Climate Change Tracker: Stormy weather2 min read . Updated: 04 Oct 2019, 07:27 PM IST
In this week’s Climate Change Tracker, we look at the increasingly destructive cyclones hitting India and elsewhere
On 24 September, Gujarat was spared potential devastation when the very severe cyclone Hikaa changed trajectory over the Arabian Sea and headed for Oman instead. It did subside into a deep depression before it reached Oman, but the close shave is central to the topic of this week’s column: cyclones and extreme weather events.
The frequency and strength of tropical cyclones are increasing due to the warming of oceans, according to a new IPCC (Intergovernmental Panel on Climate Change) report that looks at the effect of climate change on the oceans and the cryosphere. And according to the report, this trend will continue even if the world were to drastically reduce carbon emissions. The sea has absorbed 90% of the heat generated by anthropogenic carbon emissions since 1970, and we are only now beginning to see the effects, like destructive cyclones.
Cyclones and hurricanes are both tropical storm systems, with the former occurring over the South Pacific and Indian Oceans and the latter over North Atlantic and north-east Pacific Oceans. Over the past few years, tropical hurricanes have stolen the limelight. Between 2016-19, five category 5 hurricanes have appeared over the Atlantic: Hurricanes Matthew, Irma, Maria, Michael and Dorian, devastating small island nations, as well as the east and gulf coasts of the US. The sheer number of storms of this size (wind speeds of at least 251 kmph on the Saffir-Simpson scale qualifies as category 5) in such a short period is a remarkable tally, but with warming oceans and rising sea levels, this will soon be the new normal.
India had its own category 4 cyclone this year, Cyclone Fani, which made landfall in Odisha in May with wind speeds of up to 200 kmph. In fact, at one stage, while still over the Bay of Bengal, Fani had reached speeds just shy of being declared a category 5. Odisha had learnt its lesson from 1999’s devastating super cyclone, as well as from 2013’s Cyclone Phailin. Phailin was a category 5 storm, which, when it made landfall in October that year, weakened to a category 4. So the state was better prepared, with 9,000 safe shelters, including dedicated cyclone shelters, and a well-rehearsed mass evacuation programme. Even then, 59 people were killed and the state suffered losses of ₹12,000 crore. Fani was an outlier because it was a pre-monsoon cyclone, and in India “cyclone season" is usually thought to be September-October. But, as the IPCC report warns, we are moving into a zone of extremes where multiple cyclones of great severity can appear in the same year.
How prepared are we? The India Meteorological Department (IMD) operates three cyclone warning centres (CWC) at Visakhapatnam, Bhubaneswar and Ahmedabad, with another three area cyclone warning centres (ACWCs) at Chennai, Kolkata and Mumbai. However, according to experts, India needs better forecasting systems that are based on the sharing of data between government departments, something that’s still lacking.
In next week’s Climate Change Tracker, we look at how global warming is causing the range contraction of mountain species. Follow the series with #MintClimateTracker.