By Andy Ford, biomedical scientist
The New Scientist magazine of 4th August makes sobering reading for anyone concerned about climate change. Some parts of the globe could become uninhabitable if present tends continue.
The human body has grave difficulty functioning at temperatures over 40oC if combined with humidity over 85%. This is because at that point the body cannot cool by sweating due to the humidity. Already, the Northern Australian cities of Darwin and Cairns experience such conditions on one or two days a year and it is predicted that by 2100 Darwin could be uninhabitable for much of the year. On the 28th June this year a world record overnight temperature was recorded – in Oman, where even at night the temperature never fell below 42.6oC.
Evidence is now emerging of changes in the dynamics of the Gulf Stream, the current which moderates the Western European maritime climate, producing less rain in the winter and fewer heat waves in summer.
The Gulf Steam has historically transported warm sea water from the Caribbean north-east towards Spain, Britain and beyond. Its effects are felt all the way up the coast of Norway keeping it ice-free all year.
As the water goes north it becomes saltier due to evaporation, and colder. The increase in density then makes it sink to a depth of 2 or 3 kilometres where it then flows back to South America, creating a permanent convection current.
In 2005 researchers at the National Oceanography Centre, Southampton, published evidence that the current had slowed by around 30%. But detractors and climate-change deniers piled in to point out that the evidence was only from five trans-Atlantic research cruises in the period from 1957 to 2004 and the researchers ‘could’ have detected a wobble.
But since then evidence to confirm the threat to the Gulf Stream has been mounting. In 2015 German researchers were able to measure sea surface temperatures from 1901 to 2013 and found a warming trend.
The Southampton researchers confirmed the finding the same year and also correlated the cold patch with blizzards in North America and heat waves in Europe.
More recent research at the Scripps Ocean Institute in California has shown that there is a complex relation between salinity and temperature, but that when changes in salinity are taken into account a possibility arises of a ‘collapse’ in the Gulf Stream where the current is switched off or even reversed. Back in 1961 oceanographer Henry Strommel had shown that the North Atlantic currents could exist in either of two states with currents flowing in opposite directions depending on a complex interaction of temperature, density and salinity. In a striking confirmation of the philosophy of science put forward by Engels in his ‘Dialectics of Nature’ there is a possibility of a relatively rapid transition between the two states.
Weakest in 1500 years
More recent research does seem to confirm the idea: warmer, fresher seas south of Greenland from 2002 to 2014, a German study which showed a 15% weakening in the Gulf Stream and a study of the deep south bound current which shows that it is at its weakest in 1500 years.
The scientific consensus would appear to be that there is a definite weakening of the Gulf Stream with a greater likelihood of colder, wetter winters and heat waves in summer. A collapse or transition is now a real possibility, but no-one knows how likely that is. Researcher Stefan Rahmstorf is quoted as saying “It is unclear how much of a push is required for collapse. As the current slows down it comes closer and closer to a theoretical tipping point that would lead to collapse”.
The effects of a collapse would be dramatic, producing an overall cooling in Europe but with heat waves in summer, a sea level rise in the eastern USA of about 25cm, more frequent blizzards in the US, heat redirected from Europe South America, and disruption of fisheries such as cod and mackerel.
The insanity of capitalism sees the denial of evidence by politicians bought, sold, and paid for by fossil fuel industries even as the world races towards a whole series of climate ‘tipping points’.
A rational world would invest some of the billions or trillions of dollars now wasting away in tax havens in clean coal and renewables such as wind, solar and tidal power. But there is little chance of that under capitalism.
Trotsky before the Second World War spoke of the German bourgeoisie ‘tobogganing towards disaster with their eyes closed’. Now it is the world bourgeoisie who could not care less as long as this year’s profit is bigger than the last.
August 11, 2018
