The chattering classes recently went into collective meltdown when Jonathon Porritt, the government’s Green adviser, suggested that couples who have more than two children are being 'irresponsible' by creating an unbearable burden on the planet, writes Julia Stephenson

Porritt, who chairs the government's Sustainable Development Commission, says curbing population growth must be at the heart of policies to fight global warming. He says political leaders and green campaigners should stop dodging the issue of environmental harm caused by an expanding population.'

With the world now straining at the seams and governments taking no real imitative to reduce carbon emissions, the best way for us all to halt the planet’s demand for energy is to produce fewer children or take the Brangelina/Madonna approach and adopt.

While no one is suggesting the Government applies a Chinese style one-child policy or that it bribes men with free radios in return for their sterilisation like they did in India (I wouldn’t turn down a free radio myself, after all I’ve done my bit by remaining `childfree’) it seems disproportionate to put so much emphasis on, for example, airport growth and switching off standby appliances, while ignoring the greatest creator of carbon emissions of them all.

Climate scientist James Lovelock wrote in last week’s Sunday Times;

`the exhalations of breath and other gaseous emissions by the nearly seven billion people on Earth, their pets and livestock are responsible for 23% of all greenhouse gas emissions. If you add on the fossil fuel burnt in the total activity of growing, gathering, selling and serving food, all this adds up to about half of all carbon dioxide emissions. Like it or not, we are the problem.

The figures say it all. The Optimum Population Trust, a campaign group of which Porritt is a patron, says each baby born in Britain will, during his or her lifetime, burn carbon roughly equivalent to 2½ acres of old-growth oak woodland - an area the size of Trafalgar Square.

The British population, now 61m, will pass 70m by 2028, the Office for National Statistics says. The fertility rate for women born outside Britain is estimated to be 2.5, compared with 1.7 for those born here. The global population of 6.7 billion is expected to rise to 9.2 billion by 2050.

It’s sometimes considered selfish not to breed, but now the tables are turning. Fortunately lazy girls like me now have the perfect excuse when asked why they don’t have children by broody potential grandmothers.  

I will explain piously that `I am childfree for the sake of the planet’. Not because I am too idle, hate getting up early and would much prefer a brood of Shetland sheepdogs.