As this article points out, one adult moose belches the greenhouse equivalent of more than two Oslo, Norway to Santiago, Chile flights every year. When asked about the necessity of killing off the moose population, a Norwegian researcher said no and commented:
"Moose have very important functions in nature. They are ruminants that eat the grass. If we don't have ruminants, we have too much grass and that changes the landscape and has consequences for the flora and fauna"
Clearly, though, coal-fired power plants, automobiles, aircraft, and other CO2 emitting tools of human civilization do not serve an important function in "nature." Of course, our priorities should be in protecting the flora and fauna, not on improving the living standards of human beings.