The run up to the Copenhagen climate talks was choc-full of celebrity endorsements of environmentalism. As momentum builds towards Paris next December, we can expect to see a lot more.

The use of celebrity is a standard trope of much campaigning work — not just climate change. It helps attract attention, from the media and possibly the celebrity’s fan-base too. Depending on the celebrity in question, they can add glamour or other presentation skills (dance, language, music, art), and possibly a fresh perspective missing from the sometimes-closed communities of professional activism.

But celebrity endorsements can also annoy people, provoking a backlash. So, to offer some warning from history, here are five slightly awkward climate comms celeb moments, and a note from some social science research suggesting we might be better off without them in the first place.

The 2007 Live Earth concerts hoped to apply the globalised power of the modern music industry to bring people together on a international issue. It ran in 11 locations — including the Rothera Research Station in Antarctica, as well as Wembley Stadium, UK, Oriental Pearl Tower, China, Copacabana Beach, Brazil, and the National Mall, USA — with over 150 acts.

Bob Geldof — whose 1985 Live Aid concerts Live Earth was clearly referencing — slammed the event as a “waste of time” adding:

I would only organize Live Earth if I could go on stage and announce concrete environmental measures from the American presidential candidates, Congress or major corporations.

They haven’t got those guarantees, so it’s just an enormous pop concert or the umpteenth time that, say, Madonna or Coldplay get up on stage.

I hope they’re a success. But why is Gore actually organizing them? To make us aware of the greenhouse effect? Everybody’s known about that problem for years. We are all [expletive] conscious of global warming.

Bradley Whitford’s declaration that he’s “a citizen of Copenhagen” — complete with occasional intense or ironic glances to the camera that characterised his role on the West Wing — may have captured a particular form of cultural momentum at the time.

But looking back, considering the large crash that followed the failure of the Copenhagen talks, it can make painful watching.

When Cate Blanchett lent her voice to a 2011 campaign for a carbon tax in Australia, she was speedily branded “Carbon Cate” by opponents.

Although the idea was to focus on moral aspects of the policy — Blanchett told the Sydney Morning Herald “I can’t look my children in the face if I’m not trying to do something in my small way and to urge other people” — the involvement of rich celebrities made it easy for conservative politicians to accuse the campaign of being “out of touch”.

The Save the Arctic campaign, launched at Rio+20 summit in 2012, included a glittering line up of endorsements, including Sir Paul McCartney, Robert Redford, One Direction, Lucy Lawless,  Penelope Cruz, Thom Yorke and Richard Branson.

Many of these involved used the campaign to highlight the problems of Rio, with Branson himself dubbing it a “tremendous disappointment.”  But, as Brendan Montague argued, at least one of the problems which made Rio such an “epic failure” was that none of the assembled press asked if low cost transatlantic travel and space tourism can be sustainable.

Ban Ki-moon, Leonardo DiCaprio and Al Gore all helped kick off the UN summit on climate change in New York this September. But it was Kathy Jetnil-Kijiner, a poet from the Marshall Islands, who moved delegates to tears and went viral with her poem written for her seven month old daughter.

Jetnil-Kijiner not only overshadowed DiCaprio, but made him look a bit ephemeral. He’s a long-standing environmental activist, and his involvement undoubtedly helped unlock some publicity for the event, and help frame it as something more than just politicians arguing.

As DiCaprio said himself in his speech to the UN, “I play fictitious characters often solving fictitious problems.” It was hard not to look at Jetnil-Kijiner — who was picked from thousands of candidates to represent civil society at the talks — and think “well, she’s living it.” Climate change was part of what gave Jetnil-Kijiner’s message so much power, rather than replying on the Hollywood power of DiCaprio to add something external to the debate.

The Daily Mail had some perhaps predicable thoughts on the star’s carbon footprint too.

Many PRs involved in the climate movement — from NGOs, the UN or scientific bodies — would argue we need celebrities to publicise the cause. One Direction’s involvement in Save the Arctic crashed Greenpeace’s website. It sent traffic, if nothing else.

But according to research published in the journal Global Environmental Change in 2013, images of identifiable people — which included politicians, a business leader, scientist, a celebrity and a member of the British Royal Family — made people in the USA, UK and Australia feel quite strongly that climate change was unimportant.

Christian Hunt, reporting on the study for Carbon Brief, notes that more work needs to be done — testing images in non-English speaking countries, for example, or how messages like Kathy Jetnil-Kijiner do or do not work — but if the conclusions hold, there could be some pretty important implications for climate campaigns.