By Peter Montague
The worldwide scientific community has reached consensus that global warming is inevitable if humans continue to dump "greenhouse gases" into the atmosphere at anything like present rates. Greenhouse gases include carbon dioxide, methane, nitrous oxide, chlorofluorocarbons (CFCs) and a few others. These gases act like the glass covering a greenhouse, letting sunlight in but stopping heat from escaping, thus driving up the average temperature of our earthly "greenhouse" sooner or later.
The main contributor to the greenhouse effect is naturally occurring water vapour, which keeps the planet's thermostat set at a pleasant 15 C or so average. But the main human contribution to greenhouse warming is carbon dioxide, which is released whenever fossil fuels are burned. Carbon dioxide levels in the atmosphere have been rising relentlessly for a century.
Global warming is one of those problems that "the market" cannot fix. In fact, the market will only make the problem worse.
Oil and coal corporations have little or no incentive to help the world change over to energy sources that will avoid global warming, such as solar power using hydrogen as a storage medium. On the contrary, oil and coal companies are in business to do one thing: sell oil and coal. Because the automobile industry is presently oil-based, and because automobiles are critical to the steel, glass, rubber and concrete industries, together the oil corporations and their allies create a political mountain that has, so far, proven impossible to move.
What are the effects we might expect as global warming comes upon us? Recently, a catalogue of global-warming-related events has been published. Organised chronologically, starting in 1990, the catalogue consists of short paragraphs describing new scientific studies, new government reports, important speeches (by insurance executives, for example), and news reports (of floods, typhoons, etc.).
Although no single piece of information in the catalogue, taken alone, is sufficient to persuade anyone that global warming is occurring and that it has real consequences, all together the information in this 150-page catalogue is impressive and persuasive. Jeremy Leggett and his co-editors have provided an important public service. [The Climate Time Bomb: Signs of Climate Change from the Greenpeace Database (Amsterdam: Stichting Greenpeace Council, 1994).]
As any reader of this catalogue will see, there is abundant evidence that warming is occurring planet-wide, as well as in particular regions. According to the consensus statement by scientists from 80 countries published in 1990, the polar regions should see more rapid warming than other regions. That is what seems to be happening.
For example, in late 1993 the US Carbon Dioxide Information and Analysis Center reported that scientists from NOAA [National Oceanic and Atmospheric Administration] find that surface temperatures at nine stations north of the Arctic Circle have increased by about 5.5 C since 1968, increasing at an average rate of 0.24 C each year. Measurements at a station in Alaska confirmed the trend.
During 1994, a series of boreholes in Alaska revealed that the temperature of the soil has increased 2 to 5 degrees C during this century. Tree ring data from the Canadian arctic show a 3 degree rise in temperature in this century.
The British Antarctic Survey in 1994 reported that air temperatures at the British Faraday Base on the Antarctic Peninsula have increased 0.5 degrees C each decade since 1947. These are the fastest temperature changes recorded since the British began making such measurements 130 years ago.
In 1994, a Swiss study of the length of 48 valley glaciers, over the period 1850 to 1990, revealed that all 48 glaciers have diminished in length by 0.86 to 1.3 meters per year. The glaciers on Mount Kenya (in Kenya) receded 40% between 1963 and 1987.
None of these reports, by itself, is persuasive; but combined with several hundred others, a picture emerges of a planet that is feeling the effects of warming — many of them bad.
The Intergovernmental Panel on Climate Change (IPCC), in its 1990 report and a series of subsequent reports, has given the basic outlines of what we should expect: greater extremes of weather (more and stronger storms, longer and drier droughts, heavier rains and increased numbers of larger, more costly floods). We should also expect altered patterns of climate and weather — less rainfall in the interior of continents, less snowfall and so forth. We should also expect the seas to rise a few inches, first because seawater will expand as it gets warmer, and secondly because ice will melt and flow off the land.
Some aspects of global warming are not often discussed — for example, the secondary consequences of heat waves, droughts and storms. In Papua New Guinea in 1994, flooding brought the threat of influenza, malaria and dysentery in the affected human population. In the midwestern US in the summer of 1993, some of the people rebuilding their homes after the flood reported that they and their neighbours had come down with meningitis and hepatitis A.
That Mississippi flood had other unexpected consequences: according to the US Geological Survey (USGS), tremendous quantities of herbicides washed off the land and into the river. At the height of the flood, according to USGS, the river was carrying 5500 kg of atrazine per day past Thebes, Illinois, where the agency took measurements. Atrazine is a herbicide that interferes with the endocrine system in wildlife and humans.
In addition to atrazine, the river was carrying other agricultural poisons in higher-than-normal concentrations: cyanazine, alachlor, and metolachlor. Furthermore, dozens of "Superfund" chemical waste dumps were flooded in Kansas, Nebraska, Iowa and Missouri, adding to the toxic soup carried downstream. At the outflow of the Mississippi in the Gulf of Mexico, a "dead zone" developed over 2300 square kilometres, a "fishing wasteland" where fish and other sea life could not survive because of sewage, urban run-off and agricultural poisons.
Unusual weather brings many unexpected side-effects. In Australia in 1993 and again in 1994, mild winter weather extended the breeding season for rodents and insects. In July 1993, mice ravaged crops in South Australia, costing farmers $100 million. Furthermore, the combination of drought, high temperatures and mice loosened soils over a large area, allowing winds to strip off 20 to 30 million tonnes of valuable topsoil and move it out to sea.
In 1994, Zimbabwe suffered a plague of rodents and insects because their natural predators (snakes, frogs, small birds and owls) had been killed off by drought.
The World Health Organisation (WHO) has suggested that many diseases will increase as the earth's average temperature increases, mainly because disease vectors (carriers) such as mosquitoes and rats will thrive in warmer temperatures. Malaria, schistosomiasis (bilharzia) and dengue fever are likely to increase, says WHO. Elephantiasis, onchocerciasis (river blindness), African trypanosomiasis (sleeping sickness), yellow fever and Japanese encephalitis are also likely to increase.
The IPCC in 1994 estimated that global warming is likely to have its severest impacts on humans by diminishing agricultural output and making food scarce. Shifting climatic zones northward will increase the arid zones and thus diminish the land available for crops. Rising seas will cover much good farmland. Increased numbers of pests will take a greater toll.
In sum, said the IPCC, "it is likely to be an enormously difficult task for [hu]mankind, not only to limit climate change to a tolerable level, but also to simultaneously achieve sufficient food production for a still rising world population".
And we face these deteriorating prospects, worldwide, chiefly so that the oil and coal companies can report acceptable quarterly profits to their shareholders.
[From Rachel's Environment & Health Weekly.]