What is climate change?

Our planet is surrounded by a blanket of gases which keeps the surface of the earth warm and able to sustain life. The more gases we release, the thicker the blanket becomes and the more heat it traps within our atmosphere. Since the beginning of the Industrial Revolution we’ve released a lot more of these gases (known as greenhouse gases) by burning lots of fossil fuels for energy, cutting down forests and using intensive agricultural practices. As a result the average global temperature is 0.87°C higher than it was in 1850.

This is already having negative consequences, both locally and globally. We are experiencing more intense and more frequent extreme weather events. An increase in temperature has major implications for ecosystems, growing seasons, animals and their habitats. Scientists believe we need to limit the rise to no more than 2°C above 1850 temperatures to avoid the worst effects of climate change.  

The Greenhouse Effect

The term ‘greenhouse effect’ was coined to describe the way some gases in the atmosphere (such as carbon dioxide, nitrous oxide, and methane) trap some of the light energy from the sun after it is reflected from the earth's surface, and  before it can escape out into space, so warming our atmosphere. This is a natural process that has been happening for billions of years, and without it the earth would be about 33°C colder – too cold for us to live on. Now, however, human influence has upset the natural balance of carbon dioxide and other greenhouse gases, and too much of the sun’s energy is being trapped, causing average temperatures to rise.

The Past and the Present

Evidence for past climate change is visible in a wide range of geological settings, including marine and lake sediments, ice sheets, fossil corals, stalagmites and fossil tree rings. Geologists have recorded climatic changes which can be related to geological events such as volcanic activity or changes in energy received from the sun. However, the evidence shows that warming since the 1970’s is happening relatively fast and is caused by human activity.

Climate Change or Global Warming?

The terms Global Warming and Climate Change are often used interchangeably in the media to refer to the fact that global temperatures are rising and the earth is changing as a result. Scientifically they mean different things:

  • Global Warming refers to an increase in the earth’s average surface temperature due to rising levels of greenhouse gases.
  • Climate Change refers to the changes in the global climate which result from the increasing average global temperature. For example, changes in precipitation patterns, increased prevalence of droughts, heat waves, and other extreme weather.