Among the constituents of the atmosphere, carbon dioxide and water vapour allow the short wave radiation of the sun to reach the earth’s surface but forbid or block long wave radiation from escaping out of the atmosphere. The net result is that earth’s surface gets heated. This phenomenon is called Green House Effect. The accelerated warming of the earth’s surface due to anthropogenic release of the green house gases is called Global Warming. The combination of green house effect and global warming has substantial effect on climatic pattern around the world.

Mountain system accounts for roughly over 75% of area in Nepal which contains sensitive ecosystem and experiences many climatic events like floods, landslides and droughts. Change in climatic conditions makes these events even more intense and frequent. The altitudinal range of Nepal ranges from 67 m to 8848 m from the sea level. This altitudinal variation in turn leads to climatic and biological variation. Warming of earth will certainly worsen the condition. The impact of global warming can be seen on our ecosystem. Rapid change in climate makes it difficult for flora and fauna to survive in native conditions. Species have to modify themselves at a faster pace so as to cope with the rapidly changing climatic conditions; those incapable of doing so perish. This results in a sudden decline in the genetic resources.

There are more than 2000 glacial lakes in Nepal and snow covered mountains run throughout the northern belt. The increase in precipitation pattern in the Himalayan belt and fast snow melting rate will increase water level in glacial lakes. Landslides, rock falls and avalanches in the lakes will cause big water waves to erode the dam moraine that may trigger the Glacier Lake Outburst Flood (GLOF). Similarly, snow covered areas will shrink causing shortage of water for drinking, electricity and irrigation. The rise in temperature will deplete snow-covered areas, so there will be less snowy area to reflect solar radiation. Every increase in 0.5°C can shift the crop line upslope by about 150 m. Thus, arable land of Tarai will be no longer fit for cultivation and only rocky mountains and steep slopes will be left for agriculture practices.

Rainfall pattern will be altered due to green house effect which creates most unpredictable and deleterious effect on land. Some areas will see scant rainfall due to dry weather while other areas will have high intensity and high frequency rainfall owing to higher rate of transpiration. This leads to different natural calamities like severe droughts, catastrophic floods, mass landslides and other disasters which we cannot even imagine now.

Climate change has substantial effects on the health of human beings. Higher temperature brings higher number of diseases. Some diseases which have been already eradicated from the Nepal may reappear. Threats to human health can be noticed in the form of increase of disease carrying vectors such as mosquitoes that amplify sickness like malaria, dengue fever, encephalitis and yellow fever. Heat strokes and skin burns are also caused by high temperature and low humidity. Starvation and deficiency of potable water enervate human health.

No single country is solely responsible for climate change and none can escape from its unseen consequences. Thus both developed and developing nations have to worry about global warming and should address the threat on time. Use of eco-friendly sources of energy instead of fossil fuels can lower the content of GHGs to acceptable limits. The alternative or renewable eco-friendly sources include solar energy, hydropower, wind energy, biogas and tidal energy. Development and promotion of engines that run with the help of these alternative energy sources is of utmost importance. As plants are the only regulators of oxygen and carbon dioxide cycle, afforestation is the key step to control increasing carbon dioxide in atmosphere. Day by day plants are being hewn down for settlements and other human activities. This should be stopped immediately. Thus, the promotion of greenery in nude areas can significantly control global warming.

The Kyoto Protocol to the UN Framework Convention on Climate Change was signed in 1997. The protocol committed the industrialised nations to reduce the emission of GHGs. The protocol also includes emission trading, under which countries or companies can purchase less expensive emission permits from countries that have more permits than they need. This protocol should be effectively and legally implemented.

Last but not the least is public awareness. People must be aware about the causes and consequences of climate change. If we are aware in time, we will certainly be able to hand over a habitable earth to posterity. If significant steps are not taken immediately, climate change might bring about an entirely new environment on earth — one where life may not be impossible but tougher and harsher than at present.

Pathak teaches Environmental Science