In this case, the object is to make huge climate simulations spanning hundreds of years, and then analyse the massive banks of data that result.

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The study, published in the latest edition of the journal Geophysical Research Letters, found that the actual rate at which summer sea ice had shrunk per decade during the past 50 years was more than three times faster than an average of 18 of the most highly regarded climate simulations.

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For example, significant cooling and strong dynamical effects after the Laki event and other high-latitude eruptions are believed to have caused decreased flow of the Nile River in Egypt and weakened African and Asian monsoons based on climate model simulations, with potentially very significant impacts on food and water supplies.

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By including such data in their computer simulations, climate modellers may be able to tell whether solar inconstancy deserves some of the blame heaped on greenhouse gases.

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Dr Chris Huntingford, of the Centre for Ecology and Hydrology, said the temperature increase was "in agreement with simulations by many independent climate centres around the world".

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In the 1970s, Dr Hansen focused on studies and computer simulations of the Earth's climate for the purpose of understanding the impact of humans.

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Simulations were also used to extend the climate forcing results from central Greenland to the entire Arctic.

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For example, in estimating how much warming is expected, the most recent report of the Intergovernmental Panel on Climate Change uses three methods, two based entirely on model simulations.

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Their simulations included the effects of eclipses and tidal heating on climate for an earth-twin in orbit around a Jupiter-like gaseous giant planet.

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