1,000-plus years of tree rings confirm historic extremity of 2021 western North America heat wave

[Jim__]

From phys.org:

Summer seasonal temperature anomalies revealed by tree rings and modern weather data, 950-2021. Credit: Modified from Heeter et al., Climate and Atmospheric Science, 2023
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In summer 2021, a stunning heat wave swept western North America, from British Columbia to Washington, Oregon and beyond into other inland areas where the climate is generally mild. Temperature records were set by tens of degrees in many places, wildfires broke out, and at least 1,400 people died. Scientists blamed the event largely on human-driven climate warming, and declared it unprecedented. But without reliable weather data going back more than a century or so, did it really have no precedent?

A new study of tree rings from the region shows that the event was almost certainly the worst in at least the past millennium. The research, published in the journal npj Climate and Atmospheric Science, established a year-by-year record of summer average temperatures going back to the year 950. Scores of abnormally hot summers showed up, many grouped into multiyear warm periods. But the new study shows that the last 40 years, driven by human-influenced warming, has been the hottest—and that 2021 was the hottest summer in the entire span.

"It's not that the Pacific Northwest has never before experienced waves of high temperature. But with climate change, their magnitude is much hotter, and they have a much greater impact on the community," said lead author Karen Heeter, a postdoctoral researcher at Columbia University's Lamont-Doherty Earth Observatory. "Being able to look at the past and compare that with climate models, and come to similar conclusions, there's a lot of power in that."

The tree-ring reconstruction and modern temperature readings show that 1979-2021 saw a sustained period of hot summers unrivaled for the last 1,000-plus years. Most of the hottest years have occurred since 2000. The second-warmest period, indicated by the tree rings, was 1028–1096—at the height of the so-called Medieval Climate Anomaly, when a natural warming trend is thought to have taken hold across large parts of the planet. Another notable hot span during the Medieval Climate Anomaly ran from 1319 to 1307. But even these periods were considerably cooler than temperatures in recent decades.

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[Duppers]

1. Wish wingers could/would accept science.

But it doesn't serve their selfish goals.