Efforts to curb greenhouse gas-emissions and the impacts of global warming will fall significantly short without drastic changes in global land use, agriculture and human diets, leading researchers warn in a high-level report commissioned by the United Nations.
The special report on climate and land by the Intergovernmental Panel on Climate Change (IPCC) describes plant-based diets as a major opportunity for mitigating and adapting to climate change ― and includes a policy recommendation to reduce meat consumption.
On 8 August, the IPCC released a summary of the report, which is designed to inform upcoming climate negotiations amidst the worsening global climate crisis. More than 100 experts compiled the report in recent months, around half of whom hail from developing countries.
“We don’t want to tell people what to eat,” says Hans-Otto Pörtner, an ecologist who co-chairs the IPCC’s working group on impacts, adaptation and vulnerability. “But it would indeed be beneficial, for both climate and human health, if people in many rich countries consumed less meat, and if politics would create appropriate incentives to that effect.”
Researchers also note the relevance of the report to tropical rainforests, where concerns are mounting about accelerating rates of deforestation. The Amazon rainforests is a huge carbon sink that acts to cool global temperature, but rates of deforestation are rising, in part due to the policies and actions of the government of Brazilian President Jair Bolsonaro.
Unstopped, deforestation could turn much of the remaining Amazon forests into a degraded type of desert, possibly releasing over 50 billion tonnes of carbon into the atmosphere in 30 to 50 years, says Carlos Nobre, a climate scientist at the University of São Paolo in Brazil. “That’s very worrying,” he says.
“Unfortunately, some countries don’t seem to understand the dire need of stopping deforestation in the tropics,” says Pörtner. “We cannot force any government to interfere. But we hope that our report will sufficiently influence public opinion to that effect.”
While fossil fuel burning for energy generation and transport garners the most attention, activities relating to land management, including agriculture and forestry, produce almost a quarter of heat-trapping gases. The race to limit global warming to 1.5 degrees above pre-industrial levels ― the goal of the international Paris climate agreementreached in 2015 ― might be a lost battle unless land is used in a more sustainable and climate-friendly way, the latest IPCC report says.
The report highlights the need to preserve and restore forests, which soak up carbon from the air, and peat lands, which release carbon if dug up. Cattle raised on pastures of cleared woodland are particularly emission-intensive, it says. This practice often comes with large-scale deforestation such as in Brazil or Colombia. Cows also produce large amount of methane, a potent greenhouse-gas, as they digest their food.
The report states with high confidence that balanced diets featuring plant-based, and sustainably-produced animal-sourced, food “present major opportunities for adaptation and mitigation while generating significant co-benefits in terms of human health”.
By 2050, dietary changes could free millions of square kilometres of land, and reduce global CO2 emissions by up to eight billion tonnes per year, relative to business as usual, the scientists estimate.
“It’s really exciting that the IPCC is getting such a strong message across,” says Ruth Richardson, the Toronto, Canada-based executive director at the Global Alliance for the Future of Food, a strategic coalitions of philanthropic foundations. “We need a radical transformation, not incremental shifts, towards a global land use and food system that serves our climate needs.”