For years scientists have strived to build models of the climate so that the effect of human activity can be assessed and the future predicted. However the climate system is highly complex and all modelling attempts have been frustrated by limitations in computing power.

Nevertheless through the 1980s and 1990s computer processors improved dramatically to the extent that today’s desktop has more power than the large mainframe computers of a mere decade ago. As computer power increased so did the complexity of climate models.

By the end of the 20th Century it proved possible to build models that reproduced well the dynamics of both the atmosphere and the oceans, ice sheets and even vegetation. The unfortunate thing was that to do this even on supercomputers required some short cuts or approximations – so called parameterizations.

Now, once you introduce such short cuts you are never quite sure if the result you get is a real result or an artifact of the parameterization scheme. To test this you need to run the model millions of times with slightly different parameter values to see how susceptible the model is to the short cuts and what the consensus result is.

Running climate models on supercomputers is very expensive, after all big powerful computers are in short supply. But what if you could run the models on ordinary machines? Would this make it possible to explore the effect of different parameterizations? Would this even be possible?

In the late 1990s Myles Allen was looking in wonder at the SETI@home project. The Search for Extra-Terrestrial Intelligence (SETI) had run into problems – they just didn’t have the computing power available to search all their radio telescope data for the tell-tale signals that might indicate radio transmissions from other worlds. But rather than just admit defeat, the SETI team had made an imaginative leap and created a computer program that almost anyone connected to the Internet could download. This program would process a tiny part of the huge volume of data the SETI team had, but only when that computer wasn’t doing much.

Even more cleverly, the program would automatically send back its results when it had finished and then request another bit of the SETI data. SETI@home proved to be hugely popular – here was a way that people could lend their computer time to help a major science project, but only when they could spare it. Myles realised that this ‘distributed computing’ offered the potential of dramatically increasing the scope, scale and speed of any experiment that is normally limited by the amount of computer power. Suddenly a key issue for climate prediction looked like it could be overcome - Myles wondered if he could set up the equivalent of SETI@home for climate prediction.

It was still a fairly mad idea - the kind of computer model used to predict weather and climate was dramatically more complex than the task of looking for potential signals from ET amongst the random background noise of space. Nobody knew whether it was even possible to use home computers to run these highly complicated models. In fact, an editor of Nature magazine even bet Myles an ice-cream that the project would never produce any results!

The task that confronted Myles was too large for any one person to undertake, so he set about getting others to join him and to get funding for the project. In April 1999 the first proposal for funding the project was rejected as being utterly unrealistic. However, just a few months later one of Myles’ colleagues at Reading University, Andy Heaps, managed to get the Met Office climate model to run on a personal computer and in September 1999 the concept was presented at the World Climate Modelling conference in Hamburg. A month later Nature published a short article called “Do-it-yourself Climate Prediction” [requires Acrobat Reader]. This was an idea whose time had come and when a website was set up so that people could register their interest in taking part in the experiment - thousands did.

By the start of 2000 Myles’ team had made enough progress to convince the Natural Environment Research Council (NERC) to help fund a pilot study. By the summer the team were working on the central computer systems that would “talk” to the participants home PCs as well as the design of the experiment, and the first full length ‘run’ of the Met Office’s model took place on a secretarial PC at the Rutherford Appleton Laboratory in Oxfordshire.

While all this was going on funding was being sought (unsuccessfully) from dying dotcoms. A bid to NERC’s eScience Programme in December 2001 finally secured funding for a public launch, with more money coming from the DTI just months later. The team was then able to grow and begin to improve the software to improve reliability following “friends and family” testing.

2002 also saw the Open University joining to help develop the educational benefits of participants effectively having a virtual planet, unique to them, in their PCs – leading to the idea that the software should include a visualization package that would allow you to actually see your virtual world.

After years of work Myles’ vision was finally coming to life. Extensive ‘beta testing’ ensured that the model gave the same results on a PC as it did on a supercomputer, couldn’t be tampered with to give different results and also checked that the software didn’t interfere with other programs running on PCs and didn’t inadvertently allow the spread of computer viruses. At last the project was released to the public on September 12 2003, with BBC Weather's Carol Kirkwood launching the the screensaver at the National Museum of Science and Technology.

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Content last updated: 05/01/2006

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