NO. 59 : THE IMPACT OF GLOBAL WARMING : Land Ice

Land Ice

Shrinking land ice is wreaking havoc across the globe.

Sea-level rise. Water from shrinking glaciers and ice sheets is now the major contributor to global sea-level rise. Long locked away in polar regions and mountains, this extra runoff is adding new freshwater to the world's oceans.

• Long-term decline in water resources. Nearly one-sixth of the world's population lives near rivers that derive their water from glaciers and snow cover. Most of these communities can expect to see their water resources peak and then ultimately decline during this century.
• Short-term increase in flash floods. Many rivers that derive their water from melting glaciers or snow are likely to have earlier peak runoff in spring and an overall increase in runoff, at least in the short term—potentially increasing the risk of flash floods and rockslides.
• Accelerated warming from albedo. Land ice in polar regions reflects some of the sun's energy back into space (known as albedo), helping keep the planet cool. As this ice shrinks and darker land is exposed, it absorbs more solar energy—creating a feedback loop that accelerates the planet's warming.

Land ice includes any form of ice that lasts longer than a year on land, such as mountain glaciers, ice sheets, ice caps and ice fields (both similar to but smaller than an ice sheet), and frozen ground or permafrost. Nearly a quarter of the land area in the Northern Hemisphere is permafrost, with layers up to tens of meters thick. Above-freezing temperatures occur at the base of the permafrost layer. 

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