By Paul Homewood
The latest sea level scare!
Ice sheets in Greenland and Antarctica whose melting rates are rapidly increasing have raised the global sea level by 1.8cm since the 1990s, and are matching the Intergovernmental Panel on Climate Change’s worst-case climate warming scenarios.
According to a new study from the University of Leeds and the Danish Meteorological Institute, if these rates continue, the ice sheets are expected to raise sea levels by a further 17cm and expose an additional 16 million people to annual coastal flooding by the end of the century.
Since the ice sheets were first monitored by satellite in the 1990s, melting from Antarctica has pushed global sea levels up by 7.2mm, while Greenland has contributed 10.6mm. And the latest measurements show that the world’s oceans are now rising by 4mm each year.
“Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and atmosphere, the rate at which they are melting has accelerated faster than we could have imagined,” said Dr. Tom Slater, lead author of the study and climate researcher at the Centre for Polar Observation and Modelling at the University of Leeds.
The results are published today in a study in the journal Nature Climate Change. It compares the latest results from satellite surveys from the Ice Sheet Mass Balance Intercomparison Exercise (IMBIE) with calculations from climate models. The authors warn that the ice sheets are losing ice at a rate predicted by the worst-case climate warming scenarios in the last large IPCC report.
Dr. Anna Hogg, study co-author and climate researcher in the School of Earth and Environment at Leeds, said: “If ice sheet losses continue to track our worst-case climate warming scenarios we should expect an additional 17cm of sea level rise from the ice sheets alone. That’s enough to double the frequency of storm-surge flooding in many of the world’s largest coastal cities.”
This is a case of “Watch The Pea”!
For a start, sea levels are not rising by 4mm a year. According to satellites, the rate is 3mm:
We are then told:
Ice sheets in Greenland and Antarctica have raised the global sea level by 1.8cm since the 1990s.
If these rates continue, the ice sheets are expected to raise sea levels by a further 17cm by the end of the century.
Over a 25-year period, 1.8cm works out at 0.72mm a year. At this rate, seas would rise by 57mm, not the 170mm promised.
So why the difference? Watch the pea:
So, the threatened 170mm is not derived from the current ice loss, but based on “worst-case scenarios”, which have been proven many times to be nonsensical.
Of course, it may be that ice melt and sea level rise are accelerating. Except that they aren’t. Ice mass loss from Greenland’s ice sheet has actually slowed down since 2012.
Last year, ice melt increased again due to a warm summer, but this has already been reversed this year, which is not yet reflected in DMI’s chart below:
And according to tide gauges, sea levels have been rising at steady rate since the mid 19thC, with the exception of a slowdown between the 1960s and 80s:
That slowdown was associated with a drastic cooling of the climate in Greenland, and indeed across most of the Arctic between 1958 and 2001:
Since then, of course, temperatures in Greenland have returned to earlier levels, with a consequent of increased ice melt. But there is no evidence that temperatures will carry on rising, or ice melt increase. Indeed the opposite is likely the case, when the AMO turns cold, as it did around 1960.
As for the Antarctic, scientists cannot even agree whether the ice sheet is growing or sinking, with NASA sure it is the former.
In short, there is no evidence that sea level rise will be any different in the next hundred years than it was in the last.
The press release which has been widely reported word for word claims that sea levels will rise by 40cm by 2100:
This is even more absurd than the 17cm quoted for ice melt.
via NOT A LOT OF PEOPLE KNOW THAT
September 2, 2020 at 08:42AM