To stop a climate catastrophe we must first believe we can make a difference

If most people think we don't have a hope of keeping global warming below 2C, it is likely to become a self-fulfilling prophecy

• James Randerson
• guardian.co.uk, Tuesday 14 April 2009 10.43 BST
• http://www.guardian.co.uk/environment/cif-green/2009/apr/14/climate-catastrophe

Climate scientists are hyping the global warming crisis in order to keep themselves in jobs, conferences and research grants to exotic locations. Their snouts are wedged deep in a lucrative trough.

So goes the familiar chant from the climate naysayers – those who are convinced climate change is not caused by people nor that its effects are overblown.

So the results of the Guardian's poll of climate experts showing that most believe we don't have a hope in hell of keeping planetary warming to below 2C – the threshold the EU defines as "dangerous" – are all the more remarkable.

It blows the lid on a very different sort of conspiracy: that climate scientists have actually been toning down their message lest the worst-case scenario becomes a self-fulfilling prophecy.

As one respondent put it, "Great things can only be achieved by everyone believing it can be done. How do you think the second world war was won? Churchill didn't stand around saying most people think we will lose the war. He said we will fight it on the beaches."

Far from over-playing their hand to swell their research coffers, scientists have been toning down their message in an attempt to avoid public despair and inaction.

Just 7% of the 261 experts surveyed (200 of whom were researchers in climate science or related fields) said they thought governments would succeed in restricting global warming to 2C. Nearly two-fifths thought this target was impossible and 46% thought a 3 to 4C rise by the end of the century was most likely.

A 3 or 4C rise might not sound much but the climatic shifts accompanying it would be massive. At 3C one to four billion extra people would face water shortages and 150 to 550 million more people would be at risk of hunger. With an extra degree of warming on top of that, seven million to 300 million would be put at risk of coastal flooding due to sea level rise.

In the face of such apocalyptic scenarios it is natural for people to feel like giving up. Small personal actions such as turning the TV off standby, turning down your thermostat and lagging the loft have always seemed pitiful in the face of a global catastrophe.

But if the scientists are saying the bad stuff is going to happen anyway then it is tempting to think we might as well stop punishing ourselves, jump on that no-frills flight and be done with it.

Unfortunately, the climate doesn't give us a milestone beyond which we can stop bothering. Warming the planet to 3C beyond pre-industrial levels is a lot worse than a 2C rise, but it is a walk in the park with mum buying you an ice-cream compared with a rise of 4C.

Likewise, stopping us getting near 5C is very much worth the effort. Sea-level rise at that global temperature increase will take out cities including London, New York and Tokyo. The poles will be transformed by warming.

Scientists must stop sanitising their message. World leaders and their people need to hear the warnings loud and clear and follow through with radical action that matches the scale of the crisis. Only if they do will future generations look back on what is looking decreasingly likely to be our "finest hour".