Towards crossing environmental limits
The global food system has fundamentally altered our planet and the resource base humanity depends on. Food production is responsible for about a quarter of all greenhouse gas emissions and therefore a major driver of climate change. Agriculture occupies more than a third of the Earth’s land surface and has led to reductions in forest cover and loss of biodiversity. Farming also uses more than two thirds of all freshwater resources, and the over-application of fertilizers in some regions has led to dead zones in oceans.
Without concerted action, the environmental pressures of the food system could increase by 50-90% by 2050 as a result of population growth and the continued Westernization of diets, we estimated in the new study. At that point, those environmental pressures would exceed key planetary boundaries that define a safe operating space for humanity beyond which Earth’s vital ecosystems could become unstable.
Crossing planetary boundaries would increase the risk of destabilizing essential ecosystems. Among others, it could lead to dangerous levels of climate change with a higher occurrence of extreme weather events, affect the regulatory function of forest ecosystems and biodiversity, result in disruptions of water flows with impacts on the global hydrological cycle, and pollute water bodies such that it would lead to more oxygen-depleted dead zones in Oceans.
Planetary option space
Fortunately, such a situation can be avoided. For analysing the planetary option space, we combined detailed environmental accounts with a model of the global food system that tracks the production and consumption of food across the world. With this model, we analysed several options that could keep the food system within environmental limits. Here is what we found:
Climate change cannot be sufficiently mitigated without dietary changes towards more plant-based diets. Adopting healthy and more plant-based diets globally could reduce the greenhouse gas emissions of the food system by more than half, and also reduce other environmental impacts, such as those from fertilizer application and the use of cropland and freshwater, by a tenth to a quarter.
In addition to dietary changes, improving management practices and technologies in agriculture is required to limit pressures on agricultural land, freshwater extraction, and fertilizer use. Increasing agricultural yields from existing cropland, balancing application and recycling of fertilizers, and improving water management could, along with other measures, reduce those impacts by around half.
Finally, halving food loss and waste is needed for keeping the food system within environmental limits. Halving food loss and waste could, if globally achieved, reduce environmental impacts by up to a sixth.
A call to action
Many of the solutions we analysed are being implemented in some parts of the world, but it will need strong global co-ordination and rapid upscale to make their effects felt.
Improving farming technologies and management practices will require increasing investment in research and public infrastructure, the right incentive schemes for farmers, including support mechanisms to adopt best available practices, and better regulation, for example of fertilizer use and water quality.
Tackling food loss and waste will require measures across the entire food chain, from storage and transport, over food packaging and labelling, to changes in legislation and business behaviour that promote zero-waste supply chains.
When it comes to diets, comprehensive policy and business approaches are essential to make dietary changes towards healthy and more plant-based diets possible and attractive for a large number of people. Important aspects include school and workplace programmes, economic incentives and labelling, and aligning national dietary guidelines with the current scientific evidence on healthy eating and the environmental impacts of our diet.
What can I do?
As an individual, you can help, for example, by adopting a healthy and more plant-based diet, call on businesses to reduce waste across their supply chain and offer more plant-based food options, and hold your politicians to account by demanding strong regulation of environmental resource use and pollution. We only have one Earth – let’s make sure we can keep it.
Read the full paper, "Options for keeping the food system within environmental limits," in Nature at http://dx.doi.org/10.1038/s41586-018-0594-0