Experiment Begun In 1991 Added 2C Heat To Rocky Mountain Meadow; It Transformed Test Plot To Desert Scrub

[hatrack]

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Every summer, people descend on the wildflower capital of Colorado to see grasslands flush with corn lilies, aspen sunflowers and sub-alpine larkspur. In January 1991, scientists set up a unique experiment in these Rocky Mountain meadows. It was one of the first (and longest running) to work out how the changing climate would affect an ecosystem. At the time, it was believed a temperature increase could lead to longer, lusher grasses. But instead of flourishing, the grasses and wildflowers started to disappear, replaced by sage brush. The experimental meadows morphed into a desert-like scrubland.

Even the fungi in the soils were transformed by heat.The experiment provided a window into the future. These meadows will disappear in the coming decades if warming reaches 2C above preindustrial levels, according to the resulting article published in the Proceedings of the National Academy of Sciences. The findings are alarming, not just for Colorado, but for mountains across the planet as “shrubification” takes over.

Electric infrared radiators warmed five experimental plots of 30 sq metres year-round. Head-height heaters were on day and night over a patch of meadow, keeping it 2C above normal temperatures with an annual electricity bill of $6,000 (£4,450). They warmed the top six inches of soil. Animals could come and graze and the natural system was preserved as much as possible.Over 29 years, researchers found that shrubs increased by 150% in warmed plots compared with those without warming. The surface of the soil was dried by up to 20%, and shallow-rooted plants became stressed. Some wildflowers went extinct in heated plots. “It’s a sign of things to come,” says lead researcher Lara Souza from the University of Oklahoma.

Scientists also noted big changes in the invisible world of soil fungi and microbes. Shrubs and sage brush don’t rely on fungi in the same way as grasses. They found a decline in fungi that help plants acquire nutrients, and an increase in fungi that decompose organic matter. “This highlights that when you have a big change above ground, you’ve likely got a big change below ground,” says Souza. “Turning back is very unlikely.”

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https://www.theguardian.com/environment/2026/mar/25/flowers-heated-2c-meadow-climate-crisis-experiment-rocky-mountains-aoe

[Wonder Why]

1. So they invented a way for Colorado to be more like Arizona? Hmmm!