The release in 2006 of the documentary film An Inconvenient Truth was a surprise box office and critical hit, as well as a landmark moment in raising awareness about dangerous climate change.

Grossing more than $50 million, it became one of the most successful documentary films ever made, and was widely regarded as having reinvigorated the global ecological movement. It also earned its creator Al Gore a share of the 2007 Nobel Peace Prize. Gores follow-up film, An Inconvenient Sequel Truth To Power, opens nationwide on August 18th.

For me, the film was an environmental epiphany an electrifying moment when everything Id been studying and trying to process emotionally for several years came crashing into focus.

By the time the final credits were rolling, I sensed my days of cynical indifference on this issue were over. Being a parent of what were then very young children sharpened its impact. After all, the timelines for catastrophe ran right through their future adult lives. Who, knowing this, could choose not to act? In Gores own words, doing nothing in the face of what we now know about climate change is deeply unethical.

I have asked some well-known figures from environmental science and campaigning for their impressions, then and now, of An Inconvenient Truth. Did the Earth move for them?

When it came out I remember feeling excited that someone had actually made a feature film about global warming. At that time it wasnt a big deal in the collective consciousness; most people hadnt really grasped the consequences of rising emissions.

I think the film had a huge impact on how we, as a society, understood climate change. It made the science of climate change accessible to a huge audience, and as an environmental scientist, I felt it helped give our work a boost and endorse our efforts for change.

Tragically, the resulting shift in awareness didnt translate in to policy changes. Even now, a decade later, we all still have our heads in the sand. We know the basic facts, we know the scale of destruction and injustice that climate change brings about, yet any real positive action is still dismissed as extreme. I hope the films sequel will help resolve this cognitive dissonance.

The International Panel on Climate Changes (IPCC) fourth assessment report came out later that year, and the real importance of the film is that it articulated the science to the public in a way that hadnt been done before.

Up till then, IPCC reports were seen as dusty old documents that were kept in a drawer. Al Gore showed their relevance by explaining the impact of climate change on us as individuals. Gore also provided leadership to the environmental movement at that time, someone they could coalesce around to express their particular concerns.

Some of the way he conveyed the science was populist, and you could pick holes in some of his arguments, as his critics tried so often to do, but the overall thrust of what he said in the film is true, and has been proven true ever since.

Gores first movie had a profound effect on me. Im embarrassed to admit it, but I cried when the credits came up because it was the moment I realised that, if we didnt solve climate change, everything was at risk. Yet the problem was so big I couldnt fathom how to fix it.

The original film did a great job raising awareness of climate change but it stopped short of providing much in the way of solutions. I think thats part of the reason it failed to make a huge impact with the public not everyone wanted to go to the cinema to get depressed.

However, Gores Climate Reality project, which came after the film, has had real impact. I am one of over 8,000 climate leaders in 126 countries who have been trained to give a version of his famous PowerPoint presentation. That may be its enduring legacy.

Has any public figure been more pilloried for their efforts to communicate the climate threat than Al Gore? Going back to his time as US vice-president, where he worked hard to put global warming on the political agenda, he has been under relentless attack from the well-funded forces of denial.

The release of An Inconvenient Truth in 2006 led to an intensification of the hate campaign against Gore that continues to this day.

In his original film one of Gores slides featured a graphic of the famous hockey-stick curve that my co-authors and I published in the late 1990s. This showed a dramatic spike in temperature over the past century.

Every bit as dramatic has been the quite extraordinary global growth in clean energy in the past 10 years. The deniers said it couldnt be done. They were wrong, yet again. Despite everything, there are still reasons for cautious optimism, and Al Gore can take a lot of credit for that.

The movie led to a breakthrough moment in public debate and media coverage of climate change. Suddenly it was a zeitgeist issue. Journalists were looking for the climate angle on almost everything. I remember reading an Irish Times profile of eight young women writers where six of them named climate change as a concern, and thinking weve made it.

Then came the economic crash, which knocked climate right off the political and media agenda. Irish vested interest groups have also worked hard to put protection of short-term private profit above longer-term public interest.

Personally, I liked the movie and the way Gore wove the story of his familys tobacco farming with his own discovery of the science of climate risk. And his nave hopes that evidence alone would sway his fellow Congress members.

There are two memorable quotes from the movie. One is the worry that people might swing from denial to despair without pausing in the middle for action. The other is that only thing preventing action is a lack of political will, and political will is a renewable resource.

Back in 2006, there was in fact a lot of political support for action on climate. The European Council that year agreed the 2020 (emissions reduction) targets. This happened around the time the film came out, and there is no doubt that it helped. Ive seen the tide go in and out on climate action over the years; An Inconvenient Truth was definitely a high-water mark.

Gores real achievement was in turning dry scientific information into easily understood, digestible material. For me, the wow moment in the film was that one graph (tracking projected carbon dioxide levels by mid-century) that went literally through the roof.

Having lived for a while in the US, I also liked the closing sequence featuring a shot of the river near his home, connecting him to the beauty of the place he grew up in Tennessee and the awareness that this really could all be lost.

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'An Inconvenient Truth': Did the Earth move for us? - Irish Times