All over the globe, the natural world and its wildlife are under pressure as never before from the demands of human society. Fish stocks, the seabeds underneath them and the seabirds above them, are everywhere being decimated by industrial-scale fishing; rainforests are being cut down on every continent on which they are found; pollution is spreading across watercourses and seas; and many of the great wild animals, the "charismatic megafauna" are being driven to extinction.

How many tigers are left in India? No one knows, but it is probably fewer than 1,500, as they have disappeared from many of the protected areas that were supposed to be their refuges. How many mountain gorillas are left in Africa? Just 700. How many northern white rhino are left in Africa, come to that? At the last count, when they were last seen in Garamba National Park in the Democratic Republic of Congo in 2006: four.

As well as the pressure from development and deforestation, it is direct poaching that is sending numbers of the world's biggest and most majestic mammals plunging down towards extinction, and it is with this background that the British Government voted yesterday to allow an enormous re-expansion of the ivory trade, which more than halved the population of the African elephant between 1980 and 1989, until it was rightly banned.

Its decision is not only reprehensible: it is mad. Africa has terrible human problems and in most of the 37 countries in which elephants are found there is simply no money to enforce wildlife protection, no money to pay rangers and give them boots and guns and Land Rovers; you can only protect wildlife if you choke off the temptation for it to be illegally killed. Yesterday's decision racks up that temptation a thousand-fold. It is truly shameful.