Gee, thanks, reindeer! By preventing shrub and tree growth, they allegedly prevent a volume of ice from melting that is 1/30-millionth the size of the Antarctic ice cap

Reindeer slow global warming

Snow cover and mostly barren tundra reflect large portions of the sun's rays. When darker shrubs and trees spring up in arctic areas they absorb more energy, heating up their surroundings and the earth's atmosphere.

Researchers in Finland have now carried out a comparison between an area in Norway where reindeer are not allowed to graze in the summer, and a similar area in Finland where grazing reindeer have kept shrubs and tree from growing.
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"The heat difference between what happens there and in the Finnish area during three spring months, March, April and May, would be enough to melt a cubic kilometre of ice. That is no small matter,” explains Professor Lauri Oksanen.

Quick Facts on Ice Sheets

Antarctic Ice Sheet contains 30 million cubic kilometers (7.2 million cubic miles) of ice.