Climate corrections

Some interesting observations by Syun-Ichi Akasofu, former director of the International Arctic Research Center at the University of Alaska...

In understanding the present warming trend, it is absolutely essential to learn more about climate change in the distant past -- or at least during the last 1,000 years. But many scientists, particularly younger ones, prefer to work only with data collected after 1975, when satellite data became available. With only 30 years worth of data, their results are little more than climatological snapshots of what is really a slow, long-term process. The latest accurate satellite images of sea ice distribution in the Arctic Ocean today can be obtained by clicking on a computer screen; but it is impossible to obtain such quality data for periods before 1975.

It is for this reason that only a minority of scientists are studying natural climate change, including multi-decadal oscillations and centurial climate change, which is the true realm of climatology. These areas have not been priorities for the IPCC.

They should be. During winter, England's Thames River would once freeze solid. This occurred on and off between 1400 and 1800 during a period called the "Little Ice Age" when temperatures dropped by as much as 1.5 degrees Celsius, which came after the medieval warm period around 1000. The anomaly of the Little Ice Age corrected itself, of course, through something called rebounding. The rebounding rate is estimated at 0.5 degrees Celsius per century. Since our present warming rate is roughly 0.6 degrees Celsius per century, the greenhouse effect caused by CO2 may represent only a 0.1 degree Celsius increase in temperature over the course of a century.

There is no doubt that global warming is in progress. But much of it can be attributed to the rebounding effect from the Little Ice Age. Recovering from a cool period is, of course, warming -- but it is nothing to panic about. Ice core data from the Greenland ice sheet show many periodic warming and cooling periods during the last 10,000 years. The present warming phase is far from the warmest.

Scientists have no clear knowledge of the cause of the Little Ice Age and of the subsequent rebound; or of the Big Ice Age; or of a warm period when the Arctic Ocean had no ice; or of the medieval warming period. In fact, IPCC scientists do not understand the causes of the rapid increase of temperature from 1910 to 1945; or the decrease from 1945 to 1975, when CO2 levels were rising. Without understanding these recent changes, it is premature for the IPCC to jump to the conclusion that CO2 is the main cause of the last 30 years of global warming.

Many people claim scientists proved the greenhouse effect with models run on supercomputers. But a supercomputer is not a crystal ball. Scientists merely enter observed (or expected) CO2 amounts into a computer and, using an algorithm, a projection emerges. No computer can accurately represent such a gigantic system as the Earth with all its unknown processes, such as the causes of the medieval warm period and the Little Ice Age.

Therefore, no supercomputer, no matter how powerful, is able to prove definitively a simplistic hypothesis that says the greenhouse effect is responsible for warming. Most people, including scientists who specialize in climatology, are not aware of this weakness. In fact, the whole science of climate change based on supercomputers and algorithmic models is still in its infancy. A supercomputer cannot provide an approximate estimate of the temperature in 2050 or 2100 because scientists are not able to instruct it with all the unknown processes that may be at play. Any conclusions drawn from such results -- which may be seen as nothing more than an academic exercise -- cannot and should not serve as hard facts on which to base major international policies.