Sea change around the icy continent

British Antarctic Survey's Huw Griffiths

The sea temperature near the West Antarctic Peninsula has risen by 2°C over the past 40 years, and further changes across Antarctica threaten upheaval among the creatures living there. So says the British Antarctic Survey’s Huw Griffiths, who has conducted a wide-ranging review of research in the region. As a marine biologist rather than a specialist climate scientist, Griffiths looked at how global warming has affected and will continue to affect life in the southernmost seas. His study was partly inspired by the Scientific Committee on Antarctic Research (SCAR) report published in November that predicted a 1.4 m sea rise by 2100.

He drew together conclusions from the SCAR figures, British Antarctic Survey (BAS) surveys, and research performed elsewhere. In particular he used the results of a collaboration between the BAS and the University of Bath that combined predictions from 18 different models of how sea ice cover will change over the next 90 years. “All of the models agreed that there’s going to be a reduction of sea ice, and most of them agree strongly where they will be,” Griffiths explained. “If you’ve got less sea ice then there’s less food available, as it’s key for all the plankton blooms.”

Another threat to Antarctic life comes as the oceans absorb CO₂, making them more acidic. “Polar regions, because cold water can take up more CO₂ than warm water, are at particular risk from ocean acidification,” Griffiths said. “We expect the animals that build their skeletons out of calcium carbonate to do badly, because calcium carbonate becomes limited as the ocean gets acidified.”

The third area that Griffiths looked at suggested that temperatures around the West Antarctic Peninsula are now at a level where warmer water species may invade the traditionally cooler seas. “Even a small change in the species you’ve already got can make a big change in the ecosystem, even without bringing in other species,” he noted.

Griffiths is clearly more at home talking about marine life than what might be causing the changes in marine life that he’s seeing. However, when I asked him to help me with the purpose of my blog – explaining climate change – he said that he was well positioned to describe some of the effects. “Antarctica is one of the best places if you want to observe real changes due to human impact,” he explained. “In the West Antarctic 90% of the glaciers that are on land are retreating. We’ve seen surface waters warming, we’ve seen sea ice reducing every summer. Our physical scientists tell me that it’s linked to human activity, as in the amount of CO₂ being released into the atmosphere, directly affecting the temperature and weather systems surrounding the Antarctic.”

While having benefited from personally seeing strong evidence about climate change, the way that some people view the debate on climate change as almost a matter of faith troubles Griffiths. “As a scientist I was always taught to take things on a case by case basis. I look at all the different indicators I’ve listed, and I can see the work behind it.” He says that even if people don’t have this depth of knowledge, it’s “incredibly important” to step back and look at the balance of evidence if presented with one piece that has been discovered to be wrong. “There are so many links between human activity and climate change. As a scientist you can never be 100% sure of your findings – there is always going to be a degree of uncertainty and that can make it difficult for people to understand the full complexities of scientific research. It is also important to remember that scientists base their findings on evidence, rather than belief.”



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