Land is under growing human pressure and climate change is adding to these pressures, according to the latest report by the Intergovernmental Panel on Climate Change (IPCC), which warned that emissions from land and food have to be tackled in order to keep global warming below 2ºC.
The IPCC, the world body for assessing the state of scientific knowledge related to climate change, looked at the climate change effects of agriculture, deforestation and other land use. Together, those activities generate about a third of human greenhouse gas emissions.
“Land already in use could feed the world in a changing climate and provide biomass for renewable energy, but early, far-reaching action across several areas is required” Hans-Otto Pörtner, Co-Chair of IPCC Working Group II, said. “Also, for the conservation and restoration of ecosystems and biodiversity.”
The report broadly suggested that farmland would need to shrink, and forests would need to grow to keep Earth from getting more than 1.5 degrees Celsius hotter than it was in the preindustrial era. Global temperatures have already risen about 1 degree Celsius in the past 150 years.
To meet that temperature target, global greenhouse gas emissions will need to fall by 40% to 50% in the next decade. Scientists say the only way to achieve that reduction is to significantly increase the amount of land that's covered in trees and other vegetation and significantly reduce the amount of methane and other greenhouse gases that come from raising livestock.
The new report offers suggestions for how countries might achieve that. For example, for countries that have lost tree cover in the past century, reforestation can help suck greenhouse gases out of the air, while also preventing soil from drying up. Reducing food waste can also help reduce a country's greenhouse gas footprint.
Controlling emissions from agriculture is also a food-security issue, the report warned. Greenhouse gases from food production create a vicious cycle. As Earth gets hotter, farming gets more difficult in many places, which forces farmers to clear more land to grow food.
“Food security will be increasingly affected by future climate change through yield declines – especially in the tropics - increased prices, reduced nutrient quality, and supply chain disruptions,” said Priyadarshi Shukla, Co-Chair of IPCC Working Group III.
The report said that about one-third of food produced is lost or wasted. Causes of food loss and waste differ substantially between developed and developing countries, as well as between regions. Reducing this loss and waste would reduce greenhouse gas emissions and improve food security.
Currently, about 50% of the globe's vegetated land is dedicated to agriculture — and about 30% of cropland is used to grow grain for animal feed. Given how much land it takes to grow food to feed livestock, meat production is a leading cause of deforestation.
“Some dietary choices require more land and water and cause more emissions of heat-trapping gases than others,” said Debra Roberts, Co-Chair of IPCC Working Group II. “Balanced diets featuring plant-based foods present major opportunities for adaptation to and limiting climate change,” she said.