Some nations, such as the Netherlands, Egypt, and Bangladesh and many small island nations, are particularly threatened by sea-level rise due to climate change. According to the IPCC, if the world is to stabilize greenhouse gases at 1990 atmospheric levels, we must reduce carbon dioxide emissions by over sixty percent, methane by fifteen to twenty percent, and other greenhouse gases between forty and eighty percent. The U.S. is the largest contributor of greenhouse gases, contributing 19.14 percent of the world wide total. The U.S. contributes approximately 22 percent of the world's carbon dioxide emissions, although the U.S. share is decreasing relative to the rest of the world due to rapidly rising emissions levels in the developing world. The main man-made source of carbon dioxide is the burning of fossil fuels.
Industry is the largest source of total gross emissions, and transportation the second.
According to the IPCC, if the world is to stabilize greenhouse gases at 1990 atmospheric levels, we must reduce carbon dioxide emissions by over sixty percent, methane by fifteen to twenty percent, and other greenhouse gases between forty and eighty percent. Methane is the second most prevalent anthropogenic greenhouse gas. Sources of methane in the U.S. include landfills, agricultural activities, fossil fuel combustion, coal mining, production and processing of natural gas, and wastewater treatment. Landfills are the largest single source, comprising almost a third of methane emissions. Emissions from agricultural activities and oil are the next largest sources of U.S. methane emissions.