Will the oceans rise?
Will crops fail?

Will future generations lament to
their ancestors (us), “What the
(bleep) were you thinking!?"

A climate scientist convinces you to do
something now about global warming.

An interview with Konrad Steffen, Ph.D.

By Ravi Dykema

 

Of all the hotly argued topics today, nothing fans the flames of debate like the issue of global warming. Opinions vary widely. Some say global warming alarmists exaggerate the evidence, and that recent global temperature increases represent normal variability of the weather. Others insist that we’re heating up, and heading for trouble.

At the heart of the debate is the very real phenomenon of melting glaciers and ice sheets in the Artic region. The Steffen Research Group has been studying climate perturbations in the Arctic region and their potential impact on global sea levels and climate changes for nearly 30 years. The project is the brainchild of Konrad Steffen, Ph.D., an internationally recognized climatologist and director of the Cooperative Institute for Research in Environmental Studies (CIRES) at the University of Colorado, Boulder. In 1990, Steffen set up a research station, known as Swiss Camp, on a platform drilled into Greenland’s ice sheet. His observations there, confirmed with satellite imagery, show an expanding melt area, including unprecedented melt in recent years, melting to a record elevation of 6,500 feet, and melting in areas where it had not occurred since satellites began mapping the ice sheet in 1978.

Steffen’s findings have appeared in scientific journals as well as BBC-TV reports and a 2005 New Yorker Magazine series on global climate change. His work, together with that of his students and associates, has heightened knowledge of arctic climate and warming and melting dynamics. Here, he talks to Nexus publisher Ravi Dykema about Artic climate changes and their impact on global warming.

RD: Are you of the opinion that the Earth’s warming trend is caused by humans?

KS: Yes. What we have been seeing in the last 10 years cannot be explained by a natural variability of the climate. The climate always has variability. We had a warming in the 1930s, which was very similar to the warming we have today. But that warming only took place in the far northern areas—around 70 to 80 degrees north. The current warming, from 2000 onward, penetrates all the way to the equator; you cannot explain it as a natural variability.

What we’re seeing now is called a greenhouse warming effect. Greenhouse gases are manmade. They also are a result of agriculture, but they’re still manmade, because we derive food from the agriculture. We actually would have expected an even bigger warming over the last 20 or 30 years, given the increased levels of greenhouse gasses in our atmosphere.

In 1984, the Montreal agreement was one of the first global change agreements among all the nations, including the United States. These nations agreed to reduce the sulfur in the atmosphere by removing it from fossil fuel burning and other sources. The sulfur actually cooled the climate, because sulfur is a particle that reflects a lot of short-wave radiation. Within 5 to 8 years after that agreement, the sulfur reduction in the atmosphere resulted in the current accelerated increase in global warming levels. That’s why we didn’t really see the warming in the ‘70s or ‘80s— we were polluting the atmosphere so immensely that not all the sun’s rays could reach the earth’s surface, thus creating a cooling effect.

RD: I’ve also heard that increased warming could produce increased evaporation, which would increase cloud cover, which would reduce warming.

KS: That’s true. We’re seeing both positive and negative feedbacks. A warmer atmosphere can have more moisture, so we would expect more precipitation. This is becoming true in the Arctic. We can see it now in the higher altitudes of the Greenland ice sheet, where the only precipitation is snow. It never rains, so all the precipitation results directly in accumulation of snow. The surface on top of the ice sheet is growing. Because we are warming, we have more precipitation. At the same time, the low-level areas around Greenland, close to the coast, are melting at a faster rate than snow is accumulating. So the whole of Greenland is actually losing mass.

RD: Are some feedbacks ominous? You’ve spoken of methane gas, an extremely potent greenhouse gas, being released from permafrost, due to melting.

KS: Yes, and that’s ominous because only a small increase in methane will increase the radiation that comes back to earth. We need only 1/20th of the methane amounts to have the same warming affect as that from carbon dioxide. The methane release we have known about for some time is from agriculture and animal production, and it has increased very rapidly in the last 50 to 100 years. But there’s another source of methane which is not produced by humans; that’s the methane in permafrost (soil that’s been frozen for two or more years). With the warming we’re now seeing in the Artic, methane that has been trapped in the frozen ground for the last 10,000 years is being released because the soil is thawing. And that will have a very strong feedback. More methane from the arctic will increase the concentration of greenhouse gasses in our atmosphere, which will increase the temperature. Methane is not only stored in the permafrost; it’s also in the shallow water close to land, what we call the shelf region. It is only 10 to 30 meters deep. There are large amounts of methane stored in that frozen ocean bottom.

RD: The sea bottom is frozen under the water?

KS: Yes, in the shallow shelf region of the Arctic Ocean. If sea ice is removed during summer in a warmer climate, the ocean water becomes warmer, the frozen shelf area begins to melt, and more of the methane can be released from the ocean floor.

RD: Is the melting sea floor a relatively new discovery?

KS: That’s correct.

RD: How much methane is stored in the ocean floor?

KS: We don’t know, but I assume it’s very similar to the permafrost, because it has been stored over a long time. Now, all these areas are starting to melt, and methane is being released.

RD: You have spent many weeks living on and studying the Greenland ice sheet, for many years, correct?

KS: Yes. In 1990, I started the Greenland project to measure the climate and track changes. I was with a climatology group from Switzerland at Swiss Federal Institute of Technology there, and we had camps around the world. We had just finished our project in China in the high mountains, where we measured very similar parameters to describe the climate. Greenland was next on our agenda.

Our plan was to put up a station on what we called the equilibrium line, where all the snow and precipitation that falls melts throughout the summer. At that elevation, the Greenland ice sheet is neither growing nor shrinking. So we set up a big camp and started to install instruments. We don’t stay on the ice all the time; we only stay for a few months. Then, after 1993, I moved to CU here in Boulder and continued to visit Greenland every spring.

We go to the camp for five or six weeks, and all the measurements between those times are done automatically by computers, by data loggers. The data comes back every hour via satellite. We have satellite links that sense the data, not only from our station—what we call the Swiss camp—but from all 25 stations I have on the ice sheet.

RD: Did you build other stations over the years?

KS: Yes. Over the years, I started to build a climate network, because you cannot assess the climate from one point. Most of my work was sponsored by NASA and, later, by the National Science Foundation. We use satellite data to look at Greenland as a whole. That’s how we’ve learned over the years that the melt in Greenland increases with time.

RD: You’ve been to the same camp, the Swiss camp, and no doubt to many of the satellite camps, since 1990. What do you see or feel there that has changed?

KS: Every year, we went to the camps, usually from the end of April into June. And it has changed. In the early ‘90s, there was plenty of snow, and it was very cold—usually -20 to -25 Celsius, which is around –4 to –13 Fahrenheit. And in the northern part of the study area, where we have other stations, the temperatures were around -40° Celsius, or about –40° Fahrenheit. For the last ten years, when we arrived there, the snow was melting already—the melt was starting much earlier in the season. Also, the melt season was much longer.

You might have heard in several news articles that Greenland is losing mass. There are several components to this. I mentioned before that Greenland gets more precipitation, so it actually should gain in mass. But along the areas that are lower in elevation, usually around 3,000 feet, it is melting rapidly. And this area of melting has increased in size over the years. So that is an indication that it’s getting warmer.

We can easily measure this melt by satellites that measure the wetness of the snow. When the snow is not melting, it’s dry, and we get one kind of a signal. As soon as we have very small water droplets around the snow grains, the signal is drastically different. So we can measure melt over time.

We have now 29 years of daily data for the entire Greenland ice sheet, where it melted and where it did not. If we compare satellite data from 1979 to the present, we see that the melt area has increased by 30 percent. That is not a linear line; there is some variability. But if you connect all these lines, the net effect is that 30 percent more area is melting. That’s why Greenland is losing mass.

Now, as more snow melts, more water is produced, and the water starts to collect in big pools, which is a new phenomena. We call these pools of water “lakes.” They are undulations on the ice sheet where the water cannot run away. They are several miles across, and they are only about 10 to 30 feet deep. When these lakes drain, the water penetrates down through the glacier. Once that water reaches the underside of the ice sheet, it lubricates it relative to the ground on which the ice rests. And then it can move downhill faster. So the melt not only reduces the volume of the ice, because it melts away, but it also starts to move the ice faster towards the coast and into the ocean.

RD: What is the extent of this melt?

KS: Satellite data shows that every year in the last 3 to 4 years, we are losing approximately 100 cubic kilometers of ice from Greenland; 150 cubic kilometers was the latest number. By way of comparison, that’s about the equivalent of all the glaciers in the Alps. That’s why we say Greenland constitutes a potential danger for future sea level increases. All that ice melting or flowing from the continent of Greenland into the ocean displaces sea water. Sea level is now rising about 3.5 millimeters per year, or about 0.0197 inches. Four or five years ago, the increase was only about 1.8 millimeters per year. So in only four or five years, the sea level increase has doubled.

RD: Do you have reason to believe it will continue at that rate?

KS: That’s our belief. There is obviously no model, and no way to make an accurate predication about what we call this dynamic loss of mass. All the models we have are based on our current understanding. The IPCC (Intergovernmental Panel on Climate Change) Report released in February predicts a rise in sea level of approximately 43 centimeters by 2100, about 1/2 meter. We—the glaciologists, the people involved in that research—believe that prediction is too low.

RD: What do you think it will be?

KS: We think it’s more on the order of one meter, more than doubling by 2100. Some of my colleagues are not as conservative as I am. They say we may have a three-meter sea level increase by 2100, or about 9 feet. The message is, there is a great deal of uncertainty.

RD: Why is there so much uncertainty, and such a wide variance in predictions?

KS: The models used in the IPCC report only predict the melting, but not the dynamics of ice movement involved. The report does not include many variables, including the sped-up motion of the ice. We can’t blame the models, because we don’t even understand all the processes. I think the next generation of models is incorporating these dynamic components, so we’ll be able to more accurately predict outcomes. If you add the latest information, the faster movement of the ice, it changes the predictions. We don’t know if that ice flow will continue, or even increase with time; that’s why some people say the sea level increase may be as much as 3 meters. Looking at the current process, it’s more likely to be 1 meter if we continue to have this kind of warming.

I say “if” we continue to have this warming. We’re seeing a trend of man-made warming. But there have always been natural variabilities in climate and temperature; these, we can’t control. Some of them are known. Some of them we can predict, because they have to do with the distance between the sun and the earth, and that doesn’t change very fast. But there are other phenomena which we don’t fully understand, such as carbon dioxide sinks, which is a process by which carbon dioxide is taken out of the atmosphere.

RD: I understand that Greenland’s climate is changing more rapidly than Antarctica’s climate, but there could be reason to think that Antarctica is going to start to look more like Greenland.

KS: That’s correct. The region of the earth where the climate is warming the fastest is actually Antarctica. It’s at the peninsula that is farthest from the pole, but that’s a very small part of Antarctica that reaches far into the southern ocean. If you look at the temperature records for the last 20 to 30 years, that part of the globe has the largest temperature increase. But it’s a very tiny region. All the rest of Antarctica is a huge area of ice that is not yet responding to the warming, I say “not yet,” because the cold area of Antarctica blocks the air masses.

The ocean rotates around Antarctica; all the big air masses also rotate around Antarctica. Antarctica is pretty high, and it is very cold, and cold air is heavy. So if an air mass that is now in the Indian Ocean moves toward Antarctica, it bounces off. You can’t really keep warm air there. And that keeps Antarctica cold. Now, very slowly, the margins of Antarctica are getting warmer. It’s very different from Greenland and the northern Arctic.

RD: What are the implications?

KS: We know that the peninsula of Antarctica that extends into the southern ocean is the region of the fastest warming. What happens if that warming goes further south, into the cold area? In that area, there are huge ice sheets—called ice shelves—that float on the ocean. They’ve formed because Antarctica produces so much ice that it flows off the continent and floats on the ocean for hundreds of miles. This floating ice shelf is 1,500 feet thick. When warming occurs, it starts to disintegrate. If you remove this big ice shelf, which is like a buffer that holds back the ice on the continent of Antarctica, then the ice can move into the ocean much faster. And that is happening right now in the peninsula.

RD: So it’s like taking away a dam that’s blocking the land ice from sliding downhill into the ocean.

KS: Correct. And the ice shelves floating on the ocean are not raising sea level, because they have already displaced the water. But if you break the ice shelf off, because it’s melting, then the ice on the land flows down much faster, and that increases sea level. So there is a potential for a large sea level rise. One of these ice shelves disintegrated five years ago; it’s called the Larsen Ice Shelf. It was a huge area, 20 percent larger than Rhode Island. The glaciers behind the ice sheet increased in speed by six times, pushing much more ice into the ocean.

Again, this is the kind of dynamic response we have to figure in to the models; it’s not only the melt. All the current models produce what we call an energy balance—how much is melting, how much snow is falling on top, and the resultant sea level rise. But current models don’t account for these dynamics, which you have to include if you want an accurate prediction.
In my view, one of the biggest threats of global warming is changing precipitation patterns and changing access to water. Any civilization needs water. Think about our region. If you reduce our precipitation by only 20 percent, the growth in Colorado is completely limited. If you look at areas where there’s a very small amount of water—parts of Africa, desert regions—people have to move if there’s a change in precipitation. So you would have large migrations of people.

Also, with a change in precipitation comes a change in temperature, and a change in where you can grow your food and a potential economic impact. For example, just imagine if the Corn Belt region of the U.S. migrated into Canada as a result of changes in temperature and precipation; that would have a huge economic and political impact.

On the other hand, let’s look at the consequences of rising sea levels. I would say 10 percent of the present population on Earth is living within 10 kilometers of the coastline. Let’s assume sea level rises by one meter, or three feet, by 2100—which is not that far away. Our kids and our grandkids may be living in that time period. Look at the disaster we had when New Orleans flooded. And that’s just a small problem; the United States is a highly civilized nation, and we should be able to deal with a catastrophe at that level. Imagine the impact of flooding in less developed regions.

Also, a rise in sea level does not mean the ocean is one meter higher everywhere. In some regions, it’s less than a meter. But in some areas, it’s higher. If a big storm hits, that one meter will drive waters far inland. So in reality, by 2100, you would have to move a large population away from the coastlines. I’m not talking about a few hundred thousand people. I’m talking about tens of millions of people. If there’s a big event—a hurricane, an earthquake, a small tsunami—huge regions would be flooded. You can’t keep the population there.

RD: So the Netherlands must be concerned.

KS: Yes, they are. But the Netherlands is a very small, wealthy country. I’m more concerned about Bangladesh, where 50 million to 100 million people are living in a region that potentially will be flooded. How do you move this number of people? The Netherlands has a few hundred thousand people that would be affected, and they have the technology to increase their dams. It’s not so much the Western population, it’s the developing countries that will suffer most from the effects of carbon dioxide and other gases produced by the industrial nations. We are the ones who produced it, but we are not the ones who will suffer the most. We’ll just turn up our air conditioners a bit more.

RD: And animal populations might have trouble.

KS: They will. For example, if you reduce the sea ice area in the Arctic, where a lot of animals live, like polar bears, you remove some of their hunting grounds. A polar bear cannot swim 500 miles to the next coast; it’s too far. However, the whole story on polar bears is getting a little blown out of proportion. The great majority of polar bears live close to land, and have always dealt with loss of sea ice in the summer. We will lose some animals, but another problem for them will be habitat changes.

For example, mosquitoes and a lot of other insects have a very short breeding season in the arctic, because the temperature is only warm enough for such a short time. In Greenland, the mosquito season is horrible; there are so many of them, you just see black in front of your eyes. And within 10 minutes, you probably have 50 bites on your face. Now take that very intense short period and double it, which could happen if the warming trend continues. It will be very tough for some of the animals—and for the human beings, of course. Mosquitoes transmit diseases as well. Will the disease rate increase then in the regions where you double the lengths of the growing season?

These feedbacks have not been studied in much detail. I think the whole area of health science will undergo much change due to global warming. One good example was the heat wave in Europe a few years ago. The increase in numbers of deaths due to the heat wave was in the tens of thousands. Researchers base this on the number of deaths during the heat wave years compared to the normal death rate. People cannot cope with these extreme events—extreme cold, extreme heat. And we will have both in a warmer climate. It’s not just that a temperature gets warmer; the extremes also get pulled further apart.

RD: So winters in some places will be colder as well?

KS: Yes, that could be.

RD: There was a report out of England called the Stearn Report, the first economic study of the impact of global climate change. It argues that spending just one percent of the GDP, or $450 billion each year, to cut carbon emissions seems like a sound investment. But according to a Wall Street Journal editorial that criticizes the report’s conclusions, spending just a fraction of this figure, $75 billion (a number the UN came up with), we could solve all the world’s major basic problems. We could give everyone clean drinking water, sanitation, basic healthcare and education right now.

KS: I cannot disagree, because global warming is not the only problem we face. You have to weigh where you get the bigger benefit for humanity. Yet global warming drives many of these other problems. It’s not a debate anymore; the question is how much global warming can we take, and for how long.

RD: What should we do, if anything?

KS: It’s not a question “if anything.” We must do something. The earlier we react to the increase in greenhouse gases, the smaller the effect will be. The effect will still be there; we will have 3° warming at least by 2100, even by reducing carbon dioxide right now. But history does not stop in 2100. It continues. Unfortunately, everybody only talks about this one day, 2100. Let’s talk about 2200, and let’s say that’s where the huge difference kicks in if we do something now. Or if we say “Oh, let’s just wait another 50 years; I think the next generation will be able to figure it out,” there might not be a next generation if we don’t do anything. That’s my fear.

Let’s say carbon dioxide doubles, and even then we don’t do anything about it. So then let’s say we have four times more carbon dioxide. I think it will warm up so much that you will change the entire agricultural structure of the earth. We will probably start to change the ocean current. Ocean currents are so influential in moderating our climate that when they are altered, the climate can change abruptly.

An abrupt climate change, one that occurs in a five-year period, is something humanity cannot cope with. You can see how badly we cope with a cold winter or a hot summer. We’re talking about changes of a much greater magnitude. And we don’t have any way of predicting it. We don’t really understand all of the feedbacks of the climate. We can’t predict weather for three days. A six-day weather forecast is only 40 percent accurate. How can we predict weather over a hundred years?

RD: What about abrupt climate changes that occurred without human intervention, before humans were on earth? Could that happen again, especially if conditions are exacerbated by humans?

KS: In the past, the climate changed abruptly when a lot of fresh water was added to the ocean—way more than we are adding right now. This was at the end of a glaciation. Huge lakes, ten times the size of all the Great Lakes, were dumping water for several years into the ocean, and that shut-off the ocean circulation. That couldn’t happen now; we don’t have that quantity of fresh water.

When temperatures increase, more and more ice melts, creating more water. If you put a lot of fresh water in the ocean, as we saw during the last ice age, you can have sudden and dramatic changes in the climate. The oceans currents are key to the climate. For example, consider the Gulf Stream, the ocean current that goes to Northern Europe and Scandinavia. If you compare Europe and Canada, which are at the same latitudes, you’ll find that very few people live in Canada at the same latitude as Scandinavia. It’s too cold. But the Gulf Stream brings heat from the Gulf of Mexico region across the Atlantic and warms up Europe. Now let’s say the ocean currents change because of large-scale ice melting, which dumps fresh water into the ocean. All of a sudden, all the people in Scandinavia have to move.

RD: Because it would be too cold?

KS: It would be way too cold. And that’s just one ocean current. But it shows you the dynamic of how strong that mechanism is—that you can move heat from Mexico all the way up to the Scandinavia. It has happened before. We cannot cope with a sudden change that dramatic.

RD: These changes may be something we can’t influence, because we are having so much difficulty predicting them. So maybe we can only try to adapt to them.

KS: We are influencing them right now. The current warming is influenced by our excess release of carbon dioxide. The warming drives the melt, which further influences weather patterns. We are not presently in danger of an abrupt climate change resulting from an ocean current change. We aren’t adding that much fresh water to the ocean now. But if we stay on the path we’re on, and continue to increase carbon dioxide at the levels we do now, we’ll have a serious problem in the not-too-distant future, 200 to 300 years from now.

And we can’t prevent it with small changes, like a backyard wind generator. We have to think big. We have to produce 30 percent of our energy by wind. Denmark can do it. Germany’s close to it pretty soon. We can do it, too. We will still use fossil fuel. We need regulation and policies to make the change. There’s no question that we need to make big changes. The only question is, when do we start?