The reports establish with "90 percent certainty" that humans are responsible for the significant rise in atmospheric temperature over the last fifty years. The IPCC believes that this rising trend is "unequivocal". The reports elucidate research showing that even if we somehow manage to stop all green-house gas emissions to the atmosphere today, temperature would continue to rise between 1.1 and 6.4 degrees Celsius throughout the 21st century because of the huge amount of carbon dioxide and other heat-trapping gases we have already deposited in the Earth's atmosphere, mostly from burning coal, oil and other fossil fuels. This rise will be accompanied by longer and more intense heat waves which will bring hurricanes, floods, drought and hunger to the poorer parts of the world. Changes in the minimum temperature which has been rising twice as fast will have disastrous effects on polar glaciers.

According to the IPCC, sea levels will rise by between 18 and 59 cm. However, there is a good chance that they would rise 1.4 metres by the end of the century because of accelerated glacial melting. If it happens many islands like the Maldives and low-lying coastal towns and villages in the Bay of Bengal would disappear under water. This phenomenon may displace as many as 130 million people worldwide creating a new type of refugees called the "environmental refugees".

These changes will hurt the poorer peoples of the world in Asia and Africa more than the richer and more industrialised ones in the West, even though, ironically, they have contributed by far the most to the atmospheric changes linked to global warming. Canada, Siberia and Alaska will have longer growing seasons because of less severe weather and more precipitation. But climate change could lead to the extinction of 25% of the world's species. Between 75 and 250 million more poor people will suffer from food and water shortages. Unfortunately, rain-dependent agricultural production will fall 50% by 2020.

The IPCC is not a lobby at the service of any vested interests. It is a highly reputable scientific institution which provides advice on climate change to the international community. It was set up in 1988 by the World Meteorological Organisation and the United Nations Environment Program to "assess the scientific, technical and socio-economic information relevant for the understanding of the risks of human-induced climate change". The IPCC has already produced three comprehensive assessment reports in 1990, 1996 and 2001 which provided the scientific foundation for the formulation of an international response to climate change including the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol. 2500 scientists from all over the world have worked for several years in the preparation of the reports published in February and April, 2007. (A third report will be published later this year.) Therefore, the governments will do well to move beyond the denial of climate change and take the findings of the IPCC seriously. It is necessary to act now by introducing new methods for the production and conservation of energy which no doubt will require huge investments in new technologies.

The truth is that a more efficient energy policy is possible and Japan has shown the way how to do it. Japan imports almost all its oil because it has no domestic oil supply. After the United States, Japan's economy is the second largest in the world. Yet it burns half as much oil per capita as the US. The International Energy Agency has confirmed that Japan's energy consumption as a percentage of gross domestic product is the lowest in the world. No wonder, Japan has earned the reputation of being the world's most efficient wealthy energy user. How have the Japanese done it?

Well, first of all, there is a common consciousness among the Japanese people that global warming is already here and that energy abuse must be stopped. Enormous self-discipline, constant innovation and design are the secrets to the Japanese success. Increasing use of energy from renewable sources, a highly efficient public transport system, hybrid cars, flexible solar panels, residential and commercial recycling have helped Japan to control carbon emissions. Japan's example should inspire other industrialised countries to take urgent energy-saving measures. There is absolutely no excuse for inaction.

Luckily, more and more governments in the industrialised world are becoming conscious of this growing danger and are prepared to take strong actions. In March, the European Union committed itself to reducing carbon emissions by 20% by 2020. It went even further by stating that if the United States were to make similar commitments, it would achieve 30% reductions. Unfortunately, Bush has steadfastly refused to sign the Kyoto Protocol and rejected all imposed cuts on carbon emissions. He feels it is pointless to join the Protocol if China and India do not come along. But Bush seems to forget that the US produces one quarter of the world's total emissions with only 5% of the population, which makes it the world's largest per capita emitter of carbon dioxide. China and India will always use this argument for not entering into serious negotiations on carbon emissions. It is time for the US to act now and break the deadlock by joining the Kyoto Protocol.

The writer is a columnist for the Daily Star.