon released only a few grams of SO2, but the act was a brazen demonstration of something long considered taboo—injecting gases into the stratosphere to try to slow global warming. Once released, SO2 reacts with water vapor to form droplets that become suspended in the air—a type of aerosol—and act as tiny mirrors, reflecting incoming sunlight back to space. Luke Iseman and Andrew Song, founders of solar geoengineering company Make Sunsets, had sold “cooling credits” to companies and individuals; a $10 purchase would fund the release of a gram of SO2, which they said would offset the warming effects of a metric ton of atmospheric carbon dioxide for a year. They had planned a launch in Mexico but switched to the U.S. after the Mexican government forbade them.

Many people recoil at the notion of solar geoengineering, or solar radiation management (SRM), as it's often called. The idea that humans should try to fix the atmosphere they've messed up by messing with it some more seems fraught with peril—an act of Faustian arrogance certain to backfire. But as it becomes clear that humans are unlikely to reduce emissions quickly enough to keep global warming below 1.5 degrees Celsius, some scientists say SRM might be less scary than allowing warming to continue unabated. Proposals for cooling the planet are becoming more concrete even as the debate over them grows increasingly rancorous.

SRM replicates a natural phenomenon created by large volcanic eruptions. When Mount Pinatubo erupted in the Philippines in 1991, it blasted 20 million tons of SO2 into the stratosphere, creating an “aerosol parasol” that cooled the planet by about 0.5 degree C over the next year or so before the droplets settled back to Earth. Studies suggest that if SRM were deployed at sufficient scale—maybe one quarter of a Pinatubo eruption every year, enough to block 1 or 2 percent of sunlight—it could slow warming and even cool the planet a bit. Its effects would be felt within months, and it would cost only a few billion dollars annually. In comparison, transitioning away from fossil fuels is expected to take decades, and the CO2 emitted until then could make warming worse. Using machines to remove billions of tons of CO2 from the skies, a process called direct-air capture, could slow warming but would be fighting itself—the machines might increase the world's energy consumption by up to 25 percent, potentially creating more greenhouse gas emissions. Because SRM could produce effects quickly, it has political appeal. It's “the only thing political leaders can do that would have a discernible influence on temperature within their term in office,” says Ken Caldeira, a climate scientist emeritus at the Carnegie Institution for Science, who is also a senior scientist at Breakthrough Energy, an organization founded by Bill Gates.

Caldeira and others say SRM should be pursued with extreme caution—if at all. It could noticeably whiten our blue sky. It could weaken the stratospheric ozone layer that protects us and Earth's biosphere from ultraviolet radiation. It might change weather patterns and move the monsoons that water crops for billions of people. And it wouldn't do anything to remedy other CO2-related problems such as ocean acidification, which is harming the ability of corals, shellfish and some plankton to form skeletons and shells.

Critics also say that the very idea of an escape hatch such as SRM could undermine support for reducing greenhouse gas emissions. Like a prescription drug, if SRM were used responsibly—temporarily and in small doses—it could be beneficial, easing what is likely to be a dangerously hot century or two and buying humanity some extra time to transition to renewable energy. But it also has potential for abuse. At higher doses it could increasingly distort the climate, altering weather patterns in ways that pit nation against nation, possibly leading to war.

For all these reasons, more than 400 scientists have signed an open letter urging governments to adopt a worldwide ban on SRM experiments. But other scientists are proceeding, if reluctantly. “All the scientists I know who are working on this—none of them want to be working on it,” says Alan Robock, a climatologist at Rutgers University. Robock, who previously showed the world how a nuclear winter could shroud Earth, studies SRM out of a sense of obligation. “If somebody's tempted to do this in the future,” he says, they “should know what the consequences would be.”

Experts who support trials note that unabated warming is just as consequential. In a recent report, the World Meteorological Organization estimated a 66 percent chance that by 2027 the world's average annual temperature will briefly exceed 1.5 degrees C above preindustrial levels—a dangerous threshold beyond which extreme damage to the environment occurs. On February 27, 2023, a few days after Iseman and Song sent barbecued sulfur into the sky, 110 climate scientists, including climate change pioneer James Hansen, published a different open letter urging government support for SRM research. The following day the United Nations called for international regulations that could pave the way for experimentation. And in June the Biden administration released a report outlining what an SRM research program could look like.

Even if SRM reduced average temperatures, it wouldn't reset the climate to its preindustrial state, says David Keith, head of climate systems engineering at the University of Chicago, who has studied the idea for over two decades. But it could lessen the hurt coming for us.

The idea that humans can change the planet's atmosphere for their own purposes has a long history. In 1962 the U.S. military started Project Stormfury, an attempt to weaken hurricanes by seeding their clouds with silver iodide particles. From 1967 to 1972 the U.S. Air Force dabbled in weather-control warfare over Vietnam and Laos; in a highly classified effort called Operation Popeye, several aircraft flew daily missions to spray lead and silver iodide powder into monsoon clouds. The goal was to increase rainfall, which would muddy up the Ho Chi Minh Trail, a network of coarse roads, interrupting Vietcong supply lines.

Almost as soon as scientists understood that rising CO2 could warm the planet, some of them proposed making Earth more reflective to counter the effect. In 1965 scientists reported to President Lyndon B. Johnson that warming caused by rising CO2 could be addressed by spreading reflective particles across the oceans. In 1974 Russian climatologist Mikhail Budyko suggested that injecting SO2 into the stratosphere via aircraft or rockets could reflect sunlight. This technology, he wrote, “should be developed without delay.” Perhaps surprisingly, these proposals did not include the idea of reducing emissions.

The idea of planet-scale engineering didn't gain much traction over the next two decades. When Lowell Wood, an engineer at Lawrence Livermore National Laboratory in California and an early proponent of the “Star Wars” missile defense system, stood up at the 1998 Aspen Global Change Institute conference to tout the cooling effects of stratospheric aerosols, the reception was chilly. “Ken [Caldeira] and I stood in the back room and almost shouted at him,” Keith recalls. He “was completely overstating how well it would work.” Their skepticism was based on simple logic: CO2, by absorbing long-wave radiation rising from Earth, warms the planet uniformly from the equator to the poles year-round, day and night—whereas sunlight warms the planet mainly at lower latitudes, with stronger effects during the summer and the daytime. They thought dimming the sun would cool the planet unevenly, Caldeira says. “You get much more cooling at the equator,” more cooling during summer, and less at the poles.

Caldeira returned to Livermore, where he also worked, and persuaded Govindasamy Bala, a climate scientist there, to test the idea with a sophisticated computer model. The model diminished incoming sunlight by 1.7 percent—enough to counteract the warming effects of CO2 levels that were double what they had been in preindustrial years. “It worked a hell of a lot better than we expected,” Caldeira says. The results, published in 2000, indicated that SRM would still cool the tropics a little more than the poles and make a bigger difference in summer than in winter, but overall the cooling would be far more uniform globally than Bala, Caldeira and Keith had thought.

A consortium of researchers that included Robock later replicated Bala's results across a dozen different climate models. But their 2013 findings revealed a red flag. As concentrations of stratospheric aerosols increased, the cooling grew less uniform, and the climate became more distorted. If stratospheric aerosols were used to offset the average warming caused by a quadrupling of CO2 levels, the tropics would be 0.3 degree C cooler than in preindustrial times, but the polar regions would still be 0.8 degree C warmer. Permafrost and sea ice might not fully recover, meaning we would fail to reverse some of climate change's most damaging effects.

Bala discovered another worrisome detail: stratospheric aerosols might reduce rain and snowfall. Researchers knew that more warming increases the evaporation of water, leading to more precipitation, so it stood to reason that the reverse would also be true. But Bala found that dimming the sun could reduce rainfall more than it reduces temperature. That's because blocking sunlight, while leaving CO2 high, slightly reduces the tendency of water vapor to form clouds. Simulations across the 12 models predicted that if SRM was used to fully counteract the warming of quadrupled CO2, some parts of the tropics would receive 5 to 7 percent less annual rainfall compared with preindustrial times, potentially harming crops or tropical forests.

This and other observations led Keith and his colleagues to suggest a lower-dose approach to SRM in which stratospheric aerosol injections would be used temporarily to reduce the effects of climate change, buying nations time to cut greenhouse gas emissions and draw down (or “capture”) CO2 from the atmosphere.

Keith sketched out this scenario in a 2018 paper co-authored with climate scientists Douglas MacMartin of Cornell University and Katharine Ricke of the Scripps Institution of Oceanography. They envisioned a world in which greenhouse gas emissions are cut and carbon capture is deployed so that CO2 peaks in 2070 at just over twice its preindustrial concentration before starting to slowly decline. This would cause roughly three degrees C of warming—a lot. To limit warming to 1.5 degrees C, stratospheric aerosol injections would be initiated around 2030 and slowly ramped up. Injections would peak in 2070 and be slowly reduced before being halted about two centuries later, when CO2 levels had fallen sufficiently. Peter Irvine, a climate scientist at University College London, ran this scenario through 13 models. The results, published in 2019 in Nature Climate Change, showed that during the period of peak CO2 concentrations, stratospheric aerosols would reduce warming and lessen precipitation extremes (including droughts and deluges) for 99.6 percent of the planet's ice-free land surface.

Other SRM methods might eventually be developed to even out the cooling. Marine-cloud brightening would involve spraying sea salt 1,000 meters into the air to seed the formation of cloud droplets, increasing the reflectivity of low-lying clouds over some parts of the ocean. In cirrus-cloud thinning, particles of silver iodide would be sprayed into clouds at altitudes of 4,500 to 9,000 meters, enlarging ice crystals in those clouds so they fell out of the sky. The remaining, thinner cirrus clouds would allow more long-wave radiation emanating from Earth to escape to space. Both methods would have more localized effects than injecting SO2 would, so it might be possible to deploy them selectively to balance the effects of stratospheric aerosols, says Sarah Doherty, an atmospheric scientist at the University of Washington who studies marine-cloud brightening. “It may turn out that doing a little bit of each [method] would allow you to maximize benefits and minimize risks,” she says.

Stratospheric aerosol injection is the best-studied approach to solar geoengineering and the closest to deployment. But making it work would require overcoming major challenges. The atmosphere 20 kilometers up is neither Earth-like nor spacelike. At that altitude, roughly twice as high as commercial jets fly, the air pressure is just 5 percent of what we enjoy on the ground—low enough to spontaneously boil the fluids out of a person's mouth and lungs. Lift against an airplane's wing is minuscule. Only a handful of research planes worldwide can operate in air this thin. The best known is NASA's ER-2, a derivative of the U-2 spy plane with a tiny fuselage and gangling, oversized wings. It is piloted by a single human who must wear a full pressure suit, like an astronaut. It carries less than two metric tons of cargo.

ER-2s have flown more than 4,500 research missions in the past 50 years, sampling aerosols and gases in the stratosphere. They have refined our understanding of how ozone is destroyed. They have flown through volcanic eruption plumes. And they have helped to create the scientific foundation on which SRM is based. But these high-altitude albatrosses will never carry tons and tons of SO2.

Planes capable of that job could be developed with largely existing technologies, says Wake Smith, a former aviation-industry executive and a climate researcher at the Yale School of the Environment. Since 2017 Smith has refined the concept of a six-engine plane based loosely on the B-47 Stratojet, a high-altitude U.S. Air Force craft designed in the 1940s to deliver nuclear bombs deep inside Soviet territory. Smith's Stratospheric Aerosol Injection Lofter would heft 15.7 tons of aerosol to a height of 20 kilometers every flight. Depending on how much SRM is desired, Smith envisions 90 to 900 planes flying missions every day by 2100. Building the first plane might take seven to 10 years; building a fleet could take 20 years.

Smith estimates that once the planes are built, the program might cost $18 billion annually per degree C of cooling. That's a small amount compared with the hundreds of billions of dollars a year it would take to remove billions of tons of CO2 from the atmosphere. But SRM has a much higher chance than carbon removal of causing nightmarish unintended consequences. Stratospheric injections by any country would affect the entire globe. Done wrong, they could disrupt weather patterns and the lives of billions of people.

A large fraction of humanity depends on a belt of thunderstorms and rain called the Intertropical Convergence Zone. The zone straddles the equator around the planet and shifts as far as 2,500 kilometers north or south with the seasons, pulled always toward the warmer hemisphere. Its movement spawns the monsoons that arrive each summer in India, Southeast Asia, Africa, and other regions, dropping more than 45,000 cubic kilometers of water annually, sustaining crops that feed 1.5 billion people in South Asia alone.

In 2008 Bala, the scientist at Livermore who first tested SRM in a model, moved to the Indian Institute of Science in Bangalore and began to study how human activities might affect that country's monsoons. His simulations showed that if aerosols were injected at the equator, they would spread over the Northern and Southern Hemispheres, with little impact on monsoon patterns. But some people have proposed a polar strategy in which aerosols would be injected at the high northern latitudes to slow rapid Arctic warming without overcooling the tropics. This well-intentioned proposal would have a “huge impact” on Indian monsoons, Bala says. His latest calculations, published in 2022, suggest that if injections sufficient to cool the planet by 1.5 degrees C were done at 30 degrees north, the monsoon band could shift southward by roughly 150 kilometers, reducing India's summer rainfall by up to 29 percent and threatening crops.

Bala's study demonstrates that stratospheric aerosol injection is never local; it inevitably has far-reaching effects. In 2021 Ricke modeled aerosol injections over the Indian Ocean meant to increase rainfall and reverse a long-standing drought in the semiarid Sahel region of North Africa. The intervention just shifted the droughts to a different set of nations, in East Africa. Another modeling study, in 2022, suggests that stratospheric aerosols could shift the burden of malaria from highland areas in East Africa to lowland areas in South Asia and sub-Saharan Africa. Some regions where the parasite currently thrives would become too cool for it; other places, currently too hot, would cool enough for it to take hold. These vast shifts in risk could harm “countries that are often outside the room when we're talking about geoengineering,” says Christopher Trisos, an ecologist at the University of Cape Town in South Africa, who co-led the malaria study.

For all these reasons, Ricke says, SRM research is in “a very dangerous place.” Most studies assume that it will be done in an internationally coordinated way, but she says modelers should also study scenarios in which injection is done haphazardly. The relatively low cost of SRM means many countries could afford it. “I think it's just inevitable that someone's going to try to do this,” Ricke says.

Imagine a nightmare scenario in which individual countries, responding to heat waves, fires or floods, begin injecting aerosols unilaterally. Imagine that Russia initiates high-latitude injections to cool its Arctic regions. This action would push the monsoon belt southward, depriving India, Thailand and Vietnam of critical rain. It might also shift torrential rainfall farther south in Brazil, triggering floods. If these countries respond by beginning their own injections to lessen rainfall, a dangerous escalation could play out in the stratosphere. One country might even destroy another country's SRM aircraft, leading to a sudden rebound of warming and perhaps war.

People who support SRM point to studies showing that it could affordably reduce climate extremes. Critics point to studies showing the havoc it could cause. But the scientists who try to forecast effects will admit that most of these predictions contain huge uncertainties. The uncertainty begins with the models being used. Although SRM has shown consistent results in more than a dozen climate models, that's not because widely varied approaches are converging on the same answers. It's because “we have too many people running climate models that are similar,” Keith says. If the assumptions underlying one model are wrong, then all the models might be wrong.

Models used to predict the effects of SRM contain dozens of variables representing physical parameters ranging from the chemical reactivity of aerosol droplets to their size. Tiny variations in the variables can have wide-ranging consequences. For example, a droplet that is one to two microns across (smaller than a red blood cell) should reflect sunlight most efficiently because its diameter is close to the wavelength of most incoming solar radiation. Larger droplets aren't just less effective—they could actually cause warming by absorbing long-wave radiation rising from Earth's surface that would otherwise escape to space. Another crucial variable is the rate at which droplets cause chemical reactions that destroy ozone. When researchers try to predict the effects of stratospheric injection, they plug in their best estimates for such variables. The problem is that most studies use similar estimates. “The big question,” Keith says, “is, Are we wrong?”

To address this uncertainty, Keith recommends running large “ensembles”—hundreds of different versions of the same model in which different combinations of numbers are plugged in. Scientists have done only a few such studies of SRM effects. Keith hopes to oversee more ensemble work at the University of Chicago. The range of climate outcomes this research produces could then be plugged into models that predict how SRM could affect crop yields, forest fires, storms, or the spread of malaria and other diseases.

Still, no matter how many large ensembles scientists run, it's impossible to know how SRM will work until it's been tested in the real world—and tested at a much larger scale than two guys releasing a balloon outside Reno. In 2011 Keith and Caldeira published an analysis suggesting that a meaningful stratospheric-injection trial would take a decade. Several hundred thousand tons of SO2 would have to be injected every year—enough, theoretically, to reverse 10 percent of the warming caused by a doubling of preindustrial CO2 levels. The minimum viable experiment, in other words, “would be indistinguishable from a deployment,” Caldeira says.

Smaller experiments could reduce uncertainties in the models. Scientists could get a better understanding of injection equipment, for example, by building it and using it to release anywhere from a few kilograms to a few metric tons of SO2 into the stratosphere. That work could reveal whether ejected droplets remain the same size while aloft, details about chemical reactions, and what effects they have on ozone. In fact, scientists have been doing studies like this since the 1960s, releasing tracers such as zinc sulfide powder or sulfur hexafluoride gas into the stratosphere to study air currents.

But when the subject of inquiry is SRM, barriers to even small experiments become extreme. In early 2021 Keith and Frank Keutsch, an atmospheric chemist at Harvard, were planning the first SRM field trial. The Stratospheric Controlled Perturbation Experiment (SCoPEx) was designed to mimic a trail of aerosol released by a stratospheric aircraft. A self-propelled balloon would ascend 20 kilometers, release half a kilogram of sulfate into the wake of its propeller, then fly back through the aerosol trail to monitor how it evolved. The experiment would release only 0.3 percent of the amount emitted by a commercial transatlantic flight. The researchers planned for the first launch, slated for June 2021 in northern Sweden, to merely test the equipment without releasing any gas. It never happened.

In February 2021 the Sámi Council, a group representing Indigenous reindeer herders in the region, protested to the Swedish government that they had not been notified of the test occurring in their airspace. They, along with Greenpeace Sweden and several other environmental groups, persuaded the government to cancel it. The protests were never about the environmental impact of the test, MacMartin says. What happened, he says, is that “the entire conversation about ‘Oh, my God, do we even want to go down this path?’ got stapled onto that experiment.”

Many SRM opponents would like to ban experiments outright. Yet some scientists are continuing the research because they believe it's the responsible thing to do. “The people who should be advocating for experiments the most are the people who think that bad stuff would happen,” Caldeira says. “The most valuable experiment that somebody could do now is one [showing] that there would be really horrible consequences.” And if SRM is going to be studied and perhaps even rolled out, it's better to start sooner and more gradually, so the downsides can be understood. Ironically, SRM might have more public support if it were delayed until climate impacts become extreme, but at that point it would have to be done urgently and rapidly. “There's a real mismatch between what is politically and environmentally risky,” Caldeira says.

Even small experiments will need the legitimacy of being funded and regulated by government, Kelly Wanser says. She is executive director of Silver Lining, a nonprofit organization that is encouraging the National Science Foundation and other government bodies to establish funding for SRM research and set up rules defining how and when experiments can be performed. Scientists would like that kind of governance, Ricke says. After all, it has long existed for other sensitive science areas, such as medical studies in humans, and has improved the quality of that research. The goal would be an international body, similar to the Intergovernmental Panel on Climate Change, that would set research priorities while considering the interests of rich and poor nations. Absent that structure, legitimate science is not progressing, Ricke says, and “rogue activities are starting to emerge.”

Two months after the Reno balloon release, on April 10, Iseman and Song visited the Berkeley Marina in California to launch three more stratospheric balloons, funded by $2,840 of cooling credits purchased by customers. “A 747 emits this amount in a couple of minutes,” Iseman said as he held high the first balloon in his right hand, with San Francisco Bay shimmering in the background and a camera crew filming. Then he let it go. A few days later the two men attended an Earth Day event in San Francisco, where they helped children launch their own small balloons, coated with chalk dust, which could aerosolize. “Our goal,” Iseman said, “is to make 1,000 new geoengineers.”