Anthropogenic influence on extremes and risk hotspots

Area of Science:

• Climate Science
• Extreme Weather Event Attribution
• Environmental Change

Background:

• Understanding the frequency and magnitude of climate extremes is critical in a warming world.
• Differentiating between natural and anthropogenic forcing factors is essential for accurate climate change assessment.
• Previous studies have utilized event-attribution techniques to analyze extreme temperature and precipitation events.

Purpose of the Study:

• To conduct spatial and temporal analyses of natural and anthropogenic factors influencing climate extremes.
• To quantify the increased risk and probability of extreme temperature and rainfall events globally.
• To identify regions ('risk hotspots') with high exposure to extreme events and significant population or economic impact.

Main Methods:

• Employed state-of-the-art time series methods for observation-based analyses.
• Utilized event-attribution techniques to separate natural and anthropogenic influences.
• Assessed population and Gross Domestic Product (GDP) exposure in identified risk hotspots.

Main Results:

• The risk of extreme temperature and rainfall events has significantly increased in most global regions.
• Probabilities of extreme temperatures and precipitation have increased by at least fivefold and twofold, respectively, in some areas.
• Anthropogenic forcing is the primary driver of increased extreme event risk, amplifying natural forcing effects. In 2018, human influence increased extreme temperature/precipitation risk affecting 94%/72% of the global population and 97%/76% of global GDP.

Conclusions:

• Anthropogenic factors are the dominant cause of the heightened risk of extreme climate events.
• The study identified specific risk hotspots where increased event likelihood coincides with high population and economic exposure.
• Urgent mitigation and adaptation strategies are necessary to address the escalating threat of climate extremes to global society and economy.