22 SCIENCE NEWS | May 7, 2022 & May 21, 2022MARIO TAMA/GETTY IMAGES PLUSTHE FUTURE OF FOODT
he food we eat is responsible for an astounding
one-third of global greenhouse gas emissions caused
by human activities, according to two comprehensive
studies published in 2021.
“When people talk about food systems, they always think
about the cow in the field,” says statistician Francesco Tubiello,
lead author of one of the reports, appearing in last June’s
Environmental Research Letters. True, cows are a major source
of methane, which, like other greenhouse gases, traps heat in
the atmosphere. But methane, carbon dioxide and other planet-
warming gases are released from several other sources along the
food production chain.
Before 2021, scientists like Tubiello, of the Food and
Agriculture Organization of the United Nations, were well awarethat agriculture and related land use changes made up roughly
20 percent of the planet’s greenhouse gas emissions. Such land
use changes include cutting down forests to make way for cattle
grazing and pumping groundwater to flood fields for the sake
of agriculture.
But new modeling techniques used by Tubiello and colleagues,
plus a study from a group at the European Commission Tubiello
worked with, brought to light another big driver of emissions:
the food supply chain. All the steps that take food from the farm
to our plates to the landfill — transportation, processing, cook-
ing and food waste — bring food-related emissions up from
20 percent to 33 percent.
To slow climate change, the foods we eat deserve major
attention, just like fossil fuel burning, says Amos Tai, an environ-
mental scientist at the Chinese University of Hong Kong. The
fuller picture of food-related emissions demonstrates that the
world needs to make drastic changes to the food system if we
are to reach international goals for reducing global warming.Change from developing countries
Scientists have gained a clearer understanding of global human-
related emissions in recent years through databases like EDGAR,
or Emissions Database for Global Atmospheric Research,Food choices
What we eat plays an outsize role in greenhouse gas emissions
By Betsy LadyzhetsSpecial Report: The Future of Food
Food Choices ............................................................................ 22
Normalizing Plant-Based Diets .......................................... 28
Six Foods of the Future ......................................................... 34
Climate-Friendly Farming in India .................................... 36
Milk Without the Cow ........................bit.ly/SN_MilkOptions