A warming Arctic weakens the temperature difference between the tropics and the poles meaning less precipitation, weaker cyclones and weaker mid-latitude westerly wind flow — a recipe for prolonged drought.
- Cody C. Routson, Nicholas P. McKay, Darrell S. Kaufman, Michael P. Erb, Hugues Goosse, Bryan N. Shuman, Jessica R. Rodysill, Toby Ault. Mid-latitude net precipitation decreased with Arctic warming during the Holocene. Nature, 2019; DOI: 10.1038/s41586-019-1060-3
When the Arctic warmed after the ice age 10,000 years ago, it created perfect conditions for drought. The temperature difference between the tropics and the poles drives a lot of weather. When those opposite temperatures are wider, the result is more precipitation, stronger cyclones and more robust wind flow. However, due to the Arctic ice melting and warming up the poles, those disparate temperatures are becoming closer.
“Our analysis shows that, when the Arctic is warmer, the jet stream and other wind patterns tend to be weaker,” says Bryan Shuman, a UW professor in the Department of Geology and Geophysics. “The temperature difference in the Arctic and the tropics is less steep. The change brings less precipitation to the mid-latitudes.”….