I've thought it myself, and I've heard other people say it 'the green movement would benefit from more artistry'; and for green movement also read protest movements generally, including the recent anti-cuts demonstrations. Well, if some recent events that I've attended are a guide, there is a growing interweaving of political action and art.
On Tuesday evening I attended 2 events; one was the launch of CityCamp in Manchester, (CityCamp is an initiative which has been launched in a number of Cities; it's not so much art focused as IT focused, using terms such as crowd-resourcing - I won't attempt to describe further, I'll let them do that themselves here
The other was a monthly organised event under the banner 'A Reasonable Cause' - I'd been to one of these monthly events before; a guest speaker on a particular campaign is bracketed with a film or two, a chance to draw pictures, and some high-quality music (the key people involved appear to be music students). This event excelled itself on the music front, with a particularly dextrous accordian player, Jim Molyneux, and a remarkable Harp Quartet, going by the name of Clouds - I'd definitely recommend them if you get a chance to see them. More info on the Reasonable Cause Facebook Page
Envirolution festival also included an artistic thread, along with discussions and entertainment, in a four hour event in the centre of Platt Fields Park.
But perhaps a clearer example of the meeting of green concerns and art can be found back in Chorlton, where 'Creative Recycling' have for several years been making beautiful objects from the rubbish that others would throw away. Some of their work can be seen in the picture below.