Man’s impact on planet enigmatic

Environmental even keel or global crisis – no one knows.

Calculating man’s impact on the planet is difficult. So it’s hard to say whether we are on an environmental even keel or hurtling towards a global crisis, new research concludes.

The slice of global land net primary productivity (NPP) – a measure of the food and carbon-containing resources that land plants make available – that humans consume could be 10 per cent or 55, according to Stuart Rojstaczer and colleagues at