Greenhouse Effect

• The overriding cause of global warming is an umbrella term known as the "greenhouse effect." As the rays of the sun reach Earth, some of the heat is absorbed and some is radiated back into the atmosphere. Greenhouse gases in the atmosphere act similarly to a gigantic mirror and reflect warmth back to Earth that in the past would have continued being radiated into space. It is this reflection of heat back to Earth that is at the heart of the greenhouse effect.
  
  

Greenhouse Gases

• These greenhouse gases that are responsible for reflecting back heat that would otherwise be lost include simple water vapor, carbon dioxide, methane and the infamous ozone. Unfortunately, there is no way to know exactly which greenhouse gas is most responsible for the greenhouse effect.
  
  

Cause of Increased Gases

• The problem of global warming has been caused by the addition of more greenhouse gas into the atmosphere. The gases responsible will rise into the air whether humans are here or not; the problem is that much of basic human activity in the 20th and 21st century produced greenhouse gas at a level never experienced before. Basically, any activity that produces one of the gases listed above is a cause of global warming; everything from driving a car to using electricity. Because trees act as a natural conversion plant to transform carbon dioxide into oxygen, deforestation contributes to global warming because the fewer trees there are, the more carbon dioxide gets into the atmosphere.
  
  

Effects

• The effects of global warming are potentially far-ranging. Increased temperatures means melting of glaciers, ice and snow around the poles, which means an increase in sea levels. Warming water will also increase the potential for hurricanes and typhoons so devastating that they will make Hurricane Katrina pale in comparison. That rise in sea levels could also mean that beachfront property will soon be found 10 to 50 miles inland from where beaches are now.
  
  

Temperatures

• The average temperature on Earth has been steadily rising since the mid-1980s, and global warming is expected to continue this trend. In addition to longer and hotter summers, rising temperatures will affect agriculture. Indeed, the effect of a hotter Earth is already increasing the transmission of infectious bacteria that thrive under warm conditions.
  
  

Hoax?

• There are still a great many people who believe that global warming is simply some kind of politically-created hoax. Those leading the charge against global warming tend to be industry with a vested interest. On the other hand, the list of scientific entities that have agreed on the reality of global warming include, among many others, the National Oceanic and Atmospheric Administration, the Environmental Protection Agency and the Royal Society of the UK.