“Those who are given a benefit and then have it removed are likely to be less happy than those who never know of its existence” Daniel Kahneman, Thinking, Fast and Slow

Increasingly I come across people saying the human population is unsustainable. It’s hardly a new concern – Thomas Malthus, for instance, was worried about it in 1798 – but the threat of climate breakdown has made more people express it recently.

Yet it’s not so much the 8 billion people on the planet that are the problem; it’s the 1 billion who consume more than half the resources and emit more than half the greenhouse gases. Most of us in Britain are part of that 1 billion.

Over the decades since WWII, we have become accustomed to – as a proportion of our income – cheap food, cheap energy, and cheap travel, priced without regard to the environment. We see all of these as basic human rights, and become very indignant when they go up in price, as is now happening.

The example of flight

An aversion to giving up what we currently enjoy seems to distort our judgement and encourage wishful thinking. Take flying, for instance. A return flight to South Africa requires around 10,000 kWh of fuel energy per passenger, order of magnitude, which is more than twice the annual electrical energy consumed by the average British household. Taking account of the losses in electricity generation, transmission and distribution, the primary energy consumption is roughly the same in the two cases.

Not much more can be done to improve engine efficiency significantly. Flying either faster or slower would only make matters worse: given the weight of the plane, a speed of circa 500 mph is pretty optimal in terms of fuel consumption. Making the plane lighter would help – but unless the lighter plane also flies more slowly (its optimal speed is lower if it’s lighter), the reduction in energy consumption is limited to around 50% even if the plane were filled with helium to make it weightless. Per passenger, that’s still the primary energy equivalent of about 6 months’ electricity consumption by the average household. And flying more slowly would not be popular. And the helium would need to be produced.

The point is that flying heavy and/or fast objects long distances is inevitably very energy intensive (assuming in the latter case a cross-sectional area that is appropriate for human comfort). No amount of technological ingenuity can alter basic physics. Yet our politicians and most of the public believe it’s a case of sorting out “green planes” that use batteries, biofuels or green hydrogen. Not even the airline industry thinks battery-powered planes could cross oceans, as the weight of the battery would stop them leaving the runway; the amount of biofuels required to replace jet kerosene would seriously compromise food production; the requisite amount of green hydrogen would entail country-sized areas devoted to the deployment of renewable energy. Politicians, and the small percentage of the world’s population who fly a lot, need to appreciate all this.

Value obsolescence

Human achievements are sometimes valuable for a limited time only. The invention of flight surely helped cultures to become better acquainted with each other during the 20th century. But whereas long-distance travel was very useful in broadening people’s horizons fifty years ago, as well as for business, the argument is much weaker in today’s world, with our global communications network and cosmopolitan cities. When this diminution of value is combined with the increasingly poor state of the environment, it can be reasonably argued that flying is today more harmful than helpful. Not an easy lesson for those like me with family on the other side of an ocean, but the truth sometimes hurts.

We aren’t good at giving things up. Niels Bohr gloomily pronounced that the only way to change ideas in society was to wait for the current generation to die out and be replaced by a new one that is more enlightened. And it seems we cling to our way of life with a tenacity no less firm than to our belief system.

Demand substitution

Perhaps the way in which technology can help us the most is not by attempting the impossible (e.g. trying to make a plane that doesn’t use much energy) but by developing green substitutes for our energy intensive demands. Virtual reality holidays, for instance, in nearby hotel complexes that reproduce the sensation of being on an exotic beach thousands of miles away; new foods like the Impossible Burger (and similar less advertised versions) that mimic the savoury experience of the meaty original; electric self-driving taxis that eliminate the need for personal vehicles.

I like to think that Kahneman may be too pessimistic; that we are capable of giving up what we have, given the necessary information, coaching and good leadership, without becoming unhappy as a result. Perhaps religion has useful insights here, even for atheists. But if we inevitably struggle to let things go, maybe they can still be teased from our grasp as long as we don’t notice the difference.