It is being increasingly realized that human activities have had adverse affect on the environmental and natural resources that sustain human life on the Earth. And among these environmental issues the principal change to date is in the earth's atmosphere. We have changed, and are continuing to change, the balance of gases that form the atmosphere. This is especially true of such key "greenhouse gases" (GHGs) as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). (Water vapour is the most important greenhouse gas, but human activities do not affect it directly.) These naturally occurring gases make up less than one tenth of one per cent of the total atmosphere, which consists mostly of oxygen (21 per cent) and nitrogen (78 per cent). But greenhouse gases are vital because they act like a blanket around the earth. Without this natural blanket the earth's surface would be some 30 C colder than it is today.

Human activities are making the blanket "thicker" through burning of fossil fuels, destruction of forests, raising cattle and planting rice. These activities result in emissions of GHGs into the atmosphere increasing their concentrations. If emissions continue to grow at current rates, it is almost certain that atmospheric levels of carbon dioxide will double from pre-industrial levels during the 21st century. If no steps are taken to slow greenhouse gas emissions, it is quite possible that levels will triple by the year 2100.

It wouldn't have mattered but for the fact that this will change the energy balance on the earth, which provides us with a comfortable temperature for life to exist on the Earth. Changes in the energy balance result from the fact that GHGs trap the sun energy reflected back into the atmosphere by the Earth Surface. Increasing concentration of these gases in the atmosphere will increase the amount of energy retained, which in turn will lead to increase in the temperature of earth surface. Changes in global temperature will have affect on the earth's climatic system and sea-level rise (melting of the ice cover due to increased temperature will increase the total volume of water). These changes are studied through what are known as Global Circulation Models, which emulate the Earth's complicated climatic system. Though these models are simplistic, given the complexities of the climatic system, representation but they give an ample indication of likely consequences.

The IPCC (Intergovernmental Panel on Climate Change) has recently completed its Third Assessment Report, which incorporates new results from the last 5 years of climate change research. Global average surface temperature is projected to increase by 1.4 ºC to 5.8 ºC over the period 1990 to 2100. This projected warming is greater than that experienced over the last 10,000 years. It is also higher than the projected increase in the IPCC Second Assessment Report, which was 1.0 ºC to 3.5 ºC. Moreover, global mean sea level is projected to rise by 0.09 to 0.88 metres over the same period, as a reult of the thermal expansion of the oceans, and the melting of glaciers and polar ice sheets.

What are the consequences? The regional rainfall pattern might change. At the global level, the evapo-transpiration cycle is expected to speed up. This means that it would rain more, but the rain would evaporate faster, leaving soils drier during critical parts of the growing season. New or worsening droughts, especially in poorer countries, could reduce supplies of clean, fresh water to the point where there are major threats to public health. It will affect agriculture production. Increased summer dryness may reduce mid- latitude crop yields by 10 to 30 per cent, and it is possible that today's leading grain-producing areas would experience more frequent droughts and heat waves. Rising sea levels would threaten low-lying coastal areas and small islands. The global mean sea level has already risen by around 15 centimetres during the past century. The most vulnerable land would be the unprotected, densely populated coastal regions of some of the world's poorest countries. Bangladesh, whose coast is already prone to devastating floods, would be a likely victim, as would many small island states such as the Maldives.

While scientists are scrambling to understand more clearly the effects of our greenhouse gas emissions, countries around the globe recently joined together to confront the problem. After the First Assessment Report published by IPCC in 1990, which highlighted the dangers increasing concentration of GHGs posses to existance of life form on earth, the world community came together and negotiated what is now known as United Nations Framework Convention on Climate Change (UNFCCC (provide a link to www.unfccc.int here)). It was a big step forward considering that the there was still a large scientific ambiguity and any measures to address the issue would affect whole of the economy. That's a significant step. It is not easy for the nations of the world to agree on a common course of action, especially one that tackles a problem whose consequences are uncertain and which will be more important for our grandchildren than for the present generation. The text of the Convention was adopted at the United Nations Headquarters, New York on the 9 May 1992. It was opened for signature at the Rio de Janeiro from 4 to 14 June 1992, and thereafter at the United Nations Headquarters, New York, from 20 June 1992 to 19 June 1993. By that date the Convention had received 166 signatures. TO date 186 countries have signed and accepted the convention. The Convention entered into force on 21 March 1994.

The Convention sets an "ultimate objective" of stabilising "greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic (human-induced) interference with the climate system." The objective does not specify what these concentrations should be, only that they be at a level that is not dangerous. It further directs that "such a level should be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.". This highlights the main concerns about food production -- probably the most climate-sensitive human activity -- and economic development. It also suggests that some change is inevitable and that adaptive as well as preventive measures are called for.

What actions does the Convention recommend? It establishes a framework and a process for agreeing to specific actions. Rather than try and provide an action plan for the issue that has still many uncertainties, a framework of general principles and institutions, as well as a process through which governments can meet regularly and evolve an action plan were established by the Convention. The Convention also recognizes the historical responsibility of developed countries in contributing to this problem and the development needs of the developing countries in addressing the issue of poverty. Therefore, it operates on the principle of "common but differentiated responsibilities". The principle lays stress on the fact that though it is the common responsibility of all the member nations to address the climate change issue, but given the circumstances and resource availability the developed countries (Annex _ I countries, countries listed in the Annex I of the Convention) have to take a lead in undertaking measures to address the climate change issue.

Yearly review meeting of the Parties that acceded to the Convention is termed as Conference of Parties (COP). COP provides the stage for reviewing the information on climate change and adequacy of measures to address it. At the first Conference of Parties, which was held in Berlin, Germany, in 1995, Parties decided that the specific commitments in the Convention for Annex I Parties were not adequate. They launched a new round of talks to decide on stronger and more detailed commitments for these countries. After two and a half years of negotiations, the Kyoto Protocol was adopted at COP 3 in Kyoto, Japan, on December 11, 1997.

The Kyoto Protocol commits Annex I Parties to individual, legally-binding targets to limit or reduce their greenhouse gas emissions, adding up to a total cut of at least 5 percent from 1990 levels in the period 2008-2012. The individual targets range from 7 percent for the United States to 8 percent for the EU and several other countries, to a 10 percent increase for Iceland. (Under the terms of the Protocol, the EU may redistribute its 8 percent target among its 15 member states. It has already reached agreement on such a scheme, known as a "bubble.")

Although they are listed in the Convention's Annex I, Belarus and Turkey are not included in the Protocol's Annex B as they were not Parties to the Convention when the Protocol was adopted.

The targets cover emissions of the six main greenhouse gases, namely:

carbon dioxide (CO2),

methane (CH4),

nitrous oxide (N2O),

hydrofluorocarbons (HFCs),

perfluorocarbons (PFCs)

sulphur hexafluoride (SF6)

Some specified activities in the land-use change and forestry sector (namely, afforestation, deforestation and reforestation) that emit or remove carbon dioxide from the atmosphere are also covered. All changes in emissions, and in removals by so- called "sinks," go into the same basket for accounting purposes.

The Protocol also establishes three innovative "mechanisms", known as joint implementation, emissions trading and the clean development mechanism(CDM - provide a link up to the cdm article on the webpage), which are designed to help Annex I Parties reduce the costs of meeting their emissions targets by achieving or acquiring reductions more cheaply in other countries than at home. The clean development mechanism also aims to assist developing countries in achieving sustainable development by promoting environmentally-friendly investment in their economies from industrialized country governments and businesses. However, while these mechanisms were agreed in principle in the Protocol, their operational details must now be fleshed out. In addition, Parties must develop the compliance system outlined in the Protocol, and further work is also needed on provisions for the land-use change and forestry sector, methodologies for estimating emissions and removals, and reporting obligations.

The Kyoto Protocol was open for signature between March 16, 1998 and March 15, 1999. Eighty-four countries signed the Protocol during that period, including all but two Annex I Parties, indicating their acceptance of the text and intent to become Parties to it (states that did not sign may also become Parties). In order to enter into force, the Protocol must now be ratified (or adopted, approved, or acceded to) by 55 Parties to the Convention, including Annex I Parties accounting for 55% of carbon dioxide emissions from this group in 1990. Although some countries have already ratified or acceded to the Protocol (as of 22 May 2000), no Annex I Party has yet done so, and most are awaiting the outcome of negotiations on the operational details of the Protocol at COP 6.