Hotter Hotspots, Drier Dryspots, Wetter Wetspots, and Stronger Storms

Hotter Hotspots, Drier Dryspots, Wetter Wetspots, and Stronger Storms

April 2022 Temperature Update

16 May 2022
James Hansen, Makiko Sato and Reto Ruedy What else is new? Hotspots are getting hotter. The major hotspot in April stretched from Iraq to India and Pakistan, and toward the northeast through Russia (Fig. 1). Temperature exceeded 45°C (113°F) in late April in at least nine Indian cities,[1] on its way to 50°C (122°F) in Pakistan in May,[2] where a laborer says “It’s like fire burning all around” and a meteorologist describing growing heatwaves since 2015 says “The intensity is increasing, and the duration is increasing, and the frequency is increasing.” Halfway around the world, Canada and north-central United States were cooler than their long-term average, but people in British Columbia and northwest United States remember being under their own record-breaking hotspot last summer.

It’s sometimes said that we are in a “new normal” and that we must reduce greenhouse gas (GHG) emissions to keep this new normal tolerable. Yes, we must reduce emissions as rapidly as practical, but our target cannot be just minimizing how intolerable climate becomes. For multiple reasons – crucially for preserving our coastal cities – we must return to a more propitious, cooler, climate. We are now in a transient climate phase that’s sure to get hotter in the near term, but in the near future – at latest by the 2030s – we must begin to manage Earth’s energy balance to restore a cooler climate. We will finish a paper soon that we hope will help illuminate this matter.

Rising temperature is the least of it. Dry places get drier and wet places wetter. Notably affected subtropical dry regions include the U.S. Southwest, the Mediterranean, and the Middle East. Tropical regions now subject to greater deluges include much of Central America, Southeast Asia and Africa. Moreover, throughout the world, wet times become wetter, dry times become drier, and storms tend to be stronger. These conclusions are not news; they were all included in a paper[3] that we and other colleagues at the NASA Goddard Institute for Space Studies wrote in 1989. The conclusions were based on physical science arguments, but also on GCM climate simulations with increased atmospheric CO2. In the climate simulations, we sorted the diagnostics into wet times and dry times at each location. This revealed that increased GHGs cause wet times to become wetter and dry times dryer, regardless of how annual-mean precipitation changes. This paper was the basis for much of the testimony of JEH to the U.S. Senate.[4]

…(Read more).

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