Arctic ice shelf loses enormous chunk
The Arctic’s largest remaining ice shelf this week lost an enormous chunk into the ocean. The shelf, called 79N, comprises thousands of kilometres of glacier hanging over the ocean to the northwest of Greenland. Now it’s more than a hundred square kilometres smaller. The loss of glacier ice like this isn’t going to be replaced anytime soon, and in combination with similar events last year, as well as wildfires raging in the Amazon and the west of the USA, it paints a bleak picture for the planet - as Phil Sansom heard from Friedrich-Alexander University's Jenny Turton...
Jenny - In 2019 and in 2020, in both years, huge chunks of ice have broken off a glacier in the Northeast of Greenland. In total, over the two years, it's around a hundred kilometres squared of ice that's been lost, which is roughly the size of Manchester.
Phil - I mean, that's a huge area.
Jenny - Yes. And way bigger than we've seen previously. Normally it's two to three kilometres squared that are lost each year. But for the last two years, we've seen a much bigger increase in the amount of ice that's lost.
Phil - When you say it's lost, it's not like it mysteriously disappeared, right?
Jenny - No, no. The technical term is carving. This is where a piece of glacier or ice breaks off into a big iceberg or multiple big icebergs and floats away in the ocean.
Phil - So this isn't a bit that was on the glacier in Greenland on the land; this was a bit that was on the sea, and now it's broken off into the sea.
Jenny - Exactly, yeah. So the 79N glacier, partly it's on land and partly it floats on the ocean, which is called an ice shelf. And the part that has broken off was already in the water.
Phil - What is it that causes something like this, and especially causes it to happen two years in a row?
Jenny - There are quite a few reasons that are responsible for carving events. They're a natural process, normally, when they're much smaller. In the last two years we've had exceptionally warm summers in Greenland; in both 2019 and 2020 we had record breaking air temperatures. And because it's floating on the ocean, it's also vulnerable to warming oceans as well. When the air temperatures get particularly warm, you get a lot of melting on the surface of the glacier. This water then drains down into cracks and adds additional pressure to the glacier, which widens the cracks. And then this can end up causing a breaking off of the ice and it floats away.
Phil - So unquestionably, this is a rare event - thanks to global warming.
Jenny - It's very difficult to pinpoint particular events to climate change. But when you are having multiple extreme events, year after year, it becomes very hard to say that it's not climate change.
Phil - What do you predict for the future? Can you track how it's melting at the moment?
Jenny - Yeah, we've got quite a lot of observations going on in tracking the speed of the ice, the thickness, how much melting is happening. In terms of predicting, it's quite difficult, but the glacier that sits just south of 79N, in the last decade, lost all of its floating aspect. And now we're starting to wonder - are we going to see the same pattern in the neighbouring 79N glacier?
Phil - What are the consequences of losing these huge areas of ice shelf?
Jenny - I think sea level rise is one of the bigger problems that we face because obviously whilst the ice breaks off locally, the sea level rise will end up being a global phenomenon. Mostly it's through indirect sea level rise. Direct sea level rise is when you lose land ice that goes into the ocean and automatically melts and causes more sea level. Because ice shelves are already floating, the mass of them is already taken into account, so when they break off we don't get direct sea level rise; but they allow more of the land glaciers to flow out to the ocean, and so then you get indirect sea level rise perhaps a few years later.
Phil - How much to you is this sort of a bellwether for climate change as a whole?
Jenny - The Arctic is always seen as a very important location for climate change because it often feels the effects earlier than in other places and also to a larger effect. And because it's quite vulnerable to changes in the ice, which then affects how much solar radiation is absorbed, just a small change in the Arctic can cause quite a big impact.
Phil - I asked because it's been quite a hot summer here in the UK. And also obviously recently in the news, there have been these horrible wildfires all down the west coast of America. Are we seeing the same phenomenon?
Jenny - Yeah, it's all related really. In 2019 and 2020 we had particularly warm summers - heat waves in most of Europe, as well as in the Arctic. And this was also responsible for the temperatures in Greenland. And rightly so, we're seeing these record breaking wildfires on the west coast that are bigger and more fierce than they've ever been before. I saw a good analogy earlier: it was, if you light a match and throw it on a green lush forest, it's going to do way less damage than if you'd like to match and throw it on a very dry, dead forest. And because we've had years of droughts on the west coast of America, the forest fires are getting more intense and more frequent.
Phil - Not good, is it.
Jenny - No, and it's not just the northern hemisphere either where we're seeing this. I mean, at the start of the year in January, we also had unbelievable wildfires in Australia. And so it's not just in one particular place, it's happening all across the globe.