Søk i GEO365.no

The global climate has been in a state of change ever since the atmosphere started developing over four billion years ago. This is clearly evident from geological research based on rocks, sediments and ice.

Halfdan Carstens

Furthermore, historical and archaeological data substantiate our impression of an Earth that has undergone continuous variations in climate.

However, our knowledge of past climate and temperatures is at best rudimentary. It is based on second-hand evidence, and the further we look back, the greater the uncertainties. Continued research of the Earth's paleoclimates, in both the near and distant past, should therefore be strongly encouraged and properly financed by governmental bodies.

We need to understand, if at all possible, the future climate. Assuming that we are now experiencing global warming caused by human behaviour, we cannot afford to avoid getting a better grip on such a relationship. Alternatively, if it can be shown that human behaviour does not cause global warming, or current interpretations of the alleged global warming turn out to be wrong, then we also need to fully understand the processes involved.

Even if the popular press and most politicians now agree that, firstly, the Earth is getting warmer, as shown by an increase in mean temperature (whatever is meant by mean temperature for a complex system like the Earth's atmosphere), and secondly, that this is happening because of human behaviour, it is useful to remember that the IPCC concludes that there is only a 90% chance of a connection between global warming and the burning of fossil fuels. In other words, there is a 10% chance - which I consider significant - that there is no connection between the two. This latter view is authenticated by numerous geoscientists (with high academic rating) within many geological and geophysical disciplines.

My message is simple. We need to be extremely cautious, and try not to be prejudiced when discussing past and, in particular, future climate. As scientists we have an obligation to remember that a theory cannot be proven. As geologists we know a lot about the past, but few of us are experts on climate, able to comprehend all the geological data and interpretations available.

Humility should be the geoscientists' buzzword of the future.