Leading article: An inconveniently persistent truth

It has been hard work in recent times to get the world to take seriously the dangers posed by global warming. Those who have been persuaded, through misguided short-term self-interest, to deny the reality of climate change, have had succour from a number of sources.

The scandal surrounding the leak of private emails from the Climatic Research Unit at the University of East Anglia was deeply damaging with its allegations that scientists fudged and fiddled the figures to bolster the case for international action. So too was the fiasco in which an unsubstantiated claim that the Himalayan glaciers could melt away by 2035 was allowed to find its way into the 2007 report of the Intergovernmental Panel on Climate Change. And the fact that the challenge of global warming was scarcely mentioned by any major political leader during the general election campaign has not helped. All this has been grist to the mill of the climate-change deniers.

Yet the inconvenient truth is that, whatever errors or over-statements individuals may make in this debate, the overwhelming body of climate science still shows that man-made climate change is real. Our report today, of solid and robust research measuring changes in temperature in our planet's great oceans and seas, demonstrates that. The satellite and float technology involved is producing evidence from a wide area. This sets in context minor disputes about the reliability of data from Chinese weather stations and other squabblings. The temperature of our deep waters does not fluctuate in the way that temperatures do on land, where they are subject to the vagaries of weather as well as urban heating.

There is a key difference between weather and climate, and the temperature of the seas is an important indicator of that. And the water in our deep seas is warming. Add to that the recent evidence from Lake Tanganyika – which was recently shown to be warmer than at any time for at least 1,500 years – and the serious evidence is all pointing in one direction only.

It may well be that heightened anxiety over the massive oil leak in the Gulf of Mexico will dispose the public to take the environment more seriously for a while. But ups and downs in public awareness must not be what determines the seriousness with which this problem is addressed. Climate change represents a serious challenge to human survival. Our political leaders must not be allowed to forget that.