Humans are very dependent on ice. Glaciers are important. For example:
- Ice helps to balance the world’s climate
- Meltwater provides water for people and crops
- Ice and glaciers provide areas for tourism which generates jobs
- Ice caps, sheets and glaciers store large amounts of fresh water, preventing sea levels rising and flooding coastal areas
How do we know that ice is melting?
Surveying the Arctic Ocean sea ice cover is one of many ways that helps experts to understand how ice cover is changing. Satellites photograph vast areas of ice, and mapping the results helps to analyse how the ice is changing.
Scientists measure the thickness of the ice. They drill into the ice to collect the data. Submarines also contribute to the collection of data.
In 1999 and in subsequent years, a detailed British survey has been taken to assess the level of change in sea ice over the Arctic. The results suggest that by 2040 the Arctic Ocean’s sea ice cover may disappear during the late summertime.
The Greenland and Antarctic ice sheets have also lost an increasing amount of ice over recent decades. When land ice melts, it adds water to the sea and causes sea levels to rise. At the same time the warmer temperatures cause oceans to expand – also increasing sea levels.
Positive effects of Arctic Ocean sea ice melting:
- It is easier to access resources under the seabed, such as oil and gas.
- Distances may be reduced as navigation routes may improve.
Negative effects of Arctic Ocean sea ice melting:
- As the Arctic ice melts it threatens wildlife, eg in polar bear habitats, earlier melting means less time to hunt and fatten up. In addition, fewer floating ice rafts mean more dangerous swimming conditions for bears.
- An increased number of icebergs could make navigation for ships dangerous.
- Less ice decreases the albedo, leading to an increase in global warming.
- As the ice melts the global sea level will rise. This will flood low-lying areas.
Why is the world’s ice melting?
Most scientists believe that increases in global temperatures are linked toclimate change, caused by increases in greenhouses gases in our atmosphere. Greenhouse gases are released, for example, from the burning of fossil fuels (coal, oil and natural gas).
Carbon dioxide and methane are greenhouse gases. Greenhouse gases help to trap heat reflected off the Earth’s surface. They are present naturally in our atmosphere and without them the Earth would be too cold to live on. However, the amount of these gases present in the atmosphere has increased, meaning temperatures rise.
During the 20th century, the average temperature on the Earth’s surface rose by about 0.75°C. At the same time, sea levels rose between 10 and 20 cm. This is predicted to get worse unless human beings make big changes to the way we use and source energy.