‘As global warming increases, Antarctica is starting to melt — this means oceans far away will also rise’

David Holland is Professor of Mathematics and Atmospheric/Ocean Science at New York University (NYU). Speaking to Times Evoke, he explains how the icy Antarctic ecosystem works — and why this is thawing now:
David Holland speaks in concise sentences that almost clickclack, one after the other — in a sense, his clipped style conveys the urgency underpinning massive geophysical changes the scientist is researching in the Antarctic.‘We are all familiar with weather maps, typhoons, monsoons and high-pressure systems,’ Holland says. ‘We are aware of how the atmosphere works — but we know less about how the ocean works.’
Yet, we should learn because, as Holland explains, oceans move life around the planet. ‘The oceans have a way of operating — this is the ‘conveyer belt’ which circulates water around Earth. The atmosphere circulates air. The ocean works differently but has the same job — it moves heat and also transports food and nutrients for species.’ Holland explains his findings, ‘Now, as Antarctica begins to melt, a lot of freshwater is going into the top of the ocean there — this could change its behaviour. That change could be very dramatic for the planet, with a possible alteration in plankton and food supplies for plants and animals.’

(Photo: iStock/ Getty images)
There are two drivers to what the Antarctic is undergoing. The first, Holland explains, is natural variability. ‘Without human-induced greenhouse gas changes, in any case, the planet naturally has different pulses and alterations. We know of these as the monsoon in Asia, El Nino in the Pacific, the Arctic oscillation, the Atlantic multidecadal oscillation and so on. The planet undergoes these in two, three, five or decadal durations where it becomes perhaps warmer or colder, there is more rain or more drought, etc. These patterns occur in short timescales. Further, ice ages also occur naturally over longer timescales like a ten-thousand-year cycle.’

CHILLING: Unabated human emissions of fossil fuels are heating up the world, making ancient glaciers now collapse in the Antarctic (Photo: iStock/ Getty images)
However, ever as nature thus stretches or folds, a new kind of change has begun to make itself felt. Holland states, ‘Since coal began to be burnt in large quantities around 1750, we’re seeing atmospheric carbon dioxide (CO2) increase dramatically with the greenhouse effect or heightened warming of Earth. Importantly, natural variability has no trend but the greenhouse effect has no variability — only a trend. This explains the increasing intensity of all the tem perature graphs we are seeing now.’

The oceans are in fact taking up 90% of heat from the atmosphere and warming. Holland explains, ‘The Arctic and Antarctic have ‘polar amplification’ — the warming-linked changes in these regions are four times bigger than in other places. This is because when the ice melts here, it is replaced by a blue ocean which absorbs sunlight — it is reflecting blue but absorbing red. White ice reflects everything back — if you replace white ice with blue ocean, you trap red heat in the water and warm the planet. This is the ice albedo feedback. It only happens in the polar regions, explaining why the Arctic and Antarctic are warming much more than other places. By the end of this century, the planet is projected to warm by four to five degrees — with 16 to 20 degrees warming in the Arctic,’ Holland states in his concise manner.

(Photo: iStock/ Getty images)
This is now manifesting itself in some of the Antarctic’s most awesome characters — glaciers. Holland researches both the Thwaites glacier and the A23a iceberg. He describes their thawing, ‘As these melt, the cold but fresh water they release stays on top of the ocean. It’s so light, it doesn’t mix with the rest of the sea. This begins to change the ecosystem because the water from below can no longer come up to the surface carrying food as the freshwater layer is there on top. The A23a iceberg break in 1986 was almost certainly a natural event. Every few decades, ice shelfs emit large icebergs as they become outsized. Thwaites is a different story though,’ Holland pauses briefly, then explains, ‘Thwaites is on the western side of the Antarctic peninsula. That ice is melting almost certainly due to warmer waters driven by human-influenced climate change. The CO2 in the atmosphere has changed the wind — this, in turn, has changed the motion of the Southern Ocean, bringing warm water to Thwaites, pushing it to melt so fast.’ Thwaites is not just a story of a remote glacier having a meltdown though. As Holland says, ‘Its potential impact for humanity is big — for sea level rise, it could mean a metre. It could also produce thousands of A23s which will collapse inland. Instead of natural melt, this would mean a catastrophic collapse of the Thwaites glacier all the way to the South Pole.’

AS THINGS THAW: Seal species can only survive living on ice (Photo: iStock/ Getty images)
If sea levels will rise, pushed by glaciers thawing thus, is investing in coastal property a good idea now? Holland muses and replies, ‘It’s all about risk. It depends on people’s timelines. If they invest in coastal property and then sell it within, say, a decade, there is likely no huge problem. For those who are in for the longer term though, like governments which invest in large infrastructure on the coast, such cities and building works will go underwater as sea levels rise. The question is, when — the research on this is intense now.’
Meanwhile, the places Holland goes to are changing before his eyes. ‘I visit Western Greenland for research — in recent years, I have seen it becoming less ice and more exposed rock. This rock has no vegetation on it, having been under glacial ice for millennia. Many species are also changing from cold to warm ones. People in the Polar regions are having to adapt,’ Holland remarks, leaving you with the thought that soon, many of us far living away from the Poles will also face changes swept in by these once-icy waters.

(Photo: iStock/ Getty images)