More snow in the Arctic is good. Less snow elsewhere may be a problem. A new cliÂmate model preÂdicts an increase in snowÂfall for the Earth’s polar regions and highÂest altiÂtudes, but an overÂall drop in snowÂfall for the globe, as carÂbon dioxÂide levÂels rise over the next century. The decline in snowÂfall could spell trouÂble for regions such as the westÂern United States that rely on snow melt as a source of fresh water.
More snow in the Arctic is good. Less snow elsewhere may be a problem. A new cliÂmate model preÂdicts an increase in snowÂfall for the Earth’s polar regions and highÂest altiÂtudes, but an overÂall drop in snowÂfall for the globe, as carÂbon dioxÂide levÂels rise over the next century. The decline in snowÂfall could spell trouÂble for regions such as the westÂern United States that rely on snow melt as a source of fresh water.
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The proÂjecÂtions are the result of a new cliÂmate model develÂoped at the National Oceanic and AtmosÂpheric AdminÂisÂtraÂtion (NOAA) GeoÂphysÂiÂcal Fluid DynamÂics LabÂoÂraÂtory (GFDL) and anaÂlyzed by sciÂenÂtists at GFDL and PrinceÂton UniÂverÂsity. The study was pubÂlished in the JourÂnal of Climate.
The model indiÂcates that the majorÂity of the planet would expeÂriÂence less snowÂfall as a result of warmÂing due to a douÂbling of atmosÂpheric carÂbon dioxÂide. ObserÂvaÂtions show that atmosÂpheric carÂbon dioxÂide has already increased by 40 perÂcent from valÂues in the mid-19th cenÂtury, and, given proÂjected trends, could exceed twice those valÂues later this cenÂtury. In North AmerÂica, the greatÂest reducÂtions in snowÂfall will occur along the northÂeast coast, in the mounÂtainÂous west, and in the Pacific NorthÂwest. Coastal regions from VirÂginia to Maine, as well as coastal OreÂgon and WashÂingÂton, will get less than half the amount of snow curÂrently received.
In very cold regions of the globe, howÂever, snowÂfall will rise because as air warms it can hold more moisÂture, leadÂing to increased preÂcipÂiÂtaÂtion in the form of snow. The researchers found that regions in and around the ArcÂtic and AntarcÂtica will get more snow than they now receive.
The highÂest mounÂtain peaks in the northÂwestÂern Himalayas, the Andes and the Yukon region will also receive greater amounts of snowÂfall after carÂbon dioxÂide douÂbles. This findÂing clashes with other modÂels which preÂdicted declines in snowÂfall for these high-altitude regions. HowÂever, the new model’s preÂdicÂtion is conÂsisÂtent with curÂrent snowÂfall obserÂvaÂtions in these regions.
The model is an improveÂment over preÂviÂous modÂels in that it utiÂlizes greater detail about the world’s topogÂraÂphy – the mounÂtains, valÂleys and other feaÂtures. This new high-resolution model is analÂoÂgous to havÂing a high-definition model of the planet’s cliÂmate instead of a blurred picture.
Snow, once on the ground, affects the local environment. After attaching itself to hillsides, blown snow can evolve into a snow slab—an avalanche hazard on steep slopes. The existence of a snowpack keeps temperatures lower than they would be otherwise, as the whiteness of the snow reflects most sunlight, and any absorbed heat goes into melting the snow rather than increasing its temperature. The water equivalent of snowfall is measured to monitor how much liquid is available to flood rivers from melt water that will occur during the following spring. Snow cover can protect crops from extreme cold. If snowfall stays on the ground for a series of years uninterrupted, the snow pack develops into a mass of ice called glacier.
So less snow means less snow melt and less water for some regions at times when they historically expect water. More snow in the polar north means the land will be colder and stay more frozen over time. As one can see predicting the effects of climate change is quite tricky.
For further information see Snow.
Polar North image via Wikipedia.