Scientists predict that warmer overall climate will lead to changes in the weather, including changes in precipitation patterns, increased drought, more heat waves, and more severe storms, including stronger hurricanes.
Warmer temperatures would result in increased evaporation. More water vapor in the air would lead to heavier rains and snow, but this precipitation would not necessarily be spread evenly over the Earth, since a change in temperature would also change air and ocean currents. Scientist predict that areas that area already dry, such as desert areas close to the Equator, would be much drier--though if they did experience rain it would be much heavier. Meanwhile typically wetter areas such as regions farther north and south and tropical areas would be wetter. Worldwide we already experience two percent more precipitation than we did 100 years ago.
Decreased precipitation in already-dry areas would increase the possibility of drought in those areas. Increased temperature can make a typical drought--which does occur periodically--worse due to the dry plants and soil which result from increased evaporation. Recently, the United States has already seen an increase in drought conditions; in 2012 over 80% of the contiguous US was considered abnormally dry. Droughts can affect agriculture and livestock. Reduced water level in rivers can affect transportation and dry land increases the possibility of wildfires. Some electricity plants require water for cooling, which means drought can also result in a loss of power.
The ways in which climate change will affect the weather are predicted to increase the number and violence of tropical cyclones (known as hurricanes in the Atlantic). Warm wet air and warm water are necessary to produce a hurricane, and increased temperatures will increase evaporation, supplying war wet air. Warm temperatures will also heat the ocean, and warm water is ultimately the engine that drives a hurricane. Hurricanes may also be more devastating as a result of climate change, due to higher sea levels and coastal erosion.
As always when talking about climate change, it is important to understand and maintain the distinction between weather and climate. Any single weather event such as a drought or hurricane is not a result of climate change. These events occur naturally and many environmental factors contribute to each event. Climate change is not creating these disasters; it is affecting the overall trends and frequency with which they occur.
For instance, it would be incorrect to say, "This drought was caused by climate change," but it would be correct to say, "More droughts like this one have occurred and are occurring over time due to climate change." The distinction between these two statements may seem insignificant, but it is a scientific subtlety that often gets lost in explanations of climate change by the media.
