Unrevised

Members present

Lord Teverson (Chairman)

Lord Addington

Baroness Browning

Lord Hannay of Chiswick

Viscount Hanworth

Lord Hunt of Chesterton

Lord Moynihan

Lord Oxburgh

Lord Soley

Baroness Symons of Vernham Dean

Lord Tugendhat

________________

Examination of Witnesses

Professor Danny Feltham, University of Reading, Professor Andy Shepherd, University of Leeds, and Professor Peter Wadhams, University of Cambridge

Q29 The Chairman: Good morning. May I welcome you to the Committee? You know the system from having observed it. Perhaps I could ask you first to introduce yourselves briefly for the broadcast. Then we will start to go through the group of questions. Perhaps, Professor Shepherd, you can start.

Professor Andy Shepherd: I am Andy Shepherd. I am the director of the Centre for Polar Observation and Modelling, which is based at the University of Leeds and is funded by the Natural Environment Research Council to provide national capability in developing satellite observations and models of the land and sea ice in the Arctic region. We also provide scientific leadership for the European Space Agency’s CryoSat mission. The evidence that I will present today is based on the work of colleagues in CPOM, so I should acknowledge Andy Ridout, Julienne Stroeve and Rachel Tilling, as well as the contribution of my late colleagues Seymour Laxon and Katherine Giles.

Professor Peter Wadhams: I am Peter Wadhams. I am professor of ocean physics at the Department of Applied Mathematics and Theological Physics at Cambridge University. Before that I spent a lot of my career at the Scott Polar Research Institute, where I became director. I have been working in the Arctic continuously since 1970 and running a research group that studies sea ice and ocean processes, especially sea ice processes, in the Arctic Ocean.

Professor Danny Feltham: My name is Danny Feltham. I am professor of climate process physics at the University of Reading, and a member of the Centre for Polar Observation and Modelling. My area of expertise is in the mathematical modelling of sea ice physics, and I run a research group on that.

The Chairman: Good. This session is obviously about sea ice. Perhaps I could ask Lord Tugendhat to start us off.

Q30 Lord Tugendhat: The sea ice has been retreating rather more rapidly recently than it has in the past, and the total extent of it has diminished somewhat. Could you tell us what, in your view, the different and principal drivers of that change are? Are we seeing something that you believe is a long-run trend, or are we seeing something that might go into reverse quite quickly? Is it different in kind from what has been known in the past, or does it fit into a pattern?

Professor Peter Wadhams: It certainly differs in magnitude from anything that has been seen in the past. We have sea-ice extent records that are not that good going back a century or more. The retreat of sea ice that we are seeing now really started in about 1950, but it has become very much more rapid in recent years. The changes that are most extreme now are the change in the summer sea ice extent and the thickness of sea ice. We can measure the thickness from submarines, and if you combine the thickness and the extent by multiplying the two you see that the volume of summer sea ice in the Arctic went down by 75% in the last 30 years from 17,000 kilometres in 1980 to 4,000 kilometres last year. That is a very serious change, and it is unprecedented, at least in the history of observations and given what we know from sediment cores from the history of the Arctic Ocean. It looks like it is heading in one direction only. It is affected partly by ocean currents: for instance, there is more warm water coming into the Arctic from the Atlantic and an increased flow from the Bering Strait. But the prime cause seems to be warmer air temperatures, especially air temperatures in the Arctic, which are rising at least twice as fast as at other latitudes. It is the warming of the atmosphere that has led to the thinning of the sea ice, and the thinning of the sea ice is the chief cause of the present collapse. The extent has held up fairly well; it has shrunk gradually. But as the ice thins dramatically—it is at least less than half as thick as it was 20 years ago—the thinning leads at a certain point to a collapse. The ice that grows in the winter melts in the summer. That is the point that we are approaching. It is not a reversible trend; it is a trend that is set to accelerate because of the collapse of the extent due to thinning.

Professor Andy Shepherd: I would add that the majority of changes in the sea ice volume or area that we have seen in the past 50 or 60 years have been attributable to greenhouse gas emissions and their effect on temperatures in the Arctic region. For example, the length of the solar melt season has increased by about five days per decade. That causes additional melting, which causes the retreat in the ice.

There are different ways of estimating the thickness, but it has certainly reduced as a function of time. We are getting better at estimating the thickness now that we have improved technology that is able to look at the whole of the Arctic region, but it is certainly true that the extent has diminished quite rapidly. So, too, has the volume, and it is the volume that is important. If you have a glass of gin and tonic, you want to know how much ice you have all the way to the bottom. Then you will be able to say how cool it will be in an hour’s time. So the thickness of the ice is just as important as the area.

On top of that, we have had, and still have, short-term situations in the climate that drive quite dramatic changes in the amount of sea ice in the Arctic region. In 2007 and 2012 we had particular weather conditions that destroyed parts of the sea ice pack over and above the long-term climate change predictions. This is the same point that Chris Rapley made earlier on: to see the signal of climate change emerging from the variability that the weather causes requires long-term records, and that is why we use long-term satellite data sets—to look at this. As Peter said, the resilience of the ice is really important. The thinner it gets, the more susceptible to changes it is. If the ice pack that collapsed in 2007 or 2012 under those weather conditions had been as thick as it was in the 1980s, it would have survived those weather events.

Professor Danny Feltham: I concur that the evidence shows an unprecedentedly rapid decrease in sea ice extent and volume. I can also say that climate models are able to replicate the extent of the sea ice lost only if they are doing the old anthropogenics that you would do.

Lord Oxburgh: Could I just ask a quick follow-up question? I know that you do not have very long time-series data, but does it look as though this is a linear change over 30 years or an accelerating change? From what Professor Wadhams said, it sounded as though it was accelerating, but roughly what does the slope look like?

Professor Andy Shepherd: It depends on whether you are looking at the thickness or the volume—the area, I should say.

Lord Oxburgh: Let us stay with volume.

Professor Andy Shepherd: That is difficult, because Peter’s data are the longest record that we have, so we would want to compare like with like over long periods of measurement. It is not so easy—Peter should answer this—to compare today’s satellite measurements, which are comprehensive, rather like the ocean temperature measurements that we have for the planet, to the sparse measurements that we have from 30 or 40 years ago.

Professor Peter Wadhams: Yes. One can conclude that the volume is accelerating while the area loss has stayed fairly linear. The area loss was about 3% to 4% per decade, but it started to accelerate about 10 years ago to about 10% a decade. This is in summer but also averaged over the whole year; there is area loss at other times of the year as well. Whether you look at the whole year or the summer, where it is exaggerated, the area loss has been linear but has recently accelerated. The volume loss shows much more acceleration, because the thickness has been measured from submarines and more recently from satellites, which have been showing an increased rate of thinning—and of course multiplying the area by the thickness gives you an acceleration of the volume loss. This is the most serious thing that we are seeing: the fact that the volume in summer is now about 25% of what it was only 30 years ago.

Lord Oxburgh: The significance for this Committee is obviously the future navigability of the Arctic Ocean and on what timescale things are going to change from that point of view.

Professor Peter Wadhams: Projection is a difficult question. The last speakers talked about models and concluded that models on the whole are quite good in predicting temperature changes, for instance, but that they had not been good in predicting sea-ice changes. In fact, there is a fairly large discrepancy between the model predictions and what has actually happened to the area and thickness of sea ice.

The Chairman: Thank you. We will look further at the future later in the questions.

Q31 Lord Soley: I think we all realise that it is difficult to study sea ice, but can each of you tell us what methods you use in your own work to study sea ice, whether the different methods that are used lead to different conclusions, and how reliable they are?

Professor Andy Shepherd: We use two different approaches. We use satellite and passive microwave imagery to map the extent of the sea ice over time. It is a really good tool because it can operate at night and through clouds. We have a long record of 30 or 40 years. It is a good climate record, and it does a really good job of discriminating between ice and the oceans. There are no differences in estimates of sea-ice decline and the area of the sea ice based on those data.

There are different approaches to measuring sea-ice thickness: you can measure it in situ on the sea ice itself; you can measure it from the ocean, as Peter does; you can measure the draft of the sea ice—the bit that is below the surface—and that is an accurate measurement; or you can measure the freeboard—the bit that pops up above the surface—with aircraft or satellite platforms. We do the latter: with satellite platforms. You find that the precision deteriorates as you move through that hierarchy of observations, but the spatial and temporal sampling dramatically increases with satellite observations, and it is really key to see the whole of the Arctic ice cap rather than just part of it.

To give a very simple example, the average thickness of sea ice in the Arctic is about 1.8 metres to 2 metres. If you miss the polar gap, which was missed by most of the previous satellite missions, you will underestimate the thickness by about 20%, so you need to sample the whole of the Arctic to see it.

Professor Peter Wadhams: We use satellite data. In our field programmes, one big area has been using British submarines to measure ice thickness. We have been doing that since 1971, and the fact that the Ministry of Defence has made submarines available over these years for scientific research and allowed the publication of data from them is really important and very valuable for science.

The Chairman: Have other navies done similar things?

Professor Peter Wadhams: The US navy has, but the data gathering in the US navy submarines is done by the US Naval Research Laboratory, so the policies have varied over the years as to whether that data is to be freely published in science. A lot of it is, and that, together with the British data, has been the basis for the conclusion about the thinning and the reduction in volume. The US navy has been more sporadic in making the data available, although it has had a lot more submarines in the Arctic than the British have.

Recently, because of difficulties with the availability of submarines—we do not have many—we have been doing much more work with autonomous underwater vehicles: AUVs. They cannot give you the same coverage of the Arctic that a submarine can, but longer-range AUVs are becoming steadily more available, so in future work under the ice can be done by those.

One of the things for the future is very much the use of autonomous buoys—Sheldon Bacon touched on this. We can put buoys into the ice that will measure important parameters of the atmosphere, the ice and the ocean and will last a very long time because they are solar-driven and have solar power plus batteries. We have 30 buoys out at the moment in a joint programme with the US, and they are measuring waves in the Arctic, which are possibly one of the causes of the rapid recent retreat in summer. These buoys are extremely valuable, and I think the future lies with them, because it is getting increasingly difficult to work in the Arctic because the ice is getting so thin, and it is getting more dangerous to work from it and establish camps on it because it is breaking up all the time. So you look for autonomous recording systems.

Lord Soley: Professor Feltham, do you have anything to add to that? Would you do anything different?

Professor Danny Feltham: I do not actually measure the sea ice. I use the measurements to test my models. The measurement techniques that are being discussed here, plus several others, including so-called EM birds and ice-tethered profilers, have been assessed by the Intergovernmental Panel on Climate Change. They find a strong consensus among the different measures of observation, so they are able to make strong statements about the decrease in sea ice volume and extent.

Lord Soley: Do the different methods that you are all using point to the same trends?

Professor Danny Feltham: Yes.

Lord Soley: You do not think that anything is out of kilter, one with another.

Professor Andy Shepherd: It requires care in interpreting these things. We had the same problem looking at the polar ice sheets of Antarctica and Greenland a couple of years ago. What matters is that you compare apples with apples and not apples with oranges. The different techniques measure very different things. If you stand on a sea ice floe and measure a column of ice, that is a very different observation from that made by a satellite, which might have a footprint of 10 kilometres on the ground. You have to take care in comparing things. It turns out that there are not that many coincidences with which we can make these intercomparisons. The best estimates are that the techniques agree to within about 10 centimetres, which is a small number compared to the thickness of a sea ice floe.

Lord Soley: Can I pick up the issue of submarines? I was pleased to hear your answer as I was going to ask you about submarines, and what you have said is encouraging. It has always occurred to me that, given the number of submarines that are wandering around under the ice for obvious reasons, if they were given the appropriate equipment they could give us much more information than they do already. Is that correct?

Professor Peter Wadhams: I think it is, although I do not think there are a lot more submarines wandering around under the ice—I think I have gone on most of the ones that go under the ice and it is only one at a time. Militarily, the under-ice environment is regarded as much less important than it was during the Cold War, so fewer submarines go up to the Arctic for military purposes. In the case of Britain, the last submarine was in 2007, when we had a fatal accident. I do not think that in itself dissuaded the MoD from sending more, but the availability of submarines has meant that there has not been a mission since then. The year 2007 was very important because there was a big retreat of sea ice in the summer, so it was a useful year, but this work is needed again.

Lord Soley: Can I ask one more question on this? Okay, there is limited information but very good co-operation with the Royal Navy, and there is some co-operation with and information from the United States. Is there any at all with Russia or not?

Professor Peter Wadhams: No, except very informally, because I know a lot of Russian scientists and in after-hour sessions at meetings they have talked about measuring ice thickness. One diagram in one Russian textbook appeared, probably by accident, showing ice thickness measured from Russian submarines. Basically, the Russians have a huge data set, which they have collected especially in the parts of the Arctic that British and American submarines do not go to—the Siberian side of the Arctic. That data set, at various times in the past, has been offered for sale to the West, when Russia was short of research funds. If we want to collaborate more with Russia, which I think is very important, we should put out feelers about that data set and say that we really need it.

Lord Soley: You would like us to explore that.

Professor Peter Wadhams: I think it would be worth exploring, even if it cost money, because the cost is very small compared to the value.

The Chairman: We need to move on.

Q32 Baroness Symons of Vernham Dean: You have explained the different ways of measuring how fast the ice melt is happening, but did anyone predict, back in the early 2000s, just how quickly this was going to happen? You particularly mentioned 2007, but did we have an idea from any of these various methodologies, or has this all happened in a way that has caused surprise? In some of the data that we have seen, it appears that nearly ice-free conditions will prevail by 2050. Is that your estimate as well?

Professor Peter Wadhams: My estimate is more like 2015 than 2050. I am speaking personally on the basis of research that I have done. I made predictions back in that period that the summer sea ice would disappear quite quickly, although we would still of course have sea ice in the winter. Even in the early 2000s, based on the trends that we were seeing then and the trends in thinning that we were measuring, it looked to me as though if you extrapolated that trend you would be getting essentially the disappearance of the summer sea ice by about 2020 or even earlier—it is still possible that it could disappear, or at least get down to less than 1 million square kilometres, by next year or the year after. That is the way the trend is going. This is completely different from the predictions from models. It is where there is a huge disconnect between observations, which are showing this very rapid decrease in area and volume, leading inevitably to the complete disappearance of summer sea ice in a very short time—“summer” meaning September but extending out a couple of months on either side. The models predict that this will not happen until 2050 or so. That is a complete disconnect. As Richard Feynman says, if you have a beautiful model but it disagrees with data, you must go with the data.

Baroness Symons of Vernham Dean: I should hope so.

Professor Andy Shepherd: Danny should comment on this.

Professor Danny Feltham: The rapid reduction of sea ice in 2007 took the community by surprise; the majority of scientists were surprised by it, especially the climate modellers. There are fundamental limitations to our ability to predict the evolution of the sea ice cover. Part of this issues from natural variability, as we discussed earlier: the natural cycles in the atmosphere or the ocean and how they affect the ice cover. There is also the fundamental uncertainty in the intrinsic physics of sea ice, which means that there are limitations in the models. Notwithstanding that, models are our best way to try to predict the evolution of the sea ice cover. Simply drawing a line through various data points does not take account of the physics of the process that is going on, so models have to be our best way of trying to estimate when the Arctic Ocean will become ice-free. Based on a sift of climate models, the estimate is currently between 2050 and 2080 to have a reliably ice-free ocean. “Reliably” means five years with the sea ice extent less than 1 million kilometres squared.

Baroness Symons of Vernham Dean: Forgive me, but that is really extraordinary. You are saying that the modelling shows one thing but the data shows something different.

Professor Andy Shepherd: No, it does not.

Baroness Symons of Vernham Dean: To a layman—I am not a scientist.

Professor Andy Shepherd: I will return to Danny, because he can explain the point, but perhaps I can just add that the CryoSat mission that we lead in my centre—I am the scientific adviser to the mission—shows a dramatic recovery in sea ice volume over the last winter. There was a decline per year of about 2.5% in summer and 8% in winter over the first three years of the mission, but there was a recovery to 8,000 to 9,000 cubic kilometres over last winter.

Baroness Symons of Vernham Dean: What period was this?

Professor Andy Shepherd: Today. The sea ice is thicker and more voluminous this year than it has been in the past four years. There has been a recovery in sea ice. You cannot just take the convenient first three years of measurements and extend them forwards in time. We need a long-term record. Unfortunately, we do not have a satellite mission going back before 2010 that surveyed the entire Arctic, which makes extrapolations of observations problematic.

Baroness Symons of Vernham Dean: Very interesting questions arise about navigation. You are saying this about the last few years, but in 2010 only four ships crossed the Arctic Ocean from Europe to Asia, while in 2013 there were 71 ships.

Professor Andy Shepherd: The sea ice in the Arctic ranges from 1 metre to 5 metres thick in places. It depends on which route you would navigate. Ice-breaking ships can go through 1, 2 and 3 metres of ice. If you have an ambition to get through that ice, you can.

Baroness Symons of Vernham Dean: I know that Lord Moynihan wants to ask questions about that, too.

Viscount Hanworth: I have a quick question. Does the hazard of icebergs affect the northern sea route, or is that hazard entirely confined to the north Atlantic?

Professor Peter Wadhams: The iceberg hazard is mainly in the north Atlantic. There is a small risk in the northern sea route caused by ice islands that break off Ellesmere Island and the north coast of Greenland. These are 100 metres or so thick and you would not want to hit them with a ship. In fact, a submarine that I was not on once hit one, but it is very rare. Shipping in the Arctic is being studied at the moment in an EU project that we are part of. We are concluding that shipping will of course increase very rapidly and is already increasing, but there will be a limit to the growth of routine container shipping, for instance. The pattern of trade means that although it might seem extremely desirable to save a very large distance in trading between the Far East and Europe via the northern sea route or between Europe and the west coast of the US via the North-West Passage, container ships want to have a regular trade route where they can dump containers en route and load other containers, whereas on a trans-Arctic shipping route you have to go from your primary source to your primary destination in one go. Surprisingly, all the shipping experts whom we consulted in our study were saying, “Well, don’t expect an Arctic boom in shipping”. That was even if it becomes ice-free for several months in summer so that you can go through the Arctic safely without needing ice-strengthened ships. The method of shipping cargo these days with containers is simply not conducive to Arctic operations.

The Chairman: We are going to come back to shipping later.

Q33 Lord Hannay of Chiswick: Professor Shepherd, Dr Bacon suggested that you would be able to answer a question that relates not only simply to sea ice but to the general warming and melting of land ice and the correlation with the sea levels. Would you be able to answer that question?

Professor Andy Shepherd: It is a very simple formula: if you warm up the ice on land, it flows straight into the oceans. In Greenland, that has been happening at an accelerating rate. The rate of loss from Greenland has increased by a factor of five over the past 20 years and enough ice is being lost to cause sea levels to rise by about 1 millimetre per year, whereas in the 1980s the contribution was very slight. Most of that is a relatively straightforward physical calculation—it is just the melting of the ice from the surface, in the same way as an ice cube might melt on this desk. Some of it is associated with more complicated behaviour and how the ice speeds up as a consequence of changes in the ocean temperature, perhaps. That is much more difficult to predict.

The amount of sea-level rise associated with a measured amount of ice loss is a straightforward calculation. You transfer a volume or mass of ice from on land into the ocean. There is a simple calculation: 350 cubic kilometres of ice is equal to 1 millimetre of global sea-level rise.

Lord Hannay of Chiswick: And none of the measurements that you have made invalidates that calculation. It is absolutely robust.

Professor Andy Shepherd: It is an absolute calculation in so far as it relies on standard temperatures for the water that it is going into. There will be a small delta associated with the dilution of the oceans, because it becomes less saline, and a very small delta associated with the change in the temperature, which would then reach thermodynamic equilibrium—Julian is better placed to answer this question—over tens of thousands of years, but this is at the level of 2% to 3%.

The Chairman: Lord Moynihan, did you want to come in on this?

Lord Moynihan: I do, but we will come back to shipping later, as you say.

The Chairman: For questions about things that climate change directly affects, such as icebergs, volume is useful, but we will come on to general shipping later on in the report.

Q34 Lord Moynihan: Fine. I have two quick points. One is that I still want to get my head around, as I think Lady Symons does, this distinction between what is coming out on volume data on the one hand and Professor Wadhams’ view on the other that, based on that data, he would go even sooner than 2020 on the potential for ice-free summers and the modelling, which has taken us not from what we were advised—2040—but potentially further than 2040. There is a disconnect between the two, and I would like you to explore with us in layman’s terms why that disconnect is so great.

The second point, which relates to that, is the evidence that we got earlier from Dr Bacon. I was fascinated by this—and I think you picked up on it very briefly, Professor Wadhams, when you mentioned wave patterns and the impact that that has had on your research recently and on the rapid retreat in the summer ice. Dr Bacon focused on it in the context of turbulence and the impact on that, which no doubt impacts on wave patterns and accelerates the retreat in summer ice.

Could you comment on both those points, Professor Wadhams—then, very briefly perhaps, somebody else on the panel—in order to pick up on the hugely important commercial implications, which you mentioned, for shipping? I absolutely understand your assessment in the context of container ships, but the huge investment that is being made—no doubt on very strong research, because no board is going to invest on that basis without having confidence in the research by people such as Mitsui and China Shipping—is not so much on the containers but on the huge potential for LNG carriers in the area, with icebreaking equipment attached to them, and the positioning of “Yamal” and the resource that allows you to go through the northern route either going east during the summer, or, indeed, going west during the winter. In that context, surely that is where your shipping boom is going to come: on the hydrocarbon potential—and the LNG opportunity—with some 20% of the global undiscovered reserves within the Arctic Circle, principally within Russian waters.

Professor Peter Wadhams: Perhaps I could start by restating my position on the speed at which the Arctic is going to become ice free. Andrew has mentioned that there was a partial recovery of ice volume this summer, but we have looked at the trend. We know that there are fluctuations from year to year and partial recoveries, but the trend, taken over 40 years, is extremely clear: the trend in volume is an accelerating downwards trend, so if we take that trend and extrapolate it—and of course in modelling one should not extrapolate very far when one is dealing with data—models in the long run are how we look at how long-term changes are going to happen, but in the short term we use models, just as Treasury models and many many models that are used in economics and politics do, that are based on taking trends over a number of years and doing a short-term extrapolation to predict what is going to happen in the next short while. The data on ice volume in the summer are very clear: the September data are very clearly so rapidly downwards that even though we know that there will be partial recoveries in odd years, such as this year, that trend will take us down to zero in a very short while—at this rate in just a couple of years. It might seem extreme to be predicting that we might see an essentially ice-free Arctic in September in a year or two, but I still hold with that prediction.

Lord Hunt of Chesterton: May I just say something on that point? I have been really very quiet.

The Chairman: Perhaps I can ask our panel to speak quite concisely in answering Lord Moynihan’s questions first, because we are quite short on time. Then we can move on to other things, such as the transport aspects, as well. I think Professor Shepherd also wants to come in.

Professor Peter Wadhams: If I could just finish that point, that might be an extreme prediction, but it will still happen in a very small number of years. It is certainly not going to be 2050, although that might be the date on which we start to see an ice-free Arctic for much of the year rather than for a short period in the summer. If we are looking at the summer, we are talking about September and then extending out by about two months either side, because the August/July extents are coming up behind quite quickly.

Regarding the mechanisms that you mentioned—the turbulence question—the whole retreat seems to be a ratchet that is going only one way, because as soon as you have a large retreat of sea ice in the summer it changes the whole ocean circulation and changes the ocean into a non-polar ocean, as Sheldon said. You get a lot more turbulence and a lot of waves. In the study that we are doing at the moment with the US navy, we are putting buoys in to measure wave penetration into the ice, because the waves in summer now are sufficient to break up the ice and cause it to retreat faster still. All the mechanisms seem to lead towards an increased retreat rate. Nothing is leading us to suppose that there will be any decrease. That increased retreat rate will give a longer and longer period each year when the Arctic is suitable for navigation.

Professor Danny Feltham: Can I just make a point of clarification? I mentioned earlier the climate models predicting that the Arctic will become reliably ice free in around 2050. I reiterate that this means less than 1 million kilometres square for five years in a row. The role of natural variability is such that you expect an ice-free Arctic some time before that. You might expect an ice-free Arctic in, for example, 2030 for one year, but the ice would then recover, so we are talking about reliably ice free. That is what the climate models say: around 2050 to 2080.

Professor Andy Shepherd: I will try to be quick. The problem is the density of the observations that we have had in the past, which are the very best observations that we can rely on. If I hold up this piece of paper and ask you how many fingers I am holding up, you have no idea. You can see two of them but there are actually four. This is what we have with the measurements that are collected from sparse submarine tracks. The sea ice pack is like a Jaffa cake: it is thick in the middle and thin at the edges, and if you are only measuring the edges in one year from time to time you cannot measure the thickness in the middle. It is worse than a Jaffa cake, because it is moving around as well. You cannot return to the same place and time to measure the same thing. From the data that we have for the past four years—and it is only four years—which are the most reliable and comprehensive assessment of the ice volume in the Arctic that we have, in 2010 by the end of summer there were 10,000 cubic kilometres, in 2011 there were 9,000, in 2012 there was 8,000, and in 2013 it rose to 10,000 again. Based on those four years of data, we could not extrapolate with a negative trend.

The Chairman: I think we will leave the shipping question for another session. Lord Hunt, did you want to ask a question very briefly on this aspect?

Lord Hunt of Chesterton: I just wanted to say—

The Chairman: Is it a question?

Q35 Lord Hunt of Chesterton: It is a comment and a question. I wanted to summarise what you have both said, which was that the original computer models, which did not forecast this rapidity, had many simplifying features; they did not include some of the processes that we now know, so that was how they got that answer. Peter Wadhams was looking at other questions; he is a wave man, so that was in there. Anyway, you asked what the problem was. The answer was that to change the Met Office climate model is a big thing, and I know this myself: it might be 10 years before something happens, whereas an individual can look at new elements.

The question that I was asked to ask was: to what extent can we work with the EU and Russia? That is the point. We work with ISA and so on, but surely with ships and all these resources we should really be having a much more significant role between the EU and Russia in order to focus on these problems. Do you think we are moving towards that?

Professor Peter Wadhams: Perhaps I can mention one Russian collaboration that has started and is, I think, very important. It is via an EU programme but it is led from Britain, and it has in it a British Antarctic Survey co-ordinator, Cambridge University and 25 other partners in Europe. It is called ICE-ARC and it is devoted to the question of the rapid Arctic change and the impacts.

One of the impacts which the Russians are studying and which we are now working with them on is the emission of methane from the Arctic offshore. This is a much more serious and immediate problem than methane emissions from tundra, and it is going to build up to be an extremely serious problem and have an extremely serious impact on climate change over the next few decades. The immediate fear is the emission of methane from shallow offshore waters off the east Siberian shelf in the Arctic in the summer. The Russians have been studying this for a number of years in a joint programme with the University of Alaska. We are now joining in and going up there with them, and we are already seeing methane plumes being emitted from methane hydrates, which are being released because the offshore permafrost is now thawing, because the water in summer is warmer because of the sea ice retreat. This is an unprecedented situation: the retreat of sea ice in the summer leading to warmer offshore waters over the shallow shelves of the Arctic, which is leading to offshore permafrost thawing, which is leading to a methane hydrate release as methane—

Lord Hunt of Chesterton: This is not in the American document.

Professor Peter Wadhams: I think it is a serious and immediate problem. It is probably the most important problem that we are facing in the Arctic, and we need to study it most strongly. Access to the area is difficult, and this Russian-American collaboration has been the only way in which this can be done. It is done every year, but now the EU is coming in on it and we are partners in it, so we will be going out there with them from this year on.

The Chairman: I am aware that it is 12.30 pm. Is the Committee happy to go on until 12.45 pm? No. We have a number of questions that we have not completed at this point that relate particularly to the scientific side. Perhaps we could very briefly ask question 7. We have UK scientific expertise and I think we have done a lot on that, actually. The one question that we will finish very quickly with relates to a different aspect. Perhaps Lord Addington can ask it and we can have a quick answer from each member of our panel.

Q36 Lord Addington: It is a bit of a jump across, but what in your view are the negative impacts of the further reduction in sea ice cover likely to be, and are there any positive impacts?

Professor Andy Shepherd: We already heard in the first session that there are many potential negative impacts: things such as the loss of natural habitats and ecosystems, impacts on local communities, increased pollution, the risk of oil spills, changes in atmospheric circulation patterns that will affect the Arctic itself and elsewhere on the planet, and an increase in storms. We have heard that the loss of Arctic sea ice might present some shipping opportunities. Peter has explained that industrial-scale commercial shippers might not see it in the same way, but tourist opportunities might be presented. It might reduce the economic costs for offshore exploration, for example. These are potentially positive implications, but that is essentially just an economic consideration, because you can still do all those things: they just cost a lot of money right now. I know that the Chairman asked the Committee not to consider the wider implications of Arctic change, but you should not lose sight of the fact that changes in the Arctic climate system impact on the rest of the planet, which impacts on finances in countries elsewhere on the planet, and the economics ought to be balanced against those considerations. If you were minded to do that, you would reach a different number than you would just by thinking about the commercial advantage of exploiting the Arctic itself. The real problem, of course, is that the commercial gains are in the private sector but the losses are borne by the public sector and consumers, and that makes this issue very easy to politicise.

Professor Peter Wadhams: Thinking about economics, we did an economic study of the implications of a large methane release from the east Siberian shelf. We assumed a 50 gigatonne release over 10 years, which had been predicted on the basis of observations done so far, and applied the PAGE model, the economic model that was used in the Stern review, which came up with a $60 trillion cost over a century. That is a staggering figure, but it represents about a 15% increase on the total economic costs of anthropogenic global change, which is even more staggering, and this is simply one effect of Arctic sea ice retreat, which is the uncovering of Arctic shelves and the enhanced release of methane from the Arctic offshore. Apart from producing a 0.6 degree increase in global warming within 20 years, it will also produce a $60 trillion cost over 100 years. That puts into the shade the economic gain from Arctic shipping and the increased ease in oil exploration and transport. Those will both be quite large benefits, but they are orders of magnitude less than the cost to the planet of having to cope with a very large methane outbreak, which is a significant enough risk that we should regard it as a top priority for studying.

Professor Danny Feltham: I suppose that most of my negative and positive impacts have already been mentioned. A decrease in sea ice cover will certainly increase local warming, but it will also lead to increased global warming from the decrease in the reflective ice cover. It will have impacts on the Arctic Ocean circulation: vertical mixing will affect ecosystems. There are also possible pathways whereby a change in sea ice cover can affect the climate more globally and in the UK from changing ocean circulation patterns—Sheldon mentioned the impact on the Gulf Stream—and from changing atmospheric patterns: longer periods of rain, for example, might be one outcome. There are various negative impacts that one can imagine might occur.

The positive impacts boil down to oil exploration, navigation, tourism and other such things, and as Andrew said these are largely in private industry.

The Chairman: Thank you very much indeed for your evidence. We were a little rushed at the end, for which I apologise. Thank you very much indeed for your contributions. You have given us a very good foundation on the environmental side to move forward on. I hereby end the public session and perhaps ask people if they could leave the room so that if there is any other business we can conduct that. I suspect there will not be.

Professor Andy Shepherd: Can I submit written evidence in response to the questions?

The Chairman: Yes.