Dear readers, my "spring break" became a summer break, the warmest and driest summer on record for a very long time. But crops survived on our small farm thanks to the lake next to it. And we have harvested more than the feed we need for our 5 suckler cows and their offspring. Soon, I will write a post about the farm, but now: something totally different: Life cycle analysis.
Lately,
life cycle analyses have become the predominant method for assessment of a
product’s environmental impact in general and its climate impact in particular.
We are exposed to various figures comparing beef to soy, organic to
conventional, local to overseas etc. Publicity-hungry researchers and media
spread those figures and conclusions all over the place. Very few make the
effort to read the research articles and even less the supplementary materials
which the articles are based upon.
At the
moment I am conducting a comparison between milk and plant-based “milks” (the
EU recently prohibited that most of them are marketed with the word milk, and
the issue is under heavy debate in the US). The work has given me reason to dig
deeper into a big pile of lifecycle analyses. Admittedly, I was already earlier
quite skeptical to the method, or at least to how the method is used, and now I
am more than skeptical. It is one thing for a company to use the method to
assess different processes to make the same product, or possibly to compare two
different products with the same function, it is something totally different when
results of comparisons of totally different production systems are supposed to
guide policy or consumer behavior.
The flaws
and shortcomings appear on many levels. Some flaws are linked to the functional
unit and how impacts is distributed among co-products. Many flaws emerge from
the use of standard values and databases to assign impacts, i.e. in most cases
the analysis doesn’t actually measure anything, just take data from other
sources and feed into the spreadsheet. Even bigger shortcomings result from the
lack of context of the analysis, little understanding of agriculture systems
and even more ecological systems and how changes in production change
consumption.
If
agronomist makes the analysis they often use land area (hectare) as the
functional unit. But if you do little
and harvest little, the environmental impact is likely to be minimal per area
unit, which is fine, but also somewhat irrelevant. Extremely extensive grazing
is (mostly) environmentally benign, but it also produce very little food. Food
products are often analyzed per kilogram. But kg is not a meaningful unit when
it comes to food. It is virtually impossible to feed a person with broccoli;
you need to eat 10 kg per day to get your energy needs from it. You can choose
calories as the measure, but then sugar will always be the most efficient
product. Protein is perhaps a more relevant measure, but in some countries
protein intakes are excessive, so it is not ideal either. Some try to make more
sophisticated nutritional indexes. Smedman et al
used such an index comparing milk with plant based milks. They estimated how
many essential nutrients were covered by at least 5 % of the daily needs when
100 gram was consumed. Their research showed that milk had the least climate
impact of all beverages tested. [i] Other researchers,
however, contested the results and showed that if one used a 20 % threshold,
orange juice was clearly the best and if one used a 2% threshold, soy milk was
the best.[ii] There is no way one can state that one kind of
functional unit is the Right one. That the choice of functional unit has such a
big influence on the results is disturbing.
How impacts
are distributed among co-products is another important issue. If you analyze
low fat milk for instance, you have butter or cream as an important co-product,
so you have to determine how much of the impact should be allocated to milk and
how much to butter or use some other method. But it goes much further than
that. Each cow also gives birth to a calf every year, and those are either used
as replacement, or killed at birth or raised for meat. And then the cow herself
will sooner or later meet her Creator and be converted into hide, meat and
other by-products. I will not expand on this technical matter here, but in the
end how you allocate impacts has a major impact on your results.
In
agriculture, changes in land use, also poses major challenges. If soy bean
production expand into the Amazon, and cause deforestation, carbon emissions
and loss of biodiversity, is that impact a function of those particular fields,
of soy bean production in Brazil or soy bean production in the world? In
addition, there is also the question for how long the impacts should be
distributed. Is it one year, twenty or hundred or even more? You can chose
whichever method, there is no right or wrong, but the consequences of the
choice is huge.
de Ruiter
at al argue that as a result of global trade soy beans are interchangeable with
many other crops, and therefore, changes in land use should be distributed on all arable land in the world.[iii] But it doesn’t stop there, recently
published research demonstrate that the importation of soy beans into Europe
has caused the abandonment of 6 million hectares of semi-natural pastures and
meadows. [iv] Other research show how the large
scale trade in feeds and grains result in accumulation of nutrients, such as
phosphorus, and eutrophication in major importing regions, such as Europe. Such
linkages are never part of lifecycle analyses.
For climate
impact, the role of methane and nitrous oxide are critical for the results, in
particular for ruminant livestock. For ruminant products more than half of the
emissions are caused by methane and about ¼ is from nitrous oxide (the exact
composition depends on local conditions. It is fairly simple to estimate carbon
dioxide emissions from the food chain as it is a direct result of the use of
fossil fuels, where one atom of carbon in oil, coal or gas will become one
molecule of CO2. For
methane and nitrous oxide things are much more complex. Those conducting LCA’s
are not measuring emissions of methane or nitrous oxide in the cases they
study. They just put in data from other sources in spreadsheet models and out
comes figures of how much nitrous oxide and methane are generated by the
process. But there are huge uncertainties and variations in these emissions, in
particular for nitrous oxide. Life cycle analysts use simple conversion factors
(from IPCC or other databases or public sources) which translate the quantity
of feed consumed, manure deposited or chemical fertilizers used into emissions.
But scientific research show how uncertain these estimates are and that there
are huge variations.
When Brazilian researchers actually measured how much nitrous
oxide was emitted from the urination of cows on pasture, they found that merely
0.2% of the nitrogen was converted to nitrous oxide. This is one tenth of the standard emission factor used by the
IPCC. A meta-analysis of 422 studies of nitrous oxide
emissions from land fertilized by animal manure or chemical fertilizer revealed
that emissions are considerably lower than the IPCC standard emission factors
for manure and considerably higher for chemical fertilizer.
While also
methane emissions can vary considerably, an even bigger problem is the
conversion of methane emissions into carbon dioxide equivalents in order to get
one figure of the climate impact. Through this conversion the real
climate impact of methane is tremendously exaggerated.
LCAs don’t
include effects in animal welfare and they also neglect social and cultural impacts,
which if course could be even more important than environmental impacts. But LCAs
also never include all environmental impacts. Effects on soil fertility and
erosion are mostly left out as well as impact on bio-diversity. Even for
categories that are often included, the indicators used are far from
satisfactory, e.g. for impacts of pesticide use (it is obviously not possible
to have one measure that will fully capture the impact of hundreds of pesticides
in very different ecological conditions).
Variability
between farming system as well as within the same system is seldom captured in
single LCAs. This is also one of the reasons for why results differ so widely
between different LCAs. For cow’s milk the land use range from 0.7 m2 to 242 m2
per liter milk according
to the meta-analysis by Poore and Nemecek recently published in Science.[v]
If an LCA is made on the farm level for oats the results will be very different
between a year with a bumper yield compared to a poor year. As a matter of
fact, it is not uncommon that the whole crop of a certain farm is classified as
not suitable for human consumption a bad year. What happens then to the LCA results
of oat milk?
*
But the
major inadequacy of LCAs is that they don’t cover system effects and effects
outside of the boundaries of the analysis. A general rule of ecology formulated
by Garret Hardin is “you can never change one thing”, because as soon as you do
that, other things change as well. In the example of “milk”. If you were to
replace cow’s milk with soy milk in Sweden, the whole farming system in Sweden
would change and the impacts on landscape, rural economy, crop rotations etc.
would be much bigger than you could read from a lifecycle analysis. In
addition, as you can’t produce soy in Sweden it would trigger expansion of soy
production in other parts of the world, thereby contributing to deforestation,
increased use of pesticides etc. If oat milk is the substitute you will again
get other results.
The most
important changes of the agricultural system in Western Europe over the past
seventy years is the abandonment of small farms, small fields, pastures and
marginal lands and the decreasing diversity of the farming systems. There are
fewer farms and each farm mechanize and specialize into a few crops or one kind
of animals. Not only farms specialize, whole regions do, even countries do.
Livestock and crop production has been separated and cycles of nutrients
between animals and crops as well as between farms and the rest of the food
system have been broken. Largely this has been ”solved” by massive application
of chemical fertilizers. The simplification of the production system has also
led to the use of pesticides. These massive changes in the agriculture
landscape are not captured by LCAs, and the drivers causing this are also not
understood by reading hundreds of life cycle analysis.
In general,
LCAs contribute little to the understanding of agriculture systems; on the
contrary, when looking into LCAs one can get many mistaken ideas. One prominent
example is the comparison of livestock production and crop production. If they
are compared side by side, product by product, almost all comparisons will
conclude that it is much more efficient (from a multitude of indicators) to eat
plants than livestock products. Subsequently professor Poore, who was one of
the researchers behind the meta-analysis of LCAs, tells
media that “A vegan diet is probably the single biggest way to reduce your
impact on planet Earth, not just greenhouse gases, but global acidification,
eutrophication, land use and water use.” But that is typical of the distorted
view of reality you get from LCAs. Apart from the fact that livestock products
have very favorable nutritional profile, which was not part of the analysis,
some livestock production actually make use of crop products which would not
otherwise be used.
A
considerable part of the crops are not edible by humans. Almost all oil crops
have protein rich by-products which can’t be eaten by people. Already now these
oil cakes are major animal feed and with no livestock products vegetable oil
production must increase even more (most likely this means even more palm oil).
And there will be more leftovers
which could have been fed to animals. Major grains, such as wheat and rice have
big shares of non-edible by-products; for wheat, normally only 80 % of the
grain harvest goes to flour and for rice it is even less. Then there are
leftovers from the production of sugar, beer and liquor, even the iconic tofu
and oat milk have by-products which are fed to animals. Add to this food waste,
straw etc. you realize that a certain proportion animal products reduce
resource use. In addition, some years, part of the wheat crop is not good
enough for flour or pasta, some of the barley is not up to specs for malt and
the oat is not good enough for oatmeal or oat milk. What happens with it? Animals
eat it of course. Finally, when livestock is integrated with crop
production rotations can be much better and yields of crops will benefit. In
essence, the miraculous increase of productivity, and the end of food shortages
in Europe 1800-1940 was largely driven by integration of livestock and crop
production.
There are
plenty of studies that clearly demonstrate that a certain fraction of livestock
products is favourable. [vi]
[vii]
One can’t quantify how high proportion as this depends on climate, water and
land resources. In addition, there are agro-ecological zones where crop
production is very challenging, but where grazing lifestock can use the land to
produce food. When the professor Poore tells media that livestock uses 83 % of
the farm land and only produces 18 % of the calories, he conveniently omits
that most of this land is far too dry, too steep or too cold for any crop
production at all.
Finally, people
are largely missing from LCAs, which means that the changes in behavior which
are triggered by new methods or new technologies are not captured. It is well
known that if a product becomes cheaper, consumption will increase. Through the
industrialization of agriculture crop production, food is very cheap, but this
has also increased food waste tremendously. Chicken
consumption has increased almost 10 times globally over the last fifty years,
and this is largely driven by higher efficiency on chicken breeding, reducing
feed use as well as labor use. Chicken
is now one of the cheapest proteins you can buy. Chicken has not mainly
crowded out more resource demanding beef and pork but rather the less resource-demanding
grains and pulses, and in the process it has lost its role as small scale food
residue converter. So, while the environmental foot print of chicken is small
compared to beef according to LCAs, in reality, the changes in production and
changes in markets and consumption has led to a huge increase in the size of
the environmental foot print of human food chains. Other similar examples can
be found with packaging and transports.
Many of
those working with Lifecycle analysis are fully or partly aware of the
limitations. Bruno Notarnicola and other LCA experts write in The
role of life cycle assessment in supporting sustainable agri-food systems: A
review of the challenges, in the
Journal of Cleaner Production that deficiencies in LCA methodology
”results in severe limitations when agricultural systems are being evaluated”
and they caution that while the LCA concept is easy to understand and the
results are user-friendly, most people, even many of those conducting LCAs, are
interpreting the results in the wrong way without due consideration of assumptions and limitations.[viii]
Lifecycle
analysis has its merits, but it is far from being the method that will give us
easy answers to all the difficult questions there are about what we will have
for lunch.
[i] Smedman,
Annika et al 2010, Nutrient density of beverages in relation to climate impact,
Food Nutr. Res. 54.
[ii]
Scarborough, Peter och Mike Rayner 2010, Nutrient density to climate impact is
an inappropriate system for ranking beverages in order of climate impact per
nutritional value, Food Nutr. Res. 54.
[iii] De
Ruiter, H, m.fl. 2016, Global cropland
and greenhouse gas impacts of UK food supply are increasingly located overseas,
Journal of the Royal Society Interface Volume 13, issue 114
[iv]
Boerema, Annelies m.fl. 2016, Soybean trade:Ballancing Environmental and
Socio.Economic Impacts of an Intercontinental Market, PLOS One 31 maj 2016.
[v] Poore,
J. och T. Nemecek 2018, Reducing food’s
environmental impacts through producers and consumers, Science 360, 987–992
(2018).
[vi] Zanten,
Hannah m.fl. Defining a land boundary for sustainable livestock consumption.
[vii]
Peters, Christian J. m.fl. 2016, Carrying
capacity of US agricultural land, ten diet scenarios, Elementa:Science of
the Antropocene.
[viii]
Notarnicola, Bruno m.fl. 2017, The role
of life cycle assessment in supporting sustainable agri-food systems: A review
of the challenges, Jorunal of Cleaner Production 140 (2017) 399-409
