  Online communication about climate change is central to public discourse
around this contested issue. Facebook is a dominant social media platform known
to be a major source of information and online influence, yet discussion of
climate change on the platform has remained largely unstudied due to
difficulties in accessing data. This paper utilises Facebook's repository of
social/political ads to study how climate change is framed as an issue in
adverts placed by different actors. Sponsored content is a strategic investment
and presumably intended to be persuasive, so patterns of who pays for adverts
and how those adverts frame the issue can reveal large-scale trends in public
discourse. We show that most money spent on climate-related messaging is
targeted at users in the US, GB and CA. While the number of advert impressions
correlates with total spend by an actor, there is a secondary effect of unpaid
social sharing which can substantially affect the number of impressions per
dollar spent. Most spend in the US is by political actors, while environmental
non-governmental organisations dominate spend in GB. Analysis shows that
climate change solutions are well represented in GB, while climate change
impacts such as extreme weather events are strongly represented in the US and
CA. Different actor types frame the issue of climate change in different ways;
political actors position the issue as party political and a point of
difference between candidates, whereas environmental NGOs frame climate change
as the focus of collective action and social mobilisation. Overall, our study
provides a first empirical exploration of climate-related advertising on
Facebook. It shows the diversity of actors seeking to use Facebook as a
platform for their campaigns and how they utilise different topic frames to
persuade users to act.
