  Communication strongly influences attitudes on climate change. Within
sponsored communication, high spend and high reach advertising dominates. In
the advertising ecosystem we can distinguish actors with adversarial stances:
organizations with contrarian or advocacy communication goals, who direct the
advertisement delivery algorithm to launch ads in different destinations by
specifying targets and campaign objectives. We present an observational
(N=275,632) and a controlled (N=650) study which collectively indicate that the
advertising delivery algorithm could itself be an actor, asserting
statistically significant influence over advertisement destinations,
characterized by U.S. state, gender type, or age range. This algorithmic
behaviour may not entirely be understood by the advertising platform (and its
creators). These findings have implications for climate communications and
misinformation research, revealing that targeting intentions are not always
fulfilled as requested and that delivery itself could be manipulated.
