Global warming is a slow steady rise in Earth's surface temperature.[1] Temperatures today are 0.74 °C (1.33 °F) higher than 150 years ago.[2] Many scientists say that in the next 100–200 years, temperatures might be up to 6 degrees Celsius higher than they were before the effects of global warming were discovered.
The basic cause seems to be a rise in atmospheric carbon dioxide, as predicted by Svante Arrhenius a hundred years ago. When people use fossil fuels like coal and oil, this adds carbon dioxide to the air. When people cut down many trees (deforestation), this means less carbon dioxide is taken out of the atmosphere by plants.
If the Earth's temperature becomes hotter the sea level will also become higher. This is partly because water expands when it gets warmer. It is also partly because warm temperatures make glaciers melt. The sea level rise may cause coastal areas to flood. Weather patterns, including where and how much rain or snow there is, will change. Deserts will probably increase in size. Colder areas will warm up faster than warm areas. Strong storms may become more likely and farming may not make as much food. These effects will not be the same everywhere. The changes from one area to another are not well known.
People in government and Intergovernmental Panel on Climate Change (IPCC) have talked about global warming. They do not agree on what to do about it. Some things that could reduce warming are to burn less fossil fuels, adapt to any temperature