Is the World Warming Up?

Some years in the future, Alaska and northwestern Canada may face some interesting policy questions created by what appears to be a warming up of the world's climate. The effects of the predicted change are likely to be greatest in this part of the world, and, being suppliers of fossil energy to the world, we northerners may be contributing to the change.

The overall global temperature is determined by the requirement that, in the long run, the earth must radiate to space as much energy as it receives from the sun. If the amount of energy coming in increases, the global temperature will increase so that the outward radiation increases--the outward radiation is proportional to the earth's temperature. Alternately, changes in the earth's radiation characteristics can create temperature changes without there being any change in the solar energy coming in.

Carbon dioxide in the earth's atmosphere traps outgoing radiation. This is the so-called greenhouse effect which keeps the earth warmer than it would be were there no carbon dioxide in the atmosphere.

Right now, there is certainty about two things. Firstly, the amount of carbon dioxide in the air has increased from about 280 to 300 parts per million in 1880 to 340 parts per million in 1980. Secondly, the global temperature has risen by about 0.4°C during the same period. The increase in carbon dioxide this past century is caused by the great increase in human use of fossil fuels, a use that puts carbon dioxide into the air. Also, the observed increase in global temperature is consistent with what scientists calculate it should be from the increase in carbon dioxide.

The question of what future world temperatures will be is muddied by the knowledge that a variety of natural fluctuations in temperatures do occur. There may be upward or downward fluctuations in solar luminosity. Large volcanic eruptions spill aerosols into the air and cause temporary global cooling. Running means (8-year averages) of the composite Alaska average annual temperature show oscillations of one Centigrade degree and period roughly 13 years, for unknown reasons. Other cyclic or quasi-cyclic variations occur with much longer periods. Altogether, these natural fluctuations create a lot of 'noise' that makes it difficult to recognize a particular change such as that thought to be associated with the carbon dioxide increase.

However, it is now predicted that there will be substantial warming during the 1980s and that the carbon dioxide warming trend will clearly emerge from the noise by the end of this century.

During the 21st century the global warming could amount to 2°C or even more. The kicker is that the warming at high latitudes will be much more, perhaps about 5°C. That is close to 10°F, and that is a lot.

One of the more serious consequences is melting of the arctic ice pack and melting of Antarctic glacier ice. Sea level could rise by ten or twenty feet in less than a hundred years. Think what that means for every coastal village and city in the world. Louisiana and Florida would grow smaller by 25 percent, and the Northwest Passage could open to shipping. Large portions of North America and Asia would become drought-prone because of accompanying meteorological changes.

A major effect in Alaska and northwestern Canada would be melting of permafrost over large areas. Foundations and roads in discontinuous permafrost areas will be greatly affected, so there would be high repair costs.

All this might be avoided if the world curtails its consumption of oil, natural gas and coal. If it comes to a decision on that issue, how will the energy-producing areas such as Alaska and northwestern Canada react? Will they be willing to reduce their income from fuel sales to alleviate the situation? Or will they have any say in the matter?