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Faster than expected – rise in sea level, especially for Australian and other coastal cities

‘The great unknown’: New climate change data lifts the sea-level threat, SMH , Peter Hannam, 23 May 17   The giant ice sheets of Antarctica and Greenland are melting faster than scientists previously estimated, raising the prospect of faster sea level rise placing at risk low-lying areas of Sydney and similar exposed cities around the world.

New research, including from the US National Oceanic and Atmospheric Administration (NOAA), has lifted the “plausible” sea level rise by 2100 to as much as two metres to 2.7 metres.

That has superseded earlier estimates, such as the 2013 Intergovernmental Panel on Climate Change (IPCC), that placed the likely top range of sea level rise at about one metre if greenhouse gas emission rises continued unabated.

Those higher forecasts have now been included in new mapping by Coastal Risk Australia that combines the estimates with national high-tide data and the shape of our coastline.

The resulting maps show airports in Sydney, Brisbane and Hobart will be largely under water by 2100 if that two-metre rise happens.

Other areas at risk in Sydney from such a rise include Circular Quay, Wentworth Park, the Royal Botanic Gardens, Woolloomooloo and Rose Bay.  ………

Rising seas

NOAA estimates global mean sea levels have risen about 3.4 millimetres a year since 1993, roughly double the average rate of increase during the 20th century.

Even the last century’s pace of increase was the fastest in at least 2800 years, NOAA said.

Global warming is driving the increase in sea levels by melting land ice – such as glaciers and ice sheets – and from the thermal expansion of the warmer oceans.

John Church, a global sea level expert at the Climate Change Research Centre at the University of NSW, said other new research indicated Antarctica’s contribution to rising seas appears to particularly sensitive to carbon emissions rates – underscoring the urgency to reduce them…….http://www.smh.com.au/environment/climate-change/the-great-unknown-new-climate-change-data-lifts-the-sealevel-threat-20170522-gwa963.html

May 24, 2017 - Posted by Christina Macpherson | AUSTRALIA, climate change, oceans