Meltdown
Global Warming by Lynn Hughes and others
Meltdown: some facts about global warming
In a brilliant, two-part article recently published in the Telegraph Weekend Magazine (Saturday colour supplement) New Yorker staff writer Elizabeth Kolbert (USA), anticipating the G8 summit, examines the latest evidence for global warming and its consequences for the future. This is an outstanding and diligently-researched piece of work, from which I have picked out some stunning facts for members to ponder.
Global warming has been known about for 25 years. Scientists’ warnings about it being the gravest threat to life on earth have gone unheeded. The earth is getting hotter, the ice-caps are melting and sea levels are rising. This is inexorable: it may not be very noticeable in our lifetime, or where we live but it will dramatically, and perhaps suddenly, affect the next and succeeding generations. Unless the trend is reversed, sea-levels could in time rise by as much as 300’.
A recent visit to a small, subsistence hunting community in western Alaska, in the Bering Land Bridge National Preserve, revealed that seal-hunters who used to travel 20 miles out over the sea-ice on dog-sleds, or more recently snowmobiles, now have to use boats. The ice has turned to slush. This has gradually been happening since the early 1990s. A 125ft strip of land at the edge of their village, no longer protected by ice, was swept away in a winter storm. The villagers are having to move to the mainland, at an estimated cost of $180m.
That’s the sea-ice. On land, the permafrost which occupies some five and a half billion acres in the northern hemisphere, and can be anything up to a mile deep, is now almost at the same temperature on the surface as it is deep down nearer the heat flux of the earth’s core, and coldest in its centre. Historically, temperature graphs have indicated straight-line fall to the surface. In Alaska, this rise is two degrees Celsius since 1980.
The surface ice above permafrost is known as the ‘active layer’, which thaws in summer, freezes again in winter. Plant life which flourishes in summer becomes deep-frozen in winter, preserved in semi-decomposed state in the permafrost by a process termed cryoturbation. Thawing of the permafrost releases trapped CO2 and methane from this material into the atmosphere. Methane, a much more powerful greenhouse gas, whose spontaneous release from permafrost in Stordalen mire in Sweden has been monitored for 35 years has increased by as much as 60%.
NASA, in monitoring the ice caps by satellite, has concluded that perennial sea-ice which covered an area of 1.7 billion acres (approximately the size of the USA) in 1979, is today reduced by 250 million acres. The effect of this is an alteration in solar radiation, changing the amount of energy the planet absorbs, or reflects back out. [The technical term for this reflection is albedo (from alba: Latin = white). A pure white surface has an albedo of one. A black surface zero. The earth in aggregate is .3, so that less than a third of solar radiation is reflected back out into space.] Sunshine on the ice-cap can register an albedo as high as .9. The ocean, on the other hand, registers less than 0.1. By exchanging the best reflective surface for the worst, we are allowing solar energy to heat the sea and melt the ice.
Changes in albedo ratios also alter the atmospheric circulation pattern, known as the Arctic Oscillation [AO], which is characterised by low pressure over the Arctic Ocean, producing high winds and higher temperatures in the far north. It is not certain whether AO behaviour is a feature of global warming or a product of it. And the effect on ocean currents is not touched upon.
Geologically-speaking, we are in an ‘interglacial’ – a warm period between ice-ages. Over the past two million years the ice advanced over the northern hemisphere and retreated at least twenty times. The present glacial era in retreat is known as the Wisconsin which began 120,000 years ago. It is known that these cold/warm interludes are cyclic, caused by slight variations in the earth’s orbit, and take approximately 100,000 years to complete. CO2 levels taken from ice-bore cores reveal that they fall precisely in synch with falling temperatures. Today CO2 levels are significantly higher than at any point in the past 420,000 years.
Mathematical climate models predict that perennial sea-ice cover will disappear completely from the Arctic by 2080. Seasonal ice will continue to form in winter, but the Arctic Ocean and the ‘North-West Passage’ will be completely ice-free. This could occur practically over-night, according to Donald Perovich of the Cold Regions Research and Engineering Laboratory in Hanover, New Hampshire, where he has been studying sea-ice for 30 years. ‘Global sea-levels have risen half a foot. It is predicted they will rise anywhere from 4” to 3’ by the year 2100’, he says.
Natural ‘greenhouse gasses’ are an essential condition to life on earth. Without the shield of CO2, methane and water vapour, the globe would freeze over in a night, as all the radiated heat would escape, and the overall temperature would drop to –18C. This was first postulated by the British physicist, John Tyndall, as early 1859. Greenhouse gasses comprise an absorbent, protective shield, filtering out radiation, which has maintained earth’s temperature at an average of 14C to date; but this is now rising. A Swedish chemist, Svante Arrhenius, even in 1894, became convinced that human activity was altering the earth’s energy balance, and began a year-long calculation of what would happen if the earth’s emission of CO2 from coal burning doubled. He announced to the Swedish Academy that it would take 3,000 years to achieve this situation. We now know he was out by 28 centuries!
In Greenland, where it never rains but snows all year round, ice-bores to a depth of 10,000’ examined for their isotopic composition provide a detailed record of temperature and climate, going back thousands of years. A climatic reversal, identified as Younger Dryas, after a plant that suddenly reappeared, occurred 12,800 years ago when the earth, which had been rapidly warming, was suddenly plunged back into glacial conditions. Greenland has remained frigid for 12 centuries, but suddenly is warming up again. Temperatures have shot up by 11 degrees in the last 10 years. In neighbouring Iceland there are examples of glaciers have shrunk by 1,100 feet since 1995.
Records from other locations show that the last interglacial (Eemian) was somewhat warmer than this one (Holocene). Sea levels are shown to have been 15’ higher. There are differing theories for this: one holds that it was Greenland ice-melt. [There is enough water in the Greenland ice sheet alone to raise sea levels by 23’]. NASA has calculated that throughout the 1990s the Greenland ice sheet was shrinking by 12 cubic miles a year. Oddly, these predictions of a 3’ rise in ocean levels by 2100 take no account of ice-melt in the Arctic regions, but are based solely on physical expansion of water as it heats up.
When sea water is frozen, salt is forced out of the pores so that the salty water actually drains and, being heavier, sinks to the ocean floor, sucking up more water from the tropic zones in a pump action that conveys heat around the globe. The melting of freshwater ice in the Arctic zones weakens this mechanism, and could lead to shut-down of ‘thermohalin ciculation’, which, among other things, would dislocate the Gulf Stream and plunge the British Isles back into an Arctic Ice Age once again. It would result in habitat change and also end salmon and other maritime migration.
Ice-core records show that atmospheric CO2 levels in the 1780s stood at about 280 parts per million, and was the same when Christ was born. A couple of millennia earlier, the same - and the same when Stone Henge was built 4,000 years ago. [This was therefore an equilibrium level]. One hundred and fifty years into the Industrial Revolution, CO2 levels were up to 315 parts per million, and then 330ppm in the 1970s, and by the mid-nineteen nineties the curve had risen sharply to 360 parts per million. Since then, ppm have risen again by 20, and if the trend continues, CO2 will reach 500ppm by the middle of this century. Every increment of CO2 above equilibrium level results in a temperature rise.
The last time carbon deposition in the atmosphere was at this level was at the Eocene, 50 million years ago. Sea levels at that time were 300’ higher, and there were crocodiles at the North pole.
‘Carbonisation’ is, to all practical purposes, an irreversible process as carbon dioxide is a persistent gas. Not infinitely so: it lasts for about 100 years. Easy enough to produce, by striking a match or turning an ignition key, difficult to reverse. [Planting more trees will not provide the solution]. The best way to measure CO2 emissions is to measure the weight of the carbon. By this method, global emissions last year amounted to 7 billion metric tons, of which the USA produced 20%. On this basis carbon emissions will amount to 10.5 billion tons by 2029, and 14 billion by 2054. Stabilising, much less reversing, this trend is the most difficult problem mankind has every contemplated.
Politics is the first stumbling block, science is another. ‘Developing nations’, like India and China, are putting in place infrastructures that guarantee they will overtake US levels of CO2 emission by 2025. China, for instance, has plans to build 562 coal-fired power stations by 2012. [And as we are intent on pouring money into developing Africa, roads, motor transport, cars, cookers and central heating must follow]. Oil and gas are finite resources and will run out; some say production will be in decline by the end of this decade. The process of ‘decarbonisation’ of fossil fuel with cleaning devices (lean-burn engines, catalytic converters, power station flue-scourers, etc) is limited in its efficacy. Alternative power sources such as space-based solar power, tapping into the earth’s core and fuel hydrogen are experimental notions, while there is widespread presumption against nuclear power. Unsightly wind farms are ineffective political gestures.
The politics of global warming control are extremely complex, and have every appearance of being self-defeating. The world has, in theory, committed itself to combating global warming:
The Earth Summit, Rio de Janeiro, 1992, organised by the United Nations, where representatives of virtually every nation on earth gathered to discuss the UN Framework Convention on Climate Change [UNFCCC] was the beginning. Its ambitious objective was ‘stabilisation of greenhouse gas concentrations at a level that would prevent dangerous anthropogenic [man-made] interference with the climate system.’ This treaty was eventually ratified by 165 countries, though ‘dangerous anthropogenic interference (DAI)’ was not defined. Did DAI mean the melting of the ice-caps and the snows of the Himalayas? At what point, and who, would declare disaster irreversible before it occurred?
One of the stipulations of Rio was that parties to the convention should meet regularly to assess progress. But there was really no progress to report. The only countries that succeeded in returning emissions to pre-1990 levels were some former Soviet-bloc countries whose economies were in free-fall.
The International convention at Kyoto, the ‘Protocol to UNFCCC’, in 1997, attempted to remedy the situation by substituting mandatory commitments for Rio rhetoric. Industrialised nations [Annex 1 nations] were singled out and given specific emission targets below 1990 levels: European countries 8%; USA 7%; Japan 6%. Emission controls extend to five other greenhouse gasses in addition to CO2: methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride, which, for brevity’s sake, are all classified as CO2 equivalents. Industrial nations can buy ‘quota’ from those underdeveloped countries which are reckoned ‘clean’, or they can qualify by investing in ‘clean development’ projects in those countries. These are mainly emergent developing nations such as China and India, and the oil-producers, Saudi Arabia, Libya and Kuwait. Subsistence economies are exempt until 2012.
From the start, it was obvious that the USA would not wear this. A Senate resolution of the Clinton administration, carried 95-0 that unless developing nations were involved the USA would not sign up. The logic of this is plain: emission controls cost money. If China and India, emerging as economic and industrial rivals to the USA, need not pay then they have an unfair advantage over US companies. On the other hand, one citizen of the USA produces greenhouse gas emissions equivalent to 4-5 Mexicans, 18 Indians or 99 Bangladeshis, and even if nations were to agree to reduce proportionately, a Bostonian would produce 18 times the noxious gas of a Bangalorean. No human should have the right to emit more gas than another. Livestock and large ruminants are another matter!
The Kyoto agreement came into force on February 16, 2005.
George W Bush’s administration began by cautiously endorsing the Bush senior/Rio approach to greenhouse gas emission policy, but then withdrew, as his government [Dick Cheyney?] believed that ‘scientific knowledge of the causes of, and solutions to, global climate change were incomplete’. Scientific knowledge is never complete.
‘Greenhouse gas intensity’ is the buzz-phrase of the Republican administration. It wishes to redefine Kyoto by relating emissions in a ratio to economic output. If, in a year, a company produces more goods on the same carbon emission level as on a previous year, it can be deemed to have reduced by the relevant percentage. The more efficient industrial nations thereby benefit, and the USA enjoys a greater GDP than developing countries. But here’s where Nonsense steps in: the target set for itself by the Bush administration is an 18% reduction over the next 10 years, while anticipating a 3% annual growth in the economy. Given that both expectations are met, US emissions will rise overall by 12%.
Critics of this approach condemn it as subterfuge, as it has no determination of DAI, although it insists that its ‘policies are predicated by sound science’. What we must remember is that America is in the forefront of climate science. Only since the 1950s when CD Keeling developed a precise methodology for measuring CO2 and the Mouna Loa Observatory in Hawaii was able to report that these levels were rising, have investigations and experiments been carried out on a global basis to arrive at our present state of knowledge. America, too, has produced a fair amount of scepticism: and there are people in high places who, despite scientific evidence, are steadfast ‘in global-warming denial’. Tech Central Station’s website, sponsored by Exxon Mobil and General Motors among others [apparently] parade an anthology of eco-warming myths and counter-myths.
It took for a Welshman of sound sense, Sir Emyr Jones Parry, Britain’s permanent representative at the UN, to place both sides of the debate in perspective when he said at a conference called ‘One day after Kyoto’: ‘We cannot go on as we are’.
Very soon, the globe will have re-heated up to temperatures close to those experienced during the last interglacial, 1000,000 years ago when man as a species closely resembling us experienced bewildering climate swings – droughts and deluges resulting in famine, pestilence and mass migration - and could do nothing about it. We, all 6 billion of us, are in a different position. Surely we cannot be content to allow self-destruction?
Lynn Hughes
July 2005
[I am indebted to Elizabeth Kolbert, staff-writer for New Yorker, for permission to quote from her article originally published in that journal in three parts in April/May and reproduced by the Daily Telegraph Weekend Magazine in two parts in June this year. Both are available on-line. LH]
AND From ENN
| The global conveyor belt thermohaline
circulation is driven primarily by the formation and sinking of deep
water (from around 1500m to the Antarctic bottom water overlying the
bottom of the ocean) in the Norwegian Sea. This circulation is thought
to be responsible for the large flow of upper ocean water from the
tropical Pacific to the Indian Ocean through the Indonesian Archipelogo.
The two counteracting forcings operating in the North Atlantic control
the conveyor belt circulation: (1) the thermal forcing (high-latitude
cooling and the low-latitude heating) which drives a polar southward
flow; and (2) haline forcing (net high-latitude freshwater gain and
low-latitude evaporation) which moves in the opposite direction. In
today's Atlantic the thermal forcing dominates, hence, the flow of upper
current from south to north.
When the strength of the haline forcing increases due to excess precipitation, runoff, or ice melt the conveyor belt will weaken or even shut down. The variability in the strength of the conveyor belt will lead to climate change in Europe and it could also influence in other areas of the global ocean. The North Atlantic atmosphere-ocean-cryosphere system appears to have natural cycles of many timescales in switching the conveyor belt. Periodic movement of excessive ice from the Arctic into the Greenland Sea appears to be responsible for the interdecadal variability of the conveyor belt. There is no evidence yet that the influx of interdecadal switching extends beyond the North Atlantic Ocean. . |
Coming to a river near you?
Photo by Daniel Beltra of Greenpeace
