Climate variations: natural and human factors

Geological records stretching back millions of years indicate some large variations in climate. These have been caused by many natural factors, including the changes in the sun, volcanoes, earth’s orbit and CO2 levels. However, there is good evidence to show that the current rapid warming is not primarily a natural change. Rather this is likely to be due to human CO2 emissions.

Click on the boxes below to read about different possible causes of climate change.

A natural climate cycle

Over the last 800,000 years Earth’s climate has been cooler than today on average, with a natural cycle between ice ages and warmer interglacial periods. The transitions out of ice ages leading to a…

Greenhouse gas emissions

The link between CO2 emissions and rising temperature is very robust. Scientists have known since the early 1800s that gases in the atmosphere trap heat. The first calculations to show the link betwee…

Solar influences

The primary source of Earth’s heat is the Sun, so relatively small changes in solar output can affect our climate. Low solar activity may well have caused a series of very cold European winters duri…