The value of attributing extreme events to climate change

Sub: Science and tech

Sec: Defence

Evolution of Extreme Event Attribution:

Previously, the IPCC argued against attributing individual weather events to climate change.
Now, researchers attribute some extreme events to climate change despite uncertainties.

Value of Extreme Event Attribution:

Attribution is seen as critical for the loss and damage (L&D) process in climate talks.
Developing countries demand L&D funding to cope with climate impacts, but criteria for eligibility are crucial.
Attribution reports could inform legal accountability for extreme events, but challenges remain.

Attribution of Asian Heatwaves:

World Weather Attribution (WWA) reported that Asian heatwaves were 45 times more likely due to climate change.
Attribution involves comparing current conditions with a hypothetical world without climate change.
Data limitations and challenges in modelling rainfall affect attribution reliability.

Challenges in Event Selection:

Selecting extreme events for attribution is challenging due to various factors.
In evaluating Asian heatwaves, WWA scientists used regional scales and various definitions, considering daily, three-day, or monthly average temperatures.
Heatwaves can be influenced by natural factors (e.g., El Niño) and human factors (e.g., urbanization, deforestation).
There is debate over whether irrigation affects heatwaves.
Extreme events are unique and often have no exact precedent, making subcontinent-scale attributions easier than local ones.

Dependency of Extreme Events on Human Action:

The impacts of extreme events depend on hazard, vulnerability, exposure, and financial factors.
Questions arise whether attribution exercises should focus solely on hazards or also consider impacts.

International Finance and Adaptation:

Consideration of international finance aspects is necessary for adaptation, mitigation, and L&D.
Historical responsibilities should be addressed to fund developing countries and support global mitigation efforts.

Resource Constraints and Cost-Benefit Analysis:

In a resource-constrained world, a cost-benefit analysis is needed for the role of attribution in climate action.
While attribution is a scientific challenge, its practical application requires careful consideration of costs and benefits.

World Weather Attribution (WWA):

WWA is an international collaboration of climate scientists conducting rapid assessments to determine the role of climate change in extreme weather events.
Collaborative Effort: Involves scientists from Imperial College London (UK), KNMI (Netherlands), IPSL/LSCE (France), Princeton University and NCAR (US), ETH Zurich (Switzerland), IIT Delhi (India), and climate impact specialists from the Red Cross/Red Crescent Climate Centre (RCCC).
Objective: Provide timely, scientifically rigorous information on links between extreme weather and climate change.
- Inform policymakers, media, and the public about climate change impacts and the need for mitigation.
Methodology:
- Uses a standardized, transparent approach comparing the likelihood and severity of weather events in current climate conditions versus a world without climate change.
- Collaborates globally, with all results peer-reviewed for scientific accuracy.
Three-Part Response to Extreme Events:
- Define the Event: Identify the geographic region and relevant weather parameters.
- Gather Historical Data: Collect weather data from 1950 to the present to compute statistics on normal and extreme weather patterns.
- Simulate the Event: Use computer models to simulate the event multiple times, comparing current greenhouse gas conditions to past conditions.

Source: TH