SCIENCE & CLIMATE DEFINITIONS
What is Ice Loss?
Ice loss refers to the retreat of sea ice and land ice mass from its historic extents. Ice at the Earth’s polar regions helps regulate our climate. Rising global temperatures threaten this balancing act by accelerating the rate of ice melt and prolonging the duration of melt. This retreat of sea ice and land ice is one of two major causes of the current sea level rise.
- raises sea level by directly adding land ice melt to ocean water
- changes climate patterns by not keeping polar regions cool. Ice reflects sun (solar energy, or heat) more than liquid water does, and sea ice keeps air cool by separating warm ocean water from cooler air.
- endangers animal and human populations, including polar bears and indigenous communities that rely on subsistence hunting
- displaces valuable stores of information about ancient climate conditions, in the form of air bubbles trapped inside ice cores
Our Future with Ice Loss
As ice melts and becomes liquid, it loses much of its reflective capacity. The world’s polar regions shift from being agents of cooling to players in a “feedback loop” that leads to greater loss of ice and further warming.
Ice masses form in various ways, but all have begun displaying persistent effects of climate change:
- An ice sheet forms on land and extends over tens of thousands of miles. Greenland and Antarctica have vast ice sheets that together contain more than 99 percent of the freshwater ice on Earth. In Greenland, today’s record summer melts bring rapid and widespread ice sheet loss. In Antarctica, the melt is slower and more localized for now.
- Glaciers and ice caps form on land. Glaciers accumulate snow, which over time becomes compressed into ice. On average, glaciers worldwide have been losing mass since at least the 1970s.
- An ice shelf forms from the outflow of land ice and floats on the sea at land’s edge. It creates a barrier that slows the flow of land ice into the ocean. In the last 30 years, both rapid disintegration of ice shelves and ice shelf collapses have been observed along the coasts of Canada and the Antarctic Peninsula.
- Sea ice forms at sea from salty ocean water. Arctic sea ice has reached record monthly and overall lows in recent years. Overall, the Earth has lost a mass of sea ice the size of Maryland each year since 1979.
While global ice loss has many negative effects on the environment, it also presents commercial opportunities. For instance, a smaller extent of sea ice opens shipping lanes and increases access to some natural resources in the Arctic region.