An increase in the average temperature of the earth’s atmosphere due to green house effect which can have far reaching effects on the climate and consequently on the key life, support systems of the planet. Since the last century, human activities, mainly burning fossil fuel, has raised the atmospheric concentration of green house gases, which may intensify the green house effect and result in an increase in the average global temperature.
Since global climate including rainfall, storms, wind patterns, ocean currents and sea level is intimately related to global heat flows and temperature patterns, there is a general expectation that the earth’s climate may be significantly modified in the next 50 years. This would, in turn, alter the earth’s delicate ecological balance.
Between the years 1878 — 1990, an increase of 0.45°C to 0.15°C has been there; during 1990 — 2025, there may be further rise by 1°C and between 2025 – 2100 there may be 3°C rise.
Besides what has been stated above, the rise in temperature will melt all the glaciers (snow-mountains), flooding the low-laying areas of the earth. An increase in global temperature is also likely to increase the incidence of infectious diseases such as malaria, dengue, sleeping sickness and yellow fever. Table 4.3 Gives some major greenhouse gases and their sources.