Global Warming or Global Cooling? by Alick Bartholomew
The last two winters have been usually severe. The East and Midwest of the US have had extreme snowfalls. How can we have very cold winters between very warm summers? It seems that the world’s weather has gone crazy.
The global warming debate is thoroughly polarised; so global warming deniers oppose the warming lobby, with few willing to consider the wider picture. The coldest December for 100 years convinced the deniers they were right. Climate scientists at the University of East Anglia were put on the defensive by the ferocity of the deniers’ attack on their evidence of glacial melting. Why? The evidence is incontroversial that glaciers in most parts of the world are melting at an unprece-dented rate. Average ocean temperatures are up, leading to a rise in sea level.
The average temperature in the North Polar region is increasing 3˚C more than the annual world increase. This is partly because the polar sea ice, whose white surface reflects the Sun’s summer heat, is shrinking, allowing the ocean to absorb more heat.
Some research suggests that, in the last two winters, the surface remained clear for longer, the ocean’s heat bled into the Arctic atmosphere, causing high pressure which allowed the cold to spread much further south than usual.
The recent unusually cold winters in the UK were balanced by unusually warm temperatures elsewhere. NASA’s global maps for December show temperatures over Spitsbergen, Iceland, Scandinavia and the UK were between ·5˚C and 4˚C colder than the average from 1951 to 1980. The temperatures in Siberia, western Greenland and northern Canada were 2˚C – 10˚C higher than usual.
So global warming is a fact – at the present time – but there is also evidence of cooling. I prefer to call what we are seeing ‘climate change’, because we are getting both warming and cooling. The media, politicians and public opinion want simple answers. For most of us, what we experience overrides logical analysis. The world environment is more complex, and in a more critical state, than most of us realise.
Climatic variations are caused by changes in the heat balance between the hot Tropics and the cold Polar regions. Equatorial heat is dissipated northwards by ocean currents and atmospheric winds. Cold air from the North Pole spreads southwards to balance the tropical heat, producing the pleasant, generally reliable, climates of the temperate latitudes.
Normal seasonal fluctuations have been disrupted in the last 20 years, resulting in more extreme weather and climates. There is strong evidence that these changes are being caused by global warming and by man-induced changes.
The Tropics hold the key to the world’s climates. The equatorial rainforests have acted as a gigantic heat engine to move heat away from the Tropics with the immense power of evapo-transpiration from trillions of m2 of leaf area. It sucks in the Trade Winds from the Atlantic, which leapfrog moisture across the continent. The outflowing winds carry rain north to the American Corn Belt and south to Patagonia, and helping to drive the Gulf Stream.#
Our destruction of the Tropical rainforests (only 60% remain), has disturbed this balancing process, as well as the unprecedented warming of the Polar summer in the Northern Hemisphere, for its coldness is as much part of the equation as is the Tropical heat. This, combined with the slowing down of the Gulf Stream due to freshwater melt from the Greenland icecap, could lead to colder winters, as its effect is stronger in the winter. More violent, unpredictable weather is another consequence.
In the last 20 years, the El Niño temperature oscillations in the Tropics have become more frequent and stronger, producing more marked droughts in the Western Pacific and deluges in the East. Its partner La Niña (cold) often follows a strong El Niño (warm), with opposite effects – e.g. deluges in Australia. Its effects may be felt further afield. Some say that the movement of the Jet Stream southwards in Europe which allowed very cold air to penetrate into Europe in the winters of 2009-10 and 2010-11, was caused by the La Niña; others say that changes in the Gulf Stream’s temperature affect it.
The Gulf Stream, which gives Western Europe its benign climates, has been slowing in the last 5+ years. There is also new disquieting evidence of technological ecovandalism, second only to our destruction of the equatorial rainforests. The US government advised BP to use powerful toxic chemical dispersants to get rid of the surface oil pollution from the 2010 Gulf of Mexico explosion. The heavy oil sank, but the lower ocean currents of the Gulf Stream are carrying the deeper pollutants out into the Atlantic. There are reports that the oil-bearing strata are still leaking.
New evidence* shows that the oil & the dispersants are destroying the natural water structures that keep the Gulf Stream coherent. The result is that it is breaking up half way across the Atlantic, much of it not reaching Western Europe.** This pollution of the Gulf Stream should eventually clear, but in the meantime it is diluting an already weakening stream. The consequences could yet be catastrophic for world climates, for the Gulf Stream is essential in maintaining the flow of the global ocean conveyor belt.
It’s too early to say whether a trend towards colder winters will stop or reverse the overall warming trend. Until we understand more about the inherent intelligence of natural systems, and particularly water’s dynamic role in regulating climate, there is still be much to learn about climate change.
Looking at to the big picture, we are still theoretically in an interglacial phase of the Pleistocene Ice Age; the last glaciation ended only 12,500 years ago (an eye-blink in geological time). Indeed some hold that the inevitable return to glacial conditions has been postponed only by the rapid rise in CO2 greenhouse gas levels.
# See article “Amazon Rainforest” at www.AlickBartholomew.co.uk and his new book The Story of Water. 27 Jan.11
** There’s a mass of evidence on Google of a cover-up by the US government and BP of the real facts of the Gulf disaster.