Glaciation
                      or
        Global
           Warming?

More and more frequently, it seems that the seasons are disappearing, the danger of drought and flood increase simultaneously, and previously unfamiliar weather catastrophes are reaching our country. Dr. János Mika, an associate of the Hungarian National Meteorological Service, sheds light on the connections of the Earth with these questions.

The tendencies of the weather in the Carpathian basin are related to the changes in climate around the Earth. The atmosphere's so-called greenhouse effect has been intensifying from at least the middle of the nineteenth century. The increases in greenhouse gases like carbon dioxide, methane, dinitrogen oxide, and the halogenated carbohydrates are responsible for this. Sunlight passes through these gases without any disturbances to the surface of the Earth, but then the longer wavelength energy originating from the surface of the planet is absorbed by the gases (and also the clouds and steam) and is reflected back to the surface of the Earth.

Models simulating climate formations show that the changes in the average temperature on Earth are measurable in degrees Celsius, and certain prognostics say the situation can get much worse! This could happen, for example, if the ocean currents, particularly the Great Conveyor Belt, suddenly comes to halt or changes. This would cause a weakening of the energy exchanges between the landmasses, which has been proven to result in a climate like that of the decades ten thousand years ago that was much colder than today. In that time the climate quite often went through many degree changes in just a few decades, that is, one order of magnitude faster (in both directions!) than should be expected from the greenhouse effect.

The basis for the functioning of the Great Conveyor Belt is the differences in the salt concentrations measured at the equator and the polar regions. However, in the course of global warming, it could happen (as most models suggest) that these differences decrease. A report prepared for the Pentagon about the forecast of glaciation by 2010 is questionable. A more probable global tendency is a slow warming up, which we are already experiencing. As a consequence of further increases in carbon dioxide and other greenhouse gases, we should expect an increase of many degrees in temperature in this century.

The Great Ocean Conveyor Belt, which ensures a relatively stable climate; the top branch is indicated red and the bottom branch is marked blue

Till now we have not done anything in the interest of regulating global climate changes or regional accommodations, because we are not completely familiar with the drawbacks (in some cases benefits) that can be caused by these global changes. This lack of understanding is due to the indistinctness in local climate variances. Today's computers can only calculate the proceedings of the atmosphere for the necessary few decades in advance with a resolution of 200–300 km. Because it is essential to create strategies for adjustments now, we need to be able to estimate the regional climate changes, which science is currently attempting to do by "downscaling."

According to present data, the climate of the Carpathian Basin, in parallel with global warming, is getting warmer, dryer, and sunnier. This will be perceptible mostly in the warmer half of the year, in the plant growing season, while in the colder months, more precipitation cannot be expected. From a "lessons from the past" type analogy, following the global warming, the winter precipitate will arrive in a greater proportion as rain and not snow.