Fact 1: Coal is used to produce electricity by burning in coal-fire power stations.

Fact 2: Coal-fired power stations can cause acid rain and contribute to global warming.

Given the two facts above, answer the question "Certain types of electricity production can cause acid rain and contribute to:" with the following options: 
- global cooling
 - global warming
 - energy usage
 - coal mining
 - deforestation
 - electrical
 - Destroy bridges
 - salinity


 

  global warming       