Heat
Temperature rise is the number one short-term effect of the global warming process. According to the Environment News Service, British scientists predict that temperatures will rise sharply over the next few decades, eventually breaking the heat records set in 1998. The scientists at Britain's Hadley Center also believe that 2014 will be 1/2 degree warmer overall than 2004, a temperature increase that normally takes 50 years to occur.
Irregular Weather Patterns
Scientists think that abnormal weather patterns are caused by global warming. According to the Big Melt, many scientists believe increased levels of water vapor in the atmosphere and thicker cloud cover are short-term effects that can be directly attributed to warming. A prime indicator of this effect is how weather cycles, usually occurring over long periods of time, are now decidedly shorter in length.
Rising Sea Levels
As the Earth's mean temperature rises, sea levels will increase. Caused by abnormal rainfall and the melting of previously frozen surfaces (glaciers and permafrost), sea levels will gradually rise in the near future. According to a 2010 study developed by the Intergovernmental Panel on Climate Change, or IPCC, the world's sea levels are expected to rise 1/10 meter, or almost 4 inches, by 2020, with gradual increases continuing over the next decades.
Drought
Although irregular weather patterns created by global warming will cause higher rainfall in certain areas, other areas will be hit with drought. Scientiests believe arid climates will have longer and more severe droughts, especially in many Third World countries. In his 2010 article, "Drought Under Global Warming," Aiguo Dai says that "increased aridity in the 21st century will be experienced over most of Africa, southern Europe, the Middle East, most of the Americas, Australia, and Southeast Asia." Dai goes on to predict more persistent droughts within the next 20 to 50 years.