The IPPR report is just another  in a series of reports and research urging envrionmentalists and those who want real action on climate change to re-think the way we communicate the issue to the public. In any public relations campaign, there is always a real danger of creating an unwanted or opposite effect from what is intended. If the PR program you design is not grounded in thorough research, usually in the form of such things as polling and focus groups, you will always be in the dark about what the actual effects are of your program are.
In the case of the IPPR report, the authors, a linguist and a textual analyst, make the sound argument that alarmist language can elicit an effect more akin to "climate porn," than a call to arms by the citizenry to tackle global warming. In other words, many public interest groups assume that melting glaciers and heat waves will scare people to action, when in fact it has the opposite effect of people tuning out the message they are trying to get across. PR professionals have known this for years, but much like smoking, we all know that alarmism is bad for us, but many of us continue to do it anyways.
As far as solutions, the IPPR report suggests instead that communications professionals and environmentalists "... make climate-friendly behaviour feel normal, natural, right and 'ours' to large number of people who are currently unengaged... the answer is not to try to change their radar but to change the issue, so it becomes something they willingly pick up."
It is this type of warning that anyone involved in communicating global warming should heed. One of the side-effects of "climate porn" is that it opens opportunities for the fringe element  of climate change "skeptics" to pop their heads out of the sand and attack.