Sea Ice, Methane, and the Future of Life on Earth – A MAHB Dialogue with Climate Scientist Peter Wadhams

Geoff Holland – How is the massive human consumption of fossil fuels like coal, oil, and natural gas linked directly to climate change?

Peter Wadhams – Well, the link is straightforward: the biggest driver of global warming is the concentration of carbon dioxide in the atmosphere. Since we started burning fossil fuels and putting carbon into the atmosphere, we have been increasing the air temperatures because carbon dioxide absorbs heat trapped in the atmosphere. So, the two go together. You can really match, say, global air temperatures and global carbon dioxide concentration. They go together, almost perfectly.

GH – Why is climate change impacting our Earth poles more than other regions?

PW – That’s an interesting question. We don’t fully understand the reason why there’s an amplification of warming in the Arctic. It’s two or three times above the lower latitudes and has a big impact on the disappearance of sea ice. But the reason for this is not simple. It’s probably because the troposphere, the lower level of the atmosphere, is thinner at high latitudes than at lower latitudes. And so the thinner layer of air has to be warmed up to achieve a given temperature difference. There seems to be a lot of speculation because as the ice disappears, the surface of the planet gets darker. Instead of having ice, you have tundra. That’s a good explanation, except that this amplification factor started way back before the ice started to disappear. So, it’s not that it’s something else. We just aren’t sure. So, we still have a mystery there to solve. Indeed, the polar regions are warming faster than any other part of the world.

GH – What is the current status of the sea ice at the poles, and how do the loss of sea ice and the change in sea surface albedo exacerbate the climate threat?

PW – The summer sea ice area is now substantially reduced from what it was just 30 years ago. The summer sea ice volume is only a quarter of what it was as recently as 1980. So there’s a big loss of ice in the summer and also during the rest of the year. We are finding that there’s a big decrease in ice and ice area thickness over the entire year, not just in the summer. It’s really diminishing.

GH – There are trillions of tons of methane trapped in permafrost, sea ice, and shallow ocean floor sediments in the Earth’s polar regions. What impact is that having on our climate?

PW  – I think this is probably the greatest immediate climatic threat that the world faces. And it’s because there’s a very strong probability that a huge amount of methane will come out of the Arctic Ocean seabed. At the moment, methane is trapped in a compound as methane hydrates under the sediments or under the surface layer, or in seabed settlements because there is a protective layer of permafrost. The crisis is that permafrost is only there because the Arctic Ocean used to be cold. It was covered in ice all year round, and that was good.

As long as there is ice, the seawater temperature doesn’t rise above zero degrees Celsius and so the seabed sediments don’t fall out – they stay frozen all year round. But now we have at least four months of the year when the Arctic Ocean is increasingly ice-free. When the ocean is ice-free, it warms up because there’s a lot of radiation. In the summer, the shelf sediments warm up and release methane. And every year that people go there, there are larger and larger plumes of methane coming out of the seabed and coming up to the ocean surface and getting into the atmosphere. So we’re facing a creep, and where it’s not creeping it’s accelerating: accelerating the threat of methane, multiplying itself by coming out of the Arctic oceans, the seabed, and flooding into the atmosphere. This is a more immediate threat than temperature rise, which is also there. Permafrost at the poles is thawing everywhere, and as it thaws, it releases various gases, one of which is methane. Now that’s a slower process, although, in the end, it is more lethal. We could see a sudden, massive increase in methane flooding into the atmosphere. That could cause a very large jump in global temperatures in just two or three years. This is a threat now, and we should be doing something about it. But of course, we don’t.

GH – Some scientists see the possibility of a runaway feedback loop with methane venting into the Earth’s atmosphere. Is this threat real, and what risk does it pose to life on Earth?

PW – Well, it is real. I mean, this is the threat I’ve been talking about. The threat of methane from melting sea ice has recently doubled. That is to say, that’s what we see in the model we use to calculate the impacts of methane being released. The more intense conclusion is that you might get 1.5 degrees of warming from a big methane release. When we wrote a paper on it two years ago, we calculated about 0.7 to 0.8 degrees of warming. But there’s a new estimate from a scientist who works for the US Air Force. So it must be true, and the threat seems certain to be double what we thought it was. So, we really should be looking to implement ways to get rid of methane on an emergency basis. If it all comes out in one go, we are in big trouble. We need to be implementing mechanisms for getting rid of atmospheric methane now.

GH – How does oil drilling make the biological risk to the Earth’s polar regions even more severe?

PW  – Job one is to massively cut the human cultural demand for oil and all other fossil fuels. Fossil fuels cause global warming… The human species is really good at trying to find cheap and easy ways out of major problems instead of actually facing up to them. Even though we’re in international agreements to reduce fossil fuel use, going for renewables, and so on… In practice, the sort of entrenched appeal of oil means people will find reasons for continuing our dependence. The British government is doing that, for example. They’ve signed all kinds of agreements, but now suddenly, they’re proceeding with developing some oil I happen to have found in the Shetland Islands. So you can’t trust governments because, well, there’s a profit to be made.

GH – What do you say about geoengineering to reduce the concentration of methane and other unwanted hydrocarbons in the Earth’s atmosphere?

PW – Well, I’m in favor, but some scientists are worried about certain aspects of geoengineering. One of the cheapest ways of geoengineering is putting aerosols or powdered material up into the stratosphere. It will reflect radiation and moderate the climate. This turns out to be the cheapest way. But it also has potentially harmful effects. Firstly, the material you put into the atmosphere might be toxic. It might do something to the climate you don’t want it to do, and you are powerless to do anything about it until the powder falls out of the air. Therefore, my favorite method of geoengineering is marine cloud brightening, where you have a drone ship. This idea was developed by a guy in Scotland. He’s a brilliant, brilliant scientist, but is not supported by the British government. Anyway, he’s got a system with drone ships, where you pump seawater up the mast and out through a very fine nozzle. And this fine nozzle puts tiny particles of seawater into the bottoms of marine clouds. It impacts low-level clouds. It makes them brighter, and that means they reflect more radiation. It’s entirely under our control. If anything goes wrong, you simply stop pumping, whereas with putting aerosols in the stratosphere, you just have to sit there and take what comes. But with this brilliant technology, you stop pumping and the climate moderating effect stops immediately. So, it’s really the best and safest answer for geoengineering. And it’s something I wish that the British government was supporting. I had a very annoying time recently at the COP26 meeting, which was supposed to be the meeting to implement all of the Paris climate agreements. All the provisions were confirmed and improved upon. It was held in Glasgow, and the person who invented cloud whitening is in Scotland. And he’s 80 years old. Nobody has actually tried this marine cloud brightening yet. One was hoping that the government would say, right, let’s show our serious concern. Let’s support marine cloud brightening because it’s a Scottish technique. But it didn’t happen. We are getting to the point where it will be too late.

GH – Climate change is a global-scale challenge unlike any seen on Earth before. At the same time, humans in every corner of the Earth are connected in real-time as never before. Does that give you hope?

PW – It does, yes. I especially get hope when I lecture children and young people because they’re much more connected than anybody else. Recently I lectured 400 school kids. Children are extremely bright and engaged in these things because they have access to all the social media. And when I lecture to slightly older people like university students, they say oh, why? Why hasn’t anybody taught us any of this? Here’s a bit of good news. The university where I’m lecturing here in Turin, Italy, has started a crash program of Master and Ph.D. courses in climate change. That’s something the students have never had before at this university. So, the fact that the effects of climate change are being more widely taught, especially to young people, is a source of hope. It has to be the people, particularly young people, who are active and who are going to determine the fate of life on Earth.

GH – You have seen the impact of human overreach and how it affects the Arctic. What do you say to people about getting together behind common standards for responsible planetary stewardship?

PW – Yes, we have to have that, but let’s do it with a common set of worthy standards for the way we treat nature and each other. There must be a common standard for getting rid of the carbon we’ve put into our atmosphere. There is a real international agreement on fluorocarbons.  It is seriously enforced, and even if it’s only enforced by shaming, it is being enforced on a global scale. Why can’t we get that done with carbon emissions? We have an international agreement, the Paris agreement. Unfortunately, we have a long, sordid history of agreements entered into by the Intergovernmental Panel on Climate Change, which everybody signs up for, and then ignores. We can’t afford to not have clear and firm commitments on emissions of atmospheric carbon and the removal of that carbon. We must at least match the existing international regulations which deal with atmospheric fluorocarbons or poisonous gases, to protect against whatever horrible things the human race would like to do to itself. We must have a global commitment to stop destroying the only atmosphere we have. We don’t have much time left to deal with this before it’s too late.

Peter Wadhams is Emeritus Professor of Ocean Physics and Head of the Polar Ocean Physics Group at the University of Cambridge, UK. He has led 40 polar field expeditions and is best known for his work on sea ice.

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