YSE Scientists Make Critical Breakthrough in Mapping Global Methane Emissions from Rivers and Streams
YSE Scientists Make Critical Breakthrough in Mapping Global ... Yale University
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Methane Emissions from Rivers and Streams: A Comprehensive Estimate
Methane levels in the atmosphere are now more than two and a half times their pre-industrial level, accounting for 25% of global warming to date. Understanding the many sources of methane emissions and how they may change in the future is vital to climate modeling and mitigation. Freshwater ecosystems account for about half of global methane emissions in the atmosphere but quantifying the specific amount has been difficult because estimates from rivers and streams vary widely and such estimates were not well documented.
A Breakthrough Study
A breakthrough study, co-authored by Yale School of the Environment Professor of Ecosystem Ecology Peter Raymond, research scientist Guiseppe Amatulli, postdoctoral associate Shaoda Liu, and a team of international scientists, provides the most comprehensive estimate to date of monthly methane emissions from rivers and streams worldwide.
“It is a big step forward. We now have a much better predictive capacity for methane.”
The research, published in Nature, confirmed that rivers are an important source of methane in the atmosphere, similar in emissions levels from lakes, which have a larger surface area. The study estimates that 27 teragrams of methane is emitted globally from rivers and streams, which is about a quarter of the methane produced by fossil fuels.
To obtain the estimate, the researchers first created a Global River Methane Database comprised of all empirical observations of methane rivers, 24,000 records of methane concentrations, and more than 8,000 measurements of methane emissions. They then combined those observations with high-resolution hydrological datasets that capture the movement of water in rivers and applied machine learning tools to predict global methane concentrations and emissions and identify the main drivers of river methane concentrations.
Implications for Sustainable Development Goals
The research will help scientists working on the Global Carbon Project, which estimates global budgets for three main greenhouse gases — methane, carbon dioxide, and nitrous oxide — and investigates the complex system of the carbon cycle, including anthropogenic emissions, redistribution in the atmosphere, ocean and terrestrial biosphere, and natural sinks.
“Methane has been gaining recognition in the global community as an important greenhouse gas and its concentration is increasing very fast. We want to understand the global drivers of methane emissions, natural sources of the emissions, and be able to predict future emissions. That’s a key step in being able to mitigate emissions at a global scale,” says Gerard Rocher-Ros, lead author of the study and a postdoctoral researcher with the Swedish University of Agricultural Sciences and the Centre for Advanced Studies of Blanes..
Challenges and Recommendations
A difficult element to estimating methane emissions is the amount of gas that can be emitted by ebullition, in which bubbles with high methane concentration are released from sediments, the researchers say. The study accounted for that flux, but the authors suggest that “more detailed and sophisticated models are needed to predict methane emissions and integrate them into comprehensive Earth system models.”
The researchers note that one their most critical, and surprising, findings was that temperature is not a key driver of methane emissions in rivers and streams, though, it is an important factor in lakes and wetlands. River and stream emissions are instead more sensitive to land-water connections and human activity that is impacting river networks. Many direct and indirect human modifications of stream and rivers, such as wastewater treatment plants, ditches, or concrete stormwater canals can lead to high methane concentrations.
Conclusion: Mitigating Methane Emissions
Study co-author Emily Stanley, a professor at the University of Wisconsin-Madison’s Center for Limnology, who first began compiling data on rivers and stream emissions in 2015, says slowing the flow of pollutants like fertilizer and human and animal waste and restoring rivers and streams could curb methane emissions that are contributing to global warming.
SDGs, Targets, and Indicators
1. Which SDGs are addressed or connected to the issues highlighted in the article?
- SDG 13: Climate Action
- SDG 14: Life Below Water
- SDG 15: Life on Land
The article discusses the importance of understanding methane emissions from rivers and streams in order to mitigate climate change. This connects to SDG 13, which focuses on taking urgent action to combat climate change and its impacts. Additionally, the article mentions the role of freshwater ecosystems in methane emissions, linking to SDG 14, which aims to conserve and sustainably use the oceans, seas, and marine resources. Finally, the article highlights the impact of human activity on river networks, relating to SDG 15, which focuses on protecting, restoring, and promoting sustainable use of terrestrial ecosystems.
2. What specific targets under those SDGs can be identified based on the article’s content?
- SDG 13.2: Integrate climate change measures into national policies, strategies, and planning.
- SDG 14.1: By 2025, prevent and significantly reduce marine pollution of all kinds.
- SDG 15.1: By 2020, ensure the conservation, restoration, and sustainable use of terrestrial and inland freshwater ecosystems.
The article emphasizes the need to integrate methane emissions from rivers and streams into climate modeling and mitigation efforts, aligning with SDG 13.2. It also highlights the importance of understanding and quantifying methane emissions from freshwater ecosystems, contributing to the target of preventing marine pollution (including atmospheric pollution that affects marine ecosystems) under SDG 14.1. Additionally, the article suggests that slowing the flow of pollutants and restoring rivers and streams can help curb methane emissions, supporting the target of conserving and sustainably using terrestrial and inland freshwater ecosystems under SDG 15.1.
3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?
- Monthly methane emissions from rivers and streams worldwide
- Global River Methane Database
- Empirical observations of methane rivers
- Measurements of methane concentrations and emissions
- High-resolution hydrological datasets
- Machine learning tools for predicting methane concentrations and emissions
- Impact of land-water connections and human activity on river networks
The article mentions the creation of a Global River Methane Database, which includes empirical observations, measurements, and high-resolution hydrological datasets. These indicators can be used to measure progress in understanding and quantifying methane emissions from rivers and streams. Additionally, the article highlights the importance of considering the impact of land-water connections and human activity on river networks, indicating that monitoring and assessing these factors can help track progress towards mitigating methane emissions.
SDGs, Targets, and Indicators Table
| SDGs | Targets | Indicators |
|---|---|---|
| SDG 13: Climate Action | 13.2: Integrate climate change measures into national policies, strategies, and planning. | – Monthly methane emissions from rivers and streams worldwide – Global River Methane Database – Measurements of methane concentrations and emissions – High-resolution hydrological datasets |
| SDG 14: Life Below Water | 14.1: By 2025, prevent and significantly reduce marine pollution of all kinds. | – Monthly methane emissions from rivers and streams worldwide – Global River Methane Database – Measurements of methane concentrations and emissions |
| SDG 15: Life on Land | 15.1: By 2020, ensure the conservation, restoration, and sustainable use of terrestrial and inland freshwater ecosystems. | – Monthly methane emissions from rivers and streams worldwide – Global River Methane Database – Measurements of methane concentrations and emissions – Impact of land-water connections and human activity on river networks |
Behold! This splendid article springs forth from the wellspring of knowledge, shaped by a wondrous proprietary AI technology that delved into a vast ocean of data, illuminating the path towards the Sustainable Development Goals. Remember that all rights are reserved by SDG Investors LLC, empowering us to champion progress together.
Source: environment.yale.edu
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