Forecast is for more snow in polar regions, less for the rest of us

A new cli­mate model pre­dicts an increase in snow­fall for the Earth’s polar regions and high­est alti­tudes, but an over­all drop in snow­fall for the globe, as car­bon diox­ide lev­els rise over the next century.

The decline in snow­fall could spell trou­ble for regions such as the west­ern United States that rely on snowmelt as a source of fresh water. The pro­jec­tions are the result of a new cli­mate model devel­oped at the National Oceanic and Atmos­pheric Admin­is­tra­tion (NOAA) Geo­phys­i­cal Fluid Dynam­ics Lab­o­ra­tory (GFDL) and ana­lyzed by sci­en­tists at GFDL and Prince­ton Uni­ver­sity. The study was pub­lished in the Jour­nal of Climate.

Forecast is for more snow in polar regions, less for the rest of usThe model indi­cates that the major­ity of the planet would expe­ri­ence less snow­fall as a result of warm­ing due to a dou­bling of atmos­pheric car­bon diox­ide. Obser­va­tions show that atmos­pheric car­bon diox­ide has already increased by 40 per­cent from val­ues in the mid-19th cen­tury, and, given pro­jected trends, could exceed twice those val­ues later this cen­tury. In North Amer­ica, the great­est reduc­tions in snow­fall will occur along the north­east coast, in the moun­tain­ous west, and in the Pacific North­west. Coastal regions from Vir­ginia to Maine, as well as coastal Ore­gon and Wash­ing­ton, will get less than half the amount of snow cur­rently received.

In very cold regions of the globe, how­ever, snow­fall will rise because as air warms it can hold more mois­ture, lead­ing to increased pre­cip­i­ta­tion in the form of snow. The researchers found that regions in and around the Arc­tic and Antarc­tica will get more snow than they now receive.

The high­est moun­tain peaks in the north­west­ern Himalayas, the Andes and the Yukon region will also receive greater amounts of snow­fall after car­bon diox­ide dou­bles. This find­ing clashes with other mod­els which pre­dicted declines in snow­fall for these high-altitude regions. How­ever, the new model’s pre­dic­tion is con­sis­tent with cur­rent snow­fall obser­va­tions in these regions.

The model is an improve­ment over pre­vi­ous mod­els in that it uti­lizes greater detail about the world’s topog­ra­phy – the moun­tains, val­leys and other fea­tures. This new “high-resolution” model is anal­o­gous to hav­ing a high-definition model of the planet’s cli­mate instead of a blurred picture.

The study was con­ducted by Sarah Kap­nick, a post­doc­toral research sci­en­tist in the Pro­gram in Atmos­pheric and Oceanic Sci­ences at Prince­ton Uni­ver­sity and jointly affil­i­ated with NOAA’s Geo­phys­i­cal Fluid Dynam­ics Lab­o­ra­tory in Prince­ton, and Thomas Del­worth, senior phys­i­cal sci­en­tist at GFDL.

Read a plain-language sum­mary of the arti­cle on GFDL’s web site.

Read the abstract.

Cita­tion: Kap­nick, Sarah B. and Thomas L. Del­worth, 2013. Con­trols of Global Snow Under a Changed Cli­mate. Jour­nal of Cli­mate.  Early online release pub­lished Feb. 6.–00528.1

This work was sup­ported by the Coop­er­a­tive Insti­tute for Cli­mate Sci­ence, a col­lab­o­ra­tive insti­tute between Prince­ton Uni­ver­sity and GFDL.


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