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FOOD AND FARMING
18 January 2016 16:00

Higher beef production could lower Brazil’s emissions, study says

Robert McSweeney

Robert McSweeney

01.18.16
Cows in Pozuzo, city of the amazon rain forest.
Robert McSweeney

Robert McSweeney

18.01.2016 | 4:00pm
Food and farmingHigher beef production could lower Brazil’s emissions, study says

Increasing beef production in Brazil could actually lower its national emissions by maximising the carbon stored by pasture, a new study says. But the benefit only holds as long as more forests aren’t cleared for rearing cattle.

This counterintuitive finding differs from recent studies that have argued reining in rising demand for meat and dairy products is fundamental to reducing global greenhouse gas emissions.

What does this mean for climate-conscious diets? Should we be eating more meat to limit climate change? Carbon Brief chews over the research.

Deforestation

Beef is by far the least climate friendly meat to eat. Producing a kilogram of beef emits an average of 290kg of CO2e. Greenhouse gas emissions come from converting and fertilising land for grazing, feed, transporting animals, and from the gases and manure produced by the cows themselves.

Glossary
CO2 equivalent: Greenhouse gases can be expressed in terms of carbon dioxide equivalent, or CO2eq. For a given amount, different greenhouse gases trap different amounts of heat in the atmosphere, a quantity known as… Read More

Brazil is home to more than 200m cows and is second only to India in terms of how much beef it exports each year.

Historically, the beef industry has been one of the principal drivers behind Brazil’s deforestation. Since the 1960s, approximately 15% of the Amazon rainforest in Brazil has been cleared for farming and around 80% of that cleared land is now used as pasture for livestock.

But there is evidence that the link between deforestation and beef production has been broken, say the authors of the new study in Nature Climate Change. Rafael de Oliveira Silva, a PhD student from the University of Edinburgh and Scotland’s Rural College (SRUC), and Prof Dominic Moran, an economist at SRUC, tell Carbon Brief:

After peaking in 2005, deforestation rates have been on a downward trend in all Brazilian biomes [habitats], while beef production has simultaneously been increasing.

If deforestation is no longer a factor, this leaves more scope for the beef industry to reduce its emissions, the researchers say, and these savings could be further propelled by increases in demand.

Grass is greener with higher demand

The study focuses on the Cerrado region that runs through the centre of Brazil (see map below). Around a third of Brazil’s beef is produced there.

Map of Brazil’s Cerrado region

Map of Brazil’s Cerrado region (shaded green). Source: de Oliveira Silva et al. (2016).

Approximately 90% of beef cows in Brazil are fed on grass. Most pastures are planted with tropical grasses of the genus Brachiaria, which are very effective at absorbing CO2 from the atmosphere and storing it as organic carbon in its roots. Studies have shown that, when well managed, these grasslands can be used to sequester carbon in the soil.

Higher demand for beef pushes farmers to get the most out of the grass on their pasture and boosts how much carbon it stores, the papers says, while low demand has the opposite effect:

Lower demand and smaller herds require less grass production, reducing the incentive to maintain or increase productivity; pastures then degrade, losing organic matter and soil carbon stocks.

The researchers tested this effect by simulating the impact on carbon emissions of a “business-as-usual” scenario of beef demand in 2030 and six scenarios of higher (+10%, +20% and +30%) and lower (-10%, -10% and -30%) than business-as-usual demand in 2030.

You can see the results in the charts below, which show the difference in emissions between each scenario and business as usual. If forests are cleared to provide pasture (light blue bars), then overall emissions from higher beef demand are much larger than for business as usual and lower demand (left-hand chart). However, without deforestation, the improvements to pasture (green bars) would mean higher demand brings lower total emissions (right-hand chart).

As the researchers explain:

Basically, if deforestation is held constant by effective policy, then any reduction in consumption or demand will likely lead to a reduced incentive to manage or improve carbon-rich grasslands. Emissions could actually go up as a result.

Modelled percentage differences in accumulated carbon emissions between 2006 and 2030 from different beef demand scenarios

Modelled percentage differences in accumulated carbon emissions between 2006 and 2030 from different beef demand scenarios, with deforestation (left-hand chart) and without (right-hand). Where DBAU is business-as-usual beef demand in 2030, and DBAU-10%, etc are lower demand scenarios, and DBAU+10%, etc are for higher demand. Bars above the origin line indicate increases in emissions, while bars below show emissions savings. Thick black lines show overall emissions for that scenario. Source: de Oliveira Silva et al. (2016).

Looking longer-term, eventually there would be a limit to how much extra carbon the grasses could take up and store, the researchers say, but this wouldn’t be reached for about half a century.

Important assumptions

So, how much difference could higher beef demand make to Brazil’s overall emissions? Quite a lot, say de Oliveira Silva and Moran:

That is a tricky question, but a rough estimate is between 10-20% of Brazil’s total national annual emissions.

As Brazil is the world’s twelfth largest emitter of CO2, that’s a sizeable chunk of emissions.

The results of the study have already fed into Brazil’s intended nationally determined contribution (INDC), the researchers say. INDCs are the pledges that countries submit to the UN, setting out how far they intend to reduce their greenhouse gas emissions.

Brazil’s INDC says it aims to restore an additional 15m hectares of degraded pasture by 2030, and enhance 5m hectares where land use is rotated between crops, livestock and forests – also by 2030.

It’s worth noting that the new study’s findings are based on a couple of important assumptions, says Rob Bailey, research director at thinktank Chatham House. Bailey wasn’t involved in the study, but has co-authored recent studies at Chatham House on demand for meat and dairy products. The first assumption is that cattle ranchers will increase the productivity of their pasture when they can’t expand into forests, and the second is that the additional carbon storage by the grasses will be as significant as expected.

That aside, the study shows how important the methods of meat production are, says Bailey:

Chopping down trees is bad. Restoring pasture and soil carbon is good. If you avoid the latter and do the former, your emissions intensity will improve and it’s plausible that in the right circumstances you can get more beef for fewer emissions, which is what the authors find in this example.

But that doesn’t necessarily mean that we should be firing up our barbecues, Bailey adds:

From the point of view of reducing emissions, however, the best thing to do is to not chop down trees and restore degraded pasture, but have no cows on it at all.

Main image: Cows in Pozuzo, city of the amazon rain forest. © Christian Vinces/Shutterstock.

de Oliveira Silva, R. et al. (2016) Increasing beef production could lower greenhouse gas emissions in Brazil if decoupled from deforestation, Nature Climate Change, doi:10.1038/nclimate2916.

Sharelines from this story
  • Higher beef production could lower Brazil’s emissions, study says
  • hkennard

    What about methane?

    • Mairita Luse

      Yes, I was thinking the same. And as Julien said before, no mention of reforestation as an alternative. Broilers are mentioned as only substitute, not the reduction of meat consumption.

      • Robert McSweeney

        Hi both, methane is factored in (see “Animals” in charts), but considered in terms of CO2 equivalent.

  • Julien Minet

    Hello,

    I really don’t get the point why “Lower demand and smaller herds
    require less grass production, reducing the incentive to maintain or
    increase productivity; pastures then degrade, losing organic matter and
    soil carbon stocks.”

    IMHO, if pastures are not longer used for beef production, why do they should degrade and losing organic matter? In not so arid climates, pastures without animals would slowly evolve to shrubland and ultimately forest. Is it not the case for that region in Brazil? The right-hand chart shows that reduction in the demand lead automatically to the same quantity of losses in pastures sequestration (ie, positive change) that the increase in the demand do (but in the opposite way). It is weird: this losses could be less, or even become negative change in carbon emission.

    The last statement of the article “From the point of view of reducing
    emissions, however, the best thing to do is to not chop down trees and
    restore degraded pasture, but have no cows on it at all.” is more in line with this idea and thus appears contradictory to the rest of the article.

    Cheers,
    Julien

    • Robert McSweeney

      Hi Julien, thanks for your comments. My understanding is that the pastures need to be maintained (e.g. spread with fertiliser) to maximise how much carbon they absorb and store in the soil. The study assumes that if farmers aren’t using pastures for grazing cows, then they have no reason to spend time/money on their upkeep. While the pastures may slowly change without cows (the paper doesn’t mention this specifically), it’s perhaps over much longer timescales, so there are gains in carbon storage in the short or medium-term that are being missed out on if the grasses degrade. As for Rob Bailey’s comments, he is making the point that the study’s findings rely on certain assumptions (e.g. as above, that pastures won’t be maintained without cows on them), and highlights that if you maintain the pastures no matter what, then you can save even more emissions by not having the cows at all. His comments appear to contradict the study because they do! We routinely ask relevant scientists (i.e. from the same field, but not involved in the study) in order to get other points of view on new research – and sometimes they disagree! I hope that helps.

      • Kevin Boyer

        Robert, thank you very much for highlighting this article.

        To help answer Julien’s question, yes these pastures would reforest, if they were taken out of production entirely, but that is not the scenario. What I took from your article is that they would continue to be used as pasture, but underutilized without the increased demand. Regardless, grasslands are actually better carbon sinks than forests in that they store their carbon in the soil, instead of in woody biomass.

        Also, my question for Mr. Bailey is how he would like to maintain the pasture without the cows? The only way to keep that kind of pasture open without herbivores would be through mowing or fire, both of which would have severe climate impacts.

        Last, the methane question is largely a red herring. Research is beginning to show that healthy soils draw down as much or more methane than the animals that subsist upon them produce.

  • Jonathan Teller-Elsberg

    As an alternative to beef production per se, there might be incentives for carbon sequestration. If appropriate pasturing of cattle accomplishes this goal, as is claimed by advocates of intensive grazing management techniques, so be it. If the ranchers accomplish sequestration of carbon in their soils through other means, so be it.

    Importantly, any such incentive program must not be allowed to function as carbon offsets for other emissions. Emissions reductions must be separated from carbon sequestration — both are needed, and one should not be used to replace the other.


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