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Dr. Koni Steffen is the director of University of Colorado at Boulders Cooperative Institute for Research in Environmental Sciences and a veteran researcher of Arctic climate. The following are excerpts from a Reuters interview with Dr. Steffen at his research camp in Greenland in which he discusses the accelerating melting of Greenlands ice cap and its effects on global ocean levels.

Q: Lets start by describing your research here at Swiss Camp.
A: We want to measure the climate over longer term to find out how it is interacting with the ice masses. The location of the Swiss Camp is unique. When we started in 1990, the amount of precipitation here and the melt of snow and ice equaled. We had zero change. This warming were currently observing in Greenland moves this line to higher elevations on the ice sheet. Warmer temperatures in spring and fall made the melt period in Greenland much longer. Therefore we see more and more melt water from the ice sheet flowing out into the ocean and decreasing the reflection of the sun. We have seen that the total melt area over the last 30 years increased by 30 percent. This is a large area. Up to 50 percent of Greenland in the inner part never melts. Its too cold and its too high in elevation, as the ice goes to 3,000 metres. But this area gets smaller and smaller.

Q: How far along are scientists in understanding ice sheet dynamics and their effect on global ocean levels?
A: One effect is the melting of the ice sheet. Another effect is the dynamic response of the ice sheet, and this is quite a new observation. In the past we all assumed the ice sheet was moving at constant speed toward the ice edge. The big glacier here, Jakobshavn Isbrae, had a velocity of 6-7 km per year into the fjord up to 1995. Suddenly, this glacier retreated in the fjord, but by 2002-2003 its speed had doubled to 14-15 km per year. This is a very large volume of ice that moves into the ocean. Every year, we lose 100 to 150 cubic km of ice in Greenland. There is an imbalance that we can only explain by the dynamics of the ice. Its moving faster into the oceans through this glacier and other glaciers on the east coast.

Q: Did the last IPCC report underestimate the forecast for the rise in ocean levels?
A: I think it definitely underestimated. We complained heavily before it was released and thats why they added a few lines that if there is a dynamic response of ice sheets the upper uncertainty might be higher. That tells you that the current IPCC report only takes into account the current understanding. We can model melt but we cannot model the dynamics. How can you actually set an uncertainty band that small if you dont understand a major process that produces now so much melt water?

Q: Could Greenland’s meltdown have an effect on the conveyor belt of ocean currents?
A: The meltdown effect is currently a hypothesis. We do know how much water is produced by melt. If you put that into a model for the conveyor belt it will not change the global circulation. The dynamic loss of ice has increased over the last five years, every other year almost doubling. If you put this curve in, some models can predict a change in the conveyor belt within 50 to 100 years. But its one out of 10 models. The uncertainty is quite large.

The way we understand this from the past, we had abrupt climate changes that happened when huge water masses were collected on ice sheets and were flushed out at once, way bigger than what we can produce now on Greenland. The theory is open. Can we produce enough fresh water to change the conveyor belt? The present situation is we doubt it. It is unlikely that we have an abrupt climate change due to the ice loss of Greenland alone. If Antarctica is reacting faster…

Antarctica is the sleeping giant. But it was cold so far. The peninsula that sticks out into the ocean was the only place you could see very strong warming its actually the place with the strongest warming on the globe currently. If that has an effect on big ice shelves if they start to disintegrate, then the ice masses from higher elevation move into the ocean, then there is a possibility that you actually produce more fresh water, which could change the conveyor belt.

The cause of the current warming is an increase in greenhouse gasses, which is worldwide, not just in the Arctic. Even with these greenhouse scenarios, we have regions that will not warm, or warm very little, and other regions will warm three or four times faster. The only thing that could stop Greenlands melting is the ocean currents, and they are very inert. They need a lot of energy to actually make changes.

Q: Short of the conveyor belt stopping, what could reverse the warming in Greenland?
A: We had a similar warming in Greenland in the 1930s. It took about two and a half decades to get that warm, but the temperatures were almost identical as they are now. But this was a local warming around Greenland. Right now we have warming all the way down to the mid-latitudes. How could it be reversed? Thats a hard question, because if you put greenhouse gasses into the atmosphere it takes a very long time to take them out. We have never had such a high carbon dioxide level in the past 500,000 years. We have good climate data from ice cores in Antarctica that go back 500,000 years and from these records we can see the ice ages and the warming periods, but the driver a lot of the time was CO2, and now CO2 is way above what we had in the past.

We cannot take CO2 out of the atmosphere, not in the amount thats currently there. It is self-regulating, yes. CO2 is taken out and put into the ocean, but its a very slow process. If we actually start now, changing our emissions through better fuel consumption or better insulation, everything helps in that way. The population of the Earth grows. We know California has grown its industry and population but its CO2 output has decreased in the last 15 years. It is possible to have an increase of the economy and population and decrease your output. Only that would help in the longer term. But the warming will continue even if we turn off all the engines today because of the memory effect in the atmosphere. It takes quite a long time.

Q: How do you view the media coverage of climate change?
A: One disappointment I would raise is if you look at the understanding of climate change by scientists lets be generous 95 percent of scientists say we understand the process and we are convinced there is global warming. The media reports it, like a lot of other stories, as 50-50. They want to always show the other side. That’s good, but Im disappointed that the media does not reflect that there is a 95-5 percent discussion. It sounds like its 50-50. The public reads this and they cant make up their mind usually.

Dr. Koni Steffen on the Greenland ice cap. Photo by Bob Strong, Reuters.