Moderate global warming does not rule out extreme global climate outcomes

Area of Science:

• Climate Science
• Environmental Science
• Global Change Research

Background:

• Communicating worst-case climate outcomes is crucial for adaptation and risk assessment.
• Current methods often rely on averaged projections at high warming levels (3-4°C).
• Existing approaches have limitations in identifying spatially consistent climate impacts.

Purpose of the Study:

• To investigate extreme global climate outcomes under moderate 2°C warming.
• To identify sector-specific, spatially consistent climate impacts.
• To improve climate risk assessment and inform policy.

Main Methods:

• Spatially averaging projected sector-relevant climatic impact-drivers across key global regions.
• Identifying sector-specific potential high- and low-impact global climate outcomes.
• Analyzing impacts on droughts, precipitation extremes, and fire weather.

Main Results:

• Extreme climate impacts (droughts, floods, fires) may occur at 2°C warming.
• These 2°C impacts can be more severe than averaged projections at 3-4°C warming.
• Identified sector-specific drivers for droughts in breadbaskets, precipitation extremes, and fire weather.

Conclusions:

• Urgent mitigation is needed to keep warming well below 2°C.
• A 2°C world may experience severe, underestimated climate impacts.
• The approach can be adapted for various sectors to enhance climate risk assessment and policy.