A temporary weakening of the ocean current which regulates global temperatures will see a slight cooling in Europe and North America, masking the effects of human-induced climate change say German researchers.
A team from the Leibniz Institute of Marine Sciences, in Kiel, Germany, has said global warming may enter into a "lull" period until 2015. The naturally occurring slowdown is due to an expected cyclical change in the Gulf Stream, the water current which conveys warm surface water from the tropical Atlantic to the northern Atlantic and returns cold water southwards at a lower depth.
However the scientists predict the Earth will once again enter into a warming phase after 2015 once the currents revert to a more warming trend.
"The IPCC [Intergovernmental Panel on Climate Change] would predict a 0.3°C warming over the next decade. Our prediction is that there will be no warming until 2015 but it will pick up after that," said Noel Keenlyside of the Institute. “We’re learning that internal climate variability is important and can mask the effects of human-induced global change.”
The results of the study were based on new computer modelling and the team stress it would be wholly incorrect to assume the problem of global warming had disappeared.
"Just to make things clear, we are not stating that anthropogenic [man-made] climate change won't be as bad as previously thought," said Mojib Latif, a professor at the Leibniz Institute.
"What we are saying is that on top of the warming trend, there is a long-periodic oscillation that will probably lead to a lower temperature increase than we would expect from the current trend during the next years."
German researchers have predicted a slowing down of global warming -- due to the weakening of the Gulf Stream. Pic: False colour image showing the warmer Gulf Stream as a winding rope of orange and yellow against the cooler green and blue waters. Credit: NASA
PB DePetrilloMay 2nd, 2008 - 07:36:47
I'll try to be brief. I am an expert in modeling time series data. I looked at the local station temperature data from several locations in the US. One station had uninterrupted data since the 1890's, Wichita, KS, USA.
well.com/user/pdeep/pages/warm07/stat02/stat02.shtml
I found no evidence of a warming or cooling trend, but plenty of evidence of cyclic variations in temperature. One of the periods of about 60 years matches pretty well with the Pacific Decadal Oscillation.
We appear to be heading into the cool phase of the PDO, which lasts about thirty years.
The question I have is why did it took a bunch of time and resources consumed by several eminent climate modeling scientists to figure out that since 1996, the Pacific Decadal Oscillation cycle has been reasonably well characterized, and probably impacts local as well as global climate.
As a former scientist, my opinion is if the global climate models could not show cyclic variations in temperature up to now, while several rural local temperature time series matched global PDO cycles quite well, the validity of the these climate models is dubious at best.
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