Thirteen hundred pages into Kim Stanley Robinson\u2019s majestic Mars trilogy, the narrative switches back to Earth.<\/p>\n
It\u2019s the middle of the 22nd century and the West Antarctic ice sheet has suddenly collapsed. A private spaceplane is circling over the South Pole and a geologist and a plutocrat are peering down at Antarctica. The geologist says the huge volumes of ice tumbling into the Southern Ocean are going to raise global sea levels by several metres. \u201cThat\u2019s it for every beach in the world,\u201d the plutocrat responds.<\/p>\n
This is science fiction, so not a reliable guide to the future. Indeed, the West Antarctic ice sheet may collapse much sooner than that.<\/p>\n
Scientists from several Australian, South African and French universities warned in a paper in Nature last week that the planet may already, even in a best-case scenario, be heading for a tipping point of unstoppable ice loss that would mean \u201cabrupt changes\u201d.<\/p>\n
\u201cAbrupt\u201d in climatological terms means happening over decades, rather than centuries. The reason, say the researchers, is that if global temperatures rise more than 1.5C above pre-industrial levels, some parts of the Antarctic environment might be more vulnerable to irreversible change than had been thought.<\/p>\n
\u2018We\u2019ve got a major problem with the West Antarctic ice sheet. Is it on its way to destruction?\u2019<\/p>\n
Martin Siegert, glaciologist<\/p>\n
Either way, experts believe a global rise in sea level of at least three metres may now be inevitable as a result of the break-up of Antarctica\u2019s giant western glaciers. That may not spell the end of beaches, but it would be enough to make the Netherlands nervous. The UK could lose Lincolnshire and parts of East and South Yorkshire unless flood defences are substantially improved. Mumbai, New York and Shanghai would all be vulnerable.<\/p>\n
The glaciology and geology of Antarctica are better understood now than when Robinson\u2019s novels were published in the 1990s. Satellites began capturing images of the polar cap in 1978 and up to this point British Antarctic Survey and other research teams had surveyed the continent\u2019s seismology using drills and dynamite.<\/p>\n
Now, researchers use airborne radar to chart the seabed under the ice, investigate the deep waters below the ice sheet using autonomous vehicles such as the Nasa-funded Icefin, and can tag elephant seals with sensors that measure temperatures 1,000 or more metres below the surface.<\/p>\n
\u201cThe fundamentals of the West Antarctic ice sheet are known fairly well now,\u201d said glaciologist Prof Martin Siegert, who is deputy vice-chancellor of the University of Exeter. \u201cIt\u2019s a marine-based ice sheet, so it\u2019s resting on a bed, but all around it is ocean water.\u201d<\/p>\n
The ice may seem solid, but it consists mostly of glaciers, such as the vast Thwaites, which flow slowly down towards the ocean. That ocean water has been getting warmer along with the rest of the planet, which create a particular problem here. The warmer water eats away at the point where the ice meets the seabed, which scientists call the grounding line.<\/p>\n
Rob Larter, a marine geophysicist with the British Antarctic Survey, says the ice shelves rise and fall by a metre or so each day, pushing the warmer water up and down and putting the glaciers under further stress. As the water separates ever-larger amounts of ice from the seabed, the ice sheet grows less and less stable, cracking up and calving icebergs.<\/p>\n
Since Robinson\u2019s Mars trilogy was published, the rate of ice loss from the West Antarctic sheet has accelerated sixfold, the Nature researchers said.<\/p>\n
\u201cThe way we\u2019re losing ice is the increased flow of these big glaciers \u2013 Thwaites, Pine Island,\u201d Larter said. \u201cThey\u2019re flowing faster. The Thwaites is the keystone of the West Antarctic ice sheet. It sits in the middle. If you take out Thwaites, you open up new fronts on the large glacier basins either side of it.\u201d<\/p>\n
Hollowing out the ice sheet would allow warmer water to start melting its underbelly.<\/p>\n
Yet Siegert said, there are gaps in the science that leave important questions open: \u201cWe know we\u2019ve got a major problem with the West Antarctic Ice Sheet.<\/p>\n
\u201cIs it on its way to complete destruction? And if it is, how long will that take? To answer that properly, we need a huge amount of geophysical data.\u201d<\/p>\n
Scientists\u2019 understanding of the ice sheet is a patchwork of studies, he said, so they are working on the next generation of radar surveys to establish more precisely factors such as how unstable the ice shelf is, and where the grounding line is retreating fastest.<\/p>\n
For Siegert and his colleagues, the solution is obvious: keep global heating below 1.5C and the worst effects will be avoided.<\/p>\n
Other scientists have suggested geo-engineering solutions, such as spraying Antarctica with sulphur dioxide to reflect sunlight back into space, scattering hollow glass beads into new ice to thicken it, or installing sea curtains to divert warm water away from the ice sheet.<\/p>\n
\u201cThe cost of these things would be absolutely huge,\u201d said Jim Marschalek, a postdoctoral research associate at Imperial College London and part of its West Antarctic team. \u201cIt\u2019s so hard \u2013 and so costly \u2013 to work in Antarctica because it\u2019s such a hostile place. You\u2019re better off spending the money decarbonising.\u201d<\/p>\n
Some scientists are alarmed that these geo-engineering ideas are being taken seriously, with projects under way in the US and EU, and are mobilising opposition. For now, science fiction is not done with Antarctica.<\/p>\n
Photograph by Nature Picture Library\/Alamy<\/p>\n","protected":false},"excerpt":{"rendered":"Thirteen hundred pages into Kim Stanley Robinson\u2019s majestic Mars trilogy, the narrative switches back to Earth. It\u2019s the…\n","protected":false},"author":2,"featured_media":92579,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[1397,90,56,54,55],"class_list":["post-92578","post","type-post","status-publish","format-standard","has-post-thumbnail","category-environment","tag-environment","tag-science","tag-uk","tag-united-kingdom","tag-unitedkingdom"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/92578","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/comments?post=92578"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/92578\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/92579"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=92578"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=92578"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=92578"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}