Climate Change

Climate change is the shift in the long term weather patterns across the Earth. Large parts of the Earth have become colder at some times and warmer at others. Over thousands of years, the Earth's climate changes in response to:

changes in processes such as solar radiation
deviations in the Earth's orbit
volcanic activity
large-scale movements of the earth's crust
continental drift, and
changes in greenhouse gas concentrations.

While most of these changes are natural, much of the build-up in greenhouse gases is attributed to human activity.

The Earth is surrounded by a layer of gases which insulates the planet, trapping heat from the sun. This is called the greenhouse effect because the gases create an atmosphere similar to that found in a greenhouse. Without these natural gases Earth would not be able to sustain life.

The layer of gasses which surrounds the Earth insulates the planet, trapping the extreme heat from the sun. Ministry for the Environment, Wellington, NZ, Understanding Climate Change Booklet, 2007, p.3

These gases are increasing in concentration as a result of practices such as coal burning and overuse of aerosol products. The temperature of the Earth has warmed by nearly 1°C over the last 100 years and scientists predict this trend will continue.

Changes in our climate and an increase in extreme weather events are said to be caused by warming of the planet. A warmer Earth may lead to changes in rainfall patterns, a rise in sea level, and a wide range of impacts on plants, wildlife, and humans.