Global emissions of carbon dioxide--the main pollutant associated with global warming--rose for the fourth consecutive year in 1987 and developing nations had the biggest growth, a federal scientist said. Worldwide, carbon dioxide emissions from the burning of oil, coal and gas by power plants, factories and motor vehicles increased to an all-time high of 5.65 billion tons, up 1.43% from the 1986 levels of 5.57 billion tons, Gregg Marland, a staff scientist at the Oak Ridge National Laboratory told the Senate Energy and Natural Resources Committee. Marland said U.S. emissions rose 1.92% in 1987 and preliminary estimates show another 3% jump in 1988. He said the highest rate of growth in carbon dioxide emissions occurred in South and Southeast Asia, a 6.2% increase over 1986 levels. Carbon dioxide is considered a primary contributor to the greenhouse effect--a predicted warming of the Earth by the accumulation of gases in the atmosphere.