How has global warming impacted Antarctica?

Huw Griffith is an Antarctic marine biologist and was interviewed by Sally Le Page about his findings from his work in Antarcica, in particular about the effect climate change has on the area. 

Huw - Any research in the polar regions has got that as a background, whether you're specifically researching climate change or not. So even stuff that I do at the bottom of the sea with a few creatures that either have loads of legs or no legs, or loads of eyes or no eyes, always in the background is how will these things be affected by climate change? Because we can see it out of the windows of our research stations; for example, we can see the glaciers retreating. I've been going to Antarctica for nearly 20 years now, and I can go places and see what's changed in my career, not my lifetime even, just my career. It is scary that we can observe these things first-hand now, and it's not just computer simulations or models of the future.

We see it with the length of season of things that can live down there for us, or we have ecosystems that reach what we call tipping points, where something switches from one way of doing things to another in a usually irreversible way. A really simple version of this is where the sea ice in the shallow water acts as a way of blocking some of the light out from getting to the bottom of the sea. Instead of a normal beach in the UK, where it's covered in seaweed, if you go just below that level in Antarctica, there would be animals dominating, covering the rock like sponges and corals and soft corals and things like that. But if the sea ice starts to get thinner earlier or even melts away earlier, you get more days of daylight at the bottom of the sea. And there's enough days then for the kelp to start to grow, and they start to grow over the top of these animals. And all it needs is a few extra days where the ice has melted a bit earlier and you get this switch to a completely different system.

Sally - It reminds me a bit of coral reefs in that once coral reefs have been bleached enough or the slimy algae grows on the top, then you'll never get your reef back. Once it's gone, it's gone. And it's really hard to get it back, even if you return to the conditions it was at before.

Huw - Exactly. We could lose some of our specialists, especially with warming. That extra bit of stress, some of these animals actually actively are fighting to keep their bodies held together in the cold, so less energy goes into reproduction or growth and things like that because you're just holding your body together in the cold water. If the water warms up a bit, some of the things you're doing could actually be harmful to you, but also the competitors that don't need to worry about doing that extra effort so they can eat faster, reproduce faster, grow faster, could all come in and out compete you. Those other animals are quite far away, but it's amazing that we thought Antarctica was so isolated, but we have tourist ships going down there now, scientific vessels, we have fishing boats going down there, all of which can carry animals backwards and forwards.

We even have things like microplastics and things washing into Antarctica, so even a place that we thought was quite safe from our impact has got things coming in. We have something like 700 million pieces of kelp floating around the Southern ocean at any one point and all you need is one particularly bad invasive species to be sat on one of those pieces of kelp and get washed onto the right beach in Antarctica in a warm year, and it could become established. That's why monitoring Antarctica and seeing where the most likely to be affected places are through climate change, ocean acidification and all these other things is the job that we do.