Just when you think scientists have agreed on the melting ice in Antarctica and how this will affect sea-level rises, a new study comes out disagreeing with the last. Now, in a new study, scientists say that while the melting of ice in Antarctica will contribute to sea-level rises this century, and will be significant as well as challenging,
the nightmare scenarios of some studies are just not realistic.
The study, led by Catherine Ritz from Université Grenoble Alpes in France and Dr. Tamsin Edwards from The Open University, now predicts that sea-level rises are more likely to be 10cm this century under a mid to high climate scenario, and that it is extremely unlikely to be higher than 30cm. Previous studies have claimed from 30 cm to one meter rises; this study says there is a 1 in 20 chance of that happening.
“In our study — those just aren’t plausible,” Edwards told BBC News.
This study is unique in that the researchers have used real world physics together with the shape of the continent’s bedrock and how the ice moves over it, with satellites that track changes on the continent supporting their data. The model revealed how the polar south would react if greenhouse gases rose at a medium to high rate.
“The bed of Antarctica is so important for what the ice sheet is doing, and there are parts of it that are just too bumpy and rough or are not sloping in a way that will allow for anything to happen too quickly,” said Edwards.
The researchers ran the model over 3,000 simulations; this is not the first time multiple simulations have been done on this; however, it is a first for the simulations to be compared with present day, and then have the comparisons taken into account.
Edwards said in a statement: “Our method is more comprehensive than previous estimates, because it has more exploration of uncertainty than previous model predictions, and more physics than those based on extrapolation or expert judgement.”
“People have done multiple simulations before, but what they haven’t then done is see how well they compare with the present day, and put that into re-weighting the predictions.
“So, we take those 3,000 runs and compare them to what’s happening now in the Amundsen Sea, and if any look as though they are going too fast or too slow, we give them a lower weight in the future.
“We’re constraining the model with the observations. Nobody has really done this sort of formal scoring before,” Edwards explained to BBC.
The study’s central estimate raises the Intergovernmental Panel on Climate Change (IPCC) central prediction of 60 cm global sea-level rise by just a few centimeters under the mid to high scenario they used. But the UK and French team’s method allowed them to assess the likelihood of sea-level rise from substantial parts of the ice sheet collapsing, which the IPCC could not due to a lack of evidence, according to the University of Bristol.
Andrew Shepherd from Leeds University, who heads the “Ice sheet Mass Balance Inter-comparison Exercise” (IMBIE) project, and where the study gained its satellite information, told BBC: “This new study is the first prediction of future ice losses to really take today’s changes into account. Because of this, we can be more confident in their findings.”
“Although extreme ice losses are an unlikely prospect, there is no reason to be complacent about the impacts of climate change on our lifestyles,” he warned.