Context

Attributing extreme weather events to climate change has gained prominence in scientific and policy discussions. Climate models have limitations, especially in capturing normal and extreme rainfall accurately, but they are more reliable for modeling temperatures at regional scales. The evolution of climate science now allows for the attribution of certain individual weather events to climate change, marking a significant shift from the position held by the U.N. Intergovernmental Panel on Climate Change (IPCC) just a few decades ago. Despite ongoing uncertainties, this capability has considerable value, particularly in the context of climate-related “loss and damage” (L&D) and the legal responsibilities of governments and corporations. However, questions remain about the maturity and reliability of attribution science for use in legal and multilateral forums.

The Importance of Extreme-Event Attribution

The process of attributing extreme events to climate change is viewed by many experts as essential for the L&D process. While no formal cost-benefit analysis of these exercises exists, the general consensus is that they are crucial for establishing historic liability for climate-related damages. Developing countries, especially those highly vulnerable to climate change, have advocated for L&D funds to compensate for the havoc wreaked by climate change within their borders. The criteria for identifying "particularly vulnerable" countries are central to these discussions.

India, for example, is a developing country in the tropics, highly susceptible to climate change impacts, yet it is unlikely to qualify for L&D funding. This raises critical questions about the focus of climate finance: should it prioritize adaptation and mitigation, or should it also administer L&D funds separately? If the latter, the role of attribution exercises becomes even more significant. However, the developed world generally opposes being held legally accountable for extreme events, fearing an influx of lawsuits.

Attribution Science in Legal and Policy Contexts

Understanding whether attribution reports can hold up in court as evidence of culpability is vital, especially as the L&D fund and climate jurisprudence gain visibility. The reliability and acceptance of these reports in legal contexts are under scrutiny. A recent example is a report by World Weather Attribution (WWA) on heatwaves in Asia, which demonstrated that climate change had significantly increased the likelihood of such events.

The methodology behind these rapid extreme event attributions involves comparing the conditions under which the events occurred with a counterfactual world where climate change did not happen. This process depends heavily on available data from our world. In cases of insufficient data, researchers run models simulating the planet's climate without increasing greenhouse gas emissions and other anthropogenic forcings. When sufficient data is available, trends are used to compare current conditions with those from a period when human impacts were minimal.

Challenges in Attribution Science

Data availability is a significant challenge, especially for rainfall and extreme rainfall events. Climate models are notoriously poor at capturing normal and extreme rainfall accurately. Even with better performance in modeling temperatures, this reliability is limited to regional scales and does not extend to very local scales.

If climate scientists can one day perform reliable hyperlocal attribution exercises, they will face moral questions about the actions that should follow. Currently, even though the L&D fund and climate jurisprudence are gaining traction, attribution exercises often seem disconnected from governments' adaptation and mitigation strategies.

Implications of Attribution Exercises

The potential implications of reliable attribution exercises are profound. For instance, if certain areas are identified as hotspots for extreme events, will people and businesses move away? This raises not just scientific questions but also significant policy and governance challenges. Governments need to be prepared to respond to such decisions, and for that, attribution science must be sufficiently reliable.

Another challenge lies in selecting the extreme events to attribute. The criteria and definitions used can vary, as seen in the WWA report on Asian heatwaves, which used different regional scales and definitions. They considered various temporal scales such as daily, three-day, or monthly averages to determine the likelihoods.

Complexity of Attribution Questions

The questions posed by climate scientists also matter. For example, the same analysis can yield different answers to whether the intensity of a heatwave was amplified by climate change versus whether the frequency or return period of a heatwave was altered. The WWA report used multiple approaches to answer these questions, asserting that the differences between them were immaterial. However, it remains unclear if these differences would be perceived as immaterial in a court of law.

Human Impact on Extreme Events

 The actual impacts of extreme events depend not only on the hazard itself but also on the vulnerability and exposure of the affected population. Financial consequences are influenced by multiple factors as well. This raises the question of whether an attribution exercise should focus solely on the hazard or consider the broader impacts.

This question is particularly relevant if L&D negotiations are to be reliably informed by attributions. Given the resource constraints in the real world, it is crucial to take stock of the international financial aspects of adaptation, mitigation, and L&D. Governments need to consider agreements on historical responsibilities to fund developing countries, close adaptation gaps, build adaptation capacity, and finance mitigation efforts for the global good.

Conclusion

In a world with unlimited resources, attribution exercises could serve as valuable scientific and intellectual endeavors. However, in our resource-constrained reality, a clear cost-benefit analysis is needed to define the role of attribution within the broader landscape of climate action. Attribution science must advance to be reliable and accepted in legal and policy contexts, ensuring it effectively supports adaptation and mitigation strategies and addresses the complex challenges of climate change impacts.

Source - The Hindu