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March 31, 1998

Global Warning:
Facts, Probabilities & Wishful Thinking

by Woody Justice

Previous articles illustrated some of the tactics used by special interest to downplay the seriousness of global warming. The absence of public interest in this phenomenon and its sweeping effects can be partially blamed on the success of such corporate spin and misinformation: credible findings published in scientific journals get less exposure than do full-page ads and guest editorials in national newspapers. An apologist might propose that well-intentioned people are encumbered with information overload: staying on top of earth-shattering events in Hollywood gossip, sports trivia, and the President's alleged affairs hinder sorting through confusing claims and counterclaims where facts are brushed off and uncertainties exaggerated. A cynic would suggest that further concern is lacking in America because it is a problem that will confront future generations, while corrective measures would inconvenience the current ones.

THE FACTS

The greenhouse effect is a natural phenomenon that keeps the planet warmer than it would otherwise be solely from its proximity to the sun. Some gases in the atmosphere have physical properties that contribute to the retention of thermal energy. They are transparent to short-waved solar radiation but trap the long-wave infrared radiation that is emitted from the warmed surfaces of the earth. This is similar to a car parked in the sun with the windows rolled up, or a greenhouse (hence the name): the glass acts like the planet's atmosphere, allowing sunlight through but keeping the heat inside. The main greenhouse gases are water vapor, carbon dioxide, methane, nitrous oxide, chlorofluorocarbon and its substitutes and ozone.

Water vapor (not clouds, which are droplets of condensed water) is the gas with the most effect on keeping the earth at a temperature that supports life. Its presence is not a direct consequence of humanity's impact. However, if the average global temperature increases significantly, we can expect more evaporation from surface waters to raise the concentration of atmospheric water vapor, providing positive feedback to the greenhouse effect, trapping more heat, evaporating more water, etc., etc...

Carbon dioxide levels have fluctuated in the past and global temperatures followed along with them. Data from ice cores allow scientists to make observations from hundreds of thousands of years ago and they conclude that CO2 concentrations and the greenhouse effect are directly linked. More recent evidence points to anthropogenic effects far outweighing the natural variation, and most of the human-induced CO2 release is from the widespread burning of fossil-fuels since the industrial revolution. Additional significant sources are deforestation, cement production and land- use change. Although there are natural methods acting to remove atmospheric carbon it has a relatively long residence in the climate system, about a century. Further, the carbon "sinks" will probably be negatively affected by warmer average temperatures. For example: as the ocean heats up it can hold less of a dissolved gas; higher temperature will promote rotting of organic compounds releasing carbon as CO2; hotter climates will promote more frequent and more severe forest fires.

Methane increases come from industrial-agriculture, mainly the growing of rice and cattle. As with CO2, natural methane production from organic decay would be expected to rise with warmer temperatures. Sources of nitrous oxide (also with a long lifetime -- about 120 years) are not well understood but production of nylon, catalytic converter operation, and nitrogen fertilizer use are all non-natural contributors. Chlorofluorocarbons (CFC) are created exclusively by humans. Their use as refrigerants and aerosol propellants have thinned the Earth's stratospheric ozone layer, allowing an increase in deadly ultraviolet radiation to reach the Earth's surface. Treaties requiring a halt to their production allows CFC-substitutes (HCFCs, HFCs, SF6) to be used in their place. These substitute gases do not destroy the ozone layer as effectively as CFCs, but they are very long-lived and contribute to a much greater greenhouse effect than the original product. (A protective ozone layer is necessary to support life, and its warming contribution is less significant than those listed above.)

Two very important considerations go hand-in-hand with these facts: The effects of these gases are often figured as CO2-equivalents; this means that a solution that does not address reductions in their emissions will require a greater corresponding limit on CO2 production. And, the stabilization of greenhouse gas concentrations does not imply that there will be no further climate change; after stabilization is achieved, global mean surface temperature would continue to rise for some centuries and sea level for many centuries. Climate change may be manageable if corrective measures are implemented without delay, but the results will be catastrophic if further delays take place.

These are not radical ideas from some anti-technological faction. This is as close to consensus as is possible given the diversity of people - scientists, a subculture responsible for technology - and ideas involved. The Intergovernmental Panel on Climate Change (IPCC), made up of 200 scientists from 80 countries, reviewed various data and issued reports over several years, each one suggesting with more confidence that the CO2 buildup in Earth's atmosphere will lead to an average global temperature increase. Despite the best efforts of a minority of dissenters (of questionable pedigree and suspect funding), the essential conclusions remain the same and there has been no evidence that has come to light to destroy those basic findings. The most recent, the 1996 Second Assessment Report, states indisputably that "The surface temperature this century is as warm or warmer than any other century since at least 1400 AD; the temperature has increased by 0.3 to 0.6 degree Celsius (about 0.5 to 1 degree Fahrenheit) over the last century; the last few decades have been the warmest this century; sea level has risen 10 to 25 cm (about 4 to 10 inches); and mountain glaciers have retreated world-wide this century."

The naysayers wonder why we aren't experiencing balmy winter temperatures in Minnesota yet if global warming is occurring. Every time an unseasonable cold-spell strikes in the south, it is pointed to as proof that the planet is not heating up. It is easy to forecast tomorrow's weather locally, harder to predict next month's even in a region, even more difficult to suggest the global climate over the course of years. The climate modeling used to make the long-term predictions is an enormous device complicated by: the effects of multiple stresses; a lack of understanding of some key processes; long time lags between emissions and effects; wide regional variations in causes and effects; and the long time-scales involved in the climate system. For example, the long residence time of greenhouse gases in the atmosphere and the lag by many decades to centuries between stabilization of concentrations and stabilization of temperature and mean sea level. Short-term predictions calculated in previous years have been remarkably accurate; results have been verified by subsequent weather patterns and this has helped refine the climate models. The IPCC: "Models that account for the observed increases in the atmospheric concentrations of greenhouse gases and sulfate aerosols are simulating the recent history of observed changes in surface temperature and its vertical distribution with increasing realism."

Record high temperatures struck the US in the late 1980s and 1991, followed by normal ranges in 1991 and 1992. This is explained as the "masking" effect of some aerosols and particulates in the upper atmosphere, a temporary anomaly that offsets the warming from greenhouse gases, and the climate models support this explanation. There is the effect of CFCs destroying the ozone layer, reducing the warming from that gas. And sulfur from pollution and volcanic sources, such as the eruption of Mount Pinatubo in June, 1990, creates airborne debris that reflects sunlight, preventing it from reaching earth's surface and converting to infrared heat. (Mt. Pinatubo's cooling effects disappeared after a couple of years and 1994 global average temperatures approached those of 1990. The National Oceanic and Atmospheric Administration reported in January that 1997 was not only the warmest on record, but it was part of exceptionally sultry decade that witnessed nine of the 11 hottest years this century.) As CFCs dissipate and sulfur pollution becomes better-controlled ozone will regenerate and the atmosphere will clear, "unmasking" the effects of the greenhouse gases which are relentlessly building up, and global warming will become undeniably apparent.

The polar regions are expected to exhibit evidence earlier than temperate zones and various sources support the estimates. Some examples: Surface temperatures at nine stations north of the Arctic circle have increased by about 5.5 degrees Celsius (9.9 degrees Fahrenheit) since 1968, increasing at an average rate of 0.24 degrees C (0.43 F) each year. A series of boreholes in the ground in Alaska revealed that the temperature of the soil has increased 2 to 5 degrees C (3.6 to 9 F) during this century. Tree ring data from the Canadian Arctic show a 3 degree C (5.4 F) rise in temperature this century. The British Antarctic Survey in 1994 reported that air temperatures at the Faraday Base on the Antarctic Peninsula have increased 0.5 degrees C (0.9 F) each decade since 1947. These are the fastest temperature changes recorded since the British began making such measurements 130 years ago. 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.

PROBABILITIES

The following are excerpts from the 1996 IPCC Second Assessment Report.

"Without specific policies that reduce the growth of greenhouse gas emissions, the Earth's average surface temperature is projected to increase by about 1 to 3.5 degrees C (about 2 to 6.5 degrees F) by 2100, a rate faster than anything observed over the last 10,000 years. The reliability of regional-scale predictions is still low, and the degree to which climate variability may change is uncertain."

"Sea level is projected to rise by 15-95 cm (6-38 inches) by 2100."

"The long atmospheric lifetime of many greenhouse gases, coupled with the thermal inertia of the oceans, means that the warming effect of anthropogenic emissions will be long-lived."

"Even with a stabilization of greenhouse gas concentrations in the year 2100, temperatures would continue to increase for several decades, and sea level would continue to rise for centuries."

The actual changes per year and per decade would still include considerable natural variability, and regional temperature changes could differ substantially from the global mean value. The uphill battle for scientists and environmental activists is to combat the comfortable but dangerous complacency such false indications can bring to leaders frightened of difficult political choices for a public used to taking the easy route.

When the effects of greenhouse gases become fully apparent, what will happen? The composition and geographic distribution of many ecosystems (e.g., forests, rangelands, deserts, mountain systems, lakes, wetlands and oceans) will change as cold regions become warmer and warm regions will become hotter. Ultimately, major shifts in ecosystems will occur as individual species respond to changes in climate; there will likely be reductions in biological diversity and in the goods and services that ecosystems provide society. Some ecological systems may not reach a new equilibrium for several centuries after the climate achieves a new balance. Rainfall patterns will change. The interiors of continents, such as the corn-and wheat-growing regions of the U.S., may become drier and less productive. A more vigorous hydrological cycle means an increase in precipitation intensity, suggesting a possibility for more extreme rainfall events and floods, more severe droughts of greater frequency. Direct human health effects include increases in mortality and illness due to an anticipated increase in the intensity and duration of heat waves, but temperature increases in colder regions should result in fewer cold-related deaths. Indirect effects of climate change include increases in the potential transmission of vector-borne infectious diseases (e.g., malaria, dengue, yellow fever and some viral encephalitis), and non-vector-borne infectious diseases - such as salmonellosis, cholera and giardiasis - also could occur as a result of elevated temperatures and increased flooding. Limitations on freshwater supplies and on nutritious food, as well as the aggravation of air pollution, will also have human health repercussions.

With such dire consequences at stake it would seem prudent to err on the side of caution, and even some capitalists are coming around. Even FORTUNE magazine, gospel of Corporate America, reported in its December 8, 1997 article, "Science Says The Heat Is On", that "Despite furious debate about the greenhouse effect, there is little doubt that we are altering the atmosphere, and that the earth is warming... On balance, that probably won't be good news." The insurance industry is taking notice as well. Munich Re, the world's largest re-insurance company (whose business is insuring insurance companies against catastrophic losses) 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 this 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 1993, Skandia, one of Sweden's largest insurance companies, stopped insuring weather-related damages. 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. Climate change could bankrupt the insurance industry.

Climate change, if left to run its course in order to see the outcome, is an irreversible experiment on the planet. Taking measures to curb global warming now is the best insurance imaginable.

WISHFUL THINKING

o Winters will become milder. Daily high temperatures will moderate. It will only rain a few days each week, 2 to 3 inches between midnight and 4 am. (Yeah, sure, it could happen but it isn't likely.)

o Frequent occurrences of severe weather are atypical and will disappear as the pendulum of natural variability swings the other way. (The data shows that such storms events are becoming more common and, though no one knows all of the mechanisms involved, such divergence from historical norms indicates a causative factor that is in synch with rising global temperatures.)

o Faster plant growth will result from higher CO2 concentrations. (This is true, but weeds seem to thrive more than desired vegetation and any potential increases in food crops would likely be wiped out by larger populations of pest species that thrive across greater ranges in the absence of cold seasons that keep them in check, if in fact food crops could be produced across regions liable to suffer unknown climatic shifts.)

o We can fix any problems as they arise. (Technology got us into this mess and each generation of quick-fixes just seems to add to the problems. As with virtually any pollution, elimination of the problem is more effective than cleanup of the results.)

o It's too expensive to contemplate. (What is "expensive"? We are faced with the immediate expense of emergency bailouts to victims of catastrophes, and offered costly and incredible long term schemes like building dikes around low-lying coastlines as sea-level rises, and removing CO2 from the atmosphere by dumping iron filings in the oceans (!) and massive tree- planting efforts -- it would take an area the size of Australia to offset our CO2 emissions. Suggested alternative solutions would reduce energy costs and provide jobs in new industries.)

o It isn't happening! (Though the consensus of experts in the field determine that it is, if it isn't then the measures we take today will only result in a cleaner environment, a more efficient economy, and a healthier planet for future generations.)


The Harbinger, Mobile, AL