FAQs - Global warming
Q. Isn't the current global warming just part of natural climate variability, that might for example reflect recovery from a cooler period several centuries ago?
A. It is very unlikely that the rapid increase in global temperatures seen over the past half century could be caused by natural factors alone.
The Intergovernmental Panel on Climate Change (IPCC), in its Fourth Assessment Report (AR4) published during 2007, concludes that most of the observed warming since the mid-20th century is very likely (i.e. a more than 90% chance) to be due to the observed increase in anthropogenic greenhouse gas concentrations.
Both the spatial patterns and trend of warming can only be explained by the inclusion of human emissions of greenhouse gases. The AR4 also shows that the global warmth of the past half century is unusual in at least the previous 1,300 years.
The IPCC's conclusions are based on a comprehensive analysis of peer-reviewed and published scientific and technical research.
Q. Has climate change been caused by humans?
A. Most scientists agree that human activities are changing the earth’s climate, and unless we change our behaviours, there is a very serious threat to human society and the natural environment. Across the world, rising levels of greenhouse gases are being driven by man-made emissions: mainly fossil fuel burning (to generate heat and power), forest clearance and burning, and agriculture.
In February 2007, the Fourth Assessment Report of the IPCC, the recognised international source of evidence on climate change, carefully evaluated all available lines of evidence. The IPCC concluded that it is very likely (i.e. a 90% chance) human emissions have caused most of the global increases in temperature since 1950. These conclusions are the most authoritative and comprehensive picture of climate change available, based on peer-reviewed science and analysis.
Further information on climate change is available at:
- Defra - Climate change and energy
- IPCC - Intergovernmental Panel on Climate Change
- Defra - Climate Change Bill
Page last modified:
22 February 2008
Page published: 22 February 2008