Article: Evidence of human influence on Northern Hemisphere snow loss — Nature #ActOnClimate #snowpack

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Click the link to read the article on the Nature website (Alexander R. Gottlieb & Justin S. Mankin). Here’s the abstract:

January 10, 2024

Documenting the rate, magnitude and causes of snow loss is essential to benchmark the pace of climate change and to manage the differential water security risks of snowpack declines. So far, however, observational uncertainties in snow mass have made the detection and attribution of human-forced snow losses elusive, undermining societal preparedness. Here we show that human-caused warming has caused declines in Northern Hemisphere-scale March snowpack over the 1981–2020 period. Using an ensemble of snowpack reconstructions, we identify robust snow trends in 82 out of 169 major Northern Hemisphere river basins, 31 of which we can confidently attribute to human influence. Most crucially, we show a generalizable and highly nonlinear temperature sensitivity of snowpack, in which snow becomes marginally more sensitive to one degree Celsius of warming as climatological winter temperatures exceed minus eight degrees Celsius. Such nonlinearity explains the lack of widespread snow loss so far and augurs much sharper declines and water security risks in the most populous basins. Together, our results emphasize that human-forced snow losses and their water consequences are attributable—even absent their clear detection in individual snow products—and will accelerate and homogenize with near-term warming, posing risks to water resources in the absence of substantial climate mitigation.

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The next coordination meeting for the operation of the Aspinall Unit is scheduled for Thursday, January 18th 2024, at 1:00 pm — Reclamation #GunnisonRiver #ColoradoRiver #COriver #aridification

Black Canyon July 2020. Photo credit: Cari Bischoff

From email from Reclamation (Erik Knight):

The next coordination meeting for the operation of the Aspinall Unit is scheduled for Thursday, January 18th 2024, at 1:00 pm.

This meeting will be held at the Holiday Inn Express in Montrose, CO. There will also be an option for virtual attendance via Microsoft Teams. A link to the Teams meeting will be emailed next week along with the meeting handouts.

The meeting agenda will include a review of operations and hydrology since August, current soil and snowpack conditions, a discussion of hydrologic forecasts, the weather outlook, and planned operations for this water year. There will also be a presentation by American Whitewater on the development of the Environmental & Recreational Flow Tool.

Aspinall Unit dams