The case of the recovering North Sea cod is an example of that increasingly rare phenomenon: the environmental good news story.
The majority of bulletins about change in the environment point in one direction only: for the worse. As the human population continues its remorseless expansion from 6 billion in 1997 to at least 9 billion by 2050, the scale and impact of human activity are taking an ever-increasing toll on the natural world. According to the Red List of the International Union for the Conservation of Nature, huge numbers of plants, birds, mammals, reptiles, amphibians and other species are threatened with extinction, and the list grows longer every year.
The good news stories tend to involve individual species which have been hauled back from the brink by the determined efforts of dedicated conservationists, such as the large blue butterfly in England or the sea eagle in Scotland.
Rarer are the examples of whole eco-systems recovering, although there are some: in terms purely of chemical pollution, Britain's rivers are cleaner now than at any time since before the Industrial Revolution. But rarest of all are the cases where natural resources are restored, especially as with fish stocks, where this concerns the "global commons" – resources which are free for everyone to plunder at will. The recovery of the North Sea cod is incredible news – as long as it can be maintained – and will provide a fillip for anyone concerned with the state of the planet.