EGYPTIANS are being urged again to take a positive part in the environment-friendly global celebrations marking Earth Day on Saturday. NGOs, which are deeply concerned about the growing threat of global warming, have appealed to the Egyptian people to symbolically join in Earth Day by observing a 60-minute electricity- homes. The Egyptians have been tacitly rebuked for last year's pointless exercise, when they ignored the invitation and kept their lights on at home and blithely watched TV soaps, talk shows or worrying documentaries about the growing threat of global warming. Egypt's participation in last year's Earth Day was embarrassingly limited to switching off the lighting on the Qasr el-Nil Bridge downtown, in the Cairo Tower, and at the Giza Pyramids and the Citadel. This had little impact on the amount of electricity Cairo uses. People living in other cities and towns didn't show the slightest interest in the efforts of environmentalists in the capital. Global warming is causing the sea level to rise. As a result, many parts of the coastal cities in Egypt could well start disappearing into the Mediterranean and the Red Sea within 30 years' time. This year, the number of countries participating in Earth Day has increased by four to 92. Let's hope the Egyptians don't let down the local environmentalists this time.