An alarming claim from from the University of Exeter, based entirely on modeling.
Study finds early warning signals of abrupt climate change
A new study by researchers at the University of Exeter has found early warning signals of a reorganisation of the Atlantic oceans’ circulation which could have a profound impact on the global climate system.
The research, published today in the journal Nature Communications, used a simulation from a highly complex model to analyse the Atlantic Meridional Overturning Circulation (AMOC), an important component of the Earth’s climate system.
It showed that early warning signals are present up to 250 years before it collapses, suggesting that scientists could monitor the real world overturning circulation for the same signals.
The AMOC is like a conveyor belt in the ocean, driven by the salinity and temperature of the water. The system transports heat energy from the tropics and Southern Hemisphere to the North Atlantic, where it is transferred to the atmosphere.
Experiments suggest that if the AMOC is ‘switched off’ by extra freshwater entering the North Atlantic, surface air temperature in the North Atlantic region would cool by around 1-3°C, with enhanced cooling of up to 8°C in the worst affected regions.
The collapse would also encourage drought in the Sahel – the area just south of the Sahara desert – and dynamic changes in sea level of up to 80cm along the coasts of Europe and North America.
“We found that natural fluctuations in the circulation were getting longer-lived as the collapse was approached, a phenomenon known as critical slowing down,” said lead author Chris Boulton.
“We don’t know how close we are to a collapse of the circulation, but a real world early warning could help us prevent it, or at least prepare for the consequences” adds co-author Professor Tim Lenton.
The study is the most realistic simulation of the climate system in which this type of early warning signal has been tested.
“The best early warning signals in the model world are in places where major efforts are going into monitoring the circulation in the real world – so these efforts could have unexpected added value’ adds Professor Lenton.
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‘Early warning signals of Atlantic Meridional Overturning Circulation collapse in a fully coupled climate model’ by Chris Boulton, Lesley Allison and Timothy Lenton is published today in the journal Nature Communications.
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By Jove! A massive negative feedback! So if Greenland ever started to melt it would flip a switch in the ocean current system and freeze itself up again. No need to worry about Greenland melting then. It is a self-limiting process.
They were rabbiting on about this a long time ago, does it really take 5 years to design a computer program to manipulate the data to demonstrate some ratbag theory?
That would be five years of funding and therefore jobs , so what do you think?
“The study is the most realistic simulation of the climate system in which this type of early warning signal has been tested.”
Sorry. How the **** do they know that?
Models are useful as long as they are kept in their place. They are attempts to represent reality. They are not a substitute for reality. Climate science has given itself permission to make expensive public policy (expensive in terms of both personal liberty and money) based on models irrespective of how well the models can survive back testing. We know from the Climategate email trove that both the models and the data was manipulated to conform to ideological expectations. That is just plain corruption of truth. Climate science is clearly a modern form of Gaia worship and collectivism.
Now, the religion of CAGW is complete. The early warning signs of the end times have been revealed to us. We shall see the cooling from our warming and know it was our sins of emission that brought this apocalypse upon the world from Gaia.
Luckily as of 2010:
”NASA measurements of the Atlantic Meridional Overturning Circulation, part of the global ocean conveyor belt that helps regulate climate around the North Atlantic, show no significant slowing over the past 15 years. The data suggest the circulation may have even sped up slightly in the recent past.”
http://www.jpl.nasa.gov/news/news.php?feature=2534
Does a circulation speed up indicate Gaia is pleased with us? Shall we sacrifice more food to biofuels?
Now, this study actually makes some sense. Their model indicates that collapse of the AMOC is signaled by certain changes. This is a testable hypothesis. Go out and start gathering data – do some science. Let us know what happens. There should be more of this sort of thing.
“Experiments suggest that if the AMOC is ‘switched off’ by extra freshwater entering the North Atlantic, surface air temperature in the North Atlantic region would cool by around 1-3°C, with enhanced cooling of up to 8°C in the worst affected regions.”
The tangles that folk get into by neglecting solar variability in their models is pure tragicomedy. With reduced solar forcing, lower land temperatures will appear at the same time as the North Atlantic warms due to increased poleward ocean transport. That’s what happened since 1995 with the AMO.