Dr. Vladimir Romanovsky, University of Alaska, Fairbanks

Interview with Dr. Vladimir Romanovsky, of the Geophysical Institute, University of Alaska, Fairbanks, AK, January, 2009

Summary: CA-CP had the opportunity to interview Dr. Romanovsky, a permafrost and climate change expert of the Geophysical Institute at the University of Alaska, Fairbanks. Dr. Romanovsky discusses his research in the field of permafrost geophysics, history of permafrost, thermokarst lakes, methane and sub-sea permafrost degradation, and his recent trip to Mongolia. Dr. Romanovsky addresses the key technical challenges in his field, the challenges of incorporating permafrost processes into models and explains the implications of crossing regional climatic thresholds. Dr. Romanovsky believes Interior Alaska is just a half a degree Celsius away from crossing such a threshold and, if global warming continues at its current rate, within 20-50 years it could be crossed. This would release large amounts of carbon into the atmosphere irreversibly, causing a positive feedback to climate change.

CA-CP: Dr. Romanovsky, can you explain the scope of your work and research and your interest in this field?

Dr. Romanovsky: I work on permafrost geophysics which means that I study the temperature field of the upper part of the earth’s crust and observe the temperatures below 0°C where material is frozen. I study the history of the development of the permafrost, the present state of permafrost, and evaluate possible changes in the future. Of course the most significant agent here is climate because permafrost is a product of a cold climate and if the climate changes then permafrost will follow sooner or later. Our major focus is to see how permafrost reacts to changes in climate. I also study whether changes in permafrost can have some feedback on the climate. This question is as interesting and as important as the direct effect of changes in climate on permafrost. Permafrost geophysicists are also interested in how permafrost changes relate to other components of the Arctic system such as the Arctic ecosystem, vegetation, carbon cycle, and hydrology - how water relates to permafrost. We also study how humans interact with permafrost, how they affect permafrost and how changes in permafrost affect humans. We use geophysical methods to study permafrost and one of the most direct methods is measuring temperature in the upper several tenths to hundredths meters in subsurface. We define permafrost as the ground, the rocks or any earth material (except for glaciers, ice sheets and sea ice) that is below 0°C for two or more years. We look to see if there is any permafrost, and we study its state- whether it’s stable or unstable, and we look at its dynamics. We look back as far back as records allow. They don’t go too far back but we are trying to establish as many sites as possible to gather data for the future to compare with current observations. This is one big part of our research - measuring the temperature in permafrost in as many places as possible. As geophysicists we use mathematical models to understand why temperatures are changing in the permafrost and to predict what will happen if climate changes. A more recent tool is remote sensing. All of our sites for measurements of permafrost are just spots in a huge area and to do some sort of correlation and interpolation between them we need to use modeling and remote sensing.

CA-CP: Experts talk of climatic thresholds – the point at which it is hard to turn back to previous conditions. How close are we to approaching climatic thresholds with regard to permafrost?

Dr. Romanovsky:
When you talk about permafrost, there are some regional thresholds. It would be hard to say there is a global threshold. In terms of regions, for example, in the interior of Alaska, we are very close to this threshold. We are just a half a degree Celsius off of it and in terms of time, it all depends on how climate will warm in the future and the rate of warming. But it could be on the order of 20-50 years.

CA-CP: If you cross this climatic threshold in Alaska, what would the impacts be?

Dr. Romanovsky:
What is happening now is that some permafrost is thawing already. It is really a threshold because you can’t go back easily and put all this ice that will melt out of permafrost that is water and put it back as massive ground ice. You’d need another glacial period, and in this case it’s not reversible. It’s hard to put ice back. If the threshold is crossed back to colder conditions it could develop new permafrost but not the same as it is now – generally less ice and less carbon. No return to the previous state. For Siberia and the icy permafrost there, there are two degrees to go before we cross a threshold. So, it is not as much threat yet. However, in southern regions of western Siberia there is a lot of carbon sequestered and the permafrost is actively warming there and thawing in some places. In terms of time scale, I think we could cross a threshold there in several decades. The Northern slope of Alaska is more stable. We maybe have another 70-100 years before we cross a threshold there - same for that area in Siberia. So for colder areas, this threshold is more distant and for warmer permafrost, which has ice and carbon in it, the climatic threshold is pretty close already.

CA-CP: We understand you were just on a trip to study permafrost in Mongolia?

Dr. Romanovsky: Yes, in Mongolia we visited our colleague who is setting up several dozens of permafrost observation sites. We spent 12 days driving from one site to another and covered 3000 km. We measured temperatures in boreholes and installed equipment to help our colleague make these measurements more technically accurate and easier to conduct.

CA-CP: If you look at the density of borehole measurements across the globe is it a fairly even distribution or are there areas of the earth that are better covered for permafrost measurements than others?

Dr. Romanovsky: In general, the research in the high latitudes is challenging and I don’t know anywhere where we have good coverage. Most permafrost boreholes are related to other activities because in the past it has been difficult to get funds to study permafrost itself. Deep boreholes are all related to oil and gas research areas, or geological research. When the boreholes are no longer used for these activities, they can be used to measure temperature in permafrost. This is why there is better coverage in the North Slope of Alaska. We have good coverage around Fairbanks, but we don’t have good coverage in many other areas. The same goes for other countries. In Russia, there are many boreholes in West Siberia where there are a lot of oil and gas activities - but almost none in central Siberia.

CA-CP: Can you explain the history of all of this permafrost carbon and how the carbon got into the ground?

Dr. Romanovsky:
It’s very important to understand history to understand what could happen in the future and it’s true of permafrost because of possible continuous warming. If you know the age of permafrost - when it was created - then you can have a good idea when it will start to thaw. Younger permafrost is less stable because it was a product of the Little-Ice Age and is thawing now very actively. We are also observing older permafrost from the last several thousand years starting to thaw. If warming continues, we will see the older permafrost developed in the last glacial period start to thaw. History is important for predictions as well. In general, it is important to know how permafrost developed and then you can explain such facts as the carbon source. There are places, especially in Siberia, where permafrost is as old as two million years. But most of the current permafrost was shaped during last glacial period – some time between 20 and 80 thousand years ago. It was much colder then than it is now and permafrost distribution was much wider. Permafrost occupied a significant part of Europe, a very significant part of northern Eurasia, practically all Russia, Mongolia, and northern China. In North America all non-glaciated areas in Canada and Alaska were permafrost areas. Canada had the largest distribution of permafrost - almost all of it was occupied by permafrost. Permafrost existed in some places underneath the huge glacier that covered North America. Remember that the sea level was 120 meters lower so permafrost was forming on all Arctic shelves because conditions were harsh – 10-15 degrees colder than now. A very specific ecosystem developed during this period of time. All of Siberia and Alaska was made up of mammoth steppe or grasses with no trees. Except for some mountain ranges all the land was covered in productive grassland and huge number and variety of big grazers such as mammoths, horses, bison, and caribou. It is important to know that they were there exactly when a significant amount of carbon was sequestered in the sediments. The sedimentation rate was high - mostly wind blown dust but also some aquatic sediments as well. Meters of this new soil could be developed in thousands of years. Because the sedimentation rate was high and productivity of this grass tundra was high, lots of carbon was buried in the soil and frozen in the permafrost almost as soon as it was deposited and since then, in many places in the present day permafrost areas, it’s still frozen. In this period of time, a significant amount of carbon was taken out of the atmosphere and deposited/sequestered in an ice complex. An ice complex is a layer of soil/ice, in some places 40-50 meters thick in a frozen state. These exist in East Siberia and in Alaska. Much of the permafrost disappeared after this last glaciation ended, some 15,000 ago. The warmer period of time continues to the present and a very significant portion of the sediments have thawed and the carbon has been released into the atmosphere. We are working on understanding how much was released. There is still a significant amount of carbon sequestered in these types of sediments which have been sequestered for tens of thousands of years. If warming continues, it could be released into the atmosphere on the much shorter timescale.

CA-CP: What causes methane gas hydrates (or clathrates) to form? Is that all anaerobic decomposition or something else?

Dr. Romanovsky:
Most of the methane is from natural gas from deeper soils in earth – from the same source that oil comes from. Some of the methane could be biogenic methane but it’s a smaller amount. Most of the methane is stored in clathrates. What is a clathrate? It looks like ice. It forms at certain temperature and pressure conditions when you have mix of water and gas and in this case we are talking about methane. It could be carbon dioxide clathrates. All gases can form clathrates. Methane clathrates formed when the gas was present in sediments, buried, and the temperatures went down and pressure rose. Clathrates are a very effective storage mechanism for the methane.

CA-CP: Is it evenly distributed around the areas that have permafrost or are there stronger pockets than others?

Dr. Romanovsky:
This is mostly related to the sources of gas and all of these gas and oil provinces in the north have clathrates. There is a strong correlation with petrochemical fields because the source of clathrates is from these fields. But if you look in the north it’s everywhere – Alaska, northwest Canada, Norway, Barents, Kara and Laptev Seas, and East Siberian Sea - because all are oil and gas provinces.

CA-CP: There has been recent discussion and study of sub-sea permafrost degradation and of how methane is getting into water columns. Can you explain what is happening?

Dr. Romanovsky:
First of all there is a huge need to study this. We have limited data available. What we know based on several scientific projects - some from Canada and Alaska – is that there is a huge amount of methane sequestered in hydrates. We also did some modeling that showed the possibility of release of methane from hydrates, in relation to long-term changes in climate like inter-glacial cycles, one of which we are experiencing right now. What we know now is that during glacial periods, formation of permafrost on the arctic shelf served to block free gas supplied from subsurface gas and oil areas. The permafrost was forming - it was impenetrable and thick and in these favorable conditions, gas and water turn into hydrates. When the last glacial cycle turned into the interglacial all the Arctic shelves were covered with sea water. The temperature at the bottom of the sea on these shelves that had been -15° C to -25° C, during the last glacial period (50,000 years ago) increased to –1.8 °C or warmer. The permafrost started to thaw from both sides - from top down because of the chemistry of salty water, and from the bottom up as the thermal process also affected hydrates as well. The question is, if hydrates decomposed at – say 500 meters – under permafrost still there will the gas can reach the surface of the earth (bottom of ocean) and if so, will it be released in the water, and then into the atmosphere? This has to be further researched but there is some evidence that permafrost is thawing from both sides and there are some methane concentrations in the sea water which exceed by one or two orders of magnitude the equilibrium concentration of methane that we would expect in sea water. This means that there is some source and we see these methane increases not only at the bottom sea water but at the sea surface. It means there is some methane coming into the water and going through the water and probably being released into the atmosphere. It is expensive to do this research, but several expeditions have studied this phenomenon. Given that permafrost on the shelf is warming now at least -2°C or warmer - and given the history of sediments (marine sediments for some period of time, then terrestrial sediment for another period of time, then again marine sediments - because of the glacier/inter-glacial cycles in the hundreds of thousands of years) there could be no ice in the marine salty sediments. Thus, there could be no problems for gas to go through this warm permafrost already thawing, through the tens to hundreds of meters of permafrost if these pathways continue all the way to the ground surface.

CA-CP: Can some of it be released through thermokarst lakes?

Dr. Romanovsky:
Yes. We were talking about the sub-sea. Thermkarst is a process that happens on land and its one of the modes of thawing of permafrost. <!--[if gte mso 9]> <![endif]--><!--[if gte mso 10]> <![endif]-->Thermokarst lakes could develop not only in warm thawing permafrost, but also in area where permafrost was thermally very stable. To develop a thermkarst lake, you don’t need general degradation of permafrost - you need local degradation which could happen because the summer thaw gets too deep, gets into icy permafrost, and starts to melt this ice. Melting ice creates subsidence, so it’s actually a very good example of a positive feedback mechanism. Subsidence will keep water on the surface which will create even warmer conditions and during the winter snow will accumulate in this area and it will get even warmer and so on. You can develop thermokarst lakes in areas where general permafrost is not affected, where it is still -5°C to -8°C. This happened in the past during the Holocene period - an explosion of thermokarst lakes in an area where there was general stability with lakes up to 10-15% of general area. This will release the carbon stored during this previous cold phase when there were no lakes.

CA-CP: - Once a thermokarst lake forms, why is it that you get accelerated thaw below it?

Dr. Romanovsky:
Imagine the surface of tundra which is flat, snow blowing during winter, not too much snow on the surface, and air temp still cold at -12°C or -10°C annual average. The summer thaw will be only a half a meter deep. For some reason there is a disturbance, with a warming climate, summers get warmer, you get a little bit deeper thaw during summertime. With an increase in summer thaw the upper part of the permafrost which is 70-80% ice starts to thaw and develop a depression on the ground surface with standing water – at first just 5cm on the surface, then 10cm. When you start to get 20cm it’s already a pretty good depth in a flat surface of tundra, soon you could have half a meter of this depression which may be several meters or tens of meters across. In tundra, generally there is lots of water because evaporation is low. So then, you start to collect water in this depression, the water on the surface during summer time is an effective way to absorb solar radiation. So albedo and penetration of solar radiation through the water increases the absorption of solar energy in the lakes.

CA-CP: So it’s a summer warming effect that forms the thermokarst?

Dr. Romanovsky:
Right. There’s a summer warming that started this and as it continues and gets warmer, more ice melts until eventually lakes can be 3-4 meters deep. And in this case, permafrost will be continuously thawing because during the wintertime only two meters of ice will form on the lake and another meter or two below will be just water - so the bottom of the lake will always be above 0°C and permafrost will be continuously thawing.

CA-CP: How has modeling of the release of permafrost carbon into the atmosphere, and the potential positive feedback mechanisms progressed? Have the main GCM models incorporated permafrost carbon? Has the IPCC?

Dr. Romanovsky:
The processes weren’t included in the IPCC. But there are several groups working on this right now. I am working with two of them – one in Colorado, and another in Potsdam, Germany. They are trying to incorporate the effect of thawing permafrost and the effect of the possible release of carbon. We want to include this in a model and let it run to see how much carbon will be released into the atmosphere. It’s a difficult task because we are adding several components that weren’t in GCM models before like permafrost dynamics and the sequestration and release of carbon. To include this is a significant improvement. But it is difficult to do the biological components of models, and to put it together to couple them. It is a really big task and I don’t know when it will be completed.

CA-CP: We understand that you work in several areas such as hydrology, ecosystem, and vegetation. In these areas and from all of your work, what impacts of permafrost thawing have you been observing in Alaska?

Dr. Romanovsky:
In terms of hydrology, it’s a combination of factors. We already see it. Thawing permafrost will affect hydrology and lower laying areas. The thawing of permafrost is already creating different soil moisture conditions - more bogs growing, more wetlands in some areas while the well drained areas are drying. There have been studies on the stress on tree vegetation in Alaska due to this drying. This could be related to changes in permafrost – a lower water level creating drier conditions, could lead to losing forests to grasslands. This is actually happening in Mongolia. On my trip, it was amazing to see that in the some areas where marginal permafrost exists, the large trees grow only where permafrost exists. Where it does not, it is too dry for trees. The changing permafrost is already affecting infrastructure. This is complicated because most engineering structures built on permafrost have a significant effect on it. In general, with warming climate, permafrost is getting warmer and more vulnerable. The stability found in colder permafrost will be lost in warmer permafrost. While there are not huge difficulties with the pipeline, they are constantly working to support integrity of it, much more work than 20 years ago because it is much warmer. In many places, permafrost is disappearing from surrounding areas and only exists under the thermopiles – the design they used to maintain frozen ground. It is unclear how long they can maintain this stability.

CA-CP: – Are you aware of new ideas to slow the thawing of the permafrost? Technical or involving R&D?

Dr. Romanovsky:
There could be local solutions - pure engineering to freeze, but they are all expensive. And these engineering solutions cannot be easily used for linear structures like roads, railroads, or runways for airports. So engineers are able to keep infrastructure safe, but it’s becoming more and more expensive. The general solution can be only to keep the status quo of climate by limiting emissions from human activities. It is difficult to control the natural release of gases from permafrost so it is better to not let permafrost thaw.

CA-CP: The community that’s doing permafrost research seems small but a tight international group. As a whole, is the research being funded at a reasonable level? Are people able to make the progress they need to make?

Dr. Romanovsky:
In different countries the situations are different - you’re right it’s small but tight. We have good leaders, like Jerry Brown of the International Permafrost Association. Norway has good funding. The US is actually getting much better. Ten to fifteen years ago it was hard to get funds. Now it is not ideal, but better. We are trying to sustain long-term observation projects that last 3-5 years. This is a long-term changing creature and we need long-term data to understand what is going on.

CA-CP: What are the key technical challenges that the scientific community need to address?

Dr. Romanovsky:
We are still working with data points that are sparsely distributed over the permafrost area. It is a major challenge to find how best to interpolate and extrapolate data to the entire area of permafrost distribution. There is some possibility of remote sensing but it is difficult. There is no direct way to measure permafrost from space.

CA-CP: What are the parameters of remote sensing?

Dr. Romanovsky:
It is challenging because all of the information you can capture using remote sensing is from a shallow surface layer. But, the combination of remote sensing, ground measurements and numerical modeling can help. For example, it is possible to measure surface temperature but still not precisely - at least within a degree.

CA-CP: How does the warming of the ocean in general affect the rate of permafrost thaw?

Dr. Romanovsky:
In many ways. Changes in sea ice cover are of course related to warming in water as well, and directly affect sub-sea permafrost making the rate of degradation much higher. It increases the temperature and probably water content in the atmosphere that goes over land. It creates a warmer summer and fall with increased precipitation. This will lead to warming in the permafrost and have a direct affect on sub-sea permafrost. Now temperatures in deep waters that were below 0°C are sometimes above it. The water is not that deep, and the absence of summer sea ice makes mixing more effective.

Visit Dr. Romanovsky’s web pages at the University of Alaska Fairbanks (UAF) and the Geophysical Institute Permafrost Laboratory (GIPL)

Learn more about Dr. Romanovsky’s work by viewing his presentation on changes in permafrost and the carbon budget at the American Meteorological Society’s Environmental Science Seminar Series (ESSS)

Learn more about thermokarsts here

Read Dr. Romanovsky’s essay on NOAA’s website