Overview
This lecture discusses the link between climate change and hurricanes, focusing on how global warming is expected to make storms more intense and cause increased rainfall.
Hurricanes and Climate Change
- Human carbon emissions have shifted the baseline climate, influencing all weather events.
- Isolating human impact on hurricanes is challenging due to their complexity and poor historical data.
- Hurricanes (tropical cyclones) are powered by heat transfer from warm sea water to the air via evaporation.
Physical Basis and Predictions
- Ocean warmth increases a hurricane's potential intensity (maximum possible wind speed).
- Global ocean temperatures are rising due to human-caused climate change.
- Climate scientists largely agree that the frequency of the most intense storms (categories 4 and 5) will likely rise as the planet warms.
Climate Model Findings
- Total number of tropical cyclones is projected to decrease slightly by the end of the century.
- Frequency of the most intense storms (category 4 and 5) is projected to increase.
- These powerful storms cause the most damage and fatalities.
- Regional projections for storm intensity are uncertain due to limitations in model resolution.
Rainfall and Flooding
- Climate models consistently project that hurricanes will bring more rainfall globally, not just in the Atlantic.
- Increased rainfall will combine with higher sea levels, worsening coastal flooding and storm surge.
- Heavy precipitation events from all types of storms are increasing in the US and are expected to continue rising.
- Warmer air holds more moisture, leading to heavier rainfall events, even in regions with less total annual rain.
Mitigation and Adaptation
- Without action to reduce carbon emissions and switch to clean energy, the worsening trend will continue.
- Improving infrastructure and regulations can help minimize damage, but emissions reduction is crucial.
Key Terms & Definitions
- Tropical cyclone — A rotating storm system over warm tropical oceans, also known as a hurricane.
- Potential intensity — The theoretical maximum wind speed a hurricane can reach, influenced by ocean warmth.
- Storm surge — Abnormal rise in sea level due to a storm, causing coastal flooding.
- Carbon emissions — Release of carbon dioxide, mainly from burning fossil fuels, contributing to global warming.
Action Items / Next Steps
- Review projections in the latest Intergovernmental Panel on Climate Change (IPCC) report regarding storms.
- Consider policy measures for emissions reduction and infrastructure adaptation.