Global warming is the rise of average temperature in the earth’s atmosphere since the late 19th century. Since the beginning of the early 20th century, the earths mean surface temperature had increased by around 0.8 degrees. Warming of the climate system had become more obvious and scientists are 90% sure that the main cause of the increase in temperature in due to the increasing concentrations of greenhouse gases due to human activities such as deforestation and burning of fossil fuels. Glaciers are melting, sea levels are rising, forests are drying and wildlife is suffering, these are all results of the apparent rise in global temperatures and it has become more obvious that humans over centuries are releasing harmful heat-trapping gases into the atmosphere known as greenhouse gases. The greenhouse effect causes the increase in global temperature as the gases which are released into the atmosphere allow light to be entered, but prevents heat from escaping. The sun firstly releases short-wave radiation which skinks into the earth’s surface, causing it to warm the atmosphere. A long wave infrared radiation which is emitted by the earth’s surface is absorbed, and then re-emitted back into space. The climate changes occur due to the increase of greenhouse gases. The greenhouse gases then trap some of the heat and the rest escapes back into space. Essentially, the more greenhouse gases released into the atmosphere, the more heat is trapped, resulting in an increase of global climate.
The above graph shows the rise in global temperatures since 1860 to 2000. The increase in global temperature can be recording using methods such as: Ice core samples; temperature recordings; dendrochronology and peat bogs.
Ice core samples
Within Ice sheets, holds records of hundreds of thousands of past climates trapped in ancient snow. Scientists can obtain the climate history by drilling cores in...