The Earth's climate is not static. Over the billions of years of earth’s existence, it has changed many times in response to natural causes.
But when people talk about 'climate change' today, they mean the changes in temperature over the last 100 years caused by human activity. Click the link to find out more.
During this time, the average temperature of the atmosphere near the Earth’s surface has risen by about 0.75 degrees Celsius.
Nearly all climate scientists agree that global temperatures will rise further – by how much depends on future emissions of greenhouse gases, and other human activities.
If the temperature rise is high, the impact is likely to be extreme and it will be difficult to cope with. There are likely to be more intense and frequent extreme weather events – like heatwaves, floods and tropical storms – and sea levels will rise further.
Unless we take action to reduce CO2 emissions now, these effects will become more likely and have a greater impact when they occur.