Environmentalists are attacked for making "Green the New Religion". This is analysed and rebutted by James Murray of Business Green in a Guardian article here where he notes that: -
'Religion can mean a "pursuit or interest followed with great devotion" – a definition which could just about allow environmentalism to be classified as a "religion".'
It is worth a read.
However, its also worth noting that with the ferocity of the Inquisition, atheist/secularist Richard Dawkins has sustained a campaign for many years against religion, with great devotion.
In 2009 he published The Greatest Show on Earth.

The Greatest Show on Earth by Richard Dawkins
In this book he promised just the evidence for it [The Greatest Show on Earth].
However, the surprise is that his 'source-villain' is finally revealed and it is not in fact 'religion at all.
In extremis the source-villain is revealed as 'the dead hand of Plato'.
God help us. There are certainly problems with 'belief systems', but 'belief in Plato'? Green as a religion, is not really a serious attack but Richard Dawkin's switching his atheist attack from religion to Plato takes the biscuit. It is like waking up in 12th Night and the Gulling of Malvolio without Sir Toby Belch and crew - in other words he's gulled himself.
Barnum and Bailey here we come . . . Crispin Tickell has noted drily that Dawkins argues so effectively for the removal of God, he's created a vacancy that he alone can fill . . . and now he's done it, yellow socks and all.
However, beware of the new straw-man . . . flying essentialist rabbits . . . the God in the way of evolutionism has floppy ears, fur and a dead paw.
Behold 'The Dawkins Delusion' - Darwin would have cringed. Here is an excerpt . . . .
Why did it take so long for a Darwin to arrive on the scene? What delayed humanity's tumbling into that luminously simple idea which seems, on the face of it, so much easier to grasp that the mathematical ideas given us by Newton two centuries earlier – or indeed Archimedes two millennia earlier? Many answers have been suggested. Perhaps minds were cowed by the sheer time it must take for great change to occur - by the mismatch between what we now call geological deep time and the lifespan and comprehension of the of person trying to understand it. Perhaps it was religious indoctrination that held us back. Or perhaps it was the daunting complexity of a living organ such as an eye, freighted as it is with the beguiling illusion of a design by a master engineer. Probably all those played a role. But Ernst Mayr, grand old man of neo-Darwin synthesis who died in 2005 at the age of 100, repeatedly voiced a different suspicion. For Mayr the culprit was the ancient philosophical doctrine - to give it its modern name – essentialism. The discovery of evolution was held back by the dead hand of Plato.
THE DEAD HAND OF PLATO