Recently it was shown that large ice sheets existed during the Turonian era, about 90 million years ago, one of the warmest periods in Earth history. It was much warmer than today or even the more extreme predictions of the global warming models for the near future. So, are the polar caps in danger of disappearing or not?

We don’t know.

In the early 1990s, when I first heard of the evidence of an increasing global temperature, I was starting my scientific career. Naturally, I had an interest in many scientific questions and the time to read about them. So, from time to time I went to the library to scan the journals Nature and Science. I frequently read about changes in global temperature.

To my surprise, there were different views on an apparently simple matter. For some, global temperatures were rising; for others, decreasing. There was no evident difference in the materials on which the studies were based as they were both using ice cores from high latitude regions. This is not unusual. The conclusions of such studies are based on assumptions and decisions ranging from the selection of the sampling locations, to the analysis of the data, to correction for predictable bias and to the interpretation of the numbers. There is a lot of room for personal opinion.  It is only by accumulation of data and discussion that ideas are tested and a consensus is reached.

This was my frame of mind about the global warming issue when I learned that, suddenly, in less than 10 years, an overwhelming consensus had already been reached: carbon emission by human activity is producing an increase of global temperature. This looked suspicious when I first heard it. One essential piece of evidence did not fit into the official thesis. Plots of temperature since the end of the 19th century show a temperature increase until 1940, a plateau from 1940 to 1980 and then a constant increase. The increase in carbon emission between 1940 and 1980 was approximately 57 percent of the total increase from 1850 to 2000.

How could such large carbon emission fail to produce an increase in temperature for 40 years? Such a discrepancy between data and interpretation is normally sufficient to cause a scientific paper to be rejected.

My suspicion about the general consensus grew when I saw that the “truth” of global warming was so strongly supported by political entities. All sorts of diagrams, models and predictions were being published in popular publications about the “consensus”.

Among colleagues from Scotland to Gibraltar and from San Francisco to Moscow, I have not found that this consensus exists. My field is Earth Sciences and it is related to certain aspects of climate change in the geological scale. Approximately 70 percent of researchers with whom I have discussed the matter think that we do not have sufficient information to be sure about the issue and that the consensus is political, not scientific. The other 30 percent do believe there is sufficient evidence in favour of man-made global warming.

Two more facts suggest that politics is overriding science in this issue.

The first is my experience of studying nuclear waste disposal. I can bear witness to the reliability and quality of the studies carried out to test the safety of underground repositories. I have also experienced the opposition of environmental groups and the impossibility of carrying on a scientific dialogue with them. Theirs is a purely political position. They succeeded in delaying the implementation of underground nuclear waste repositories everywhere in Europe. Ironically, climate change will now be used to convince the public that nuclear power is necessary.

The other fact is the designation of Al Gore as the recipient of the Nobel Peace Prize last year. Most recipients have worked for years to solve intractable human conflicts. Some have suffered terribly for their beliefs. Al Gore just made a profitable documentary. His unsuitability shows how powerful the environment lobby is.

This panorama is a distressing one. There are reasons to believe that global warming is happening and reasons to believe it is not happening. Neither possibility has been scientifically proven. But if, after all this hype, the global warming theory is proved wrong, citizens will look at scientists with suspicion and perhaps with contempt. We could enter a new Dark Age of hostility towards research. And the ones to blame will be scientists themselves.

Javier Cuadros is a specialist in earth science. He works in London.