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Climate Change – Which Way Up?

 In the last few days I have seen various mentions in the news of a report on the state of the system of currents that form the Gulf Stream, which keeps northern Europe warmer than its latitude would normally allow. As I understand it, when a lot of fresh water pours into the North Atlantic, usually as a result of the melting of ice sheets in North America, the salinity of the ocean is reduced and the currents drop lower, rather than staying near the surface. As a result of global warming, there has been a lot of quite rapid melting of glaciers in Canada, and the current system is becoming unstable. If it collapses completely the warming effect of the Gulf Stream would stop, bringing about (fairly swiftly, probably over a couple of decades) abrupt cooling of north-western Europe.

A New York Times news item this morning explains: ‘… a crucial ocean circulation system in the Atlantic Ocean, which helps stabilize the climate in Europe, is now starting to slow down. While the [IPCC] concluded with “medium confidence” that the system was unlikely to collapse abruptly this century, it warned that if the planet keeps heating up, the odds of such “low likelihood, high impact outcomes” would rise…’ However, the authors of this article quote this merely as an example of the overall effect of continued global warming - which the IPCC, by the way, rather alarmingly now considers to be beyond human ability to stop, even with the enormous efforts to control carbon emissions that are now under way. 

The authors of the New York Times article don’t, however, make the more interesting connection that I’d like to explore here. The northern hemisphere, with its enormous landmasses, especially east of the Atlantic in the form of the Eurasian super-continent, governs global weather just as much as carbon dioxide levels do – possibly more. Historically, from the evidence of land and ice cores, if the northern hemisphere landmasses cool, the climate in general cools. When they get warmer, the knock-on effect is also for the global climate to warm. Why is no one pointing out that this would solve the global warming problem, at least for a while?

In my next blog, I’ll explore the history of cooling and warming in a bit more detail for those who are interested. It is a lot more complicated (and interesting – perhaps even reassuring) than current popular climate science would suggest.

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