Thread by @PeterGleick

A climate 🧵.
Are you wondering why and how #climatechange can worsen /both/ floods and droughts?
Here's a short explainer:
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#floods #droughts

First, both droughts and floods occur naturally as extremes of weather. As humans have started to change the climate, we're affecting both extremes.
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Droughts are worsening in some places for two main reasons. First, higher temperatures from global warming dry out soils, increase evaporation of water, accelerate snowpack loss, & more. Second, changes in atmospheric circulation divert rains away from some regions. Both...
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effects worsen the frequency & intensity of drought. This is what is happening in the US Southwest & California. It's hotter & the storms bringing water from the Pacific are hitting further north.
At the same time, other regions are seeing more intense rains & floods. Why?
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Again, two main reasons. First, a warmer atmosphere holds more water. That water has to go somewhere. Second, because of the way atmospheric water circulates, many wet areas are getting wetter. Sometimes this manifests as severe storms that are now MORE severe. Hence...
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the intense rain events this week in Missouri and Kentucky. These storms might have occurred anyway, but because of human-caused climate change, they carried more water and were more intense than they would otherwise have been.
Finally, a little ...
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graphic shows this.
The two curves represent the range of hydrology for the past (blue) and present (red) changing climate. The "tail" ends of the curves are droughts (left/red) and floods (right/blue). As the climate changes, the extremes get more frequent and intense.
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Finally, the same thing is happening with heat extremes except the new climate curve for temperature is just shifting right as the planet warms, leading to both higher average temperatures and more severe and frequent heat disasters.
These trends will continue and...
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worsen until we stop emitting greenhouse gases.
Thanks for listening.
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One more: some good references to learn more.
link.springer.com/article/10.100…

citeseerx.ist.psu.edu/viewdoc/downlo…

link.springer.com/article/10.100…

go.gale.com/ps/i.do?id=GAL…