Can electric vehicles solve the climate crisis? Not by themselves.

Electric vehicles are necessary, but on their own, they are not sufficient to solve our climate problems. We need a wide range of policies that include measures to reduce vehicle ownership and usage.
Can electric vehicles solve the climate crisis? Not by themselves.

“So Alex, should I buy an electric car?”

That’s a question I get a lot. As someone who researches the sustainability of transportation systems, people expect me to be able to tell them whether electric vehicles (EVs) have a net positive or negative effect on the environment.

Unfortunately, the answer I want to give — the one my research has led me to — doesn’t seem to satisfy anybody. “Buy an electric car if you want,” I say. “But the real question is, do you even need a car at all?”

EVs have no emissions at the tailpipe, but they are not zero-emission vehicles. The electricity they run on must come from somewhere, and right now a substantial share comes from fossil fuels. For example, in the U.S., 61% of the total 2019 electricity generation came from coal and natural gas.

On top of that, EV batteries are very energy intensive to produce. The greenhouse gas (GHG) emissions associated with making electric vehicles are currently higher than conventional internal combustion engine vehicles.

What you really need to do is compare the emissions over the lifetime of an EV with those of a traditional internal combustion vehicle. Researchers like me do this using a tool known as Life Cycle Assessment, and our answer is generally positive: if you look at GHG emissions per mile travelled in the U.S., EVs usually come 50% lower than internal combustion.

But that doesn’t necessarily mean that electrification is the solution to our climate problems. The Paris Agreement says that we need to keep the increase in global average temperatures to less than 2 °C above pre-industrial levels by the year 2100 if we are to avoid extreme, inescapable, and irreversible impacts on ecosystems, communities, and the overall global economy. For the past few years, I’ve been obsessed with the question of whether the GHG emission reductions offered by electric vehicles would, on their own, be enough to meet this target.

To answer the question, I needed two key elements. First, a model that accurately estimates the transient effects of deploying new technologies in the passenger vehicle fleet. While sales of EVs are growing fast, the fact that U.S. vehicles have an average lifetime of around 15 years means the effects of internal combustion will be felt for decades to come. The Fleet Life cycle Assessment and Material-flow Estimation (FLAME) model I created accounts for this.

Second, I needed to translate the Paris Agreement target into a GHG emission budget for the U.S. passenger vehicle fleet. To do this, I used an integrated assessment model (the Global Change Analysis Model - GCAM) to obtain realistic sectoral and national-level GHG emission budgets that are consistent with my chosen target.

The results shocked me. Assuming no changes to our travel behaviour, meeting the target would require up to 350 million electric vehicles in the U.S. by 2050 — about 90% of the fleet. To put that into perspective, there are currently 0.05 million electric vehicles in the U.S., or only about 0.2% of the fleet. Even the most optimistic projections from the International Energy Agency suggest that the U.S. fleet will only be at about 50% electrified in 2050.

Still, 90% is at least theoretically possible, isn’t it? Just last week, California announced plans to ban sales of new internal combustion vehicles by 2035, which would be consistent with our analysis of required deployment if applied nationally.

But there is another problem: this level of electrification would severely challenge the country’s electricity infrastructure and the supply chain of many critical materials required to produce the batteries. It would require widespread smart charging infrastructure, stronger renewable energy source deployment and new electric battery technologies. I am not saying it is impossible, but I believe it is unlikely.

So what? Shall we give up, accept our collective fate, and stop our efforts at electrification? On the contrary, I think we should re-examine our priorities, and dare to ask an even more critical question: Do we need that many vehicles on the road?

There are only three ways to reduce GHG emissions from passenger transport: avoid the need to travel, shift the transportation modes, and improve the technologies. Electric vehicles only tackle one side of the problem, the technological one.

And while EVs do decrease emissions compared with internal combustion engine vehicles, we should really be comparing them to buses, trains and bikes. When we do, the GHG emission reduction potential per mile travelled disappears.

Electric vehicles are necessary to solve our climate problems, but they are not a silver bullet. They don’t get us out of doing the things we already know we need to do, including massive investments in rail and public transit, as well as infrastructure for active transportation, such as cycling and walking.

The road to decarbonization is long and winding. But if we are willing to get out of our cars and take a shortcut through the forest, we might get there a lot faster.

Photos by Alexander Popov and Milica Spasojevic on Unplash.

I thank Tyler Irving at University of Toronto Engineering News for helping me shape this article. 

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Go to the profile of Lu Liu
over 2 years ago

Is the integrated assessment model called Global Change Assessment Model (GCAM)? I think you wrote "Analysis" instead of "Assessment".

Go to the profile of Alexandre Milovanoff
over 2 years ago

Thank you Lu. The model (GCAM) is the Global Change Analysis Model. See here for documentation: 

Go to the profile of Lu Liu
over 2 years ago

I see. I didn't realize they updated the name. It was called "Assessment" in their previous publications. Thanks for your reply!