Communication strongly influences attitudes toward climate change. In the advertising ecosystem, we can distinguish actors with adversarial stances: organizations with contrarian or advocacy communication goals towards climate action, who direct the advertisement delivery algorithm to launch ads in different destinations by specifying targets and campaign objectives. We present a 2 part study; part 1 is an observational study (N=275,632) and part 2 is a controlled (M=650) study. Collectively, they indicate that the advertising delivery algorithm could be actively influencing climate discourse, asserting statistically significant control over advertisement destinations, characterized by U.S. state, gender type, or age range. Further, algorithmic decision-making might be affording a cost advantage to climate contrarians. These findings have implications for climate communications and misinformation research, revealing consequential ways in which the advertising algorithm could be skewing delivery decisions away from targeting intentions, thereby influencing audience attitudes towards climate change.