Slowing tropical cyclones very bad news

Hurricane Harvey caused $126bn of damage. Image: By Jill Carlson (jillcarlson.org), via Wikimedia Commons

A report from Climate News Network:

Tropical cyclones are moving more slowly. As temperatures rise, the pace at which a hurricane storms across a landscape has slowed perceptibly in the last 70 years. But the slowdown means each hurricane has more time to do more damage and deliver more flooding.

“Tropical cyclones over land have slowed down 20% in the Atlantic, 30% in the northwestern Pacific and 19% in the Australian region,” said James Kossin, of the US National Oceanic and Atmospheric Administration’s national centres for environmental information.

“These trends are almost certainly increasing local rainfall totals and freshwater flooding, which is associated with a very high mortality risk.”

He reports in the journal Nature that thanks to atmospheric warming as a consequence of the profligate combustion of fossil fuels in the last century, the summer tropical circulation has slowed and, along with it, hurricane and typhoon speeds. Overall, since 1940, cyclone movements have slowed by 10%; over some land areas, they have slowed much more.

But as the temperature goes up, the capacity of the atmosphere to hold moisture increases – by at least 7% with each degree Centigrade. That means a tropical cyclone – a whirling system of terrifying winds bearing huge quantities of water – has both more water, and more time to drop it over land.

And Dr Kossin cites the example of Hurricane Harvey which in 2017 dumped more than 1.25 metres of water on Houston, Texas and the surrounding countryside in just five days. Devastating floods displaced 30,000 people, and 89 died. Economic losses were assessed at more than $126bn.

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$126 billion!!!!  And the denialists still maintain that it's "too expensive" to reduce carbon emissions.  The effects of global warming are being felt right now.  We don't have to wait for decades to go by to feel the impact of climate change.  All that will happen is that the effects will just get worse.  Start slashing emissions now, world, before it's too late.