Exclusive? Gulf Stream to weaken by 25 to 30%

'It is very likely that the northward flow of warm water in the upper layers of the Atlantic Ocean, which has an important impact on the global climate system, will decrease by approximately 25-30 percent.'

Well here's one that seems to have gone straight under the media's radar. Probably because its scare-mongering, you might be thinking.

Who is it making these exaggerated and irresponsible predictions? Some group of eco-nuts way out west of Greenpeace, skeptics might well presume.

Unfortunately not. In fact it is the Geological Survey of none other than the United States of America - good 'ol Uncle Sam in person, in effect, previously a.k.a. the self-proclaimed climate change skeptic in chief.

Astonishing what a change at the top will do. Let us just hope its not too late. It is now perilously close to it - wait for the update on CO2 and others, later this week, Inshallah.

An unimpeachable source, then. Or as near as we are likely to get to one. Here's what they have to say in their Newsroom feed March Science Picks released on 6 March (all bolding is mine):

'The United States faces the potential for abrupt climate change in the 21st century that could pose clear risks to society in terms of our ability to adapt. A new report led by the USGS makes the following conclusions about the potential for abrupt climate changes from global warming during this century:

'Climate model simulations and observations suggest that rapid and sustained September Arctic sea ice loss is likely in the 21st century.

'The Southwestern United States may be beginning an abrupt period of increased drought.

'It is very likely that the northward flow of warm water in the upper layers of the Atlantic Ocean, which has an important impact on the global climate system, will decrease by approximately 25-30 percent. However, it is very unlikely that this circulation will collapse or that the weakening will occur abruptly during the 21st century and beyond.

'An abrupt change in sea level is possible, but predictions are highly uncertain due to shortcomings in existing climate models.

'There is unlikely to be an abrupt release of methane, a powerful greenhouse gas, to the atmosphere from deposits in the earth. However, it is very likely that the pace of methane emissions will increase.'

The feed summarises US Climate Change Synthesis and Assessment Report 3.4. Abrupt Climate Change. Assessment and Findings which is a quick read in 4 pages replete with graphs, excellent diagrams and some pretty pictures.

It all sounds positively reassuring until you adjust to the cool scientific language. Then you may not find statements like those that follow quite so reassuring.

(The AMOC referred to is the Atlantic Meridional Overturning Circulation, of which the Gulf Stream is perhaps the most famous component.)

'Inclusion of these ice-sheet and glacier processes into future modeling experiments will likely lead to sea-level rise projections for the end of the 21st century that substantially exceed those presented in the Intergovernmental Panel on Climate Change fourth assessment report (IPCC AR4).'


'It is very likely that the strength of the AMOC will decrease by approximately 25–30 percent over the course of the 21st century in response to increasing greenhouse gases, which will affect the distribution of heat in the North Atlantic. Even with the projected moderate AMOC weakening, it is still very likely that on multidecadal to century time scales a warming trend will occur over most of the European region downstream of the North Atlantic Current in response to increasing greenhouse gases, as well as over North America.'

'It is very unlikely that the AMOC will undergo a collapse or an abrupt transition to a weakened state during the 21st century. It is also unlikely that the AMOC will collapse beyond the end of the 21st century because of global warming, although the possibility cannot be entirely excluded.'

'The summer arctic sea-ice cover has undergone dramatic retreat since satellite records began in 1979, amounting to a loss of almost 30 percent of the September ice cover in 29 years. Climate model simulations suggest that rapid and sustained September arctic ice loss is likely in future 21st century climate projections. It is notable that climate models are generally conservative in the modeled rate of Arctic ice loss as compared to observations, suggesting that future ice retreat could occur even more abruptly than simulated in almost all current models.'


'While a catastrophic release of methane to the atmosphere in the next century appears very unlikely, it is very likely that climate change will accelerate the pace of persistent emissions from both hydrate sources and wetlands. Current models suggest that wetland emissions could double in the next century. Methane release from the hydrate reservoir will likely have a significant influence on global warming over the next 1,000 to 100,000 years.'

On the last, my suspicion is that the data used did not include the latest findings which came in right at the end of the Arctic summer last September covered previously in 'Apocalypse shortly? We should know next summer.'

As to a 25% to 30% reduction in the Gulf Stream, for those living in the atypically warm areas on the west coast of Europe bathed in its currents the best analogy I have been able to come up with so far is someone turning the central heating down permanently by that a quarter to a third.

Enough to make most folks complain, it would seem fair to say. As well as reach for the duvet jackets...if not take to bed permanently, were it not for the countervailing effect of global warming

'a warming trend will occur over most of the European region downstream of the North Atlantic Current in response to increasing greenhouse gases, as well as over North America.'

expected to result in a net rise in temperature.

Put the two together,and that sounds like they are expecting the planet to heat up. I suppose you could say 'quite radically'. Which all sounds like bad news all around - particularly for most of the rest of the world that does not have the countervailing effect of a weakening Gulf Stream to cool them.

Add in unstated, highly uncertain effects on the weather, and there is a lot to be concerned about.