‘Climate Change’ has now emerged as the most urgent and challenging global issue, with potential to destroy life on the planet unless addressed immediately through collective and concerted efforts.
 
The climate of the planet is regulated primarily by the sun and the interaction between the earth’s atmosphere, hydrosphere and biosphere.  A balance in the atmospheric composition is crucial in maintaining the earth’s congenial climate. Human activities such as energy generation from burning fossil fuels, deforestation and habitat degradation, agriculture, extraction of transportation fuels and industrial processes have added vast amounts of greenhouse gases (Carbon dioxide, Methane, Nitrous oxides etc) to the atmosphere. These GHGs are trapping and accumulating solar radiation within the earth, thereby gradually warming up the planet.
 
In the past 150 years, the average surface temperature of the earth has shot up by 0.76 degree C. This has had disastrous consequences on much of the planet; sea levels have risen by 20 cm, submerging several populated islands in India and the rest of the world, there have been increased incidences of extreme weather events, such as storms and droughts, which have claimed millions of lives, high altitude and latitude ice caps have been melting rapidly, causing floods in the flood plains of glacial rivers. In addition, several species have been dying out because of changes in ecosystem composition and increasing temperatures.
 
This century is projected to experience even more rapid warming by up to 6.4 degree C, bringing with it increase in sea levels of up to 59 cm, complete disappearance of the Tibetan and Himalayan glaciers, extinction of a million species, drop in rainfall and food production by 30% and drying out of entire rivers. This climatic change will kill millions of people and put an additional one billion people at risk of starvation.

Why is ‘Climate Change’ happening? 
  
Naturally occurring climatic changes have punctuated the earth’s history consistently since eons. These have occurred because of changes in the earth’s orbit, volcanic explosions spewing vast quantities of ash into the atmosphere and blocking solar radiation, meteorite impacts and less often, because of changes in the concentration of greenhouse gases in the atmosphere. These naturally occurring greenhouse gases, such as carbon dioxide, methane, nitrogen oxides etc, have the capacity to trap solar radiation within the earth, thus keeping the earth warm enough for life to sustain.
 
Over the past two centuries, human beings have vastly increased the concentration of greenhouse gases in the atmosphere through a combination of energy intensive activities such as power generation, transportation and industry, for which fossil fuels such as coal, petroleum and natural gas have been exploited; natural resource intensive activities such as land use change for agriculture, housing and infrastructure development, which has resulted in massive deforestation and vegetation loss, and spontaneous release of giga tonnes of carbon dioxide captured in vegetation and agricultural activities, which release methane and nitrogen oxides; and through waste disposal and open combustion. This has resulted in greater amounts of methane and other greenhouse gases being released.
 
Power generation is most responsible for the increase in greenhouse gas emissions. World over, obsolete and inefficient thermal power stations burning coal and other carbon constituted fossil fuels are releasing vast quantities of carbon dioxide. The same carbon fuels are also fuelling the world’s transportation and industrial production, which our materialistic lifestyles are further stimulating.
 
The vast increase in the human population beyond levels that can be sustained by the planet has required the clearance of vast tracts of forests, natural sequesters of GHGs, for food cultivation. A combination of deforestation, agriculture and allied activities such as livestock and fertilizer application has also contributed immensely to emissions.
 
A combination of these factors, and a gross failure in accepting the crisis and in reducing emissions through energy efficient practices, both at the individual level and in national policy structure and international frameworks, has resulted in a rise in GHG concentrations to 430 ppm and the earth warming consequently to 0.76 degree C.

If this crisis is disregarded through a persistence of the same development pathway, the earth will warm by up to 6.4 degree C this century, spelling catastrophe for life on the planet.
 
What are the consequences?
 
Climate change will have enormous and catastrophic impacts around the world, with impacts on every single component and square inch of the Earth’s surface. The IPCC projects that ecosystems, agriculture, coastal regions and wetlands, oceans, water supplies, human society and even human health will be adversely impacted, varying in response to warming between 1.4 and 5.8 degree C expected this century. 
 
Extreme weather events will greatly increase in frequency and intensity over the next century with serious consequences for human health and well being. According to IPCC projections, heat waves, droughts and famines, wild fires, severe storms, floods and dust storms will cause economic, ecological and social damage of an unprecedented scale.
 
Agriculture in tropical and low latitude regions such as India will be gravely impacted, with crop yields expected to drop by 30% by 2050. Coupled with India’s rising population, this will have a devastating impact on the country’s food security and millions of people will be pushed into starvation.
 
Sea levels are projected to rise by up to 59 cm. This will cause coastal flooding, intrusion of saltwater into cultivable lands, and submergence of small island states, which will in turn cause displacement and migration.
 
Hundreds of millions of people will face acute water scarcity, as rainfall drops by up to 30% this century. At maximum risk is drought affected regions, where instances of water shortage related fatalities will increase in frequency.
 
Ecosystems will suffer enormously because of climate change, with 30% or a million extant species becoming extinct because of warming climates. This will only be exacerbated by habitat loss and degradation.
 
High latitude and altitude glaciers are highly sensitive to warming climates, and are showing a rapid retreat. This is especially disastrous for mountain glaciers from which a majority of the Asian rivers originate, as this will cause flooding followed by acute water scarcity.