Yale University researcher Eric Toensmeier has been investigating the most effective ways to capture carbon dioxide for more than a decade. His work for Project Drawdown has involved modelling the impacts of 23 land-based climate solutions.
Somewhat surprisingly, Project Drawdon found that a little-known grazing system called silvopasture emerged as the most powerful agricultural production practice and the ninth most powerful method overall for addressing climate change.
Silvopasture combines trees, livestock (ruminants like cattle, sheep and goats) and grazing. Farmers plant trees or manage the land to encourage spontaneous tree growth. Trees provide shade, timber and food for livestock, while the carbon captured in the soil and trees cancels out the greenhouse gas animals emit through farts and burps. One study of intensive silvopasture in Colombia found livestock emissions were equivalent to a quarter to half of the carbon sequestered in soil and biomass.
According to Toensmeier, Silvopasture is practiced on an estimated 15% of the world’s grazing land. Improved or “managed” grazing systems to mitigate grassland climate impact have been found to have modest impact per hectare, but Project Drawdown found that Silvopasture can double the global impact of managed grazing on a fifth of the land.
It’s great news, so why isn’t everyone doing it? The simple answer is not everyone can. In many cases grasslands are too dry to support healthy tree growth. High establishment costs, and limited resources to help graziers choose the right tree species, the correct spacing and the steep learning curve associated with caring for trees are limitations to widespread adoption of the practice. A more serious drawback is that the stored carbon could be lost if the land is degraded due to mismanagement or as a result of climate change itself.
Toensmeier estimates silvopasture could make beef farming more climate-friendly on more than one-fifth of the globe’s 3.5bn ha of grasslands which are humid with enough rainfall for tree growth. Project Drawdown has called for and additional 73m ha of silvopasture by 2050, which could potentially remove and store roughly 31bn t of carbon dioxide between 2020 and 2050. That’s the same impact that Project Drawdown projects for the adoption of rooftop solar and commercial LED lighting combined.
Access to financing and knowledge are key to adoption, with recovery of establishment costs taking 3 to 4 years to be recovered. The Costa Rican, Colombian and Nicaraguan governments all offer payments to ranchers to convert to silvopasture. In Costa Rica, an incredible 90% of pastures now incorporate trees.
Will silvopasture allow the world to eat all the meat it wants? No, there is simply not enough land to meet global beef and dairy demand using silvopasture and managed grazing. In the US around 50 to 60 grams of animal protein is consumed daily, while improving grazing systems will only deliver 7 to 18 grams per person each day. Improved grazing systems must be combined with reduced demand if aggressive climate targets are to be met.
Grazing of livestock is the world’s largest use of land and by adding trees – where possible – beef farming could actually help fight climate change.