Causes & Effects

Causes & Effects

Global warming

The earth is naturally warmed by rays (radiation) from the sun, which pass through the earth’s atmosphere and are reflected back out to space again. The atmosphere is made up of layers of gases, some of which are called ‘greenhouse gases’. They’re mostly natural and form a thermal blanket around the earth. This lets some of the rays back out of the atmosphere, keeping the earth at the right temperature for animals, plants and humans to survive (60ºF/16ºC). A certain level of global warming is therefore necessary but as extra greenhouse gases are produced, the thermal blanket gets thicker and too much heat is retained within the earth’s atmosphere causing the global climate to become warmer.

How do our actions contribute to climate change?

Carbon dioxide has been identified as the main man made contributor to global warming and climate change. Increased industrial activity and the burning of fossil fuels like coal, oil and natural gas to power our homes and vehicles have resulted in a dramatic increase in the level of carbon dioxide released into the atmosphere. Coupled with deforestation and the partial destruction of the earth’s natural carbon sink, this human activity is now recognised and known to be disturbing the natural balance of greenhouse gases, which is causing our climate to change.

What does this mean to us?

The earth’s climate has been changing throughout its history and, until now, this has been mostly due to natural causes. Recent changes in the climate however have been more dramatic. According to the Intergovernmental Panel on Climate Change (IPCC) the increase in surface temperature over the 20th century for the northern hemisphere is likely to have been greater than that for any other century in the last thousand years. Global temperatures have increased by approximately 0.6 degrees since the beginning of the 20th century, with about 0.4 degrees of this change occurring since the 1970s. Nine of the 10 warmest years on record have occurred since 1990, including 1999, 2000, 2001, 2002 and 2003.

Scientists now say that the average world temperature is rising by 0.15 degrees every decade, and confidently predict many changes to the global environment as a result. The following may happen:

  • Water expands when heated and oceans absorb more heat than land, so sea levels would rise.
  • Sea levels would also rise due to the melting of the glaciers and sea ice.
  • Places that usually get lots of rain and snowfall might get hotter and drier.
  • Lakes and rivers could dry up and there would be more droughts, making it hard to grow crops.
  • Some plants and animals might become extinct because of the heat.
  • Hurricanes, tornadoes, high winds and other storms which are caused by changes in heat and water.

What is causing the increase in carbon dioxide emissions?

Government evidence suggests that the UK contributes about 2% to global man made emissions. Although this may seem small, it is estimated to range between 22.8 and 25.3 billion tones of carbon dioxide equivalent per year. Carbon dioxide accounted for approximately 84% of the UK’s man made emissions in 2005.