• Nonrenewable energy sources can cause a variety of environmental problems.OIL image by brelsbil from Fotolia.com
  
  With scientists the world over working to increase energy efficiency and implement renewable energy sources such as solar power, the fact remains that much of the world continues to rely on nonrenewable sources of energy. The vast majority of nonrenewable energy sources come with their own individual concerns, from health risks to environmental impact. Some of the most common nonrenewable energy resources include coal, oil and natural gas.
  
  

Coal

• While coal is a nonrenewable resource, it is the most abundant in the world, surpassing oil and nuclear power by far. In the United States, coal is most often used to produce electricity, while developing countries still use coal for heating purposes. Concerns about coal as an energy source are quite high, as burning coal creates toxic gases, and coal mining creates environmental problems such as erosion and destruction of nature.
  
  

Oil

• Oil is similar to coal in that much of the world still relies on it for energy production; it differs, however, in the fact that it is in far more limited supply than coal. Oil is used for heating homes and fueling vehicles, among many other things. While oil is considered to be a cleaner burning resource than coal, concerns over health risks are still abundant, as well as the fact that many scientists believe that burning oil has contributed significantly to global warming.
  
  

Natural Gas

• The popularity and usage of natural gas has risen exponentially in recent years, due primarily to its ability to burn clean and transport rather easily. Today, natural gas is used mainly for heating and cooking, and is even starting to be used to power vehicles. While it is among the cleanest-burning nonrenewable resources, the fact remains that it will run out, with the world's current supply thought to run out in approximately 100 years.