Caring for the environment should mean not caring how you look, our environment correspondent Richard Black argues in The Green Room.
Once upon a time it was easy to spot an environmentalist.
Fashion is a luxury we do not need, a bauble that blinds, an environmental dead end
He or she would be the messy shambles of a figure loping along the street, rainbow beanie-hat on head and battered parka held together by peace badges.
Alternatively you could use your nose for identification - washing facilities are necessarily limited in anti-nuclear camps and treetop sit-ins.
How things have changed.
When I go to meetings now on issues like renewable energy, climate change or water resources, not a beanie can be seen.
Men in grey suits and clean shoes sit in serried ranks of serious intent, just the occasional overly green tie or orange sock betraying that this is not a city bankers' clan gathering or old school reunion.
Women - too few - sit in equally serious islands of red, green and peach.
All have gone through that process, mysterious to the true eco-warrior, known as "grooming".
Chairing a TV discussion recently, I saw something I had never expected - the environmentalist wearing a tie, the pro-business libertarian an open-necked shirt.
What is the world coming to?
To some, this smartening is a sign that environmentalism has grown up. The modern green spirit wants to influence politicians and businessmen, to look good in a TV soundbite or on a conference platform.
Men in suits: The modern face of environmental progress
To do so, they believe they must adopt the same language and the same uniform.
But there is a major downside; and typically it is displayed outside the conference venue, as smart-suited delegate after smart-suited delegate arrives and leaves by taxi.
The reason? Our peacock-brained obsession with looking smart.
Government ministers must have every hair cemented in place, green businessmen must keep their pinstripes parallel, eco-worriers have to remain fragrant under planetary-scale stress.
Which makes the greenest form of urban transport, the bicycle, unthinkable.
So you have 200 people gathering to talk about reducing greenhouse gas emissions, and virtually all using a highly-polluting form of personal transport.
Progress? I don't think so.
Taking it by the scruff
Now I am far from being an eco-saint; and as a BBC journalist I am obliged to remain neutral on issues such as the science of climate change, and let the evidence speak for itself.
But I am doing my piffling bit for the natural world; I have released my inner scruff.
You have 200 people gathering to talk about reducing greenhouse gas emissions, and virtually all using a highly-polluting form of personal transport
When I go to meetings and conferences now, all else being equal, I will cycle, as I usually do on other urban journeys.
I will find a seat among the smart serried ranks and let the sweat evaporate. I might bring a clean T-shirt along; then again I might not.
The secret is simply not to care.
Quite frankly, if they want to find ways of reducing energy consumption, curbing greenhouse gas emissions and tackling urban pollution, they can put up with the sweaty armpits on my T-shirt.
After all, in most parts of the world, most people have to manage without looking smart; they can't afford it.
My great-grandparents had one bath a week and two sets of clothes, one for work and one for Sundays.
Their carbon footprints were a lot smaller than mine.
Suited to purpose
There are many wonderful aspects of progress, and I would not argue for throwing off many of them.
Consumption of proper amounts of food is undoubtedly a good thing; consumption of medicines when you are ill, of books, of CDs, of wooden furniture (sustainably sourced, of course) - fantastic, bring it on.
But fashion we can do without; it is a luxury we do not need, a bauble that blinds, an environmental dead end.
Cyclists can wear anything if they're not worried about looking smart
It is fashion which leads a friend of mine to "need" 14 watches so she always has one that matches; fashion which leads a relative to possess more than 40 pairs of shoes.
Let's not even talk about the resource implications.
At the Oscars last week, I learn from elsewhere on this website, "Ziyi Zhang dazzled in a black bustier with a full skirt covered in Swarovski crystals by Giorgio Armani while Jessica Alba sparkled in a gold Versace halterneck".
Now, Ziyi Zhang and Jessica Alba would look gorgeous in my dad's pyjamas - and he hasn't had a new pair since 1979.
I am sure the same goes for George Clooney and Leonardo DiCaprio.
But you, environment minister, and you, green business person, are never going to look like Ziyi Zhang or George Clooney, however many Armani bustiers (whatever they might be) you wear.
And you know what? You don't have to. Your business is not to look good; your business is to do good.
And for you gold-cluttered youth, you sultanas of bling with your four-wheel drives and well-groomed doglets; a global conscience is not a fashion statement, ok?
So don't bother about how you look. Forget convention, it is there to be overthrown; release your inner scruff, jump out of your taxi and onto your bike.
Scruffy really is the new green. Darling.
The Green Room is a weekly series of opinion articles on environmental issues on the BBC News website
Do you agree with Richard Black? Has fashion got in the way of caring about the environment? Should we release our inner scruff and get onto our bikes?