Rapid, global climate change is one of the most vigorously debated subjects at the beginning of this century. How bad will it be and is there anything we can do about it? For the first interview in the Comment:Visions series, Dr. Olav Orheim, a distinguished polar researcher and world authority on climate change gives his opinions and speculates on how we humans will meet the challenge.

Olav Orheim has spent his entire career in the cold.

His first research trip was made to the Antarctic while still a student. As a glaciologist, he has returned 18 times and made more than 50 field trips to the Arctic. His study of the poles has made him an expert on one of the century's hottest topics - global warming.

His advice on climate change is sought by academic institutions, governments and royalty. He was knighted in 2007.

Euronews met Dr. Orheim in a century-old inn overlooking the Norwegian capital Oslo.

No longer a matter for conjecture, global warming is accepted as a reality by virtually every authority.

Interviewer: So, how severe will it be and what is responsible?

Olav Orheim: "The culprit is very clearly us. There may be other phenomena as well in nature that is working sometimes in the same direction as us, sometimes not. But the main culprit, there is no issue about that. We are releasing, because of our use of fossil fuels, we are releasing carbon dioxide into the atmosphere."

Interviewer: "This is not the first time we've had global warming, it's not a new phenomenon in the geological record - why is this one different?"

Olav Orheim: "Nature has always been making changes to our climate, but on top of that we have put the human signal - we have increased greenhouse gases. And so what we have now is a constant increase in the human effect and on top of that we will have nature's variations, also into the future.”

Interviewer: "You've talked about, or other scientists have talked about, a 3 or 4 degree increase in the Earth's average temperature by the end of the century: do you agree with that figure?”

Olav Orheim: “Yes, I think that's the best number we have. We are going to see...climate science is quite a young science, it's only been going on for 20 or 30 years. So we are going to see that there are still many, many things we are going to learn better than today. And as I say the big uncertainty is not now the climate science,although that has many uncertainties, it is how we humans behave that is a far bigger uncertainty.And what worries us today, is when we are looking at the model predictions and we look at the way the Earth is behaving on the whole the behaviour of the Earth, the increase in temperature, the increase in sea level is on the upper range of the previous predictions and some scientists have gone out publicly and said that we are perhaps facing a 6 degree increase in temperature by the end of the century."

Interviewer: "What would be the consequences for us if, say, we get a 6 degree rise in world temperatures"

Olav Orheim: "Six degrees means for example that the heatwave that we saw in Europe in 2003 with a lot of additional deaths in France, in Germany - that is going to be standard throughout the Summer. But the biggest impact on infrastructure will probably be the associated changes in sea level. 6 degrees and certainly Greenland will disappear with a 6 degree warming - before that actually. Greenland will give us a 6 metre sea level rise. And a 6 degree, 6 metre sea level rise means that most cities in the world would lose all their infrastructure. Most cities in the world are within 6 metres of sea level.”

Interviewer: "One strategy that has been proposed is Carbon Capture and Storage, there are others, do you think these strategies will be successful?"

Olav Orheim: "There's no question, they have to be effective because we have no choice. This globe will not be habitable for most parts of the world and for most people if we end up with that kind of climate change. Now there is no single one that will pick up most of this problem, so we're talking about a whole host of solutions. Carbon Capture is one of these that is actually in its infancy and we really don't know how well that will work, but we have others like obviously changing how we produce energy, it's a very obvious one. I think we're going to see atomic power coming in in different ways. The big hope, of course, in which a lot of research is going on now is to find second or third generation solar cells that are more efficient than the ones we have today. Wind power is another one, so if we can harness solar energy, or its associated wind energy we would be a long way towards having a carbon neutral society.”

Interviewer: "What would you say to politicians and governments charged with the responsibility for coping with global warming."

Olav Orheim: "We have to reduce our dependency on oil. And the challenge I should say is how you change a completely oil and gas, particularly oil- dependent societies, because that's the way we've been living. We've had this very, very cheap energy - we've had this for about 100 years. We're going to see that being phased out and that means enormous changes to society. Many of these things will take 15, 20, 25 years to find the solutions. It's very hard for politicians, as you say, to look in those long-term perspectives. The public has to accept that certain things have to be done for it to be solved in 20 years or 30 years. I'm an optimist on the future because this is a human-made problem - us humans have made it, so that means it's also possible for us humans to solve it and that would be my final word to politicians: go out and solve this and have a long-term perspective and we will all be better for it."