Global Warming - The stupidity of Human beings and the wrath of Nature

Global warming and climate change has become one of the hot topic of the 21st century in the global mass media. The fourth assessment report of the IPCC (Intergovernmental Panel for Climate Change) briefs about this serious problem and man is in part responsible. Today, it is considered as one of the world's top ten greatest challenges.

In simple words, Global warming is defined as the increase in the earth's average surface temperature.

Greenhouse effect:
The earth receives energy from the sun, which warms the earth's surface. As this energy passes through the atmosphere, a certain percentage(about 30%) gets scattered. Some part of this energy is reflected back to the atmosphere through land and ocean surface. The rest(70%) actually remains behind to heat the earth. In order to establish a balance, therefore, earth must radiate some energy back to the atmosphere.

As the earth is much cooler than the sun, it doesn't emit energy in the form of visible light instead it emits as infrared or thermal radiation. However, certain gases in the atmosphere form a sort of blanket around the earth and absorb some of this energy emitted back to the atmosphere. Without this blanket effect, the earth would be around 30^oC colder than it normally. These gases like carbon dioxide, methane and nitrous oxide along with water vapour, comprise less that 1% of atmosphere. They are called as green house gases as the working principle is same as that which occurs in a greenhouse.

Causes for the problem
Scientists say the observed increase is due to the increase in the anthropogenic(man made) green house gases like Carbon dioxide(CO₂), Methane (CH₄), Nitrous oxide (NO₂) and Chloro Floro Carbons (CFCs).
Nature maintains a perfect balance of the green house gases sources and sinks, but increasing industrialization and consumerism evoke human beings to upset this balance by introducing new sources and destroying the forests. Changes in the atmospheric abundance of green house gases and aerosols, in solar radiation and in land surface properties alter the energy balance of the climate system.

• The amount of carbon dioxide in the atmosphere in 2005(379ppm) exceeds by far the natural range of the last 6,50,000 years (180 to 300 ppm). The primary source of the increase in the CO2 is fossil fuel use, but land-use changes also make a contribution. Carbon dioxide is the most important anthropogenic greenhouse gas.
• The amount of methane in the atmosphere in 2005(1774ppb) exceeds by far the natural range of the last 6,50,000 years (320 to 790 ppb). The primary source of the increase in the methane is very likely to be a combination of human agricultural activities and fossil fuel use.
• Nitrous oxide concentrations have risen from a pre-industrial value of 270 ppb to a 2005 value of 319 ppb due to human activity and primary agriculture.
• CFCs are emitted from the air conditioners, refrigerators and aerosols or spray can propellants which plays a predominant role in ozone depleting. Today, India and China are the greatest emitters for CFCs.
  

Impacts of global warming
Since the end of 19th century the earth's average temperature has increased by 0.3-0.6 degree celcius. over the last 40 years, the rise has been 0.2-0.3 degree celcius. Some important aspects of our lives can be affected through changes in weather patters and some of these are discussed here.

• Agriculture: The steady-increasing human population has led to a rise in the demand for food. As more land comes under agriculture cultivation there will be more pressure on the natural ecosystems. Climate change will affect agricultural yield directly because of alterations in temperature and rainfall, and indirectly through changes in soil quality, pests and diseases.
• Weather: A warmer climate will change rainfall and snow fall patterns, lead to increased droughts and floods, cause melting of glaciers and polar ice caps, and result in accelerated sea-level rise. Sea level rise could adversely affect coastal agriculture, tourism, fresh water resources, fisheries and aquaculture, human settlements and health.
• Health:Climate change will lead to several direct and indirect impacts on health. The wide-ranging harmful effects include increase in heat-related mortality, dehydration, spread of infectious diseases, malnutrition and damage to public health infrastructure.
• Global Warming doesn't only increase temperatures in hot areas. It also decreases temperatures in cold areas. Even 1^oC increase in the temperature can destroy hundred and thousands of species.
  

Positive effects:
It's a good news at least for those who enjoy wild mushrooms. According to recent scientific investigations, Mushrooms have doubled the length of their fruiting season and according to the survey some mushrooms even fruit twice a year now, mirroring the rise in local temperature.

Higher the level of greenhouse gases may significantly boost production of fruits and seeds in crops such as wheat, rice and soybeans according to a recent study because crops have higher yields when more carbon dioxide is available. But it is again a double-edged sword; the increase in the yields appears to be linked to a decrease in the nutritional value of these crops.




Solutions
Climate change will lead to serious problems which all countries must get together and solve, Since human activities have a large impact on the climate, a large part of the solution lies in our hands.

• We can bring down the use of fossil fuels, cut down on consumerism, halt deforestation, promote reforestation and use more environment friendly agricultural methods.
• In the energy sector, emissions can be lowered if the demand for energy is reduced and if we shift to cleaner sources of energy which do not release carbon dioxide. These include solar, wind, geothermal, and nuclear energy.
• Governments all over the world should see that forest cover is maintained because plants use CO2 to grow and help remove it from the atmosphere.
• Biotechnology can be used to produce water requirement of crops, increase crop yield, and reduce the use of fertilizers and pesticides.

All countries must serve to cut down the greenhouse gases emission as per the Kyoto protocol.
If our house is set ablaze we can run away, if our planet started warming up where will we hide. Every individual must act immediately to reduce the effects of global warming otherwise we should be ready to face the dangerous consequences.

Thanks for reading
Srinivas