Question: Raising livestock, such as sheep and cattle, results in the production of large amounts of methane gas (CH4). Methane has the same effect in the atmosphere as carbon dioxide (CO2). As more livestock are raised to provide food for humans, what is the most likely effect of the increase in methane?

  Options: 
 A. acid rain
 B. ozone thinning
 C. water pollution
 D. global warming
Answer: D