SCIENCE AT THE SHINE DOME canberra 7 - 9 may 2008
Symposium: Dangerous Climate Change: Is it inevitable?
Friday, 9 May 2008
Dr Neil T M Hamilton
Director, WWF International Arctic Programme
Neil Hamilton has a degree in geology and a PhD in geography. He worked in the mining industry before turning to research in coastal geomorphology and marine and coastal conservation planning with CSIRO. He was founding research director of the Institute for Sustainable Futures at the University of Technology in Sydney, and led the team establishing the Co-operative Research Centre for Greenhouse Accounting. Neil has extensive experience in the planning and development of large international research programs, having worked for the International Geosphere–Biosphere Programme, and was deputy executive director of the International Human Dimensions Programme on Global Environmental Change. Before taking up his current position, Neil was executive director of the Forum for European–Australian Science and Technology co-operation, the organisation established by the European Union and the Australian Government to highlight, promote, and above all facilitate research collaboration in all fields between Australia and Europe.
Keynote address: The Arctic: Is dangerous climate change upon us?
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Good morning, ladies and gentlemen. Thank you for inviting me to speak in this august forum. It is always a great pleasure to come back to Australia and to see old friends, and particularly to be able to share some of my more recent thoughts and experiences with you.
I should probably begin by saying that I am going to do what Kurt Lambeck said we shouldn't do, to mix science and politics, because I don't think we can keep them independent any more.
An Inuit elder in Canada recently said to me, 'Go and tell the world what's happening. Tell them what's happening to my life and the life of my children and my communities.' And I said to him, 'I don't think people care. I'll tell them, but I don't think that's what's going to change the world. I think people need to understand the impacts of climate change on their own lives and their own countries, rather than on the lives of others.'
So what I am going to try to do is not to define 'dangerous climate change', not to talk about whether 2° is the right number or the wrong number; I am going to translate it. I am going to try and say that the question about dangerous climate change is: Dangerous to whom – or to what? Or, particularly, how dangerous?
The animal you see on the screen here, the polar bear, is extremely dangerous to the seal that it is about to kill. It may be a little bit dangerous to you or me if we happen to walk relatively close to it. But it is of no danger whatsoever to an Australian, sitting in Canberra. Understanding what danger means is a critical component of what we need to do.
The photos that I am going to show you, just by way of background, are taken by an extraordinary woman called Mireille de la Lez, who has spent the last three years more-or-less living in a tent in the Arctic, taking photos like this. They are quite extraordinary, and I really have great honour in presenting them to you.
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For the benefit of those who live in the Southern Hemisphere, I am going to give you a very brief introduction to the Arctic. It is a place that most of us know about, but most of us know very little, in fact, about what it is and what is happening to it. And what is happening to it is profoundly important to the lives of people around the world, not just the four million people who live in what we call the Arctic.
The first thing is that it's a very, very big place – it is much bigger than Australia. It is about half ocean, half land. It is the territory of five countries, most of which constitute global superpowers.
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It is an incredibly important area. Not only is it large, but it is very valuable in terms of the biodiversity. And it is quite pristine. Outside Antarctica I think we can say it is probably the most pristine place on Earth. The models that we have run have shown that fragmentation due to development is going to reduce that dramatically over the next 20 years, but it is still a place that is worth saving.
It is home to all of the icons that you think of when you think of the Arctic, but it is also a place where there is essentially untrammelled development going on right now. I will give you an example, fisheries: 55 per cent of all the fish that is consumed in North America comes out of the Bering Sea, 50 per cent of the fish that is consumed in the European Union comes out of the Barents Sea, 40 per cent of the fish that are caught in the Barents Sea are stolen, illegally. This is what we call 'good fisheries management'.
It is also a key area for fossil fuel extraction. Whether you believe the numbers or not doesn't really matter; somewhere between 15 and 25 per cent of the world's remaining petroleum resources are thought to lie within the Arctic. There is a gold rush going on at the moment to secure those resources. I won't even go into what is going to happen to the carbon cycle if we use those resources at the present rate.
The result of all of this intent to extract natural resources is that there is heightened international tension in the Arctic at the moment. There are skirmishes monthly. People are playing games – there are mock bombing runs being made on Norwegian cities by Russian bombers, for example. All of this is going on quite openly. It is not hidden; it is not submarine games under the ice any more.
But, most importantly, as the subject of this talk I argue that the Arctic is the key to the global climate system. It is the place where we see the impacts of climate change and it is the place where we have the potential to trigger feedbacks which will change the climate of the world.
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Beyond the physical stuff, there is a spiritual element to it. Anyone who has ever been to the Arctic knows that it is a haunting place. It is a place that you never ever forget, if you have ever been there. This is just one photo of the Northern Lights. You understand Creation stories when you've seen this stuff; it's truly inspiring.
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To return to the facts: this is the Arctic. It is the territory of five states, the boundaries being as marked. Currently the area inside the hatched box here, called the 'doughnut hole', is international waters. Within about 15 years – it depends on when the decisions are made – there will be only two tiny areas, one in the south around Gakkel Ridge and one at the northern end, that remain international waters. Every single other part of the Arctic will be the personal property of one of those five states.
Why is this happening? It is because there are large natural resources on the sea floor and in the water column that countries wish to exploit, and those resources are the last remaining unexploited resources in the world. You may have seen a Russian guy called Artur Chilingarov plant a flag on the North Pole last year. Interestingly enough, he was the guy who founded Greenpeace Russia, 20 years ago.
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The Arctic is also a place that has extraordinary ecological attributes. I don't have the time to go into very much of this, but I will give you one example. This bird, the Arctic tern, doesn't see night. It lives in the Arctic in summer and migrates to the Antarctic in the northern winter, so as far as we know it doesn't sleep – not in the way that we think about it, anyway. It is also part of the greatest animal-induced nutrient flux in the world. The transport of nutrients out of the Arctic by birds is bigger, as far as we can work out, than the nutrient flux in rivers like the Amazon. It's enormous, and that's because of the pulse of primary productivity that occurs in the spring at the ice edge and produces all the little algae which then produce the krill which these things feed on.
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And, of course, the Arctic is home to that icon the polar bear. This is one very scary creature. It is the natural-born killer. There are about 25,000 in 19 sub-populations around the Arctic. Almost all of those sub-populations are already declining. There are two that are declining, we know, directly as a result of climate change.
The polar bear is a marine mammal. It is totally dependent on the sea ice biome. Without sea ice it cannot survive. As the sea ice declines, the krill decline, the fish decline, the seals decline and therefore the polar bear declines. It is a direct indicator of the impacts of climate change.
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Let's just go back to what we are talking about. We are talking about 'dangerous' climate change. There are a whole range of changes in the Arctic, some of which are human induced – the extraction of natural resources; some of which are climate induced; and some of which are due to pure human greed. The arguments over sovereignty in the Arctic currently have very little to do with need.
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We know what's happening in the Arctic. You see here a very bland statement, buried on page 655 of the Fourth Assessment Report of the IPCC [Intergovernmental Panel on Climate Change] Working Group II. Why it's on page 655 and not on page 1, I do not know. That is a profound statement, and if we don't take notice of it we will suffer the consequences.
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So again I will tell you what you would already know.
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We are driving this change, directly, through our behaviour. We are actually underestimating the change. We are underestimating both the driving forces and the impacts.
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And we are doing very little about it. Here is a nice quote from the World Energy Outlook which came out late last year, and on a bad day it makes me wonder whether we can change the future. On a good day, it's the challenge that we need to overcome.
You would all have seen the Stern report, I am sure you have all read Ross Garnaut's report. What is really important to understand is that we have limited time to change. So there is a moral dilemma writ large here, and Kurt alluded to this at the beginning of the symposium. We can do more science, we need to do more science, but we can't put off making decisions because we don't know enough.
What I will try and show you in the rest of my talk is that we do actually know an enormous amount, and I believe we know enough to act now.
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The data that I am going to present comes from two reports, the Arctic Climate Impact Assessment report which was published in 2005 by the Arctic Council, the peak intergovernmental forum for discussion on issues of the Arctic, and which really is based on data from about 1997 to 2003, and this report in my hand, an update of the Arctic Climate Impact Assessment which we published two weeks ago and which is available on our web site.
The important thing to understand is that what happens in the Arctic is a magnification of what happens in the rest of the world.
This slide shows one scenario for winter warming in the Arctic – this is temperature increase over the 100 years from 1990 to 2090. The warming in the Arctic in winter is a factor of 4 larger than global warming. A couple of points need to be made. The graph goes down to about 50° N. Most climatologists consider the Arctic to be 60° N and above. Well, 60° is in southern Norway and I can assure you that Oslo is not Arctic. The warming is magnified as you go towards the pole, and it is strongest in the Barents Sea around Novaya Zemlya and Spitsbergen, or Svalbard.
A 12° warming in winter changes all of the Arctic ecosystems from arctic to sub-arctic or beyond. This is a conservative scenario. It is based on conservative models driven by conservative assumptions. The warming that is predicted here for 2090 is now predicted for something like 2050.
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This is the report that I held up to show you. There are really three big conclusions. Everything that was in the Arctic Climate Impact Assessment is true. However, there are even more changes going on than are in the Arctic Climate Impact Assessment. And, finally, those changes are much, much worse than the Arctic Climate Impact Assessment or the IPCC Fourth Assessment Report says.
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I am going to run quickly through some facts. This is all data out of those two reports; it is all peer-reviewed literature and I have got the references if you want them.
Temperature is rising at double the rate that you find in the rest of the world. We are already higher than 2° above the 20th century average across the wider Arctic. And as you go closer to the pole, we are even more than that. So if you want to use a 2° average, we are there.
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Surface air temperature and pressure patterns are quite different in the last five years to those that have been seen in the 20th century, and the standard models of how the Arctic functions seem to be breaking down. There are those who are arguing that we are actually entering a new state of atmospheric circulation in the Arctic.
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When you put all of the models together – all of the IPCC Fourth Assessment Report plus other models – you get a range for climate sensitivity which is somewhere between 3° and 9°, in that 3° is under the most conservative scenarios, 9° is under some of the more extreme scenarios within the IPCC family. It is probably going to be much more than that. Those are annual averages: 3° to 9°.
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I think we have got evidence to say that we are going to go way beyond that range. In the summer of 2007, temperatures in several of the Arctic seas were 5° above average. That is enough to start the permafrost on the sea floor melting.
The Bering Sea, between Alaska and Russia, conventionally thought of as an arctic ocean, climatologically is now a sub-arctic ocean. Fish stocks in the Bering Sea have moved 800 kilometres as a result of temperature changes, and we are seeing changes from benthic-dominated food chains to pelagic-dominated food chains, which is exactly what you would see as a result of these oceanographic changes.
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Snow cover across the Arctic has decreased quite dramatically already. Across the Arctic, we have seen a 10 per cent decrease; in some areas we have seen a significantly greater decrease. And the projections are that we are going to lose another 20 per cent within the next 50 years. That is an ACIA [Arctic Climate Impact Assessment] summary; I think it is probably significantly worse than that.
The reason this is important is that snow melt is absolutely critical to ecological function in terrestrial ecosystems in the Arctic. We are making the snow melt come earlier, and we are making it come faster. This puts a whole different nutrient balance into coastal ecosystems, into the rivers and so on.
We are also seeing that early onset of melting leads to problems in feeding of species like reindeer, because you get early melt and then you get freezing overnight, which causes crusting, which means the reindeer can't get through. The reindeer are the fundamental basis of life for most of the indigenous peoples of the Arctic. Their herds are decreasing dramatically already, and it is not clear what is going to happen in the future.
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Most people are worried about Greenland because of the implications of melting of the ice sheet for sea level rise. I confess that I am more concerned about the influx of fresh water and the implications that has for ocean circulation. I will talk a little bit more about Greenland later.
Glaciers on Greenland, in Alaska, on Svalbard, are melting. We have one recorded glacier in Greenland that receded 7 kilometres in one year, and another receded 5 kilometres in the summer of 2007. Two weeks ago I visited a glacier in the middle of Svalbard, well away from the sea so it should be relatively protected: it has receded 5 kilometres in three years, having been stable since records began.
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We don't really understand what is happening in Greenland. We know a number of things. It is melting, and we know that it isn't the surface melt that is dominating the processes, it is the changes in ice dynamics in Greenland. None of the models that are being used to predict what is going to happen to Greenland include an understanding or a parameterisation of the ice dynamics, because we simply don't understand what is going on. Things in Greenland are moving much, much faster than anyone anticipated.
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Sea-level rise in the Arctic is also magnified, like temperature. It causes a whole range of things to happen that we did not anticipate. Coastal erosion in the Arctic is now a major problem, largely because ice-armoured coasts are now no longer ice armoured. Sea-level rise therefore causes dramatic coastal erosion. It exposes permafrost which was previously buried, and that increases the rate of melting and erosion.
This has dramatic impacts on the people who live there, but it also has the potential to liberate carbon into the atmosphere from that permafrost that was not in the atmosphere before.
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There are about 400 cubic kilometres more fresh water going into the Arctic from four rivers, the Ob, the Yenisey, the Lena and the Mackenzie. This has a dramatic impact on the freshwater budget of the Arctic Ocean, which is essentially a closed ocean with only two entrances, the Bering Sea and the Fram Strait. This is what will drive, if anything, changes in ocean circulation. We are up 25 per cent over the average flows already.
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As a result, the oceans freshen. It is not quite clear, even to those who are very close to this, what the implications are. There are models, there are studies which show different things happening. Some people say the North Atlantic thermohaline circulation is slowing, others don't. The balance of probability is that it is slowing, but exactly what will happen in the future is poorly understood.
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So this is the thing that everybody should be aware of already: the melting of the sea ice in the Arctic Ocean. This graph shows the anomaly – it shows the difference between the annual figure and the average. The brown curve is winter and the purple curve is summer; there are a couple of linear fits to that.
The average is about 7 million km2. In summer it goes up to about 12 million km2. It is important to note several things here. It is not just summer sea ice that is disappearing. Winter sea ice is disappearing as well – not quite as fast, but at a significant rate. The difference is, of course, that there is a lot more winter sea ice than there is summer sea ice.
Let me show you what happened in 2007. In September 2007 we fell off the edge of the curve. I have not heard a single scientist say that is natural variability. What is really interesting is that the anomaly shown here exceeds the amount of melting that you would see simply as the result of temperature rise. There are already feedbacks occurring in the melting of the sea ice in the Arctic that are accelerating the rate of sea ice loss. (That one silences every audience in the world!)
We hit 4.2 million km2 last summer. There was no ice in the Beaufort Sea; there was no ice at all across the north coast of Russia; and there was no ice through the Northwest Passage. We put a swimmer at the North Pole who swam a kilometre in an open lead at the North Pole to try and raise the awareness of the world of what was going on. And it made a bit of a hit. But, to be frank, I am not quite sure that people understand the magnitude of the problem that we are facing.
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If your accountant or bank manager or stockbroker showed you figures like this, you would act. You would move your pension fund, you would change your mortgage, whatever you would do. We don't change our behaviour when it comes to seeing figures like this on Arctic climate impacts.
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We lost almost a quarter of the sea ice in two years.
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And this is the figure that nobody knows. The sea ice is thinning dramatically – 80 per cent of the volume in my lifetime.
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I think you would all accept that the ice is melting.
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I am just going to show you a few figures. I have tried to scale them so that we can see a couple of hundred years here. I haven't talked a lot about permafrost and I won't – the numbers are still quite dodgy – but there is no doubt that permafrost is melting, and it has profound implications.
In this graph headed 'Permafrost Area', the blue is data, the red is models, driven by SRES [IPCC Special Report on Emissions Scenarios] scenarios. Whatever happens, we are going to lose a dramatic amount of permafrost over the next 20 to 50 years. We actually don't understand what that means, we don't understand what the implications are. I will just throw a random sentence in here: that permafrost is the biggest single carbon store on the planet.
This second graph represents ice thickness – a really interesting graph produced by amalgamating all the data sources and some models. It is now several years out of date and the situation is actually worse than this. When we were playing submarine games under the ice, it was three or four metres thick and it needed a missile to blast through. Predictions are that somewhere around 2030 we get down to a couple of metres thick, and that we get down to less than a metre by 2100. Anecdotally, we are somewhere about the 2050 prediction already. No-one really knows how thick this Arctic sea ice is, because measurement is quite difficult, and the satellites and the laser altimetry and the submarine data that we use don't work very well and it has enormous spatial resolution – 10 km pixels on the satellites. The ice is melting much, much faster, and the thickness is decreasing much, much faster, than we think about.
The third graph represents the ice extent. This is the ice area, again represented through ensemble runs from GCMs [general circulation models] linked into ice models. It shows us going over the edge of a tipping point somewhere around 2030. Last year we had 4 million km2 of ice. We are 20 to 30 years ahead of what the models are saying.
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This graph, headed 'Arctic September Sea Ice Extent: Observations and Model Runs', is the one that really scares me. The models are wrong. The models are systematically underestimating the area of sea ice melt every year, because they don't include the processes – and we don't know how to include the processes at the moment – of what is going on. The blue here is the standard deviation, the dotted line is the mean of all the decent ice models, the red is actually the observations. Last year we went down even further. We are getting worse, not better.
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Let me look into the near future, September this year. What is going to happen? Well, this winter was not so bad; it was normal. That, of course, triggered a whole lot of sceptics to come round saying, 'Oh, there's no problem. It's all frozen again.' It did freeze, but it froze pretty thin. However, it wasn't back to normal. The extent of sea ice at the March maximum, roughly six weeks ago, was half a million square kilometres, 500,000 km2 below the 1979–2000 average maximum sea ice extent. And that was mainly in the Barents, the Bering and the Beaufort Seas.
Because we have melted so much in the past, most of the ice cover this spring is one-year ice. And one-year ice has two attributes: it is thin, and it melts much more quickly than old ice.
The melt has already started. I was in Svalbard two weeks ago, and it was spring. The average rate of decline of sea ice area throughout the month of April was 6000 km per day faster than the melt in April 2007.
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So let's estimate what sea ice is going to look like in September this year. For a simple estimate of the likelihood of breaking last year's record, we can apply the survival rates from each of the past 25 years (which is the data that we have got) to this year's April ice cover. That gives us 25 estimates, one for each year. To avoid beating the September 2007 record, more than 50 per cent of this year's first-year ice has to survive. That has only ever happened once in recorded history. If we apply the survival rates, averaged over all of those 25 years of data, to current conditions, the end of summer ice extent will be 3.6 million km2. If we apply the survival rates of summer 2007 to today's sea ice, the minimum for 2008 will be 2.2 million km2. By comparison, the record – the record that beat all records, last year – was 4.2 million km2.
Have we passed a tipping point? You be the judge.
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What does this look like? I am just going to show you a very short movie to explain.
The initial image here is 1979. The white ice is old ice, ice that is in excess of five years old. The dark blue ice is one-year-old ice, and as the blue gets lighter we have two-, three- and four-year-old ice.
I will call the dates out by year, 1980 to 2007, so that you can watch the patterns, and you will see the circulation and what happens. The red things are buoys that get frozen into the ice, and they will show you some of the trajectories.
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Ladies and gentlemen, there is no old sea ice left.
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Let's go back to Greenland for a moment. We have been trying to estimate the area of melt on Greenland for quite some time. The figures that were produced for the Arctic Climate Impact Assessment in 2005 (they are really 2003 figures) said that about 50 cubic kilometres a year of Greenland ice was melting. Using laser altimetry we were able to calculate that the area of ice that was lost between 1997 and 2002 on average yearly was about 80 km3 a year. So we are going up slightly.
Then we stuck up a satellite called GRACE [Gravity Recovery and Climate Experiment]. The average ice loss that GRACE has measured between 2002 and 2006 is 250 km3 a year, and the scientists I have spoken to recently say that we are in excess of 300 km3 now.
The figures that we are making policy on are the Arctic Climate Impact Assessment figures, 50 km3 a year. How do you make good policy when you are using science that is just plain wrong?
In 2007 the summer melt was 60 per cent higher than any previous record, and much higher than any model would predict due simply to temperature rise. The belief now is that the ice dynamics on Greenland have fundamentally changed, and there are no models that realistically simulate the responses of this ice sheet any more.
In 2007 the melt index – that is the area x the length of the season – increased in one year by 150 per cent. So Jim Hansen, a leading US climate scientist whose name at least I am sure you would know, argues that the Greenland ice sheet has begun to respond non-linearly. The science that most of you have probably read says that Greenland is not going to melt quickly; it is not going to melt for hundreds of years. If it responds non-linearly, that is not true any more.
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And this is the sting in the tail. The melt that we are seeing, the changes that we are seeing in the Arctic, are due to warming that is only half the warming that we are already committed to.
Are we committed to dangerous climate change?
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This is a slide produced by a colleague of mine whom many of you know, Pep Canadell (and probably Mike Raupach as well), talking about the vulnerability of the carbon cycle. The Arctic contains enormous stores of carbon: the boreal forests, the permafrosts, the frozen soils, the wetlands. All of these are changing very, very quickly.
This is one of the big uncertainties that remain in the Arctic: what will happen to the terrestrial ecosystems? There are place-based studies which now show that we are getting thermokarst created (that is, you are getting holes in the ground caused by the melting of permafrost) which is causing a release of carbon because of changes in the water balance and so on.
What is important to understand is that we don't do very much work on terrestrial ecosystems in the Arctic – we actually do less work on marine ecosystems in the Arctic – and the changes are occurring as we speak. It is very important that we do more science, quickly, to understand what is going on here. There is a lot of carbon there, and once it starts to melt and once the positive feedback kicks in, we may have a problem.
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This is my second quote from the Fourth Assessment Report of Working Group II, this time on page 662. (This one was buried deep.)
The IPCC Fourth Assessment Report did no new work on the Arctic. It picked up the Arctic Climate Impact Assessment work – I'm not quite sure why – and it made a few statements like this, alluding to 'potential' change in the Arctic.
I was at a workshop with some leading industry, government and academic methane hydrate experts less than a month ago. All of them said that methane hydrates as an energy source are way down the track, at least 10 years. All of them said, 'We have a major problem with the release of methane from terrestrial and marine ecosystems that we can't control, simply as a result of warming.'
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The Fourth Assessment Report identified the sea ice biome as the marine ecosystem that was most likely to be affected by climate change. Confirmation of declining trends for a range of marine species around that sea ice biome is already there. Ringed seals, ivory gulls, grey whales, polar bears – it's as clear as daylight.
Work since the Arctic Climate Impact Assessment confirms the risk to polar bears from the earlier and substantial decline in area of sea ice, and it shows changes in reproductive capacity, in body condition, in size and in behaviour. For every week earlier that the sea ice breaks up, a female declines in weight by about 30 kilos. And when you understand that a female has not eaten for six months and has usually had two cubs over the winter and comes out very, very hungry, you realise that is the difference between life and death.
Increasing air and water temperatures, and a reduction in the sea ice, have coincided with a major shift in the last decade from an arctic to a sub-arctic ecosystem in the Bering Sea. We have got preliminary evidence which says that the Barents Sea and the Laptev Sea are also going this way. These seas, as I have pointed out, are the 'breadbasket' – the fish basket – of Europe and North America.
It is not clear to me what any arctic ecosystem will look like in 20 or 50 years' time, terrestrial or marine. The organisation I work for is a conservation organisation. It is supposed to be 'protecting' ecosystems. We no longer are trying to protect the Arctic.
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Let me give you just one example of what is happening to a species. It is the old favourite, the polar bear, because this is the species where there has been the world's best study of the impacts of climate change on a species. It was performed by the USGS [United States Geological Survey] as part of the process of listing the polar bear under the Endangered Species Act – which the US government has refused to do, so that we have taken it to court for the first time in 25 years, for breaching its own legislation.
The US geoscientists linked a set of climate models with a set of ice models with a set of ecosystem models with a set of population models and an expert system, and they did two completely independent sets of modelling. And this is the best they could come up with, under the most conservative scenarios, which use a loss of sea ice by 2070.
Two years ago ACIA said the sea ice in summer will be lost by about 2070. In 2007, people were publishing papers saying 2050, 2040. In December last year a very reputable group, which produced the first model that included sea ice dynamics, said that there would be no summer sea ice by 2013. That is five years away, and based on last year's melt we might even be there sooner.
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So we try and do things like understanding behaviour, like doing denning surveys, like trying to actually map what is the potential extinction of this species.
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One of the bizarre effects that are occurring is that as a result of loss of food, polar bears are now coming into human settlements much more often, so we run patrols to, essentially, shoo them out of communities, particularly indigenous communities in Russia.
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Why does this matter? Why should we care? Because the Arctic affects the world.
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Most of you would know this better than I do, so I won't go through it: there are positive feedbacks from the Arctic on the rest of the global climate system.
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The question we have to ask ourselves is whether this is dangerous. Well, I have answered it for myself. And I don't think it's a scientific question any more; I think it is a political question.
Climate change impacts of the nature that we are seeing in the Arctic have the potential to seriously destabilise the global climate system if we do nothing.
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But we do have the potential to do something. The best evidence that I have seen says that we have got five years. Pick a number, a small number, no-one really knows – it is a very small number. What I have shown you decreases that number by a large amount. Essentially, we have got 18 months to secure a global agreement which will set the world on the path to a carbon-free future. If we fail to do so, I guess you can answer to your children.
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I believe this is a place that has intrinsic values. Most of those intrinsic values I can no longer save – they're gone. Whatever I do, whatever you do, the intrinsic values of the Arctic that we know today will not exist within my lifetime. And I think that is very sad.
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I will finish with this: we need to create a new future. For the first time in history, we have the capacity to change the future of the world. We have already changed the future of the Arctic; we now have to redesign what the Arctic might look like.
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That is an extraordinary thought, and it is one I will leave you with, but I don't believe that we can wait any longer before we act on dangerous climate change.
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Discussion
Question (Amanda Lynch): Thanks very much. I really appreciated hearing a talk about the Arctic, having lived there myself. I want to correct a misinterpretation, and then ask a question.
First, concerning your comment that there was no new work done in the Fourth Assessment Report, in the Arctic chapter: I was an author on both the ACIA report and the Arctic chapter of the Fourth Assessment Report, and I can assure you that there was a lot of extra work done in the second case, and different communities engaged.
The question I want to ask is this: there has been some really interesting work done by the Canadian Geological Survey and the Iñupiak communities up there on polar bear-grizzly hybrids, and it appears these hybrids are quite vigorous and quite successful in competing for their territory. I am wondering what your perspective is on how we value these hybrids.
On one level they are preserving a genetic heritage of the polar bear, but on the other hand they are very strong evidence of the problems that the polar bears are facing in their own ranges. How do we value these new species?
Neil Hamilton: Do you value a liger? I'm not sure what the answer to that is. There's no doubt, they do interbreed. There are a small number of recorded examples. It's very unclear what the ecological implications of that are.
I guess my feeling is not to judge whether that's good or bad, but to think that the loss of the polar bear and what it represents in terms of the ecosystem is actually far more important. The diversity does reduce when you start to interbreed those species. The loss of 19 genetically quite distinct sub-populations of the polar bear, I think, is a loss that we should be aware of.
But from my perspective it isn't actually about the polar bear. It's about the polar bear sitting at the top of a food chain and representing all of the things that are underneath it. So we lose ringed seals, we lose ivory gulls, we lose the fisheries, we lose the krill, and so on. We get something totally different.
Re IPCC: I stand corrected. My point, I guess, is that the work that is published in the report shows extraordinarily little change from either the Third Assessment Report or the ACIA report – and there was other science out there that didn't appear in the final work. But we can talk about that 'off line'.
Question: We know that the temperature of Greenland was a good deal warmer than it is now, about 1000 years ago. Do we have any idea of what the concomitant sea ice arrangement was, back in those days?
Neil Hamilton: I will have to take that one on notice. We do know something: the difference is that the forcing factors now are an order of magnitude higher than even in the Last Interglacial. There is very little evidence in fact recorded, even in proxies, for rates of melt in the last 10,000 years. So I would have to check and get back to you.
Question: If the loss of the sea ice is inevitable in the near term, which is where we seem to be getting to, what are the consequences of that for regional temperatures, given the albedo flip and so on, and what impact would that have on the rate of melt of Greenland?
Neil Hamilton: I honestly can't answer that. I am not aware that we have actually ever done any modelling – that anyone has done any modelling – to answer that question. They are probably quite large effects; I think that is about as far as I can go. Maybe Amanda Lynch can answer that one. It is a really important question.
Graeme Pearman: In part, the existing models and the projections of existing models include that feedback…
Neil Hamilton: In part.
Graeme Pearman: But only to the extent that the rate of change of the ice is at the rate that they were anticipating, which is a lot slower than what we are observing. So the models themselves actually include the feedback, and that is part of the reason why the warming is occurring faster in those areas than other parts of the planet.
Neil Hamilton: But, to qualify that, Graeme, the resolution is important, because once we start to get the break-up of the ice beyond the size of the pixels in the models, then we start to get some problems.
Question (Neville Nicholls): You mentioned that the sea ice is melting or disappearing faster than the models predict, and faster than you would expect from warming. What are the factors that are contributing to that? One in particular I was just wondering about: what about the increased river inflow into the Arctic Ocean?
Neil Hamilton: Again I am honestly not sure what the direct impact is – and I am not sure that anyone has actually modelled it, either – of the influx of fresh water. One issue in the melting is that once you get break-up of ice into small blocks, it melts much faster than a large block. The other issue is that when you have a model that is based on parameters for melting of multi-year ice and you start to have single-year ice, you get much faster melting. Those are the sorts of factors that are built in.
Question (Kurt Lambeck): Neil, we have the Last Interglacial, which is an analogue in many ways of the current Interglacial that we are living in. Is there anything we can learn from that? I think we know that during the Last Interglacial the Arctic sea ice did break up, and obviously the polar bear has survived that period, because it did come back again. So is there anything we can learn from that?
But you can also imagine what we might call a hypothetical situation. If we look at the end of the Last Interglacial, we see some evidence for fairly rapid fluctuations. We know that temperatures in northern Europe are quite a lot higher, because we have got the boreal forests up in areas where they haven't been seen through the Holocene, and I think one can explain that as a regional phenomenon rather than necessarily global. But when we look at the onset of the next glaciation, where it starts is not where you expect it. Where it starts is over in Siberia, where during the Last Glacial Maximum there was no ice. Now, that's an intriguing observation, and the reason is that there was no moisture – it wasn't that it was warm but that there was no moisture.
It suggests to me that with the opening of the Arctic Ocean there is some feedback mechanism. It is bringing warm water into contact with cold air, it is creating precipitation and it is creating the initiation of the ice sheets. So that is one of these feedback mechanisms that we really know, quantitatively, very little about. It is something that we need to think about and have answers for, because people are asking these sorts of questions.
Neil Hamilton: Sure. There are people in this room who know far more about the dynamics of Quaternary climate change than I do, and I wouldn't presume to speak for them. But I think there is at least one factor that is fundamentally different, and it is the rate of change. We are now dealing with a system which is not a system which is internally regulated. We are now dealing with a system where we are driving it way faster than it was driven, as far as I am aware, at any stage in the Quaternary. That is an important difference.
Question (cont.): Yes, I totally agree with that. That's correct.
Neil Hamilton: The other difference, I guess, is that we weren't around as a civilisation 120,000 years ago. So there is a value judgment in there, and the preservation of our society and our way of life, and what we value, is something that has to be taken into the political decisions that are being made about what we do about climate change.
Question: Given that what we are now seeing in the Arctic is really occurring at levels of CO2 in the atmosphere of somewhere between 350 and 380 (that is when this warming/melting started), what does that say about the targets that we should be heading for in terms of our global negotiations?
Neil Hamilton: Something very low! It is a hard question to answer – or maybe very simple. The best guess, from the modelling that I have seen, says that it isn't just about concentrations, it is about rates of stabilisation as well. We probably have a little bit of time to pick a number, but we have no time to start decreasing the rate of emission. So it is really important that you pull stuff down early. Is that right, Graeme?
I have seen work that says you have to go way below current levels. I am no judge of that; that's not my field.
Question: What would you have to do to get the Arctic sea ice back, to the full extent?
Neil Hamilton: Step 1 is to wait a significant period of time. It is going to take several hundred years to get the CO2 and the warming potential out of the atmosphere. And beyond that we don't know.
Question (cont.): We've put it up there. Presumably we could actually do something to take it out. So if we had a positive regime to solve the problem, and if you wanted to get the Arctic ice back quickly, what would you have to do?
Neil Hamilton: I've never asked that question. I'm not sure. Amanda, is there an answer to that?
Amanda Lynch: I don't think anybody has run a model on the basis of removing it.
Neil Hamilton: To the level that is necessary, no.
Amanda Lynch: I don't think anyone has actually run a scenario where we suck the CO2 out and see what happens, but a lot of these systems, although they decay very rapidly, would rebuild relatively slowly. I think that even if we did that, we would have to cool things down very, very fast, especially with permafrost.
Question (cont.): It has been suggested that it would take 20 years if you could get the CO2 levels down enough, but that would presuppose the right conditions at the start.
Amanda Lynch: Yes, you could get the sea ice back pretty fast, but what you can't get back very quickly is the permafrost, especially on the ocean floor. And restoring the salinity and temperature profile in the underlying ocean is quite important for the biosphere.
Graeme Pearman: Could I just comment that I think the issue about targets is a very interesting one, and indeed my take on this symposium is not that we should really go down that track but that in fact the discussion of what is dangerous is part of the management of risk – that if these things are possible, then that actually is a predeterminant in how much effort you put into setting targets, and where the targets are and how long you take.
While we are not going to discuss in detail how to go down that track, this kind of discussion about how hard you go with those targets is fundamental. There certainly are people out there, in the literature, that are looking at 350 ppm, and I will talk a bit about that in the final talk today about the energy system and what some of the opportunities are to significantly lower the emissions.
But if we were to find out in the next year or two, as we may if Neil's projections are correct, this will be a significant component in any policy development around targets, because people will feel compelled to do something about it at a rate that was not thought of only a year or so ago.
Question: This is just a comment on the ice in the Arctic. As you would be aware, there is a 2300-year periodicity, both in the palaeoclimate in the Swiss ice pack and in solar activity. We had maximum effects from the Sun at the time of the Romans, and we are moving towards maximum effects in 2300. So from this point onwards, we have got the Sun and the anthropogenic effects. Have you modelled the possibility that it will be the Sun alone that will stop the ice pack coming back for, say, 500 years?
Neil Hamilton: I have not seen modelling that answers that direct question. There is a lot of modelling which is pulling the impact of solar radiation out from the warming. The interesting thing is that in the Arctic it is actually a much lower component of the melt than you would expect in other parts of the world. So the impact of changes in solar radiation is less important in the Arctic than one would otherwise think.
The direct answer to your question I actually don't know. I haven't seen work that answers that question.
Question: I am a science teacher, so I approach things on a very simple level because I always have to deal with students. One of the things that I try and teach my students about ice is the fact that, as it is heating, the temperature will rise at a certain rate and then, due to latent heat, the water is kept at a stable temperature until all the ice is melted. And then the heat will increase the temperature dramatically.
To my mind, the ice packs keep the world at a very stable temperature. They are melting very rapidly, as you have pointed out, and a lot of people have been aware of it for a very long time, but the world is going through a status quo because the world 'seems' stable, as the water would be while the ice is melting.
But do we know how much heat is actually required to do the melting that is happening, and therefore how much heat is actually going to start heating up the water, once that ice is gone? Once that stability is gone, the temperature of the world must rise. People have been saying 'a few degrees over 100 years'. I don't believe it; I've never believed it. Since back in 1993, when I was aware that the temperatures were definitely rising, I have been worried about the fact that everything has been underestimated for a long time, so what you are telling me about these graphs is not surprising.
But the world is not concerned enough. We have a government that has just been proud about all the coal we are about to sell to Asia, and I'm thinking, 'We don't want to sell that coal.' So the government doesn't believe it. What is happening to try and actually show that this is really happening? I know that you have got a talk here today, and that helps, but I fear that when we walk out of this room it is going to be status quo.
So part of the question is about the heat: do you know about the heat? And the other part is a statement: we need to be more concerned. Thanks for your time.
Neil Hamilton: We do know about the heat. It forms the basis of the GCMs that are modelling ocean circulation. So we know that; we have a relatively good handle on it, I guess you would say. It is part of the basic parameterisation that is done.
The political statement is absolutely true – and it is one of the reasons I am here. There is a requirement that we act soon. I guess that, if I put myself in the shoes of the politicians, you have to be convinced that your short-term political future is able to withstand the shocks, the impacts, of trying to do something that may well hurt part of your constituency. I think we do acknowledge that while, in essence, adapting to climate change and engaging in mitigation programs is not all that costly in the long run, it is going to have effects on sectors like, for example, the coal industry. So the question of how you do it is something that each country is treating quite differently.
I can give an example from Norway. Norway has decided it is going to be the world's first carbon neutral country. But it is going to do it by buying carbon credits in China. Also, the state oil company has just invested in tar sands in Alberta, Canada – one of the most greenhouse-intensive industries in the world. So there is a lack of reality between what I have been showing you and politically what we are doing.
Hopefully, over the next 18 months that gap will shrink as we go into the Copenhagen negotiations. What I am seeing in those negotiations is an increasing realisation that there is a need for some big decisions, but those are very hard political decisions to make.
Question: I am from an institute of medical research and know very little about this game, and so it is wonderful to be able to absorb this sort of knowledge from the experts. I seem to have seen data that suggested that there could be a 700-year lag between the carbon levels stored in the ice and the effect. So, Neil, that would suggest to me that it really wouldn't matter whether it is 18 months or 'do it tomorrow', we may be doomed anyway and there is very little we can do about it. Would either you or Graeme like to comment on that suggested lag effect: is it real, and is that serious?
Graeme Pearman: Just very briefly: there are lags. The time scales of the climate system vary from seconds to thousands of years, and in fact it has for a long time been the argument that it will take a long while for the deglaciation of Antarctica to happen.
On the other hand, if there are mechanisms that we have not included in our consideration of these and that mean some of these sheets dynamically are less stable than we thought – we'll hear more about that later, I think – then we may have overestimated how long we actually have.
Neil referred to this, actually, in his presentation. It might have gone past some of you, but he said that we have already committed to twice the change we have seen so far. And that is part of the lag effect – that is, the changes that we have already made to the composition of the atmosphere have in store for us, once we've allowed for the lag particularly of the oceans and the slower heating of the oceans, another degree of warming. It means that, irrespective of what we do today, we are going to get that – unless we can get into the concept of a rapid reduction of the overall concentration.
So you are absolutely right, there are lag effects. And Neil's point is that mixing the time scales of politics with these longer strategic time scales of the climate system is not easy.
Neil Hamilton: I will close by saying that ultimately this comes down to a moral issue. I don't believe we are 'doomed'. I do believe we have the opportunity to act. I do believe we have the opportunity to make a change for the better that will reduce the worst impacts, and that we can do that if we act quickly.
Graeme Pearman: I would like to thank Neil for an overview of, and a way of expressing, the concern about the potential for dangerous change. This will be followed up with some presentations that will take up some of the more specific issues, some of which he has already referred to, in some more detail.
Please join me in thanking Neil again for his presentation.
