Climate change blamed for Arabian Sea’s unexpected hurricanes

https://www.newscientist.com/article/climate-change-blamed-arabian-seas-unexpected-hurricanes/

By Aylin Woodward
Nov. 13, 2017

In the last four years the Arabian Sea has experienced unprecedented storms, and a new study reveals that climate change has made such events more likely to strike.

The Arabian Sea sits between Yemen, Oman and India. Cyclones are rare there – yet in 2014, cyclone Nilofar caused flash-floods in north-east Oman, killing four people. A year later, two cyclones hit back-to-back for the first time. Chapala and Megh both made landfall in Yemen as “extremely severe cyclonic storms” – with winds as strong as hurricanes – killing 26 people and displacing tens of thousands.

These events puzzled Hiroyuki Murakami at Princeton University in New Jersey. He says storms this severe typically occur in spring, months before the monsoons. Yet the three deadly cyclones all hit in October and November, late in the monsoon season.

Wondering if climate change might be changing cyclone behavior, Murakami and his colleagues used a sophisticated climate model to compare conditions in 2015 to conditions in 1860, when humanity’s carbon footprint was much smaller. They found that, in 2015, 64 per cent of the increased hurricane risk in the Arabian Sea was down to climate change.

“We’re seeing that human activity affects not only climate, but shorter events like rainfall and cyclones,” says Murakami.

•••••

They tracked the births and paths of hundreds of such storms and found that they are shifting towards the poles: further south in the Southern Hemisphere and farther north in the Northern Hemisphere. Not only are they forming further from the equator, they are covering greater distances. That means they are creeping closer to continents like Europe.

Researchers have also found that more hurricanes could reach Europe in the future, and that the west coast of the United States and the UK may see more extra-tropical storms.