Writing about places on earth, and the foods, drinks and scents connected with them, necessitates travel.

Travelling, though, is no longer an innocent activity. Humans are adjusting the disposition of gases in the world’s atmosphere and pushing vulnerable species (and eventually, perhaps, the less vulnerable too) into premature extinction. Part of the way in which we are doing that is by reckless travel.

Bustle on bright cityUnder these circumstances, how do I behave responsibly? When I go to London, I bike to the station and get the train (or take my bike on the train). Yet one needless flight renders a decade’s assiduous bicycling irrelevant.

Carbon offsets can be purchased. (I do.) Yet this is a sop to the conscience as much as a practical benefit; saner not to fly in the first place.

How does one decide if a flight must be taken? With difficulty. The ideal is to maximise the amount of work derived from a single journey, yet this is often hard to predict in advance, due to the "dynamic" nature of commissions for the free-wheeling and sometimes free-falling freelance. In terms of raw income, there is almost always some other way in which one could earn the same amount of money without travelling, though it is often a much duller way, and in the end one’s fertility as a writer in this field diminishes without the manure of travel.

The gilded cross and the playground of contrailsTravel, alas, is the part of my job I enjoy the most. I have always considered it a precious privilege to visit a multitude of places, and to meet those in foreign lands whose lives were intimately bound up with earth and sky, with plants and seasons. Now, of course, I am beginning to understand just how costly a privilege it is. Compared to the citizens of Guinea-Bissau or Mauritania, my lifetime carbon footprint is gross, distended, elephantine, macabre.

The opportunities to travel are numerous and corruptingly attractive. In the last two weeks, I have turned down invitations to visit New Zealand, Mauritius, Bordeaux and Portugal.

I am always surprised that these invitations are extended without any reference to climate considerations, almost as if inviter and invited had mutually agreed in advance to pretend the problem didn’t exist. I remember meeting up with a journalist a year or two ago who had been flown from Australia to London (business class), simply to attend the launch party for a new Champagne. The journalist was in London for two or three jet-lagged days at the most, and the entire jaunt would have filled up perhaps half a page in a magazine. I don’t blame her (she was doing her job) so much as the Champagne house which decided that instigating such a journey was a good idea in the first place. None of us can plead ignorance any more.

Travel for the purposes of wine or food writing may perhaps save others making similar journeys, since you are providing information about products which customers wish to understand better. At best, you help readers to stay in their armchairs. Not so with newspaper travel writing, which is almost always an incitement to the reader to travel for himself or herself.

Brimful of waterI haven’t travelled by air since last October, but I will soon have to begin again. I walked across the river Thames towards St Paul’s Cathedral on Thursday 24th January and took the three photographs posted here. It was a bright, breezy day; aircraft contrails scored the sky; our city bustled and prospered.

On Tuvalu, meanwhile, the sea is percolating up through the sub-surface coral, poisoning the crops. Costa Rica’s cloud forests have lost their Golden Toad; Antarctica’s Larsen B ice shelf is now just so much seawater. And, in underground trains, buses and cars, thousands were heading for Heathrow.