Research by Briton Dr. Andy Thorpe of University of Portsmouth has found that methane emissions are playing a more significant role in global warming, as their proportion is on the rise.
Compared to CO2, which has increased by 31 percent during the past 250 years, methane has increased by 149 percent during the same period. Moreover, methane is far more potent, trapping 72 times more heat than CO2 over a 20 year period. Dr. Thorpe stated, "Methane emission growth… has been increasing exponentially within the developing world due to rising incomes [causing] increased demand for meat proteins and developed countries sourcing meat from developing markets." Dr. Thorpe suggested reducing methane emissions via livestock down-sizing and corresponding reduced meat consumption.
At the same time, he also warns against shifting from eating meat to fish, saying that this would be devastating to the ocean ecosystems.