The COP26 conference on climate change may have solved little, but it was a brilliant opportunity to recycle hoary clichés about overpopulation.
Professor Paul Sutton, of the University of Denver, was a delegate for the American Association of Geographers at COP26. He wrote in The Hill , the largest independent political news site in the US: "without population stabilization and eventually degrowth, all the other approaches to climate change will not work."
He wants an aggressive program of population control: "The least costly and most effective policy to control future CO2 emissions from fossil fuel combustion and thereby climate change is to curb global population growth by simply providing contraceptive care to all women in the world who want it but do not currently have access."
Closer to home, Daily Express columnist Leo McKinstry says that "curbing population explosion should be top of the COP26 agenda".
Observers have remarked on the absence of Presidents Xi Jinping and Vladimir Putin but the most significant absence, he declared, is the lack of emphasis on population control. We are "perhaps the biggest cause of environmental degradation".
"There are currently 7.9 billion people on Earth, a total expected to rise by at least one billion every 12 years. It is a level of growth whose insatiable demands not only put an intolerable strain on our natural resources, but also fuels the ruination of eco-systems, from rivers to rain forests. ...
"The decision to avoid this question at COP26 is the equivalent of holding a conference on obesity without mentioning calorie intake or lack of exercise."
And with a grand rhetorical flourish he concludes: "Overpopulation is an engine of social injustice and eco-destruction. It should be at the heart of COP26 proceedings."
There is a kind of twisted logic in these gentlemen's pronouncements, since if people are not born, they cannot harm the Planet, but neither can they help it.
In fact, however, global birth rates are also in decline . The population growth we now see is caused by people living too long - a problem stemming from greater prosperity.
For those who argue that there are "too many people", it makes more sense to kill people already born than to kill the unborn - unless they wish the human race to die out altogether.
Perhaps they do - apart from themselves of course - which explains lamentations about the problem of the "ageing population" alongside a clamour for the right-to-die and quiet moves to make it easier for old, the sick and the disabled to refuse treatment .
Just to add to the general mood of merriment and optimism, the consumer organisation Which ? is telling Britons that eco-friendly households should give plastic Christmas trees a miss this year. Which's sombre message is that you will need to keep a plastic tree for at least 12 years to offset its carbon footprint.
But they shouldn't buy real ones either. The greenest things to do are to hire a real fir tree (expensive), grow your own (do you have the patience?), or make a fake one out of sustainable materials (who has the time?).
If we continue down this slippery green slope, it can only be a matter of time before Christmas itself, with its feasting and present-giving, will be abolished as being detrimental to the environment. And after all, bowing down to a baby - when babies are supposed to be ruining the Planet - rather than to the 95-year-old misanthropist David Attenborough, is so un-green.
Malthus is on the nose because of the experience of forced population control in China and India. But it is being revived.
It is of course heavily disguised as Caring for the Planet, and in a sly inversion of the Biblical morality which tells us that the first shall be last and the last shall be first, it seems the first shall continue to be first and the last shall be prevented from being born.
Whether or not the nobs talk openly about overpopulation, if COP26 has its way, the rest of us will be poorer, colder and sicker - and without children to console us in our old age. That's the kind of unwanted Christmas present we can all do without.