The Greenhouse effect is about the fact that this globe- our atmosphere, our earth surface and the oceans – are getting warmer everyday. The cause is an increase in the amount of carbon-dioxide released in the air. What CO2 does is as follows: In the normal circumstances, the heat from sunlight that hits the earth surface is radiated back into the atmosphere. Carbon dioxide absorbs this heat and does not allow it to go very high into the sky. So, the air near the earth’s surface gets heated up. More CO2 we have in the air, warmer our surroundings get. I may mention here, why the name greenhouse effect. In a glass greenhouse which has plant and nursery, the rays of sun penetrate through the glass and reach the plants but the heat absorbed in the greenhouse floor and flowerpots cannot go out of the greenhouse because of the glass walls. The CO2 in the atmosphere acts like the glass walls. Hence the name ”Greenhouse Effect.”
Now, as I was saying, more CO2 we have, greater is the warming of the globe. Where does this extra CO2 come from? It comes from emission from cars, airplanes, industry, homes, agricultural fields, human beings and anything you name it.
When Life began on the Earth, there was a balance of CO2 emission and Earth’s requirement of this gas. As we all know, we exhale CO2, which was used by plants, and vegetative life as well as it absorbed heat. This absorption of heat by CO2 was essential and carefully provided by Nature. If there was no CO2 there would be no life on earth because without the heat absorbed by this gas the Earth would be too cold for any life to survive. Thus it is ironic that what was intended by Nature to be an instrument of survival for humanity, is today getting a source of great hazard to humanity itself. And this is due to the doings of human beings themselves, as I said earlier about the sources of CO2 emission. Take for example, airplanes. It has been estimated every time an airplane crosses Atlantic i.e., flies from London to New York or the other way round, the flight produces about one ton of CO2 per passenger. Similarly, an average car produces four times it’s own weight of CO2 each year. These two modes of travel are responsible for adding 25% of the 5 billion tons of CO2 being added each year by man-made processes. The remaining 75% is due to industry and other sources.
The increased human population and decreased forests have also contributed to the increase in CO2 content in the air.
The tremendous input of CO2 in the atmosphere is absorbing tremendous quantities of heat thereby raising the temperature of the Earth.
It has been estimated that compared to today, the global temperature rise would be 1 degree C by year 2030, by 3-4 degree C by 2050 and about 5-6 degree C by the end of the twenty first century, if the present rate of CO2 emission continues.
Such temperature rises are likely to-
1. Reduce food production.
2. Decrease water availability.
3. Would cause ocean levels to rise by several feet, thereby inundate low-lying areas.
4. Higher Temperatures generally- apart from being highly uncomfortable- may cause extreme heat waves.
5. More intense cyclones may be expected.
6. Increased likelihood of forest fires.
7. Melting of glaciers.
8. Negative effect on human health.
Certain things should be done immediately to reduce the CO2 content in the atmosphere. One is reduction in air travel, second the car manufacturers should be persuaded to make engines which are more efficient and less polluting. As far as the individual car drivers are concerned, stick to the speed limit, use fuel efficient cars and keep them properly tuned.
Right now, Scientists all over the world are finding ways and means to prevent the Earth’s atmosphere from turning into a hothouse and its inhabitants from being roasted. At least the debate is hotting up.
I may mention here that apart from CO2, a gas called methane is also a big culprit in global warming. The big source of methane, apart from industrial plants and rotting garbage are the paddy fields. Large quantities of methane rise from such fields. Methane’s capacity to absorb heat is about twenty times more than that of CO2, i.e., one molecule of methane absorbs 20 times more heat than one molecule of CO2. Thus the rice eaters of the world have some responsibility to share, regarding global warming.