‘SOCIAL STUDIES ARE NEEDED TO INCREASE THE SCOPE OF ATTRIBUTION?’

Researchers have established that the Pakistan deluge was made worse by global warming. But fixing responsibility of such events on historical polluters is not easy, KRISHNA ACHUTARAO, climate scientist at the Centre for Atmospheric Sciences, Indian Institute of Technology, Delhi, tells AKSHIT SANGOMLA. Excerpts:

- AKSHIT SANGOMLA

What can attribution studies tell us about historical responsibility of countries?

In weather attribution studies we estimate how much of a particular extreme weather event was made worse by cumulative greenhouse gas emissions coming up to this point. So you compare the two scenarios-one with emissions and the other without. Then a fractional attribution is calculated which informs that a particular part of the event is due to human-made climate change.

So if it were just about who is emitting today, then it is easy to fix responsibility. But when you go back and say it is the cumulative of everything that has happened, then you start your accounting at some point, from where you say this is who has emitted the most and therefore, cumulatively their share is highest.

In the recent study on Pakistan floods, you analysed five-day and 60-day extreme rainfall events to say that the downpour in Sindh and Balochistan was 75 per cent more intense due to warming. How would you link this with historical emissions?