Which of the following is not a major reason to focus on carbon dioxide (CO2) when planning for climate change mitigation efforts?
a) CO2 is the biggest contributor to anthropogenic warming of the climate
b) CO2 emissions are easier to reduce, since they are less as closely connected to energy production than other greenhouse gas emissions
c) CO2 contributes directly to ocean acidification, while other greenhouse gases do not
d) CO2 emissions lead to long-lasting climate change, due to CO2 long lifetime in the climate system