We often think of climate change as something distant from our everyday lives. But climate change is with us at our dinner tables every day. Why? Because our food affects climate change and because climate change affects our food.
Food and climate change may be thought of as a two-way street. Producing, food affects climate change through the greenhouse gas emissions that growing, harvesting, processing, and transporting food causes. With all these processes combined, getting food to our table is responsible for about one third of total human-caused GHG emissions.
Worse, the rate at which the food system contributes to the heat-trapping gases emitted by human activities globally is increasing each year. If those emissions continue to increase at their current pace, meeting the Paris Agreement’s 1.5°C (2.7°F) goal would be impossible even if non-food system emissions fell to zero today.
One big source of GHG emissions is the clearing of forests to create fields, As the downed trees decay, they release the CO2 that they had absorbed from the air. Other sources of emissions include: use of fertilizers, which release nitrous oxide (N2O), and use of fossil fuel-driven (and CO2-emitting) tractors and other farm machines to plant, tend, and harvest the crops. Rice paddies produce methane (CH4), as do beef and dairy cattle and their manure ,Off farm, fossil fuels are also used to dry, store, cool, transport, and package produce.
In the other direction, climate affects food through heat, drought, rain, and floods. Climate change is already creating significant risks to the food system, with rising temperatures and changing weather patterns threatening enormous damage to crops, supply chains, and livelihoods. These impacts have begun to occur already, and they are projected to get much worse in the decades ahead.
Farmers are dealing with a changing climate that is altering planting and harvest dates (the growing season), bringing high temperatures during critical growth stages, and shortening growing periods, causing more heavy downpours that can ‘lodge’ crops and waterlog soils, more droughts in some regions, and more pest infestations.
What we eat plays a role in climate change, because most animal-based products have higher total greenhouse gas emissions than do plant-based foods. Beef production generates high emissions of heat-trapping gases per pound of food because cattle produce methane, a powerful greenhouse gas, as part of their digestive process. Their manure also produces large quantities of methane and nitrous oxide.
According to recent estimates, producing a pound of beef releases about 130 pounds CO2eq, lamb and mutton about 50 pounds, and, surprisingly, cheese 46 pounds. Food that comes from plants produces 10-50 times lower CO2 eq emissions than most animal products. [Scientists have devised a way to show the combined effect of different greenhouse gases, called ‘carbon dioxide equivalent’, abbreviated CO2eq. The measure totals the heat-trapping contributions of all greenhouse gases,based on their potential to cause global warming over the length of time they are active.]
There are also links between climate change, food, and health. Decreases in protein content and micronutrients have been found in crops grown under high CO2 conditions. Unhealthy high-calorie diets (such as those rich in refined carbohydrates, added sugar, saturated fats and red meat) are associated with diabetes, hypertension, and heart disease. Diets that are rich in plants foods can help to ameliorate those conditions, as well as lower greenhouse gas emissions.
But climate change is not just about what is grown and raised on farms, eaten on our dinner tables and how it got there – It is in our trash bins as well. About one-third of food that is produced is either lost during harvest or on its travels to the consumer. It may be thrown out by restaurants, cafeterias, and grocery stores, or discarded in our homes. Incredibly, about 8% of the world’s total energy consumption is used to produce food that is lost or wasted. Thus, about 8% of human-caused greenhouse gas emissions that can be attributed to producing, shipping, storing and processing food that is either lost or wasted.
What can be done to create food systems that are both healthy for people and for the planet?
On the supply side, the main ways to reduce greenhouse gas emissions are limiting conversion of natural lands to agriculture, sequestering carbon in soils, using more efficient farming techniques that lower GHG emissions per unit of production, and developing efficient supply chain and distribution systems.
On the demand side, the main ways to reduce emissions are lowering food waste, adopting healthy and sustainable diets that are rich in plant-based foods, using lower-emission cooking technologies, and improving waste disposal systems. Better waste disposal can capture methane emissions from solid food waste in landfills and then burn it to generate energy.
Ways to improve the resilience of our food system to climate change include the development of heat, drought, and flood-tolerant crops, improved efficiency in irrigation systems, and creation or expansion of insurance programs to protect farmers from the impacts of increased climate risks. Another key way for farmers to be prepared for climate change is to nurture biodiversity in and around agricultural production areas, and lowering reliance on single species. Shortening supply chains where possible and distributing storage facilities closer to markets can also improve flexibility and lower the vulnerability of our food system.
Climate change is indeed at our dinner tables and in our trash bins. There is much that we can do to create a ‘dinner’ that is good for Earth as well as our bellies.