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Science

Earthquakes and global warming

Global warming

Dust from volcanoes reflects heat radiation from the Sun, leading to cooling. But dust from factories reflects heat radiation from cities, stopping it from escaping. This leads to warming in urban areas.

Carbon dioxide is a greenhouse gas. It absorbs heat energy that is radiated from the Earth’s surface and prevents it from escaping into space. This keeps the Earth warmer than it would otherwise be. But human activities are increasing the amount of carbon dioxide in the atmosphere. This increases the greenhouse effect and leads to global warming.

The percentage of carbon dioxide in the atmosphere has risen from 0.028 in 1700 to 0.035 in 1990.

Carbon dioxide in the atmosphere has risen at a higher rate since the 19th century

The earth's global average temperature has risen from  13.5º C in 1860 to 14.4º C in 1995 (temperatures over a 5 year average).

The temperature of the earth has risen over the years

Human activities leading to global warming include:

  • increased use of energy
  • deforestation - cutting down trees

Increased use of energy

Most of the energy we use comes from burning fossil fuels. These release carbon dioxide when they burn. So the increasing use of energy is leading to increasing amounts of carbon dioxide in the atmosphere.

Deforestation

When land is cleared for timber and farms, there are fewer trees to remove carbon dioxide from the atmosphere by photosynthesis. Also, if the fallen trees are burned or left to rot, additional carbon dioxide is released into the atmosphere.

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