July 2023 was officially the hottest month in recorded history — and, as such, was a regrettable milestone in the history of climate change. Scientists lamented the "new abnormal" that made itself apparent throughout that month, one that included extreme weather events like wildfires, tropical storms and freakishly scorching heatwaves.
Ninety-seven percent of scientists agree that this global warming is primarily caused by human activities such as burning fossil fuels, and as such July 2023 has increased public pressure on political officials to impose effective environmental regulations.
In the midst of these developments, researchers from the United Kingdom, South Africa and Chile published a paper in the journal Frontiers in Environmental Science. Simply titled "Antarctic extreme events," the authors analyzed a wealth of data about extreme weather events in Antarctica and the Southern Ocean. They did so across a range of environments and timescales, with the purpose of determining the extent of the continent's vulnerability.
Their conclusion was sobering. Reaching the Paris Agreement's 1.5°C goal will be tough, they surmise, unless we take strong action now to cut down greenhouse gas emissions to zero by 2050. Otherwise, the authors write, "it is virtually certain that future Antarctic extreme events will be more pronounced than those observed to date." In other words, the extreme weather we're seeing this year, from floods in Alaska to wildfires in Hawaii, could get even worse.
To learn more about the world of the Arctic and Antarctic, and how climate change will change these regions, Salon spoke with the study's lead author Prof. Martin Siegert, a glaciology professor, vice president at the University of Exeter, and former co-director of the Grantham Institute for Climate Change at Imperial College London.
The following interview has been lightly edited for length and clarity.
When can we expect there to be no more ice in the Arctic and Antarctic?
That's a good question. The answer to the Arctic is very different than the answer to the Antarctic.
The Arctic is largely an ocean surrounded by land and over the ocean, the Arctic Ocean, there is a thin layer of sea ice. And that has been retreating pretty much every year since the 1970s. Maybe before that, but that's when we started measuring. There have been predictions about there being no summer ice — ice grows in the winter, it shrinks in the summer — somewhere around the mid-century. Some people say 2030. I think that's a bit too early, but somewhere around mid-century: 2050, 2060. In the wintertime it'll grow back, of course, because it's still pretty cold.
The massive ice sheet in Greenland, that's going to take some shifting. Those massive ice sheets, they take an awfully long time to build up and to melt. The last time we were between ice ages, which was about 125,000 years ago, the ice sheet would've been far less extensive. It would've been only occupying the northern part of Greenland. So large parts of southern Greenland that now have a big ice sheet would have been free of ice.
Now Antarctica is a different matter entirely. The Antarctic ice sheet has been in a pretty persistent state for about 14 million years, and it would take a colossal amount [of climate change] to totally get rid of that, and it would take tens of thousands of years to do it. But the ocean is different because the ice sheet will only sort of come and go when there is surface melting to take it away — because it's in the central part, it's on land — but the sea ice and the periphery of the ice sheet can be melted by the atmosphere and also, importantly, the ocean. And its ocean warmth that is melting the Antarctic ice sheet at the moment...
That makes sense. How much will sea levels rise if the climate change-vulnerable regions of the Arctic and Antarctic melt, and how many people will be impacted?
We've done some research on that. The IPCC [the United Nations' Intergovernmental Panel on Climate Change] has projections of sea level rise from now to 2100, and then running onwards after that. It says somewhere between half a meter [20 inches] and a meter [39 inches], depending on which scenario and which model — but I think that's an underestimate, and other glaciologists do as well.
What do you think if it is instead half-a-meter or a meter?
Yeah, it could be higher. The way the IPCC works is it's all bounded in probabilities, so it's likely for sea levels in 2100 to be somewhere between half a meter and a meter higher than today. But what that likely means in IPCC speak is a 66% probability of that range. And what they're telling us is that there's a one in three chance of it being outside that range. There is no chance it's going to be less than 50 centimeters. So that means there's a one in three chance it is going to be higher than a meter.
You can't discount that. That's far too likely. And I and another glaciologist have pointed this out: you wouldn't discount there being one-and-a-half, maybe two meters by the end of this century now — and it doesn't stop at 2100. It just keeps going. So it's quite possible for there to be five meters by 2150, and five meters by 2150 will be a disaster. Lowline Pacific nations are going to go, the Netherlands probably won't be able to survive, downtown New York City will probably be underwater. There is real significance we could be talking about under that scenario.
Let us talk about the lower range of the estimate, half-a-meter to a meter. If it just rises that much, will New York City still be underwater? Will the Netherlands still be underwater? I'm guessing Venice will be in trouble, to put it mildly.
Yes, yes, all of those things. It's not just the sea level itself. It's the spring tide. It's the low pressure zone. When you have low pressure over the ocean, artificially, you have lots of water trying to run off into the ocean that's got to go somewhere. We've got a lot of winds pushing the water in one direction. Sometimes you get this sort of coalition of all of those things together: Low pressure, lots of water trying to get out of the rivers, the wind also pushing the ocean back into a certain place. And that's a flooding event, right? That's what you get: A spring tide flooding event. Add another meter on top of that, and it's even worse. Add another five meters on top of that, and it's a total disaster of course.
And that's really what we're talking about. We're talking about a billion people on the planet that are close to at the water's edge right now. They will be displaced. They will have to go somewhere.
I appreciate you being so thorough. I'm going to pivot a little bit. What glaciers do you think will be the "last glaciers," and how do glaciologists feel about that depressing prospect?
I'm just about to go to the Alps for holiday — going to go by train, low carbon route, very conscious of the carbon footprint — and the Alps glaciers are shrinking fast. They're going back at 10, 20 meters a year, so you can see them lose over time. I was there about five years ago, so some of the glaciers are going to be 50 to 100 meters retreated compared to what it was the last time I was there. You just need to revisit this place. That's a concern.
But there are parts of the planet where ice is going to stay around for a long time. In the East Antarctic that will definitely be the case. I said the East Antarctic ice sheet has been around in a persistent state for 14 million years. And there are parts of East Antarctica that are going to take some shifting [to melt]. The last time there was no ice on the planet, no ice at all, would've been during the Paleocene–Eocene Thermal Maximum. That's 55 million years ago.
That's when CO2 levels in the atmosphere were a thousand parts per million. They're about 400 at the moment. And the temperature was about 12 degrees warmer in Africa than it is today. Even though Antarctica was in complete darkness for six months, like it is right now, the blanket of greenhouse gases kept the planet so warm that ice couldn't form. Now we are nowhere near that. The answer to your question, Where will the last bit of ice to go be? It will be in Central East Antarctica, but it's so far off. We've got so many more problems to face before we reach that.
This question is very important to me on a personal level because I believe that people can better understand climate change if they visualize it, if they can hear it and feel it. When talking about the disintegration of large sections of the Larsen A, Larsen B and Wilkins ice shelves, can you help readers viscerally understand what that was like when these ice shelves collapsed? I think of the opening scene in "The Day After Tomorrow," which recreates the real-life collapse of Larsen B ice shelf in 2002. My question is, if a human could stand in the middle of this, what would it be like?
You wouldn't want to be in that situation. I actually watched "The Day After Tomorrow" for the first time again since it first came out just recently. It's brilliant imagery, but it was an iceberg calving event. A great big crack through the ice shelf happened, and their camp happened to be right in the middle of that. It was sort of split, the tents went one way and the other [stuff] went the other way. A bit unlucky really, but that's Hollywood for you, I guess.
That's not how Larsen B ice shelf broke up. Those ice shelves, the ones that broke up, would've had lots of melted water on the surface. In "The Day After Tomorrow," there was no melted water at all. There'd be ponds everywhere, and those ponds melt on the shelves — and down into the ice shelf, into the floating slab of ice through a hole. And if they hit the bottom, then that punctures the structural integrity of the ice shelf. And these ponds would've put a hole in many of them — dozens of holes, hundreds of holes — all around this ice shelf.
All of a sudden, your slab of ice goes from being a really strong body of ice to really weak. And what happens is a catastrophic domino effect, possibly with a bit of tidal influence, because this ice shelf is lifted up and falling down all the time. A crack appears, and because you are puncturing holes all around it, then the ice slab simply falls. It topples over, it knocks the next one over and the next one over, and it all goes really quickly.
So this massive slab of ice disappears in about like three days, like it just blows up. And it does that because of the meltwater on the surface puncturing down into the ice itself. And that just causes weakness, structural weakness, to the whole slab of ice. And so once one bit falls, the rest of it kind of goes.
