Global warming or the greenhouse effect is an environmental phenomenon that deals with the global climate change due to increased levels of 'greenhouse' gases in the atmosphere. Certain gases in our atmosphere serve to regulate the amount of heat that is kept close to earth's surface. Scientists theorize that an increase in these (greenhouse) gases will translate into increase in temperatures around the globe, which could result in many disastrous environmental effects. The Intergovernmental Panel on Climate Change (IPCC) predicts in its "Third Assessment Report' released in February 2001 that over the next 100 years, global average temperature will rise between 2.4 to 10.4 degree Fahrenheit. That sort of global warming is a threat to the human kind because the oceans will flood the land. Since this is a common issue, it should be handled collectively by all nations for the good of the generations to come. -BISMA ABBASI, Karachi, via e-mail, November 20.