June 1, 2023 by Climate Interactive
The June 2023 update to En-ROADS adds more developed modeling around land use and the transitions of land. This means that the dynamics around shifts in land from forests to cropland—and vice versa—are better captured and En-ROADS users can explore how food choices drive land-use changes and climate outcomes. The most important consequence for food and agriculture discussions is that:
En-ROADS now includes options to bolster plant-based diets and reduce food waste. Both contribute to reducing the amount of crops needed, resulting in less deforestation, and less greenhouse gases.
The new “Food from animals” and “Food waste” sliders in the advanced view for Deforestation, show the significant impact that food has on forests. For example, when both sliders are set to the maximum rate of reduction, like in the scenario shown in the graphs below, less food production is needed, which requires a smaller area of farmland (left graph) and the deforestation rate (right graph) declines significantly. To learn about the implications of this for climate outcomes, read our article on Land and Forests in En-ROADS.
The impact from the food and agricultural sector on greenhouse gas emissions and removals comes from four major sources.
Diets and agricultural practices in En-ROADS affect CO2 emissions released from deforestation, CO2 removals from forests that are left intact, N2O emissions from fertilizer use, and CH4 emissions from animals and decomposing organic matter.
The best graphs to see the change in the net greenhouse gas emissions, when plant-based diets are increased and food waste is reduced, are the “CO2 Net Emissions from Land Use” and “Non-CO2 Greenhouse Gas Emissions” graphs (below and in this scenario).
Beyond dietary choices and food waste, three other factors drive global food demand in En-ROADS: global population, GDP, and crop yield. However:
Climate change reduces crop yield and economic growth, which affects food demand and deforestation.
In the Baseline Scenario crop yield is growing throughout the century. This trend aligns with the growth of crop yield that has occurred historically with advancements in science and technology to meet food demand. However, crop yield growth is slowed by climate impacts such as more frequent and intense droughts and floods, which can be observed in the “Crop Yield” graph (Graphs > Land, Forestry, and Food) below and the figures “Decrease in Crop Yield from Temperature” (Graphs > Impacts). This feedback from temperature change can be modified by the slider “Effect of temperature on crop yield” (found under Simulation > Assumptions > Agriculture).
The feedback whereby climate change reduces economic growth is covered in detail in our article on the Economic Damage Function in En-ROADS. This feedback has a wide array of impacts, not limited to food and agriculture.
The expansion of agricultural land for food production is one of the major causes of deforestation. When the farmland available is insufficient to meet the crop production required, more deforestation occurs. The June 2023 version of En-ROADS shows that nearly 4900 million hectares of land are currently being used for farmland globally—this includes land for growing commercial crops and grazing land for livestock. In the Baseline, global forest area declines as food demand leads to greater farmland expansion. Because of this linkage between food systems and deforestation, En-ROADS includes the food-related sliders under the Deforestation slider.
Producing animal-based foods uses more land, on average, than plant-based foods, because large areas of cropland are used to produce animal feed rather than to feed humans directly. The “Food from animals” slider is the global average percent of food that comes from animal sources (such as dairy products, meat, and eggs) in 2100. En-ROADS uses the 2022 indicators of the FAOSTAT statistical database to determine the current value of animal-based global food consumption of around 24% of diets.
Addressing food waste can reduce the amount of farmland needed to meet global food demand. The “Food waste” slider in En-ROADS represents the global average percent of food wasted, which is currently about 30% according to the IPCC (2019). Food waste occurs both in the supply chains that move food from farms to consumers (e.g. when there are limitations on refrigerated storage and transport networks) and when food isn’t sold or consumers don’t use what is purchased.
The amount of crop production needed, whether for growing food for human consumption or for animal feed, and the productivity of the land (i.e., crop yield and grazing productivity on pastures), determines how much farmland is required to meet global food demand. When the land available for farming is insufficient to meet the crop production needed, the expansion of the farmland area comes partly from forests, which are often fertile for growing crops when cleared. Crop production and deforestation generate greenhouse gas emissions that contribute to worsening climate change impacts.
In addition to the graphs featured above, here are a few others that are helpful to testing the new food-related features. The majority of the relevant graphs can be found in Graphs > Land, Forestry, and Food category.
The “Crop Production Needed” graph is the best graph to see the impact that more plant-based diets and less food waste have on the total amount of food needed, which then drives the farmland area needed to produce them, and the consequent deforestation rate.
The “Percent of Food from Animals” graph displays the percent of diets that are animal-based food. Users can infer the plant-based food consumption by subtracting the value on the graph from the 100% of the total diet.
Methane and nitrous oxide emissions are now visible by their sources at Graphs > Greenhouse Gas Emissions. Users can test how different actions on the food and agriculture sectors in En-ROADS can reduce agricultural emissions (the yellow wedge). Among other things, food waste is accounted for in the Agriculture section of these graphs, rather than under “waste.” Reductions in N2O and CH4 emissions from agriculture can also be implemented with the slider “Adoption of best agricultural practices” in the Methane & Other Gases advanced view.