Yesterday the UK’s Department of Energy & Climate Change (DECC) launched a tweetathon around the hashtag #BackClimateAction. The idea was that each hour between 9am and 7pm people would tweet on a different theme – everything from Cities & Homes to Sport.

Now, DECC’s previous attempts at public engagement have included an unmitigated disaster – the infamous ‘bedtime story’ in 2009 (above) signed off by a certain Ed Miliband MP. So, despite the change in administration at DECC, I must admit I was more than a little sceptical before I started, but I dutifully chose Business Hour at 3pm and settled down in front of Tweetdeck with a cup of tea.

Reader, I tried my best. I tweeted resources, I asked questions, I answered others’ questions.

The results?

I had a couple of brief interactions with people I already knew while a torrent of noise slid past on TweetDeck. After 30 minutes, I gave up and started writing this piece.

To be slightly more objective, I put out a question at the end of the hour asking whether anybody had found it of value. Three people got back to me to say they had picked up some good ideas.

That said, the numbers taking part were certainly impressive – DECC says they got 100 million ‘impressions’. But the exam question is, did all this effort lead to ANY engagement of the disengaged?

I know this is non-scientific I couldn’t see one person tweeting who didn’t already have a strong vested interest in sustainability (apart from the ubiquitous semi-clad spam merchants who pick up on any trending hashtag). This effect is known as an ‘echo chamber’ – people who agree on something agreeing rather noisily and at length. They tend to assume that it attracts a wider audience, but this is debatable – witness all those exasperated #CameronMustGo tweeters complaining that the mainstream media is ignoring their protest against the British PM.

But in a way, this lack of wider engagement is inevitable. The whole point of a hashtag is to bring people of similar interests together, not to attract those on the sidelines. As a rallying call to the faithful, the tweetathon was obviously successful, but we need to go beyond that – and fast.

Engaging the disengaged is the biggest challenge in sustainability, but a hashtag probably isn’t the way to go about it.