Today’s evening talk was about Extreme Climate Change delivered by Mr. Hugh Baker. Climate change is not only an interested study topic of mine, but also a problem regarding lives and human civilization. The paragraphs are too limited to cover this enormous issue, so do please attend this talk in person in the future if you really care!
Mr. Baker briefly introduced what extreme events are and how to determine whether extreme events are becoming more likely under climate change. This part should be easy to understand though involved with some statistical concepts.
Then it came to the attribution of past extreme events. First, the event should be defined. It is not hard to accept that a temperature event (such as a heatwave cold-snap) is much easier to define than a flood, drought or a forest fire. Therefore, the methodology should be a combination of quantitative and qualitative methods. Second, perform ensemble runs for the current day conditions and the world that might have been. As the events are so rare, it’s unlikely we would see such an event occurring in an individual simulation of the climate. So, scientists will remove all human influences from the model and use climateprediction.net, a volunteers’ platform, to perform thousands of these ensembles to build up GBs of data. Finally, they perform data analysis and see how often and how extreme the event of interest is in both cases.
The lecture included specific terminology such as risk ratio (“present day” probability over “world that might have been” probability) and put forward some forefront opinions. For example, presumably we expect all heat extremes to increase under global warming and that warmer air can hold more moisture, but we can’t expect more rainfall everywhere.
The talk ended after another brief introduction to the Paris agreement and potential future extreme events.
From what I’ve learnt, in recent years, lawyers are becoming increasingly interested in using climate research to hold CO2 emitters to account for causing these extreme events. Whilst no case has been brought before a court on extreme events, there have been several successful cases where law companies have sued governments for not doing enough to keep air pollution to acceptable levels.
Maybe in near future, we can expect people who lose out due to extreme events to potentially be able to sue governments and companies for the damages caused. And more importantly, we can expect a world as beautiful as it once was.