Why land and water are ‘planetary boundaries’ – not population

When it comes to food production, humanity is on a collision course with the planet. Agriculture is one of the biggest drivers of global ecological degradation: farming displaces natural ecosystems, uses valuable freshwater, pollutes rivers and estuaries, and releases potent greenhouse gases. And yet we undeniably need more of it – 1 billion people are still starving or malnourished in today’s world, surely one of the greatest moral outrages of our time. Looking to the future, we must feed more than 9 billion people by 2050, an increasing fraction of them on meat and dairy-heavy First World diets. To do that, agricultural production must be doubled, whilst the damaging environmental impacts of farming must be more than halved.

The challenge sounds like Mission Impossible. But it can be tackled effectively, according to a world-leading group of experts who have just published what may turn out to be one of the most important scientific papers this year. Entitled ‘Solutions for a Cultivated Planet’ (free PDF here), the article – by the University of Minnesota’s Jonathan Foley and colleagues – demonstrates that land use ranks with climate change as a planet-scale problem – and may be much more difficult to solve. Whilst there is no fundamental shortage of energy – thanks to renewables, nuclear fission and other low-carbon options – land is absolutely limited, and ranks as a top-level ‘planetary boundary’ because of its importance in maintaining the resilience of the Earth system.

In my new book ‘The God Species’ I outline all nine proposed ‘planetary boundaries’ – which include biodiversity loss, climate change, land use, water use, nitrogen loading and various other global ecological threats – and conclude that all must be considered simultaneously if we are to avoid simply replacing one critical problem with another. There is no place for simplistic linear thinking in a complicated and globally-interdependent human society and environment.

The proposed ‘planetary boundary’ for land use is for cropland to be limited to 15% of the Earth’s ice-free terrestrial surface. About 12% of this is already committed, so expansion alone cannot provide the needed increase in food. Moreover, agriculture has already destroyed 70% of grasslands, 50% of savannas, 45% of deciduous forests and more than a quarter of tropical forests. Agricultural expansion in the tropics emits more than a billion tonnes of carbon per year, and threatens biodiversity treasure troves in rainforests. What is needed instead is more efficient agricultural production elsewhere – getting more from less in land areas that are already used in cultivation. But doing this successfully will mean reassessing some of our most cherished notions about farming and the environment.

First off, organic farming is no silver-bullet solution. Whilst the organic movement has delivered valuable lessons about how to conserve soils and produce food in more wildlife-friendly ways, it is in general only half as productive as conventional farming and thereby – directly or indirectly – uses twice as much land for the same amount of food. Moreover, improving yields in highly unproductive agricultural areas in parts of Africa and Asia will mean using more not fewer artificial chemical fertilisers. The scientists estimate that closing ‘yield gaps’ could increase food production by a billion tonnes, or nearly 30% worldwide.

The organic movement has also erred by ruling out genetic modification as a critically-important technology to improve yields. Because of ill-considered public opposition, mainly in well-fed rich countries, very little genetic engineering effort has so far gone into key food crops like wheat, potato and rice, meaning big opportunities still exist to make these staples produce much more food for less water, nitrogen and land inputs. With both freshwater use and nitrogen capture ranked as ‘planetary boundaries’ in their own right, achieving much greater production efficiencies is a globally-important environmental goal.

In addition, my judgement is that very little can – or should – be done about global population growth. Populations are growing in developing countries largely because fewer people are dying, rather than because more children are being born, and this improvement in life expectancies can only be a good thing. Whilst I personally think access to family planning services is a human right in any civilised society, I do not think it is necessary to try to control population increase for the sake of the environment. In any case, the majority of people who will be alive in 2050 have either already been born or will be within the next decade, and they all have to be fed.

So what can we as consumers do? Whilst few people will be persuaded to embrace full vegetarianism, pressure on the land can be reduced by shifting away from grain-fed beef to grass-fed beef, as well as pork and poultry, which use land more efficiently. Subsidies which encourage food crops to be turned into biofuel must also be eliminated. We must also waste less: according to some analyses, as much as half of world food production is simply thrown away. Above all, solutions must be practical and pragmatic – there is no room for ideological narrow-mindedness in an age of ecological scarcity. We can certainly feed ourselves and reduce the ecological burden of agriculture simultaneously – but to do so we need to do things very differently, starting now.

© Mark Lynas
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