To offset the greenhouse impact of an economy round-trip flight between New York and London, you would have to recycle approximately 40,000 plastic bottles.

Fly first-class, however, and that number increases to a whopping 100,000 bottles.

The rudimentary Three R’s – reduce, reuse, and recycle – are drilled into us from the day we start primary school: the yogurt pottles and tuna cans go in one bin, while the apple cores go in another. But a pious commitment to recycling could actually be doing more harm than good, both to the economy and the environment.

John Tierney, in The New York Times last Sunday, argued that recycling is both expensive and ineffectual. While it is obstinately endorsed as a goal in and of itself, there is little understanding of the relative costs and benefits of recycling.

In New York City, “the net cost of recycling a ton of trash is now $300 more than it would cost to bury the trash instead”.

Our own Dr Eric Crampton did some back-of-the-envelope calculations for the costs of recycling in Christchurch several years ago. The most conservative estimates put the cost of disposing regular trash at $42 per tonne and recycling at $75 per tonne. More realistic midpoint estimates suggested $31 per tonne for landfill and $110 per tonne for recycling.

Recycling one tonne of paper, tin cans and cardboard can save about three tonnes of carbon dioxide emissions. But trying to recycle materials like different grades of plastics, food scraps and glass requires far costlier processes with far fewer environmental benefits. You would need to recycle three tonnes of glass to save about one tonne of carbon dioxide emissions.

Estimated carbon savings from recycling also fail to account for the water used in rinsing recyclables. Or the fuel required for tankers used to transport trash to recycling facilities. Or that recycling is a labour-intensive activity that produces goods of little value, while the real cost of human labour has been increasing over the past few centuries.

Even if recycling is not all that beneficial for the environment or the economy, at least it makes people feel good. And that is what matters, right?