Insights into Editorial: Did climate change cause those floods?
28 March 2016
A lot has been discussed about weather-related extreme events and their impact on day-to-day activities. Events such as heavy downpours followed by floods, droughts, storms, heat and cold waves, and wild fires often destroy lives, property and ecosystems. At the same time such events also stretch the capacities of disaster management departments and coffers for emergency funds in various parts of the world.
- However, such events are often thought to be caused by climate change. One of the main impacts anticipated from climate change is an increase in the intensity, frequency or duration of extreme events.
Is climate change behind all these extreme events?
No. It is because most extreme events have one or more components that are not related to climate change. For example, incompetent forest management practices contribute to fires. Poor land use planning contributed to heavy downpours and floods in Chennai last year.
- Also, we can attribute such extreme events to climate change only when there is reliable data, based on sound physical principles, consistent evidence from observations, and numerical models that can replicate the event, available. But, all these conditions are not satisfied for every type of extreme weather event.
- Besides, contribution from non-climactic factors such as human activity is often not considered when attributing such events to climate change.
- Another confounding issue is that there is a natural variability in the occurrence of weather events in any case.
- For these reason, it is difficult for a scientist to be absolutely sure that a particular singular event has been caused by climate change.
What should be done?
To understand the real consequences, it is first necessary to separate the climate signal from everything else. Two approaches in this regard are helpful-
- Climate models, which help simulate an event.
- Observational record which are helpful in estimating the statistical chance and magnitude of an extreme event.
Why scientific study in this regard is necessary?
- Scientific studies of extreme weather events and their attribution to global warming may help various groups such as planners, emergency responders, policymakers and insurance companies.
- Also, better knowledge of the risk contributes to how communities, governments, investors and others prepare for the future, with regard to planning cities, proposed infrastructure, natural resources or food security.
As efforts to improve our understanding of extreme events improve, the ability for attribution is expected to improve. As in any other kinds of scientific studies, the accuracy improves with various advances including validation across different approaches, advances in modelling methods, and the accuracy of historical records of such events. However, it is necessary to address anticipated risks even before all our models become accurate enough to estimate every detail of climate extremes. Otherwise, we will reach thresholds beyond which making corrective improvements to deal with climate change may not yield the protection we need.