DATE: November 13, 2018
SNIP: Even modest temperature rises agreed under an international plan to limit climate disaster could see the ice caps melt enough this century for their loss to be “irreversible”, experts warned on Monday (Nov 12).
Scientists have known for decades that the ice sheets of Greenland and Antarctica are shrinking, but it had been assumed that they would survive a 1.5-2°C temperature rise relatively intact.
However, according to a new analysis published in the journal Nature Climate Change, even modest global warming could cause irreversible damage to the polar ice, contributing to catastrophic sea level rises.
“We say that 1.5-2°C is close to the limit for which more dramatic effects may be expected from the ice sheets,” Frank Pattyn, head of the department of geosciences, Free University of Brussels and lead study author, told AFP.
His team crunched data on annual temperature rises, ice sheet coverage and known melt levels and found that both Greenland and Antarctic ice sheets would reach a “tipping point” at around 2°C.
“The existence of a tipping point implies that ice-sheet changes are potentially irreversible – returning to a pre-industrial climate may not stabilise the ice sheet once the tipping point has been crossed,” said Pattyn.
Many models of the 1.5-2°C scenario allow for the threshold to be breached in the short term, potentially heating the planet several degrees higher, before using carbon capture and other technologies to bring temperatures back into line by 2100.
The study warned against this approach, however, saying that a feedback loop set off by higher temperatures would “lead to self-sustained melting of the entire ice sheet” even if those rises were later offset.
For Greenland, the team said with 95 per cent certainty that major ice sheet decline would occur at 1.8C worth of warming.