Sunday, August 11, 2019

IPCC Climate Change and Land - on food waste (and diet)

Sou | 9:13 PM Go to the first of 9 comments. Add a comment
Local vineyard
The most recent IPCC report, Climate Change and Land, was released last week.  The report covers a lot of ground (pardon the pun), including desertification, land degradation and food security.

I've been reading it, slowly. (It's no easier to read than any other IPCC report.) I've also seen a few articles that came out at the same time or shortly after its release.

Over time, I hope to cover more aspects of the IPCC report. Today I'll just comment on one issue that's been picked up around the traps, and that's food waste, and I'll make passing mention of diet. The food waste issue has been raised a few times since the report was released and, in my view, the articles range from fairly good to overly simplified to plain wrong. I'm not about to give easy answers or point to specific articles, just offer some food for thought (don't waste it).

Countries have strategies to reduce food waste

Food waste is a widely recognised problem throughout the world. In 2013 the Food and Agriculture Organisation (FAO) released a report "Food Wastage Footprint: Impacts on Natural Resources".  The report estimated about 1/3 of the food produced (for human consumption) was lost or wasted each year. In 2015, the UN set out sustainable development targets, including Target 12.3:
By 2030, halve per capita global food waste at the retail and consumer levels and reduce food losses along production and supply chains, including post-harvest losses 
Many countries (including Australia) have begun to develop strategies and plans to achieve this in their own country. On page 9 of Australia's National Food Waste Strategy there are examples of how food waste occurs along the supply chain.

Reducing food loss and food waste is definitely worthwhile. One of the bigger benefits in reducing loss and waste is that it may help improve food security. It may mean more food produced from the same acreage will end up being consumed, which will be needed as the population increases.

Will reducing food waste or changing diet reduce greenhouse gas emissions?

Curious cattle on Australian pasture

There may be opportunities to reduce greenhouse gas emissions by reducing the population of ruminants, and/or changing their feed and/or genetic makeup so they burp less methane. It would be sad to end the strong relationship humans have developed with cows and sheep, and make them functionally extinct, when they have served us so well for so many centuries. However, that may be one of the prices other species have to pay for the sake of humans.

This leads me to comment on a sentence I came across in section of the IPCC report, which was:
When the transition to a low-meat diet reduces the agricultural area required, land is abandoned and the re-growing vegetation can take up carbon until a new equilibrium is reached. This is known as the land-sparing effect.
As I've written elsewhere, if farmland is abandoned there's no guarantee any "re-growing vegetation can take up carbon" better than it did when it was farmland. It's more likely it will take up less carbon unless there is a deliberate investment in revegetation. (There's a high likelihood it will to revert to weeds or saltpans, not magically regenerate to a pre-farm state.)

It's not a one for one relationship

Although carbon emissions associated with food waste has been estimated, it doesn't mean that reducing waste will necessarily reduce greenhouse gas emissions in the same proportion. For example, food losses from adverse weather on farms happens on different farms each year. That means that farms look for ways to reduce waste e.g. send product that won't sell solely for visual reasons to be processed. It doesn't mean farms will give up just because one year's crop was damaged.

Finding more ways to use spoilt produce won't necessarily reduce greenhouse gas emissions (all else being equal). If it means processing the spoiled food rather than selling it as fresh food, it might increase emissions.

Reducing waste in the retail sector or in homes won't necessarily reduce greenhouse gas emissions in proportion either. That's not to say it's of no benefit. It most certainly is of benefit to reuse or recycle waste food (using it for composting, packaging etc. rather than sending it to landfill.)

Food from around the world for Londoners (UK)

There may well be some reduction in emissions, or wasted emissions, by not buying excess food. It wouldn't happen immediately though. In the short term, the waste will be passed back up the chain, to the retailer or the farm until supply is reduced to match the new and lower demand, and supply/demand is stabilised at the new level - for that product. (Farms will shift to another food or feed product that is more in demand.)

If food is composted instead of going to landfill it will still release greenhouse gases; however, at least much of the nutrient content can be recycled, which is better than adding to the waste problem.

In some countries, some of the food wastage is because of inadequate facilities for food storage, such as cool rooms. Improving these facilities along the supply chain will help reduce food waste, but in order not to add to emissions they'll need to be powered by renewable energy.

Other waste with food

I'd like to see more attention paid to other aspects of food consumption. For example, why do some shops sell pre-packaged food in still more packages? That seems so wasteful. I'm thinking of the natural packaging of bananas, oranges, watermelon, kiwi fruit and lots of other fruit and vegetables.

Oranges packed twice over

Why is plastic packaging still so ubiquitous? Why not make more use of non-saleable food or food by-products and turn these into biodegradable packaging?

This is already happening to some extent, but is still worth thinking about from an environmental perspective. Maybe it will and maybe it won't help, but these and other ideas are worth considering.

Food waste and food security and climate change

To wind this up, in my view it's a mistake to think that reducing waste will necessarily lead to a reduction in greenhouse gas emissions. It's a lot more complicated than thinking there'll be fewer farms (and if there were, who'd care for the abandoned land?) Some waste reduction strategies may even lead to an increase in emissions in the short term. Nevertheless reducing food waste is an imperative, for future food security.

Reducing food waste is going to become more critical over time because climate change is going to make food production more difficult.


  1. Reducing CO2 emissions would have been so much easier if real action had been taken about the time of the Kyoto Agreement. But even Kyoto was too much for Dubya. And now history repeats itself as Trump seeks to remove the US from the marginally less ineffectual Paris Agreement.

    1. You're absolutely right, Andy.

      I've read a bit more of the IPCC report and what's sinking in is that changes to land use are much more complicated than shifting from fossil fuels to renewable electricity and clean transport.

  2. We've solved much of the food waste problem by changing purchasing habits.

    My daughter is a vegan and buys bulk food from Food Assets. They now toss out almost nothing as waste, what little fresh scraps they have winds up in a compost pile. The deer usually come and eat most of that!

    Food waste is really an issue of how people purchase their food, how it's prepared and how much needs to be stored. Bulk food (if dry) can last decades, with zero waste (cook what you need, eat it), but fresh food is different, has to be eaten in season and spoils fairly quickly.

    Dry food also solves the problems associated with packaging by the way. The cans can be easily recycled or even used for something else.

    Where we see the most waste is in our garden. We've done freezing, canning, blanching and refrigeration, but the crops come in large bunches, so there is definitely some waste. But since it's our own production, it's actually a non-issue. Doesn't involve hardly any energy or oil to produce, most of it is just manual labor and a little water to be added to keep the crops growing.

    Food waste arises from perception (tossing out perfectly edible food at supermarkets and homes), packaging (non-recyclable one time use packaging), preparation (cooking too much, tossing the left-overs), processing (damaged or contaminated food), and storage (improper storage conditions).

    The sheer need to constantly go to the supermarket to buy food needs to be factored in too. This activity consumes a tremendous amount of time and oil energy, contributing to pollution and greenhouse gasses. It may seem a "normal" activity but actually it's not. People used to buy in bulk and prepare from dried foods, then grow much of the rest at home. Now, almost nobody does that.

    It's obvious that a solution to food waste would be to return to that type of home production / consumption habits.

    1. Yes, we've changed our habits over the years.

      I went from what you described (growing and preparing and preserving food), to joining the rat race and having little time for anything let alone growing food.

      Now life is a bit more relaxed, so I can revert to better habits once again. There's still a way to go yet :D

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  4. Supermarkets should have relationships with pig farms. Turn the food waste into pork and freeze it.

  5. There is little reason to believe we will end our relation with livestock, including beef and sheep.

    GHG-eq emissions of beef, for a general example, vary wildly among different global areas. Most beef environmental degradation effects occur in developing countries, by the world's poorest citizens, whose very lives depend on the meat, milk and other products their cows provide. Nevertheless, according to the UNFAO, globally, 86% of what a cow eats in unfit for human consumption.

    In the US, otoh, virtually all beef cows attain 2/3 to 3/4 of their final weight eating nothing but grass irrigated by rainfall. Much of their feed is made from grain and cereal chaff, as 90% of crop agriculture biomass is wastage.

    In the US, the entire livestock industry produces less GHG-eq emissions than crop agriculture, and livestock produce a ton of worthwhile products besides meat, milk, and eggs.

    All of this may change due to AGW-related desertification of American grasslands. We will all be worse off if/when that happens.

    1. The IPCC report on Climate and Land doesn't adequately reflect the intricacies of connections in the human food, feed and fibre systems IMO. Some of the reports in the media are similarly overly simplistic.

      Unfortunately the authors (with I think one probable exception) were not specialists in food systems, they were mainly climate people, ecologists and some on-farm agric people.

      The problem comes from drawing arguably misleading inferences from global numbers without allowing for the interconnections (some of which you've referred to, Gingerbaker.

      We certainly need to reduce net emissions from land use, including forestry, agriculture and urbanisation. We also have to produce enough food for a growing population. That will mean producing food in different ways from different sources. It doesn't all have to come from conventional agriculture. There is already a lot of work going on exploring other options.

      I should add that it would be wrong to assume there haven't been efforts by ag producers and researchers over decades to have more sustainable food production. These efforts continue. (It's good to get people engaged and shift demand for even more sustainable production, but in doing so, they also need to be careful to do good, not harm.)


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