Melting Antarctic ice may cause sea level rise of 17 FEET by 3000 AD

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The Daily Mail 2021-12-24 Link

By Ian Randall For Mailonline Published: 23:49 AEST, 24 December 2021 | Updated: 23:57 AEST, 24 December 2021 367 View comments When Busted sang about having been to the year 3000 — where 'not much has changed, but they lived underwater' — who'd have suspected it might be prophetic? In fact, sea levels may rise by as much as a whopping 17 feet by the millennium's end if the Antarctic ice sheet continues to melt under current global warming trends. This is the warning of a team of researchers led from Hokkaido University, who modelled the fate of the Antarctic ice sheet beyond the 21st century.  While the 'business as usual' forecast is bad, this fate may be averted if greenhouse emissions are curbed, the team said, keeping sea level rise to under one foot. Substantial sea level rise could render large areas of densely populated coastal land uninhabitable without extensive and expensive coastal modification to protect it. Sea levels may rise by as much as a whopping 17 feet by the millennium's end if the Antarctic ice sheet continues to melt under current global warming trends. Pictured: Antarctica In their study, Dr Chambers and his colleagues built on models previously consulted by the Intergovernmental Panel on Climate Change in their recent  Sixth Assessment Report . This United Nations body exists to advance our understanding of human-driven climate change and provide objective and comprehensive scientific information on the subject. However, it does not conduct original research or monitor the progress of climate change — but rather conducts a periodic, systematic and thorough review of existing scientific literature in relevant fields. 'This study demonstrates clearly that the impact of 21st-century climate change on the Antarctic ice sheet extends well beyond the 21st century itself,' said paper author and meteorologist Christopher Chambers of Japan's Hokkaido University. 'The most severe consequences — multi-meter contribution to sea-level rise — will likely only be seen later,' he added. 'Future work will include basing simulations on more realistic future climate scenarios, as well as using other ice-sheet models to model the outcomes.' In their study, Dr Chambers and colleagues build upon existing research — the so-called 'Ice Sheet Model Intercomparison Project for the Coupled Model Intercomparison Project Phase 6', or 'ISMIP6' for short. This verbosely titled international project employed the latest generation of climate models to estimate the impact of global warming on both Antarctica and Greenland's ice sheets come the end of the current century. The results — which informed the recent  Sixth Assessment Report of the Intergovernmental Panel on Climate Change — found that, under unabated warming, the Antarctic will contribute some 3–12 inches (8–30 cm) to sea level rise. This figure, however, could be curbed to just 0–1 inches (0–3 cm) in scenario where greenhouse gas emissions were significantly reduced. The researchers extended ISMIP6's projections further into the future — considering both unabated warming and reduced emissions trajectories — using an ice sheet model known as 'Simulation Code for Polythermal Ice Sheets (SICOPOLIS). Up until the year 2100, the simulation ran exactly the same as in the original ISMIP6 experiments — beyond which, the team assumed that the late 21st-century climatic conditions remained constant, so no further climate trend was applied. From the models' outputs, the team focussed on the total mass change of the southern continent's ice sheets and regional changes in East and West Antarctica and on the Antarctic Peninsula — as well as the contributors to such. The researchers extended ISMIP6's projections further into the future — considering both unabated warming and reduced emissions trajectories — using an ice sheet model known as 'Simulation Code for Polythermal Ice Sheets (SICOPOLIS). Pictured: simulated mass loss of the Antarctic ice sheet from 1990 until 3000 expressed as sea-level contribution By the year 3000, sea levels could rise by as much as 4.9–17.7 feet (1.5–5.4 metres) under current warming trends — resulting in the largest part from the collapse of the West Antarctic ice sheet. Could emissions be curbed, however, the researchers' models suggest that sea level rise could be constrained to just 0.4–1 feet (0.13–0.32 metres). The potential collapse of the West Antarctic ice sheet would be made possible, the team noted, by the fact that it is grounded on a bed that is mostly below sea level. The full findings of the study were published in the Journal of Glaciology . Global sea levels could rise as much as 10ft (3 metres) if the Thwaites Glacier in West Antarctica collapses.  Sea level rises threaten cities from Shanghai to London, to low-lying swathes of Florida or Bangladesh, and to entire nations such as the Maldives.  In the UK, for instance, a rise of 6.7ft (2 metres) or more may cause areas such as Hull, Peterborough, Portsmouth and parts of east London and the Thames Estuary at risk of becoming submerged. The collapse of the glacier, which could begin with decades, could also submerge major cities such as New York and Sydney. Parts of New Orleans, Houston and Miami in the south on the US would also be particularly hard hit. A 2014 study looked by the union of concerned scientists looked at 52 sea level indicators in communities across the US. It found tidal flooding will dramatically increase in many East and Gulf Coast locations, based on a conservative estimate of predicted sea level increases based on current data. The results showed that most of these communities will experience a steep increase in the number and severity of tidal flooding events over the coming decades. By 2030, more than half of the 52 communities studied are projected to experience, on average, at least 24 tidal floods per year in exposed areas, assuming moderate sea level rise projections. Twenty of these communities could see a tripling or more in tidal flooding events. The mid-Atlantic coast is expected to see some of the greatest increases in flood frequency. Places such as Annapolis, Maryland and Washington, DC can expect more than 150 tidal floods a year, and several locations in New Jersey could see 80 tidal floods or more. In the UK, a two metre (6.5 ft) rise by 2040 would see large parts of Kent almost completely submerged, according to the results of a paper published in Proceedings of the National Academy of Science in November 2016. Areas on the south coast like Portsmouth, as well as Cambridge and Peterborough would also be heavily affected. Cities and towns around the Humber estuary, such as Hull, Scunthorpe and Grimsby would also experience intense flooding.  Share what you think The comments below have not been moderated. The views expressed in the contents above are those of our users and do not necessarily reflect the views of MailOnline. We are no longer accepting comments on this article. EXCLUSIVE 'VVIPs' Prince Harry and Meghan Markle are flanked by FIVE bodyguards as they warmly embrace competitors at the Invictus Games while being filmed by Netflix crew amid UK security row  Published by Associated Newspapers Ltd Part of the Daily Mail, The Mail on Sunday & Metro Media Group