US electric car sales ‘could stem a tenth of global cropland expansion’


A faster shift to electric vehicles (EVs) in the United States would avert about 10% of the global cropland expansion expected over the next 30 years, according to a new study.

Instead of growing maize (maize) to make biofuel for American cars, modeling in the ecological economics article suggests that vast tracts of land could be left to absorb carbon dioxide (CO2).

This land preservation would result in “substantial” emissions savings, in addition to the direct benefits of electrifying U.S. road transportation, the researchers say.

The findings come as activists and some governments have pushed to end the use of crops for biofuels in the face of soaring food prices and fears of world hunger.

A scientist not involved in the study told Carbon Brief that it highlights an “understudied” benefit of vehicle electrification, which “could have significant indirect effects on agricultural production and greenhouse gas emissions. greenhouse effect on a global scale”.

The shift to sales of 100% electric vehicles is far from reality in the United States. However, the study suggests that by choosing cleaner transportation, Americans could significantly reduce global demand for corn, reducing both emissions from agriculture and food prices.

Ethanol fuel

The United States is the world’s largest corn producer, providing a third of global supplies. About a third of this production is used to make ethanol.

Most gasoline sold in the United States must contain up to 10% corn-derived ethanol. This policy came about due to various factors, including the government’s efforts to reduce dependence on foreign oil, reduce CO2 emissions and stimulate the rural economy.

However, the expansion of biofuels has led to changes in land use, as farmers have replaced forests and grasslands with crops of corn, which absorbs less carbon dioxide (CO2).

Additionally, many have questioned the logic of using so much farmland to produce ethanol, especially during a global food crisis.

With that in mind, Dr. Jerome Dumortier, associate professor of agricultural economics at Indiana University-Purdue University Indianapolis and lead author of the study, says he realized that as as more fuel-efficient and electric cars hit the road, ethanol demand would likely collapse. He tells Carbon Brief:

“If you have more electric vehicles [in the US]… you essentially release 10% of the world’s corn production.

This topic is clearly on the radar of the US ethanol industry, whose members have expressed concern in light of President Joe Biden’s policies to expand the use of electric cars, including a non-binding goal for 50% of new car sales in the United States will be electric by 2030. .

Nevertheless, experts tell Carbon Brief that this issue has been largely ignored in the scientific literature.

corn patterns

After undertaking similar work on the fuel efficiency of American cars, Dumortier and his colleagues set out to explore the ripple effects of increased electric car sales.

They modeled the demand for and use of cars and light trucks – known as “light-duty vehicles” – between 2015 and 2050, using US Energy Information Administration (EIA) projections as a benchmark.

A variety of electric vehicle sales targets were then imposed by the researchers, ranging from 50% of cars up to 100% of cars and light trucks by 2050.

The results of this modeling were then incorporated into a global “agricultural outlook” model, covering economic outcomes for corn as well as soybeans, rice and wheat through 2050, under different electric car sales scenarios. .

One of the key outputs of this step was data on land allocation for crops. This was then used to calculate biomass and soil carbon emissions related to changes in agricultural land, using data on the potential for vegetation growth in different areas.

Expert analysis straight to your inbox.

Finally, all of these assessments were conducted under three different Shared Socio-Economic Pathways (SSPs) – tools from climate science that allow researchers to model different futures for the planet, with different population sizes, economies and attitudes towards collective action.

Even in the baseline scenario without EV targets, the authors found that corn demand for ethanol would drop by 2050, due to the increased fuel economy of U.S. vehicles and the market share of electric vehicles. However, this decline in ethanol demand would be much greater if all new vehicle sales went electric.

Lower demand for ethanol would mean less land used to grow corn, but not just in the United States. In fact, the modeling suggests that American farmers would end up exporting a lot of corn overseas, as Dumortier explains:

“The United States is very efficient at producing corn… low cost, very high yield, very productive and therefore you have this surplus corn [which] is essentially being dumped on the world market.

As maize becomes less profitable due to lower demand, this ripples through the entire global agricultural market, with farmers increasing their production of other crops and thereby lowering their prices as well.

Earth spared

According to the study’s reference scenario, the area of ​​land used to grow crops expands until 2050 from 47 to 64 million hectares, in order to feed a growing world population.

This has implications for the climate, as it could mean that more carbon stores – such as forests – are converted to agricultural land.

But the authors found that if 100% of U.S. vehicle sales were electric by 2050, between 5.1% and 9.4% of that expansion could be avoided.

As the chart below shows, the avoided cropland expansion over the next three decades is highest in Brazil, China, and India, and relatively low in the United States itself. While this may mean lower economic output for these countries, from a climate perspective it makes sense, as Dumortier explains:

“If you think about carbon stock…the United States compared to other countries is actually relatively low…You’re not going to have rainforest in Iowa.

In contrast, Brazil’s cropland expansion could initially bring economic returns, but would likely affect regions with large carbon stores.

Evolution of the area of ​​cultivated land (in millions of hectares) between the scenario and the reference in 2050 for the four products considered in the analysis – maize, wheat, rice and soya. The different shared socio-economic pathways (SSP) are indicated by different colors of bars. Source: Dumortier et al. (2022).

The study concludes that the scenario of selling 100% electric vehicles would save between 417 million tonnes of CO2 equivalent (MtCO2e) and 551 MtCO2e by 2050, in addition to the benefits of removing fossil fuel vehicles from the circulation.

Dr Kemen Austin, a policy analyst at RTI International who was not involved in the research, told Carbon Brief that the study’s estimates of land cover change related to biofuel demand appear high compared to previous research.

However, Stephanie Searle, who leads the US fuels program at the International Council on Clean Transportation (ICCT) and was also not involved in the study, notes that land-use change modeling is “notoriously uncertain”. She tells Carbon Brief:

“Estimates vary widely depending on who you ask. So even if the authors estimate very high land-use change emissions per liter of biofuel, this does not mean that they are wrong.

Additional Benefits

Austin tells Carbon Brief that while a lot of work has explored the impacts of the growing demand for biofuels, she is not aware of any research that calculates otherwise:

“This study highlights an important point that has been understudied so far in the literature – that electrification of vehicles could have important indirect effects on agricultural production and greenhouse gas emissions in the world. on a global scale.”

The authors conclude that when assessing the emissions benefits of electric vehicles, avoided land-use change and emissions from agriculture must also be considered.

As it stands, the EIA’s most recent projections suggest that with policies in place by the end of 2021, sales of battery electric vehicles and plug-in hybrids will still only represent around 13% of sales of light vehicles in 2050 – far from the 100% modeled in the study.

However, this projection seems pessimistic compared to the widespread view in the auto industry that about half of electric car sales will be electric by 2030, in line with Biden’s goal.

Searle says that despite the obvious benefits of reducing biofuel use to free up land, she thinks the US government is unlikely to recognize this given its enthusiasm for “actively promoting biofuels.”

The Guardian reported in June that the United States would “continue biofuel production, the assistant agriculture secretary said, despite growing concerns about a global food crisis.”

Dumortier et al. (2022) Electrification of the Light-Duty Vehicle Fleet in the United States and Its Effects on Global Agricultural Markets, Ecological Economics, doi: 10.1016/j.ecolecon.2022.107536

Sharelines of this story


Comments are closed.