Impact of Climate Change and Aerosols on Southwest U.S. Drought: A Study Aligned with Sustainable Development Goals

Introduction

In the late 2010s, Assistant Professor Flavio Lehner, formerly with the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, was frequently consulted by water managers regarding the persistent drought in the Southwestern United States. Key questions included whether the low precipitation was a natural variation or influenced by climate change, and if the drought was a permanent condition. This inquiry aligns with several Sustainable Development Goals (SDGs), particularly SDG 6 (Clean Water and Sanitation), SDG 13 (Climate Action), and SDG 15 (Life on Land).

Research Findings

A recent study led by Lehner and his team, published on July 9 in Nature Geoscience, provides critical insights into the causes of drought in the Southwest. The research isolates the effects of human-induced climate change and aerosols (air pollution) on regional precipitation, concluding that these factors have significantly reduced rainfall and made drought conditions inevitable. This study supports SDG 13 by enhancing understanding of climate change impacts.

Key Observations

1. Precipitation Trends: A decline in precipitation began around 1980, initially linked to La Niña-like conditions in the tropical Pacific Ocean.
2. Climate Change Influence: Contrary to expectations, El Niño-like warming trends did not increase precipitation due to overriding effects of climate change and aerosols.
3. Atmospheric Circulation: Anthropogenic warming and aerosol emissions create circulation patterns over the North Pacific that suppress precipitation in the Southwest.

Implications for Climate Teleconnections

The study reveals a systematic change in the teleconnection between tropical Pacific weather patterns and the Southwestern U.S., driven by human activities. This finding is crucial for SDG 13, emphasizing the need for adaptive climate strategies.

Future Outlook and Air Quality Improvements

• Reduction in Aerosols: Expected decreases in aerosol concentrations due to air quality policies in East Asia may improve precipitation levels.
• Warming Offset: However, ongoing global warming is likely to counteract these benefits by increasing atmospheric dryness.

Methodological Advances

The research team developed novel simulation models that integrate satellite data and statistical analyses to accurately assess the individual impacts of climate change and aerosols on sea surface temperatures and precipitation. This methodological innovation supports SDG 9 (Industry, Innovation, and Infrastructure) by advancing scientific tools for climate research.

Applications for Water Management

The findings provide valuable information for water resource managers in the Southwest, where water rights and usage are tightly regulated. Understanding the drivers of drought supports sustainable water management practices, directly contributing to SDG 6.

Collaborations and Support

• Co-authors from NCAR, NOAA, and Monash University contributed to the study.
• Funding was provided by NOAA, the U.S. Department of Energy, the National Science Foundation, and the Australian Research Council Centre of Excellence for Climate Extremes.

Conclusion

This study underscores the critical role of human-induced climate change and air pollution in shaping drought conditions in the Southwestern United States. By enhancing understanding and predictive capabilities, it supports global efforts toward sustainable development, particularly in managing water resources and mitigating climate impacts.

1. Sustainable Development Goals (SDGs) Addressed or Connected

1. SDG 6: Clean Water and Sanitation
   • The article discusses drought and water scarcity in the Southwestern United States, highlighting the importance of managing limited water resources effectively.
2. SDG 13: Climate Action
   • The core focus of the article is on the impact of human-caused climate change and aerosols on precipitation and drought conditions, emphasizing the need for climate action to mitigate these effects.
3. SDG 3: Good Health and Well-being
   • The article implies concerns about air pollution (aerosols) which affect air quality and public health.
4. SDG 11: Sustainable Cities and Communities
   • The reduction of air pollution through policies in East Asia and globally relates to creating sustainable and healthy environments in urban and industrial areas.

2. Specific Targets Under Those SDGs Identified

1. SDG 6: Clean Water and Sanitation
   • Target 6.4: By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals to address water scarcity.
2. SDG 13: Climate Action
   • Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries.
   • Target 13.2: Integrate climate change measures into national policies, strategies, and planning.
3. SDG 3: Good Health and Well-being
   • Target 3.9: Reduce the number of deaths and illnesses from hazardous chemicals and air, water, and soil pollution and contamination.
4. SDG 11: Sustainable Cities and Communities
   • Target 11.6: Reduce the adverse per capita environmental impact of cities, including air quality improvements.

3. Indicators Mentioned or Implied to Measure Progress

1. Precipitation Levels and Drought Frequency
   • The article discusses measuring precipitation changes and drought conditions in the Southwest, which can be tracked by indicators such as the percentage change in precipitation and drought severity indices.
2. Aerosol Concentration and Air Quality
   • Indicators related to aerosol emissions from vehicles and industry, such as particulate matter (PM2.5 and PM10) levels, are implied as measures of air pollution and its reduction.
3. Temperature Trends
   • Warming trends in the tropical Pacific and overall atmospheric temperature increases are indicators used to assess climate change impacts.
4. Water Use Efficiency and Water Rights Accounting
   • The article mentions water rights and accounting of water from the Colorado River, implying indicators related to water use efficiency and sustainable water management.

4. Table of SDGs, Targets, and Indicators

Source: news.cornell.edu