The sea level could rise one foot in the next 35 years and two in the next 100. Hurricanes, tornadoes and other extreme storms may become more frequent. Centers of large continents, such as the U.S. Great Plains, may be drier even if the overall world rainfall increases somewhat. Heat waves may be more common. Movement of just 1 percent of a future population of 6 billion people due to higher sea level, drought, or other climate change would produce 60 million migrants, many times the number of all refugees today.
Carbon dioxide stimulates plant growth.
However, heat increases demand for water. Growing zones will shift if weather patterns change. Warming that expands the tropics will also expand the range of tropical diseases such as malaria and other insect borne maladies. Possible mass extinction may occur as conditions change faster than species can move or adapt. Urban and agriculture development leaves few wilderness corridors for migration.