David Holland speaks in concise sentences that almost click-clack one after the other – in a sense, his clipped style conveys the immediacy of the large-scale geophysical changes the scientist is researching in the Antarctic. ‘We are all familiar with weather maps, typhoons, monsoons and. High pressure systems,’ says Holland. ‘We know how the atmosphere works – but we know less about how the ocean works.’
Still, we must learn because, as Holland points out, the oceans drive life around the planet. ‘The oceans have a way of operating – they are ‘conveyor belts’ that circulate water around the Earth. Air circulates in the atmosphere. The ocean works differently but its function is the same – it transfers heat and also transports food and nutrients for species.’ ‘Now, as Antarctica is starting to melt, a lot of fresh water is moving into the top of the ocean there – this could change its behaviour,’ Holland explains of his findings. That change could be very dramatic for the planet, with potential changes in the food supply for plankton and plants and animals.’
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There are two drivers of what the Antarctic is going through. The first, Holland explains, is natural variability. ‘Without human inspiration greenhouse gas Changes In any case, the planet naturally has different movements and changes. We know these as monsoons in Asia, El Nino in the Pacific, Arctic Oscillation, Atlantic Multidecadal Oscillation, etc. The planet goes through these over two, three, five or decadal periods where it potentially gets warmer or cooler, has more rain or more drought, etc. These patterns occur over short time scales. Furthermore, ice ages also occur naturally on long time scales, like ten-thousand-year cycles.’
Chill: Unabated human emissions of fossil fuels are warming the world, causing ancient glaciers in the Antarctic to collapse (Photo: iStock/Getty Images)
However, as nature thus expands or bends, a new kind of change begins to make itself felt. ‘Since coal began to be burned in large quantities around 1750, we have seen a dramatic increase in atmospheric carbon dioxide (CO2) in line with the greenhouse effect, or Earth’s rising temperature,’ says Holland. The important thing is that natural variability has no trend but the greenhouse effect has no variability – only a trend. This explains the increasing intensity of all the temperature graphs we are seeing right now.’
The oceans are actually absorbing 90% of the heat from the atmosphere and becoming warmer. ‘There is ‘polar amplification’ in the Arctic and Antarctic – changes associated with warming in these regions are four times larger than in other places,’ explains Holland. This is because when the ice here melts, it is replaced by a blue ocean that absorbs sunlight – it reflects blue but absorbs red. White ice reflects everything back – if you replace the white ice with a blue ocean, you trap the red heat in the water and warm the planet. this is snow albedo responseThis happens only in polar regionExplaining 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 the Arctic expected to warm by 16 to 20 degrees,’ Hollande said in his terse way.
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This is now manifesting in some of the Antarctic’s most amazing features – the glaciers. Holland researches both Thwaites Glacier and A23a Iceberg. He describes their melting, ‘As they melt, the cool but refreshing water they release remains over the ocean. It is so light that it does not mix with the rest of the ocean. This begins to change the ecosystem because water from below can no longer bring food to the surface because there is a layer of fresh water on top. The breakup of the A23a iceberg in 1986 was almost certainly a natural phenomenon. Every few decades, the ice shelves release larger icebergs as they grow larger. However, Thwaites is a different story,’ Holland pauses, then explains, ‘Thwaites is on the western edge of the Antarctic Peninsula. That ice is almost certainly melting due to human-influenced warming Climate changeCO2 in the atmosphere has changed the wind – this, in turn, has changed the movement of the Southern Ocean, bringing warmer water into the Thwaites, causing it to melt so fast.’ However, Thwaites is not just the story of a remote glacier melting. As Holland says, ‘The potential impact of this for humanity is huge sea level riseIt could mean meter. It could also produce thousands of A23s that would collapse inland. ‘Rather than natural melting, this would mean a catastrophic collapse of the Thwaites Glacier to the South Pole.’
As things melt away: Seal species can only survive on ice (Photo: iStock/Getty Images)
If melting glaciers will cause sea levels to rise, is it a good idea to invest in coastal property now? Holland thought and replied, ‘It’s all about risk. It depends on people’s timelines. If they invest in coastal property and then sell it within a decade, there will be no major problem. However, for those who are investing for the long term, such as governments who invest in large infrastructure on the coast, such cities and building construction will go under water due to sea level rise. The question is when – research on this is still intensive.
Meanwhile, the places Holland visits 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. There is no vegetation on this rock, it has been under glacial ice for millennia. Many species are also changing from cold to hot. Holland comments, ‘People in the polar regions have had to adapt, which makes you think that soon, many of us living away from the poles will also have to face the changes caused by these icy waters. .
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