Researchers from Australian National University have created the world's first comprehensive visual atlas of global rainfall projections during the next 100 years based on all of the models used by the Intergovernmental Panel on Climate Change in its most recent report.

PhD researcher Wee Ho Lim and Michael Roderick from ANU have created the Atlas of the Global Water Cycle, which contains about 300 pages of global maps and tables showing current and projected measures of rainfall, evaporation and run-off.

The atlas illustrates the projections of each of the 20 computer models used by different countries to forecast future water cycles, data drawn upon by the IPCC in its reporting on climate change, but not visualised in the same way and place until now.

"We know that as the world warms there is likely to be more rainfall on a global average basis," Dr Roderick said.

"But where is this increased rainfall going to occur, and which areas might get drier?

"These are simple questions to ask, but it is surprisingly hard for an individual to get an answer, whether they're a farmer, civil engineer, teacher or interested citizen," Dr Roderick said.

"As researchers active in the field we could not answer the question with certainty.

"In fact, until now we've never seen a compilation of the individual rainfall predictions made by all the different climate models."

Dr Roderick said the Atlas of the Global Water Cycle would make all the current best information on modelling for future rainfall more easily available so that individuals and communities could make more informed decisions about how to plan for the century to come.

He said the climate models, such as the one used by the CSIRO in Australia, each take slightly different approaches to forecasting future rainfall patterns, and that their different findings tended to be averaged out for ease of communication.

The Atlas of the Global Water Cycle was launched in Canberra last week and is available for sale in hard copy or free download from ANU at: http://epress.anu.edu.au/global-water-cycle-citation.html