Climate Science

IPCC Answers to Frequently Asked Questions (FAQs)

Climate Science

The following climate change questions are answered by the Nobel-winning International Panel on Climate Change. To see the answer, click on the question you want answered.

FAQ 1.1

What factors determine Earth’s climate?

FAQ 1.2

What is the relationship between climate change and weather?

FAQ 1.3

What is the greenhouse effect?

FAQ 2.1

How do human activities contribute to climate change and how do they compare with natural influences?

FAQ 3.1

How are temperatures on Earth changing?

FAQ 3.2

How is precipitation changing?

FAQ 3.3

Has there been a change in extreme events like heat waves, droughts, floods and hurricanes?

FAQ 4.1

Is the amount of snow and ice on Earth decreasing?

FAQ 5.1

Is sea level rising?

FAQ 6.1

What caused the ice ages and other important climate changes before the Industrial Era?

FAQ 6.2

Is the current climate change unusual compared to earlier changes in Earth’s history?

FAQ 7.1

Are the increases in atmospheric carbon dioxide and other greenhouse gases during the Industrial Era caused by human activities?

FAQ 8.1

How reliable are the models used to make projections of future climate change?

FAQ 9.1

Can individual, extreme events be explained by greenhouse warming?

FAQ 9.2

Can the warming of the 20th Century be explained by natural variability?

FAQ 10.1

Are extreme events, like heat waves, droughts or floods, expected to change as the Earth’s climate changes?

FAQ 10.2

How likely are major or abrupt climate changes, such as loss of ice sheets or changes in global ocean circulation?

FAQ 10.3

If emissions of greenhouse gases are reduced, how quickly do their concentrations in the atmosphere decrease?

FAQ 11.1

Do projected changes in climate vary from region to region?

All FAQs can be viewed and printed as part of a single document from the source website of the International Panel on Climate Change (2007):

http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-faqs.pdf | IPCC 2007

Climate Science Updates

Climate Science

Earth more sensitive to CO₂ than previously thought

December 7, 2009 SCIENCE DAILY – In the long term, the Earth's temperature may be 30-50% more sensitive to atmospheric carbon dioxide than has previously been estimated, reports a new study published in Nature Geoscience. Alan Haywood, a co-author on the study from the University of Leeds, said "If we want to avoid dangerous climate change, this high sensitivity of the Earth to carbon dioxide should be taken into account when defining targets for the long-term stabilisation of atmospheric greenhouse-gas concentrations." >>>> Read the full article in Science Daily.

Science Daily | Earth more sensitive to carbon dioxide than previously thought

Journal Reference | Daniel J. Lunt, Alan M. Haywood, Gavin A. Schmidt, Ulrich Salzmann, Paul J. Valdes and Harry J. Dowsett. Earth system sensitivity inferred from Pliocene modelling and data. Nature Geoscience, 6 December 2009.

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