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Global warming

Pasterze Glacier, which lies directly beneath the Grossglockner, Austria's highest mountain. The length of the glacier is...Read More >>Pasterze Glacier, which lies directly beneath the Grossglockner, Austria's highest mountain. The length of the glacier is retreating by about 10 m (33 ft) each year. Its volume has fallen by half since the first measurements were made in 1851. The Earth is becoming warmer. The average temperature has risen by more than 0.5°C in the past century and is predicted to rise by 2°C by 2050—although this figure is far from certain. The effects may be felt by more frequent droughts or floods, violent storms and changing climates. Glaciers are retreating (shrinking). The ice caps at both poles may start to melt, resulting in rising sea levels and the flooding of coastal regions where most cities are located. The acidification of the oceans, the extinction of many animal species, and the steep decline in crop yields are among the other disastrous possible effects of global warming. Most scientists are convinced that human activities—industries, power stations, cars and planes—has contributed to a huge increase in what are known as greenhouse gases (including carbon dioxide and methane) in the atmosphere, causing global warming.


Emissions from power stations, traffic, aircraft—even from cattle—all contribute directly or indirectly to the increase in...Read More >>Emissions from power stations, traffic, aircraft—even from cattle—all contribute directly or indirectly to the increase in greenhouse gases that cause climate change.

Greenhouse gases prevent some of the Sun's rays reflecting back to space, warming up the planet.

Greenhouse effect

The Sun’s rays warm the surface of the Earth. The surface then reflects this radiation back into space. Some gases in the atmosphere, such as carbon dioxide (CO2) and methane, trap part of this outgoing radiation, keeping the surface warm—just like a greenhouse. But an excessive amount of these greenhouse gases warms up the Earth too much. Human activities have resulted in a large increase of greenhouse gases, especially carbon dioxide, in the atmosphere. Vehicles and power stations give off exhaust gases from burning oil or coal (“fossil fuels”). These add billions of tonnes of carbon dioxide to the atmosphere.
Carbon circulates between the Earth's surface and the atmosphere in what is known as the carbon cycle. Carbon dioxide, its...Read More >>Carbon circulates between the Earth's surface and the atmosphere in what is known as the carbon cycle. Carbon dioxide, its gaseous state, is taken in by plants during photosynthesis. The plants are eaten by animals, which release carbon dioxide into the atmosphere as they breathe. When plants and animals die, they also release carbon dioxide into the atmosphere. Carbon dioxide is also given off by the weathering of limestone, erupting volcanoes—and the burning of fossil fuels.

The ice shelves of West Antarctica are so vast that, if they melted completely—global warming may one day achieve this outcome—the water released into the ocean from these alone would cause sea levels to rise globally between one and three metres (3–10 ft).

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