KARACHI - KARACHI - Fossil fuels are responsible for climatic change, as burning produces waste products due to impurities in the fuel, especially particulates and various gases such as sulfur dioxide, nitrogen oxides, and volatile organic compounds. These waste products may affect our environment or people, in harmful ways. We have gone to great lengths to minimise the adverse effects of fossil fuel combustion and continue to make progress. Climate change refers to the variation at global or regional level over time. It describes the variability or average state of the atmosphere or average weather over time scales ranging from decades to millions of years. These variations may come from processes internal to the earth. Just as weather patterns change from day to day, the climate changes too. Being occurred naturally, it is driven by internal and external factors. However not all changes are due to natural processes, as we humans have also exerted their influence. Through widespread use of land, use of fossil fuels and the building of cities, we have changed our climate. The major technological and socio-economic shift of the industrial era with reduced reliance on organic fuel, the accelerated uptake of fossil fuels and deforestation, we have contributed to the natural greenhouse effect. The key areas for concern are those related to variability and extremes, not simply changed average conditions. There is an accumulating body of evidence of observed impacts relating to regional changes, and that these are having fearful effects on the world around us. At the other extreme, all burning produces carbon dioxide and water vapour as by-products. This is because carbon is part of what makes fossil fuel useful. Whether these by-products are harmful or beneficial, it is a matter of public debate. Some argue that they are beneficial, because water and carbon dioxide are necessary for plant life on earth, being the basis for all life. Some believe, however, that our carbon dioxide emissions contribute to harmful global warming and climate change, either now or in the future. Those who fear climate change have proposed new government policies to drastically reduce the use of fossil fuels. Those who do not fear climate change are sceptical of these proposed policies. There is also great debate about the science of climate change. Apart from this, there are serious disagreements over whether some effects of fossil fuel use are harmful at all. In some cases the amount of waste is too small to be detected. Mercury-rise from coal burning is an example. Interestingly, there are already people who have become climate refugees and millions more are expected in the future. Research shows that temperatures across the globe are most certainly rising; the 1990s was the warmest decade in the last thousand years. Sea surface temperatures have increased 0.4-0.8_C (0.7-1.4_F) since the late 19th century, and over the period 1961 to 2003, global ocean temperature has risen by 0.10_C (0.18_F) from the surface to a depth of 700 m. The world has warmed 0.74_C in the past hundred years and scientists are clear that the world will get warmer this century due to further increases in greenhouse gas concentrations. Global average temperature is forecast to rise 4_C (7.2_F) toward the end of the 21st century. In addition to warming of the Earths surface, there has been an increase in heat waves, warming of the deep oceans. There are fewer frosts, glaciers are fast melting and sea ice is decreasing. Worse still, a few degrees of global warming will lead to more heat waves and fewer frosts, more wildfires and drought is expected across the globe. The human induced climate change is a major stress in a world where the social system is already experiencing pollution and unsustainable management practices. We must move quickly to renewable energy as the source of our electricity and transport fuels.