Later this month, a meeting in Berlin is scheduled to evaluate how well governments are doing in their commitment, made at the United Nations Conference on Environment and Development in Rio de Janeiro three years ago, to reduce their emissions of greenhouse gases. It is already clear, however, that far too little has been done. The Australian government has no prospect whatsoever of meeting its commitment to reduce greenhouse emissions to 1990 levels by the year 2000, and most governments have been similarly inactive. Now, as PETER MONTAGUE reports in this article from Rachel's Environment & Health Weekly, new scientific evidence indicates that rapid climate change has already begun. On the following page, we reprint a warning from scientists around the world on the need for urgent action to save the environment upon which we all depend.
According to Scientific American, a new report from AT&T Bell Laboratories shows that "not only has global warming arrived, the signal should have been obvious years ago".
AT&T engineer David J. Thompson — a well-known researcher in the field of signal processing — used a novel approach to analyse climate change. He examined locations around the world with long historical records, such as central England, where climate records date back to 1651.
Among such records, Thompson examined the dates when the change of seasons occurred. In a paper presented in December to the American Geophysical Union (and not yet fully published), Thompson reports that the timing of the seasons changed slowly — about one day per century — until 1940; since 1940, a "pronounced anomaly in the timing of the seasons has appeared in Northern Hemisphere records", says Scientific American.
Thompson's novel approach allowed him to "sidestep completely the nasty problem of compiling an accurate global average temperature from limited historical records", says Scientific American.
Jeffrey J. Park of Yale University says, "The important result of [Thompson's] paper is that the match between this timing shift [in the change of seasons] and the CO2 increase [in Earth's atmosphere] is very good, unlike the match (or lack of it) between CO2 and the global temperature increase in the last century. The seasonal shift since 1940 appears to be an anthropogenic [human-created] signal."
Not whether, but when
CO2 is carbon dioxide, a gas that is increasing steadily in Earth's atmosphere, trapping the sun's energy, and thus — sooner or later — heating the planet. CO2 is released by the burning of fossil fuels — oil, natural gas and coal. The chief scientific debate over global warming is not whether it will happen, but when its effects will become undeniably obvious. The scientific problem is one of detecting the evidence among the natural fluctuations of weather and climate.
In 1990, in 1992 and again in 1994, the Intergovernmental Panel on Climate Change (IPCC) — made up of 140 scientists from 80 countries — issued reports published by the World Meteorological Organisation and the United Nations stating their consensus belief that the CO2 build-up in Earth's atmosphere will lead to an average global temperature increase of between 1.5 and 4.5 degrees Celsius during the next century.
John Houghton, a British climate researcher who co-chaired the scientific working group that produced the IPCC's 1994 report, said, "It is interesting that in this very uncertain area, over a period of five years, the essential story remains the same. There's been no evidence that's come to light to destroy those basic findings." In the USA, the National Academy of Sciences said in 1990, "The future of the earth's climate and, perhaps, its inhabitants, depends on how much concentrations of carbon dioxide and other trace gases are likely to rise."
CO2 concentrations in the atmosphere have increased about 25% since the 18th century, and are steadily climbing. The academy said in 1990 that the "greenhouse effect" — whereby the CO2 in Earth's atmosphere acts like the glass covering a greenhouse, trapping heat to produce a warming effect — "explains why gases produced by human activity will probably cause the earth's average temperature to increase within the lifetimes of most people living today".
Even earlier, in 1989, the editors of Science magazine concluded that global warming is the most serious environmental problem that humans face. Science is the official (and profoundly conservative) voice of the American Association for the Advancement of Science. "As serious as the problems of acid rain, toxic waste, and depletion of the ozone layer are, the greenhouse effect looms over all of them because it poses such great potential damage to the environment and is by far the most difficult to solve."
Science then called for "a massive effort to use solar power", saying, "To develop solar energy technology to supply large amounts of power ... should be a major priority of our civilization".
The IPCC's 1994 report offered new information concerning efforts to curb emissions of greenhouse gases. In 1992, 155 nations signed a treaty in Rio de Janeiro pledging to stabilise atmospheric concentrations of greenhouse gases at an unspecified level. Toward that goal, developed nations agreed in a non-binding way to scale back their emissions to 1990 amounts by the year 2000. The treaty does not say whether countries must cap their emissions after that time. The wealthy nations produce about 80% of greenhouse gases.
The 1994 IPCC assessment concludes that the guidelines set in the Rio treaty will not stop the atmospheric accumulation of greenhouse gases. To stabilise concentrations at today's amounts or even twice those, nations will need to decrease their emissions to well below 1990 levels, Houghton told Science News.
Weather extremes
The IPCC and the US National Academy of Sciences agree that one major effect of global warming is likely to be more extreme weather — longer droughts, worse floods, hotter summers and colder winters, more and stronger hurricanes, tornadoes and wind storms.
In 1994, the head of the IPCC, Professor Bert Bolin of Stockholm University, warned: "Most of the damage due to climate change is going to be associated with extreme events, not the smooth global increase of temperature that we call global warming".
In the USA, the winter of 1994 broke low temperature records in several eastern states. In June 1994, heat records were broken in the south-western US when the thermometer hit 49 C. In Europe, 1994 set heat records from the Netherlands to Hungary and Poland. A heat wave in Japan set records in Tokyo in 1994, and prolonged heat in India in June 1994 killed thousands of people.
In early 1995 the New York Times reported that the Earth's average temperature during 1994 "approached the record high of almost 60 degrees [Fahrenheit — 15.6 C] measured in 1990". The all-time record, set in 1990, was 59.85 degrees Fahrenheit; the 1994 average was 59.58, making it the fourth hottest year since record-keeping began in 1880.
(During 1991 and 1992, the Earth had cooled about one degree Fahrenheit as a result of the June 1991, eruption of Mount Pinatubo in the Philippines, which reduced the sunlight striking the planet.)
Dr James E. Hansen, who heads the NASA Goddard Institute for Space Studies in New York, told the Times in 1995 that he is "more confident than ever" that there is "a real warming which is not just a chance fluctuation but is a long term trend, and that trend is due to the greenhouse effect".
Hansen in 1981 published the first paper showing that the average temperature of the Earth had, in fact, increased during the past 100 years, a finding that is now widely accepted; the cause of that temperature rise is still in dispute because not all climatologists are yet convinced that the greenhouse effect is causing the observable warming.
Insurance
However, unlike climatologists, much of the insurance industry is coming around to the view that extremes of weather are increasing along with global temperature, and that greenhouse gases are the cause. Munich Re, the world's largest re-insurance company, observed in 1993 that in the 10-year period 1983-1992 insured losses from natural disasters were almost 12 times higher than in the decade of the 1960s, even allowing for inflation.
Commenting on Munich Re's analysis, Lloyd's List International (a publication of Lloyd's, the London insurance giant) writes, "The convenient theory that the increase in the size of losses is mainly a reflection of higher wealth — and consequently, of insured values — in those countries affected by natural disasters seems to be incorrect. It is far more likely that other causes, such as climatic changes, have already taken over as main factors pushing losses upwards."
In late 1993, Skandia, one of Sweden's largest insurance companies, stopped insuring weather-related damage. Ake Munkhammar, Skandia's expert on storms and natural catastrophes, said climatologists have the luxury of delaying their decision as to whether the bounds of natural variation in the weather have been exceeded, but insurance companies do not.