A United Nations climate report on Thursday warned that the world’s unsustainable use of land is boosting greenhouse gas emissions, contributing to climate change, and threatening future food production. But the report also said that land use, farming, and food consumption can shift in important ways that could help mitigate climate change.
The Intergovernmental Panel on Climate Change, the world body for assessing the state of scientific knowledge related to climate change, said that the food system — everything from clearing land to farming practices to shipping and food waste — accounts for 23 percent of global greenhouse gas emissions, roughly equivalent to electricity generation.
Although the exploitation of land and water resources “is unprecedented in human history,” the world’s forests, peat bogs, and grasslands still act as the planet’s lungs, pulling carbon from the air and mitigating climate change. The world’s lands still sequester more carbon than agriculture, forestry, and lands emit, the World Resources Institute points out.
As croplands expand, however, deforestation mounts, and unless agriculture is better managed, farmland itself can lose fertility. Tillage increases soil erosion 100 times faster than soil is created, the report notes, increasing pressure to expand into more virgin forests and marshlands. Only about 9 percent of Earth’s ice-free land mass consists of forests that are minimally used by humans, the report said.
At the same time, land affected by drought has increased by about 1 percent a year since 1960, afflicting those who live in the poorest regions of the world. As climate change accelerates, heat waves, droughts, wildfires, rainstorms, and dust storms are also increasing in intensity, the report said.
In a warmer climate, crop yields would decline and grains would become less nutritious. At the same time, water shortages and poor farming practices will turn formerly fertile regions into uninhabitable desert landscapes.
Those threats could increase the flow of human migration, experts told the New York Times, as people try to flee to safer and more economically prosperous areas.
The report did point to ways that land and agricultural emissions could be reduced, though afforestation, or planting new forests, and reforestation; farming in a way that increases organic matter in the soil; cutting food waste; and encouraging the consumption of grains, nuts, legumes, vegetables, and fruits — while reducing meat consumption.
Although difficult, these measures would help limit global warming to less than 2 degrees Celsius as envisioned in the Paris climate accord, which President Trump has pledged to exit.
The report did not endorse the use of biofuels and biomass — such as burning trees for electricity generation or adding corn-based ethanol fuels to gasoline. “Increased value of bioenergy puts pressure on land, ecosystem services, and the prices of agricultural commodities, including food,” the report said.
It also said that capturing carbon from biofuels and storing it has not yet proven viable and that any climate mitigation potential would need to take into account the local and regional impact on food security and the environment.
“In the immediate term, I would focus most of our attention on protecting tropical forests (especially forests being cleared in Brazil right now), reducing food waste, shifting to more plant-rich diets, and deploying more sustainable, regenerative farming practices,” wrote environmental scientist Jonathan Foley on his blog.
Separately, Democratic presidential candidate and New Jersey Sen. Cory Booker introduced a climate change bill focused on farms and land use. The Climate Stewardship Act of 2019 would support voluntary climate stewardship practices on more than 100 million acres of farmland, plant more than 15 billion trees to revive deforested landscapes and expand urban tree cover, restore more than two million acres of coastal wetlands, and invest in renewable energy for farmers and rural small businesses.