John Schellnhuber, climate specialist, has warned of a potentially rapid change in environmental conditions.
When the Queen made her unprecedented call for action on climate change at last week's Anglo-German conference, it coincided with John Schellnhuber's appointment as CBE in recognition of his work on the issue.
Professor Schellnhuber, of the Tyndall Centre for Climate Change Research at the University of East Anglia, has warned that too little is known about 12 environmental "tipping points" - such as the North Atlantic current, Asian monsoon and West Antarctic icesheet - that could lead to rapid climate change.
Climate change and the Bush Administration's reluctance to sign up to the Kyoto Protocol was expected to be on the agenda this week when Tony Blair becomes the first foreign leader to visit the White House since the American elections.
An attempt to forge a new global agreement is expected to be a priority when Mr Blair takes the presidency of the G8 grouping of industrial nations next year.
Professor Schellnhuber said in a recent BBC interview: "We're investing too much in things like improving the accuracy of our weather forecasts, while the really vital elements in the earth's system are the unstable phenomena like the monsoon.
"We should have a much better understanding of these tipping points, and we have to do everything we can to stop short of triggering these instabilities."
He added: "Scientists have begun to realise that change could be sudden, not gradual - in some cases it could happen within a few decades."