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Global Warming

When the possibility of global warming was first raised in the 1980s, it was a controversial subject. The scientific evidence was incomplete. The computer models of climate and climate change, based on incomplete evidence, were not totally accurate and sometimes were contradictory.

Now, 20 years later, there is no question that global warming is occurring. Even the White House conceded last summer that global warming is a reality. (Though this administration doesn’t want to do anything about it.) The only technical controversy today is just how warm we will get in the next 100 years. All the models agree that, at a minimum, the earth will get 1.5 degrees C (2.5 F) warmer. The computer models differ on the maximum possible warming; some predict eight degrees, others predict 20 degrees F as the maximum warming in the next 100 years. This would mean a significant climate change for Albany; warming of 6 F would give us the climate of Philadelphia and 10 F would make us as warm as Washington, DC, right now.

The source of global warming is the increase in “greenhouse gases” – carbon dioxide, CFCs, methane – in the atmosphere. These gases allow heat from the sun to warm the earth during the day, but trap the heat that should be radiated out into space at night. The effect is tiny – the increased warmth is about equivalent to the heat generated by one small Christmas tree light on every 10 square feet of area of the whole earth. Yet this tiny bit of increased warmth, generated year after year, has a significant cumulative effect on the climate.

Since there is controversy over the maximum possible temperature increase, perhaps it is best, when thinking of consequences, to focus on the changes already observed that are due to the increase in average global temperature of one degree in the 20th century, and on the predicted changes for the minimum further increase in average temperature of 2.5 F in the 21st century.

The serious geological consequence for humanity from global warming comes from an increase in sea level. As the ocean warms, its water expands and sea level goes up. If the world becomes warm enough to melt glaciers and the Greenland and Antarctic ice sheets, sea level could rise dramatically. One prediction is that sea level will rise three feet (one meter) every 20 years in the next century. The observed rise in sea level over the last century, about an inch per decade, already threatens the existence of low-lying islands in the Pacific. Flooding in New York City, the gradual disappearance of Florida and the Mississippi and Louisiana coasts, and the loss of Venice and much of Holland all are possibilities.

No particular event (like hurricane Katrina) can be attributed to global warming; it is a statistical effect that appears in slowly changing trends in climate. The increased heat (a form of energy) in the atmosphere and the oceans means that storms are likely to be more frequent and stronger than the long term trends would indicate. At higher latitudes effects are more noticeable: melting of the Arctic sea ice with a consequent threat to the survival of polar bears, a growing season in England that is two weeks longer, the conspicuous absence of the ten days or so of –20 F weather that happened annually in winter in Albany 25 years ago. Anyone who has lived in the same place for 25 years or more can point to evidence of warmer weather. My own example is leaf raking in the fall. Mid-raking season was right around Halloween in the late 1970s, but now is about two weeks later (This year, we were raking right up into December.)

Ecologists have done some studies of the interactions of climate and biology. A group in Holland, for example, has studied a bird that migrates from northern Africa every Spring. The start of the migration is determined by the length of day, which of course has not changed with climate change. Eggs are laid and chicks hatch at the same time as 40 years ago, but the birds’ favorite food, a particular caterpillar, now emerges two weeks earlier than it did 40 years ago. This means that the birds are late for their best food source, and hatchling survival is threatened by the lack of food.

In the human sphere, we can expect the spread of mosquito- and warm water- borne diseases such as malaria, yellow fever, dengue, and cholera. Other tropical infectious diseases may invade temperate areas where gradually warming winters will result in less winter die-off of organisms that spread the diseases. West Nile virus is a good example.

In most scientific controversies that impinge on the political sphere, the politicians get very exercised about the hazards, while the scientists tend to be more restrained. In the case of global warming, exactly the opposite is the case: Scientists are emphatic in their belief that strong actions must be taken now, while politicians hesitate. The scientists understand that a “tipping point” may occur with global warming. That is, one tiny continuation of previous activities may result in a complete and irreversible change in the world’s circumstances. Think of being in a canoe: one can rock the canoe back and forth, with no consequences, until it is rocked just an inch too far and tips over. With global warming the possibility exists that at some point, one further small change in the global heat balance might result in tipping the major ice sheets towards melting and sliding into the ocean, with a consequent huge rise in sea level. The way to prevent this catastrophe is to reduce greenhouse gases now, and reduce the rate of warming of the atmosphere. But the effect would not be apparent for a hundred years, and if the predictions are inaccurate, it might never happen. Politicians, who think in four year cycles, are unwilling to disturb the current economic and social climate on the chance that something bad will happen after they are dead.

There are things that we, as individuals, can do to reduce energy consumption and possibly slow global warming. (Every little bit helps. Think of it as removing one or two or ten of those Christmas tree lights that are warming your house or back yard.) Long-life low-energy light bulbs, fuel efficient cars, living in town instead of commuting from the country, energy efficient houses and appliances all reduce the use of power and the generation of carbon dioxide. Reducing electric power consumption is especially important, because of losses in efficiency in power plants and transmission lines. Each watt of electricity that a consumer uses requires the combustion of the equivalent of 10 watts of coal.

Businesses are already making changes in their energy consumption to reduce their costs. Large reductions in energy use that do not reduce costs will come only with government encouragement in the form of subsidies for development of new products and regulations that maintain a level playing field for competitive industries. The election and appointment of government officials who are willing to begin the process of reducing energy consumption is especially important.

For further reading: Scientific American is available in most public libraries. Authors are scientists actually involved in the work, writing for a generally intelligent, nonscientific audience. Articles in the last two years on global warming are readable and provide accurate information.

Richard Alley, Abrupt Climate Change, November 2004, pg. 62.
Daniel Grossman, Spring Forward, January 2004, pg. 84
James Hansen, Defusing the Global Warming Time Bomb, March 2004, pg.68.
Amory Lovins, More Profit with Less Carbon, September 2005, pg.74.

Global Issues Study Group

The Global Issues study committee will once again host a Great Decisions discussion group in 2006. The Great Decisions book is published by the Foreign Policy Association and will available, locally, in early January.

The eight topics are:

• UN Reform

• The U.S. and Iran

• Energy Resources

• Brazil

• Human Rights in an Age of Terrorism

• China and India: Partners or Competitors?

• Turkey

• Global Health Pandemics and Security

The first meeting will be held on January 30 at 9:30 A.M. Email lwvac@crisny.org for more information.

We will read and discuss, with the assistance of a facilitator, the first chapter for the first meeting. At that time we will set up the calender for the remaining discussions.