Global warming - is it alarming?

Dr. Senarath Tennakoon

Between AD 900 and 1300, the Earth warmed by about one and half degrees. Scholars have named this period one of the most favourable periods in human history (The Medieval Climate Optimum). During this period, food production increased as winters were milder and there was more rainfall.

There were fewer droughts and fewer floods. The food growing periods became longer than before and the temperature was bearable and comfortable. The morbidity and mortality patterns changed for the better. As people spent less time in crowded damp places infectious diseases, in particular Tuberculosis declined. Deaths too declined. People in general did not die of hunger as food was available and cheap. There was prosperity all over the world. Creative arts as well as scientific inventions developed.

In Europe, massive cathedrals were built. In Asia, huge temples came up. The windmill and the spinning wheel as well as new iron casting techniques entered the daily life pattern. Farming flourished and began to spread far and wide in England, Scandinavia, Japan and Russia.

But scientists are alarmed at what is happening in the Arctic Ocean. There has been a massive increase in the amount of ice that is melting in the Arctic Ocean each summer and scientists fear that there will be no summer by 2030.

The Arctic is warming up rapidly than any other place. While the global temperature has risen by less than one degree over the past three decades, the rise in the Arctic Ocean has been by around three degrees.

Where ice has disappeared, the rise has been by five degrees Centigrades. This warming extends even to the land masses of Siberia, Alaska, Canada, Greenland and Scandinavia and to their snow fields, ice sheets and permafrost (Pearce, 2009). It has been observed that in 2007, the North American Arctic was more than two degrees C warmer than the average for 1951 to 1980, and parts of Siberia over three degrees C warmer. In 2008 most of Siberia was two degrees C warmer than average.

Permafrost contains organic carbon in the form of long dead plants and animals remained frozen for thousands of years. When the permafrost melts much of this carbon is likely to be released to the atmosphere, Professor Edward Schuur of the University of Florida has estimated in 2008 that the carbon locked in the permafrost to be 1,600 billion tones which is about one third of all the carbon present in the world’s soils.

The danger of melting permafrost is the dangerous release of methane. Recent studies have shown that the methane levels have begun to rise, and the source could be the melting. Arctic permafrost. The danger is that with rising methane emissions the atmospheric temperature will rise despite human attempts to curb greenhouse gas emissions.

The effects of this meltdown are frightening to most scientists and even catastrophic in outlook. James Overland, an Oceanographer at the Pacific Marine Environmental Laboratory in Seattle observes the loss of summer sea ice leads to more heat absorption in the ocean which is given back to the atmosphere in early winter. This would change the wind pattern which in turn favours additional ice loss. As the Arctic warms, the melted permafrost flows down as fresh water and enter the oceans thus raising their water levels.

This extra water could weaken the pump that drives the thermohaline circulation, or ocean conveyor current. As water gets warmer and less salty this pump could slow down. Fear is that this pump might get shut down. The biggest consequence of monsoon warming would be faced by Asia says Buwang Dong of the Walker Institute for Climate Systems at the University of Reading, U.K. He has predicted severe droughts in Asia.

Asia is the heavily populated continent where growing food crops is the chief way of living for over two billion people. If the monsoon pattern changes they would starve because of the warming Arctic.

But there is another optimistic view about global warming. In the 1980’s it was thought that New York and Bangladesh would go under water due to global warming. But so far no such thing has come true. If temperatures warm a few degrees there will be more moisture in the air more snowfall, more ice in the polar regions. The expected increase in the carbon dioxide (CO2) levels due to burning fossil fires would create a ‘plant heaven’ as CO2 acts as a fertilizer to plants. Doubling the yield of carbon dioxide would raise crop yield by half. It will also boost wildlife. Any global warming in the 21st Century would be moderate bringing back one of the most pleasant and productive environments - humans and wildlife have ever enjoyed (Avery, 1999).

\Several scientists have raised the issue of environmental warming cause by various human activities resulting from the additional amounts of carbon dioxide that is released to the environment. This carbon dioxide together with the water vapour absorbs the log rays emitted by the Earth and this energy in turn goes back to the surface of the Earth causing an increase in the Earth’s surface temperature.

This is the Greenhouse effect. It is feared that the Greenhouse effect would increase in the near future. Not only carbon dioxide, there are other gases like methane, nitrous oxide and chloroflurocarbons that are entering the living atmosphere.

There is no doubt that the environment warming is influenced by the Greenhouse effect. Environment warming too is influenced by changes in sun’s energy, activities of volcanos and natural changes in the environmental warming up cycle itself. The concern over global warming resulted in the establishment of the Inter Governmental Panel of Climate Change (IPCC) in 1988. In 1990 the IPCC, reached the following conclusions:

1. If the prevailing conditions continued to exist the CO2 level would double during 2025-2050 period.

2. As a result, the central temperature of the Earth would increase by a value between 1’5-4.5 degrees centigrade.

3. The warming up would not be uniform on the Earth surface. It would twice higher in the polar regions that over the equator.

4. Rainfall might decline over the years in many places.

5. The world will have to face drying of the Earth surface and a shortage of water resources.

6. The warming of the Earth would lead to a rise in the sea water level by 0.3-0.5 metres in 2050 and by one metre in 2100 respectively.

7. There would be changes in the weather and climate patterns.

Carbon dioxide, thermal energy and radio active wastes are just three of the many disturbances man is inserting into the environment at an exponentially increasing rate.

It is not known how much CO2 or thermal pollution can be released without causing irreversible changes in the Earth’s climate or how much radioactivity, lead, mercury or pesticide can be absorbed by fish, plants or human beings before the vital processes are severely interrupted (Meadows et al, 1972) Climate change will have drastic effects on most ecosystems. Many organisms are very sensitive to fluctuations of the carbon dioxide concentration in the atmosphere (Fajer, 1989). Many are worried about the fate of the polar bears.

But global warming could be a threat to biodiversity and could be a cause for the loss of some susceptible species. (Shiva et al, 1991).

The consequences of ecological degradation affect the whole world. Until 1950, pollution remained a circumscribed problem. In the 1970s, it became a regional problem and began to globalize.

By 1980 it became evident the pollution problem is really the result of human activity (Pintasiligo, 1996). Mega cities and super highways that arise in developing countries impose excessive demands on nature. Still nature is being looked upon as a passive entity that should support every human activity.

But in essence the quality of the environment is a crucial dimension for establishing a sustainable equilibrium.

Biodiversity and access to natural resources are immediate ingredients of the quality of life (Pintasiligo, 1996).

A positive change in the knowledge, attitudes and practices of the human subject that favours the development of a new equilibrium, where there is harmony between the nature and human existence is valued and respected, would save the future world for the posterity.