A group of experts convened under a UN umbrella has been taking a look at what aspects of our global society are the least sustainable; which things are depleting natural resources fastest, which are causing the most environmental damage, and which are the biggest threats to the prosperity of future generations.

It's bad news, I'm afraid, because the biggest culprits are the things we need most fundamentally: food and energy.

We're used to emissions from fossil fuels being fingered as the principal drivers of the man-made greenhouse effect.

But the report from the UN Environment Programme's International Panel for Sustainable Resource Management also points up the immediate polluting effects (and health consequences) of burning coal, wood, oil and gas.

Meanwhile, other types of emission also compromise human health and the natural world, such as nitrogen run-off from agricultural land, which causes eutrophication in freshwater systems and the seas.

On the resource side, the report flags up the coming declines in oil and gas reserves as stumbling blocks on the developing world's path to prosperity. But shortages of key ingredients for alternative technologies - such as platinum and rhodium - are also causes for concern, it says.

When it comes to the Earth's self-replenishing resources, wood and fish are the ones we are using least sustainably.

Farming, meanwhile, is fingered as the principal reason why natural habitat is being lost for so many plants and animals, with high consumption of meat - relatively heavy on land and water use - flagged up as a particularly unsustainable aspect of western diets.

More than half of the crops we grow are used to feed farm animals.

Much of this, you may be thinking, is not terribly radical; it's the usual depressing story of people trying to live ordinary lives, and copping the blame when what they need to live and progress starts running out or overloading nature's waste-processing capacity.



What I think is interesting is the way the global picture is re-framed.

So rather than talking about "stopping climate change" or "reducing the health impacts of wood-burning" or whatever, the panel makes two principal offers.

Firstly, it's using real, quantified studies to pin down as far as is possible the real costs and benefits of many of the things we do; and it's doing so in a holistic way.

Secondly, it's offering choices rather than a prescription: rather than the language of "we have to stop doing this", it's a matter of "if society develops this way, these are likely to be the consequences for your children's generation; and here's how it changes if you develop that way instead".

In some ears, this will be ringing an alarm bell that resonates to the tune of "here's another UN anti-growth message".

It actually isn't; it's about rationalising growth. As the panel summarises its remit:

"All economic activity takes place in a limited, natural world...so what economic activities contribute most to the use of natural resources and the generation of pollution?"

And having produced answers, choices and some solutions then emerge.

As one of the panel's co-chairs, the eminent German scientist Ernst Ulrich von Weizsaecker, told me:

"One strategy is to decouple wellbeing from resource consumption. Another is to select resources in relation to their environmental impact, and so it's important to know where the big impacts are."

This report doesn't offer an easy path to curbing the expansion of our global footprint; it doesn't come close, in fact.

But it does suggest a way in which the overarching issue encompassing the world's environmental, economic and social ills might be addressed, and development maintained, without costing the Earth.