We Can't Fix Climate Change Without Fixing Global Diets
Imagine that if instead of slapping
science-challenged "GMO-free" labels
on food products, we mandated a labeling scheme based on a given
product's real-world environmental impact. The metric would be some
index tied to relative greenhouse gas (GHG) emissions and it would look
like the current nutrition labels mandated in the US and other
countries. Instead of calories, however, a consumer would see a number
representing a given product's deviation from a baseline of zero
additional GHG emissions.
At the very least, within this scheme it would become that much more difficult for people to fool themselves, or be fooled by marketers pitching products as "green" that aren't particularly green at all. The average Whole Foods denizen would be surprised.
Food production alone is poised to reach or exceed total global targets for greenhouse gas emissions by 2050 (as in, emissions targets for everything). We may tend to focus on energy and energy production as represented by coal-based power plants and fracking, but the food system is a massive semi-hidden variable in the global warming progression. A study out today in the journal Nature Climate Change once again makes the argument that changing the global food system is crucial to slowing climate change and for ensuring food supplies in general.
Fortunately, according to the study, this food system shift doesn't involve everyone jumping to soylent-based diets so much as jumping to generally healthier diets in the conventional food pyramid sense. Healthier diets tend to be more efficient diets at the production end, which in turn means tearing up less land and hacking apart fewer GHG-sponging trees.
It is "imperative to find ways to achieve global food security without expanding crop or pastureland and without increasing greenhouse gas emissions," the report concludes. And make no mistake, the trend is firmly toward expansion. Research has shown conclusively that future population growth coupled with current food and biofuel demands means a rough doubling of global crop production by 2050. Slowly but surely farmers are increasing crop yields, but only at about half of the rate needed to meet future demand.
Filling in this gap is where things get precarious, from a climate perspective. "Agriculture is the main driver of losses of biodiversity and a major contributor to climate change and pollution, and so further expansion is undesirable," the paper notes. "It is therefore imperative to find ways to achieve global food security without expanding crop or pastureland and without increasing greenhouse gas emissions."
The alternative, according to the paper, is the loss of a further tenth of Earth's pristine tropical forests and a 42 percent increase in global cropland overall. This means less biodiversity, more carbon emissions, and still more methane emissions, the result of increasing livestock numbers.
Food security researchers have previously proposed different methods of "sustainable intensification" that might be useful for filling in so-called yield gaps. Basically, this means growing more crops in the same amount of space ideally within lengthened growing seasons. This brings us back to the current research. "In this paper we use a transparent, data-driven model, to show that even if yield gaps are closed, the projected demand will drive further agricultural expansion," the paper says.
"There are basic laws of biophysics we can't evade," said Bojana Bajzelj, the study's lead researcher and an engineering professor at the University of Cambridge, in a statement.
"The average efficiency of livestock converting plant feed to meat is less than 3 percent, and as we eat more meat, more arable cultivation is turned over to producing feedstock for animals that provide meat for humans," Bajzelj said. "The losses at each stage are large, and as humans globally eat more and more meat, conversion from plants to food becomes less and less efficient, driving agricultural expansion and land cover conversion, and releasing more greenhouse gases. ... our food choices matter."
Solving the global food problem will take a combination of things. Changing diets is one aspect, but it doesn't work alone. Crop yields still need boosting, a challenge that will likely depend on some degree of bioengineering, and food waste needs to stop. That's the third piece of the puzzle: waste. Food gets wasted in developing parts of the world thanks to poor storage and transportation options, and in the developed world it happens mostly just because we suck at food: cooking more than we need and throwing the rest away.
Rest assured, the healthy eating described by the researchers still involves some amounts of animals: two portions of red meat per week, five eggs per week, and a serving of poultry every day. We should be able to deal with that—and the alternative is much worse.
"Unless we make some serious changes in food consumption trends, we would have to completely de-carbonise the energy and industry sectors to stay within emissions budgets that avoid dangerous climate change," noted co-author Pete Smith. "That is practically impossible."
At the very least, within this scheme it would become that much more difficult for people to fool themselves, or be fooled by marketers pitching products as "green" that aren't particularly green at all. The average Whole Foods denizen would be surprised.
Food production alone is poised to reach or exceed total global targets for greenhouse gas emissions by 2050 (as in, emissions targets for everything). We may tend to focus on energy and energy production as represented by coal-based power plants and fracking, but the food system is a massive semi-hidden variable in the global warming progression. A study out today in the journal Nature Climate Change once again makes the argument that changing the global food system is crucial to slowing climate change and for ensuring food supplies in general.
Fortunately, according to the study, this food system shift doesn't involve everyone jumping to soylent-based diets so much as jumping to generally healthier diets in the conventional food pyramid sense. Healthier diets tend to be more efficient diets at the production end, which in turn means tearing up less land and hacking apart fewer GHG-sponging trees.
It is "imperative to find ways to achieve global food security without expanding crop or pastureland and without increasing greenhouse gas emissions," the report concludes. And make no mistake, the trend is firmly toward expansion. Research has shown conclusively that future population growth coupled with current food and biofuel demands means a rough doubling of global crop production by 2050. Slowly but surely farmers are increasing crop yields, but only at about half of the rate needed to meet future demand.
Filling in this gap is where things get precarious, from a climate perspective. "Agriculture is the main driver of losses of biodiversity and a major contributor to climate change and pollution, and so further expansion is undesirable," the paper notes. "It is therefore imperative to find ways to achieve global food security without expanding crop or pastureland and without increasing greenhouse gas emissions."
The alternative, according to the paper, is the loss of a further tenth of Earth's pristine tropical forests and a 42 percent increase in global cropland overall. This means less biodiversity, more carbon emissions, and still more methane emissions, the result of increasing livestock numbers.
Food security researchers have previously proposed different methods of "sustainable intensification" that might be useful for filling in so-called yield gaps. Basically, this means growing more crops in the same amount of space ideally within lengthened growing seasons. This brings us back to the current research. "In this paper we use a transparent, data-driven model, to show that even if yield gaps are closed, the projected demand will drive further agricultural expansion," the paper says.
So, according to the current study, we're left with the demand side of the equation: "improved diets and decreases in food waste are essential to deliver emissions reductions, and to provide global food security in 2050." Improved diets in this case means less meat, a food source that's been demonstrated again and again to be highly inefficient. Basically, it takes a lot more corn or other feed to sustain a cow than it does to just sustain a human directly without the livestock intermediate. You might get, say, 900 calories from a piece of steak or hamburger, but it would've taken several times that number to actually produce the meat end-product. Civilization can't really afford that anymore.There are basic laws of biophysics we can't evade.
"There are basic laws of biophysics we can't evade," said Bojana Bajzelj, the study's lead researcher and an engineering professor at the University of Cambridge, in a statement.
"The average efficiency of livestock converting plant feed to meat is less than 3 percent, and as we eat more meat, more arable cultivation is turned over to producing feedstock for animals that provide meat for humans," Bajzelj said. "The losses at each stage are large, and as humans globally eat more and more meat, conversion from plants to food becomes less and less efficient, driving agricultural expansion and land cover conversion, and releasing more greenhouse gases. ... our food choices matter."
Solving the global food problem will take a combination of things. Changing diets is one aspect, but it doesn't work alone. Crop yields still need boosting, a challenge that will likely depend on some degree of bioengineering, and food waste needs to stop. That's the third piece of the puzzle: waste. Food gets wasted in developing parts of the world thanks to poor storage and transportation options, and in the developed world it happens mostly just because we suck at food: cooking more than we need and throwing the rest away.
Rest assured, the healthy eating described by the researchers still involves some amounts of animals: two portions of red meat per week, five eggs per week, and a serving of poultry every day. We should be able to deal with that—and the alternative is much worse.
"Unless we make some serious changes in food consumption trends, we would have to completely de-carbonise the energy and industry sectors to stay within emissions budgets that avoid dangerous climate change," noted co-author Pete Smith. "That is practically impossible."
