Guest opinion: Michael Wysession: 4 factors driving 2023’s extreme heat and climate disasters

Factors Driving 2023’s Extreme Heat and Climate Disasters

By Michael Wysession

Between the record-breaking global heat and extreme downpours, it’s hard to ignore that something unusual is going on with the weather in 2023.

People have been quick to blame climate change — and they’re right, to a point: Human-caused global warming does play the biggest role. A recent study determined that the weekslong heat wave in Texas and Mexico that started in June 2023 would have been virtually impossible without it.

However, the extremes this year are sharper than anthropogenic global warming alone would be expected to cause. Human activities that release greenhouse gas emissions into the atmosphere have been increasing temperatures gradually, at an average of 0.2 degrees Fahrenheit (0.1 Celsius) per decade.

Three additional natural factors are also helping drive up global temperatures and fuel disasters this year: El Niño, solar fluctuations and a massive underwater volcanic eruption.

Unfortunately, these factors are combining in a way that is exacerbating global warming. Still worse, we can expect unusually high temperatures to continue through at least 2025, which means even more extreme weather in the near future.

1. How El Niño is involved

   El Niño is a climate phenomenon that occurs every few years when surface water in the tropical Pacific reverses direction and heats up. That warms the atmosphere above, which influences temperatures and weather patterns around the globe.

2. Solar fluctuations

   The Sun may seem to shine at a constant rate, but it is a seething, churning ball of plasma whose radiating energy changes over many different time scales.

   The Sun is slowly heating up and in half a billion years will boil away Earth’s oceans. On human time scales, however, the Sun’s energy output varies only slightly, about 1 part in 1,000, over a repeating 11-year cycle. The peaks of this cycle are too small for us to notice at a daily level, but they affect Earth’s climate systems.

3. A massive volcanic eruption

   Volcanic eruptions can also significantly affect global climates. They usually do this by lowering global temperatures when erupted sulfate aerosols shield and block a portion of incoming sunlight — but not always.

   In an unusual twist, the largest volcanic eruption of the 21st century so far, the 2022 eruption of Tonga’s Hunga Tonga-Hunga Ha’apai is having a warming and not cooling effect.

All of this comes on top of anthropogenic, or human-caused, global warming.

Humans have raised global average temperatures by about 2 F (1.1 C) since 1900 by releasing large volumes of greenhouse gases into the atmosphere. For example, humans have increased the amount of carbon dioxide in the atmosphere by 50%, primarily through combustion of fossil fuels in vehicles and power plants. The warming from greenhouse gases is actually greater than 2 F (1.1 C), but it has been masked by other human factors that have a cooling effect, such as air pollution.

If human impacts were the only factors, each successive year would set a new record as the hottest year ever, but that doesn’t happen. The year 2016 was the warmest so far, in large part because of the last large El Niño.

What does this mean for the future?

The next couple of years could be very rough.

If a strong El Niño develops over the next year, combined with the solar maximum and the effects of the Hunga Tonga-Hunga Ha’apai eruption, Earth’s temperatures would likely soar to uncharted highs. According to climate modeling, this would likely mean even more heat waves, forest fires, flash floods and other extreme weather events.

Both weather and climate forecasts have become very reliable in recent years, benefiting from vast amounts of data from Earth-orbiting satellites and enormous supercomputing power for forecasting the flow and interactions of heat and water among the complex components of the ocean, land and atmosphere.

Unfortunately, climate modeling shows that as temperatures continue to increase, weather events get more extreme.

There is now a greater than 50% chance that Earth’s global temperature will reach 2.7 F (1.5 C) by the year 2028, at least temporarily, increasing the risk of triggering climate tipping points with even greater human impacts. Because of the unfortunate timing of several parts of the climate system, it seems that the odds are not in our favor.

Michael Wysession is a professor of Earth, Environmental, and Planetary Sciences at Washington University in St. Louis.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

SDGs, Targets, and Indicators

1. Which SDGs are addressed or connected to the issues highlighted in the article?

• SDG 13: Climate Action

2. What specific targets under those SDGs can be identified based on the article’s content?

• Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters
• Target 13.2: Integrate climate change measures into national policies, strategies, and planning
• Target 13.3: Improve education, awareness-raising, and human and institutional capacity on climate change mitigation, adaptation, impact reduction, and early warning
• Target 13.a: Implement the commitment undertaken by developed-country parties to the United Nations Framework Convention on Climate Change to a goal of mobilizing jointly $100 billion annually by 2020 from all sources to address the needs of developing countries in the context of meaningful mitigation actions and transparency on implementation and fully operationalize the Green Climate Fund through its capitalization as soon as possible
• Target 13.b: Promote mechanisms for raising capacity for effective climate change-related planning and management in least developed countries and small island developing States, including focusing on women, youth, and local and marginalized communities

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

• Indicator 13.1.1: Number of deaths, missing persons, and directly affected persons attributed to disasters per 100,000 population
• Indicator 13.2.1: Number of countries that have communicated the strengthening of institutional, systemic, and individual capacity-building to implement adaptation, mitigation, and technology transfer
• Indicator 13.3.1: Number of countries that have integrated mitigation, adaptation, impact reduction, and early warning into primary, secondary, and tertiary curricula
• Indicator 13.a.1: Mobilized amount of United States dollars per year between 2020 and 2025 accountable towards the $100 billion commitment
• Indicator 13.b.1: Number of least developed countries and small island developing States that are receiving specialized support, and amount of support, including finance, technology, and capacity-building, for mechanisms for raising capacities for effective climate change-related planning and management

4. SDGs, Targets, and Indicators