What is extreme event atrribution (EEA)
It is type of study or analysis done to assess the degree of contribution of climate change to a particular extreme weather or climate events such as flood, extreme precipitation, heatwave etc.
Why EEA is necessary?
Several decades of research has already indicated that anthropogenic climate change has significantly altered the frequency and intensity of extreme climate and weather events, such as extreme precipitation,hurricanes, flooding and heatwaves. Even without climate change such events might exists due to natural variability of Earth climate, so one question generally pops up,
Question
To what degree the human-induced climate changes has altered the characteristics of a particular extreme event? Having a reliable and quantitaive information on this question can be imporatnt for public understanding, resource prioritization, policy and planning formulation to adapt/mitigate the impacts of future extreme climate events.
Current progress
- Two main approaches exists: probabilistics EEA approach and storyline EEA approach
- Probabilistic EEA approaches are based on statistical properties of classes of events
- Storyline EEA approaches examine how anthropogenic climate change influenced the characteristics of a specific event as it unfolded, given the initial meteorological conditions
- Rapid attribution studies within days of an event. Highest confidence for large scale phenomena like extreme heat and cold events, large-sclae heavy rainfall events. But low confidence for small scale process like convetive storms.
Emerging direction
- Extreme event impact attribution (EEIA) to understand the role of climate change on the impacts of extreme events. Goes one step forward from EEA. EEA only focus on quantifying influence of climate change on extreme event hazard characteristics.
- Some studes have translated changes in hazard to impacts using impact response function or process-based models.
Challenges
- Difficult to do EEA for events governed by small-scale process such as severe convective storms are not accurately represented by global climate models (~ 50 - 300 km resolution).
- Understand how much climate change is influencing natural modes variability of climate suchs as El Niño and La Niña.
- Attribution of compound and cascading events also remains a challenge.
- In the Global South, insuficient historical obsevered data is limiting EEA and EEIA studies.
Todos for researchers
- Develop and improve methods, impact response functions, and process-based models with particular focus on hazards and regions that lack reliable data and tools.