They tell us not to drive Hummers.
They tell us to disconnect our cell phone chargers, once our cell phones are juiced. They tell us to switch off our laptops, burn candles rather than electric light, and sail boats rather than fly planes.
But do they ever tell us to wean ourselves off the animals that we cynically use as substitutes for our failed relationships with other humans?
I only ask because an article from the New Scientist has wafted in front of my breakfast bowl and slapped me about my flappy jowls.
Quoting such luminous organizations as the Stockholm Environment Institute at York, UK, the article purports to suggest that our pets have all the eco-friendliness of that Northwest Airlines flight that forgot to land in Minneapolis and just kept on going to Wisconsin.
Please, I understand that dogs and cats are lovely beings that just want to love you and lick you as long as you feed them and wash them.
However, the SEI seems to believe that a cat has almost the same carbon footprint as a VW Golf.
Here is a sentence from the article that I know may make some of you rather unwell: "As well as guzzling resources, cats and dogs devastate wildlife populations, spread disease and add to pollution."
Yes, I know you thought it was only multinational corporations that do that. So please imagine that there is a book, written by Robert and Brenda Vale, called "Time to Eat the Dog?: The real guide to sustainable living."
Because you are more numerate than me, I will leave you to examine their figures in lascivious detail. However, the Vales estimate that a 4.6-liter Toyota Land Cruiser has an eco-footprint that is less than half that of a medium-size dog.
It is largely to do with the amount of meat and cereal that dogs chow, but this is surely a vale of tears for those who need their dogs in so many different ways: to get exercise, to get companionship and to become attractive to members of their target sex.
In case you are not quite thoroughly depressed by this estimation of our ultimate demise, might I offer you two further calculations from the Vales?
Well, should you own two hamsters, that is the eco-footprint equivalent of your plasma. And one goldfish? Well, it's the energy-sucking equivalent of two cell phones.
To continue this cheery mood for just a little longer, please hark these words the New Scientist quotes-- they were uttered by David Mackay, a physicist at the University of Cambridge: "If a lifestyle choice uses more than 1 per cent of your energy footprint, then it is worthwhile reflecting on that choice and seeing what you can do about it."
The average cat, he estimates, represents 2 percent of a human's footprint. And as for dogs, oh, it really doesn't bear thinking about.
It seems to me, therefore, that you have some harsh choices to make in order to save our world.
Your goldfish or your family plan? Your hamsters or, at the very least, the plasma in your bedroom? Your dog or your Audi?
Your animal companions or your technological ones? Life just doesn't get easier, does it?