W. Atmospheric CO2 Already @ Pliocene Levels, Pliocene-Style Monsoon Seasons Possible In American SW

[hatrack]

EDIT

The story of what happened then is the story of what will happen to a warming world. Summer rainfall in the Pliocene created wetter conditions and a landscape of lakes—not the deserts of today. And now, she notes, atmospheric carbon dioxide levels are once again what they were in the Pliocene: “It’s a snapshot of the world we’re likely to go toward if we don’t curb emissions.”   The leaf waxes reveal that the Pliocene had intense monsoons during the summer, shifting the narrative of previous research that attributed wetter conditions only to winter rainfall. “Our paper presents the first direct evidence that monsoon changes caused wet conditions in the middle Pliocene,” Bhattacharya says.

The Southwest currently has a monsoon season that typically runs from June to September and stretches from Western Mexico into Arizona, Nevada, New Mexico, and some parts of California, Colorado, and Utah. These rains can be severe: Earlier this summer, a so-called 1,000-year-storm flooded the driest place in North America, Death Valley, stranding hundreds of visitors and causing extensive damage. In Las Vegas, two people drowned and a casino flooded during what was called the worst monsoon in a decade. In Arizona, monsoons flashed through the state during July and August.  

Monsoons today will likely follow the Pliocene pattern and intensify, but also expand their range in Southern California. (Bhattacharya says additional data from other sedimentary deposits would help map the expansion in more detail.) Their extremes, she adds, will likely match what was normal during the Pliocene. That’s bad news for a region not built to withstand the storms. 

“Those floods made headlines because they were so unprecedented. You have to think about how intense extreme rainfall puts unique stress on infrastructure,” Bhattacharya adds. “It’s worth thinking about how we plan infrastructure for more extreme intense rainfall in places that don’t get a lot of rainfall today, like the desert Southwest.”

EDIT

https://www.wired.com/story/pliocene-like-monsoons-are-returning-to-the-american-southwest/

[bucolic_frolic]

1. All I get is storms and power outages

Been at least 4 this year. Twenty years ago zero was the usual annual total.

Makes one wonder about owning property. Insurance rates. Rental increases. Ownership. All separate entities.