Why does the climate change?

The Earth’s climate has always been changing. Scientists have been able to track these changes for the last 500 million years. They can be explained through natural causes like:

  • Plate tectonics
    (the process by which the continents drift about the world)
  • Changes in the Earth’s orbit
    (eccentricity, axial tilt, and precession)
  • Meteor strikes
  • Volcanic eruptions
  • Sunspots

Scientists can study these changes by observing patterns in:

  • Ice cores
  • Lake and ocean sediments
  • Corals
  • Pollens
  • Tree rings

The recent changes in climate, however, cannot be explained through natural causes. Scientific studies have revealed that these changes are mainly due to human activities, such as burning fossil fuels (through the use of cars and heating, for instance) and changing the landscape (e.g. deforestation) causing the release of more CO2 into the atmosphere. CO2 is a greenhouse gas that helps trap energy in the lower layer of the atmosphere causing it to get warmer. This phenomenon is called the greenhouse effect. The substantial increase in the atmospheric concentration of CO2 since the beginning of industrialization is considered to be the strongest evidence that the recent climate change is man-made.