In 2019, moving people and things around on millions of individual cars, planes, trains, trucks and ships produced 8.5 Gigatons of CO2 (16% of total global emissions).  What would it take to get this number to zero? 

1. Efficiency is a good start

For decades, environmentalists have approached this question with a key insight: efficiency is the most abundant, cheapest, cleanest energy resource that we have.  Efficiency can mean meeting our personal transportation needs with less fuel – for instance, by driving cars with better gas mileage. But it can also mean meeting our personal transportation needs with fewer cars – for instance, by providing accessible public transit. And it can mean organizing our societies and our lives so that we meet our human needs with less transportation – for instance, by building walkable cities, or shortening supply chains so that we can meet our material needs with less shipping and trucking.  These are all important transportation solutions.  We’ll discuss them more in the section on public policy.  In the meantime, check out these essays in Drawdown to see just how much solutions like these can help:

  • Walkable Cities, p. 86
  • Bike Infrastructure, p. 88
  • Mass Transit, p. 126
  • High Speed Rail, p. 138
  • Ridesharing, p. 144
  • Trains, p. 156

All of these are important ways to make progress – and they have many other benefits, from reducing our footprint on the land, to improving quality of life, reducing social isolation and building public trust.  (This article by David Roberts is full of insight on how American suburbs deprive us of good things in life.)

All of these forms of efficiency are ways to reduce our greenhouse gas emissions.  But we need to eliminate emissions.  Efficiency can make the job a lot easier, but as Saul Griffith writes in Electrify, “We can’t efficiency our way to zero.”  To get to zero, we will need new technologies.  That’s what this section is about.

2. Technology to get to zero

A Boeing 747-8 can lift off the ground in London with 467 people and fly to Sydney without refueling.  Modern passenger cars are a bit more modest, but they’re still pretty impressive. A 4500-pound SUV can travel from New York to Indianapolis on a single tank of gas.

Both of these feats of engineering are possible because fossil hydrocarbons – long molecular chains of hydrogen and carbon atoms, with large amounts of energy stored in the chemical bonds connecting the atoms to each other – can be extracted from the earth as petroleum, then refined into liquids such as gasoline or jet fuel, which can carry 9600 Watt-hours (Wh) of energy in a single liter. (Petroleum carries so much energy, because each liter of it contains the stored energy of 25 metric tons of ancient sea life, compressed and slow-cooked by the earth.) Fossil hydrocarbons power almost every mode of transportation today, from cars and planes to long-haul trucks and cargo ships. To decarbonize transportation, we will have to replace fossil hydrocarbons in all of these different applications.

There is no single replacement that will work for all cases. To understand the factors that determine which solution will be needed to replace fossil fuels in each application, it will help to start by looking at two applications – passenger cars, and long-haul aircraft – and using them to anchor opposite ends of a continuum. Passenger cars are pretty light, and can be refueled relatively often. This makes them easy to electrify; and electrification will certainly take over most of the sector in the next two decades. Long-haul aircraft are heavy, have limited space for fuel, and need to fly for thousands of miles without refueling. These will require hydrocarbon fuels for at least the next few decades. To decarbonize this sector, we will need to greatly expand production of hydrocarbons that are not derived from petroleum, and that do not have the carbon footprint that fossil hydrocarbons have. (These are called “Sustainable Aviation Fuels,” or “SAFs”.) In between these two poles are applications like shipping, long-haul trucking, and medium-haul aviation where other solutions, like hydrogen or hydrogen-derived fuels, will likely take hold.  For many of the applications in between the poles of cars and long-haul aircraft, it’s an open question which solution will win the day.

The transportation continuum

Credit: Our presentation derives from the analysis that Micheal Leibreich illustrates with his Hydrogen Ladder.

Left end of continuum: electrifying cars

Let’s start with cars. By now, everyone understands that we can decarbonize passenger cars by electrifying the motors that drive them, and using lithium ion batteries to store electricity.

Lithium ion batteries weren’t invented until 1976, and they were initially far too expensive to use in an electric car (and they were not energy dense enough to give an electric car a practical range). So, at the outset, small personal electronics provided the main market for lithium ion batteries. But just like wind and solar, lithium ion batteries are on a learning curve, with prices falling about 19 percent with every doubling of capacity. From 1991 to 2021, as falling prices spurred ever greater demand, prices dropped by an astonishing 97%.

Right now (in 2022), global demand for electric cars has begun to take off (doubling in 2021 from the previous year, and continuing to accelerate in 2022), so that demand for the minerals that go into batteries suddenly exceeds supply.  As a result of current mineral shortages, battery prices have stopped falling. But battery makers are continuing to innovate furiously, so as more mines come online to meet pent-up demand for battery minerals, prices are expected to resume falling rapidly.

Battery Electric Vehicles (BEVs) are already cheaper to own and operate than cars with internal combustion engines (ICE vehicles). That’s partly because BEVs are much simpler, with many fewer moving parts to break down, and so are much cheaper to maintain.

And because electric motors are 3x or 4x more efficient than gas-burning engines, the cost of fuel (electricity) per mile driven is far lower.

In the next few years, as battery prices decline, even the upfront cost of an EV is expected to fall below the upfront cost of an ICE vehicle. And as anyone who’s driven one will tell you, they’re much, much more fun to drive. (A cheap, low-end EV has acceleration to match a high-end ICE sports car.) It’s only a matter of time before EVs take over the world.

Right end of continuum: SAFs

Batteries aren’t only getting cheaper.  They’re also getting better at packing more energy into a smaller weight and volume.  (In fact, that’s part of the explanation for why they’re getting cheaper: you can now drive the same distance with fewer, more dense battery cells than you could a few years ago.) In 1991, lithium ion batteries could carry 200 watt-hours per liter (Wh/L) – which was more than twice as dense as the lead-acid batteries that preceded them. Lithium ion batteries today carry more than 700 Wh/L; and energy density is continuing to improve. Batteries are already energy-dense enough to power small electric planes, capable of carrying 6-9 passengers for 400 miles; manufacturers think that further developments in battery technology will allow them to test a 100-seat electric plane, capable of one-hour flights, by 2026.  So, as batteries continue to improve, should we expect eventually to see fully electrified long-haul flights?

Batteries will certainly march rightward along the transportation continuum, taking over more, and no one is sure how far they will go. But unfortunately, we can be very sure that they won’t reach long-haul aviation – at least, not with any technology foreseeable today. Let’s suppose, for the sake of argument, that within a decade we will have lithium ion batteries with an energy density of 1000Wh/L.  Jet fuel, by contrast, carries 12,000 Wh/L. That’s not a fair comparison as it stands: the best jet engines are only about 40% efficient, so that translates into a density of only 4800 Wh/L of useful (unwasted) energy (that is 40% of 12,000 Wh/L), whereas electric airplane engines are 95% efficient. Still, it’s clear that, even if the most optimistic goals for improving lithium ion batteries are met, we will be nowhere near a world in which batteries can power long-haul air travel. The chemical bonds within molecules (such as hydrocarbons) simply offer a much more compact way of storing energy than any way that we have found of storing electrons.  For the foreseeable future, long-haul air travel will need some form of chemical fuel.

Fortunately, there are several ways of obtaining hydrocarbons that are chemically similar to jet fuel, but that do not involve pulling buried carbon out of the earth. The general term for these non-fossil jet fuels are Sustainable Aviation Fuels (SAFs).   These are “drop-in” fuels that work in existing jet engines, and can be stored and transported with existing infrastructure. This broad category includes biofuels and electrofuels.  Biofuels are the only kind of SAFs being used right now, so let’s start by examining those.

Biofuel SAFs

Biofuels are made from plants or other biomass – this is the “feedstock” that supplies the carbon and hydrogen atoms for the hydrocarbons that make up the biofuel.  When plants photosynthesize, they suck carbon out of the air and incorporate it into their bodies. When plants (or animals that have eaten them) decay, they then release much of the carbon they contain back into the air as carbon dioxide, CO2, (unless they decay in conditions without oxygen, in which case they release it as methane, CH4).  When biofuels are burned, they release carbon dioxide (and other pollutants), too, just as fossil fuels do. But because the carbon released by their combustion is carbon that was recently pulled from the air by plants and that would have anyway been re-released to the air when the plants decayed, biofuels can be accounted as low-carbon fuels on net, when taking into account their entire life-cycle. (They are not zero-carbon on net, because some carbon dioxide is emitted in the course of turning organic matter into biofuel and transporting it.)

“First-generation” biofuels, including SAFs, are made from food crops such as corn, soy, palm oil, or sugar. These food-based fuels have very dubious environmental benefit. Corn ethanol, which is blended into almost all gasoline sold in the US by law, and which can also be turned into an SAF, provides a cautionary tale.  Approximately one third of all corn grown in the United States is converted to ethanol, requiring an area of cropland equivalent to all the land planted to corn in Iowa and Minnesota combined. Unfortunately, a recent study has concluded that the lifecycle carbon intensity of corn ethanol is likely at least 24% higher than that of gasoline.  Several factors contribute to this dismal result, including the fact that corn is grown with intensive use of fertilizers that are themselves produced from fossil methane. For our purposes, the most important factor to understand is that because corn for ethanol requires so much cropland, it reduces the supply and drives up the price of corn on world markets, as well as wheat and soy (which could be grown on the land used for ethanol).  This increases economic pressure to clear the Amazon and other rainforests in order to grow soy and other crops to feed the world’s growing population. The same thing happens when sugar is grown to produce ethanol in Brazil, or Palm Oil is used in Indonesia.  In all of these cases, use of food cropland for biofuel production contributes to higher food prices worldwide, deforestation, and biodiversity loss – without producing much if any climate benefit.

⇒ For a good explanation of the way in which biofuels contribute to deforestation, biodiversity loss, and food shortages, read this article by Michael Grunwald.

“Second generation” biofuels (or “advanced biofuels”) are somewhat better, because they are not produced from foods, but rather from other forms of biomass, such as foodcrop waste (e.g. the “corn stover” that is left over after the cob is harvested), waste vegetable oil (from restaurant deep fat fryers), forest waste, and biomass crops (such as switch grass). Most of these do not require removing cropland from food production. However, they face a fundamental problem: there is just not enough biomass to go around. This would be true even if the only important use for biomass was to produce aviation fuel. In fact, the same “waste” biomass that can be used to produce biofuels can also be used as an alternative feedstock to produce chemicals and plastics that are currently produced from fossil fuels, and can also be used as a cost-effective way to remove carbon from the air and then sequester it. All of these are critical climate needs, but there is not enough waste biomass fully to meet even one of them, let alone all of them.

Potential “third generation” biofuels could be produced from algae; and “fourth generation” biofuels might be produced by microorganisms (including algae) that have been genetically engineered using synthetic biology so that they secrete fuels directly. Either of these, if made to work economically and at commercial scale, would offer significant advantages over other kinds of biofuel. (They do have their own problems as well, as many approaches would require large amounts of water and fertilizer as inputs.) These are promising ideas, very much worth developing. (In fact, if you like biology, this would be a great field of endeavor in which to build a climate career!) But right now, it’s too early to tell whether these approaches can scale up economically so as to provide an important climate solution.

⇒ For more, listen to this My Climate Journey podcast interview with the CEO of Lanzajet, a growing biofuel SAF startup.

Our takeaway:

Right now, SAFs make up a tiny fraction of all jet fuel, but many airlines, and some nations, have pledged to increase their use of SAFs substantially in the coming decades, and biofuel SAFs will scale up rapidly. Those that come from food crops will not be real climate solutions, and policy-makers should push hard against them; but waste-based biofuels could be wins for the climate. They are limited, however, in two ways: (1) there’s not enough biomass to meet all the needs of long-haul aviation, let alone other important climate needs; (2) while these fuels are lower carbon on net than fossil jet fuel, they are still far from zero carbon.  Because the aviation sector is projected to grow between three-fold and seven-fold by 2050, this is a real problem.  Biofuels made with algae or engineered microorganisms could help a great deal, if they can be produced economically; so could electrofuels.

Electrofuel SAFs

“Electrofuels” (also called “e-fuels,” “synthetic fuels,” “power-to-fuel,” “power-to-liquid” and “power-to-X”) are produced by using renewable electricity to electrolyze water to free up hydrogen atoms and to electrolyze carbon dioxide (captured from air or from exhaust streams) to free up carbon atoms, and then using electro-chemical processes to assemble these elements into hydrocarbons that are chemically similar to those in fossil fuels and biofuels. Like biofuels, electrofuels are “drop-in” replacements for fossil fuels that can be used in existing engines. Like biofuels, the carbon dioxide that is emitted when electrofuel is combusted is carbon dioxide that would have been in the air anyway – and whereas transporting and processing biofuels still involves carbon emissions, so that biofuels are only low carbon on net, electrofuels can be close to zero carbon on net. And whereas biofuels require biomass as their “feedstock” (as the source of their carbon and hydrogen atoms), electrofuels require no feedstocks other than water and carbon dioxide, which we have in unlimited supply, and electricity. Moreover, electrofuels are purer than either fossil fuels or biofuels, and so they emit fewer non-carbon pollutants (such as NOx), when combusted.

Right now, several companies are working on electrofuel technologies, but no one is producing electrofuel at commercial scale, and no one has demonstrated a path toward economic viability. Working with today’s prices for the inputs to electrofuels (hydrogen produced via electrolysis, captured CO2, and clean electricity), one analyst has estimated that the cost of electrofuels produced today would be at least five times the price of fossil fuels. But we have already seen that the cost of clean electricity is declining rapidly. The cost of electrolyzers is also declining, and the cost of equipment to capture carbon dioxide is expected to do so, as it is a focus of intensive research and development. So there is good reason to hope that, by the time we begin to bump up against the limits to the supply of biomass with which to produce second-generation biofuels, electrofuel SAF may be ready to step in and play a role.

⇒ For more, listen to this Watt it Takes interview with Dr. Etosha Cave, co-founder of Twelve.

Hydrogen in the middle

Let’s look again at the transportation continuum.

At one end, passenger cars, along with local delivery trucks and local buses, are easy to electrify with current technology. (So are smaller forms of surface transport, like the 3-wheel tuk tuks that are common in much of Asia.) This is a sector in which it’s clear that electrification will beat out other decarbonizing technologies handily. As we move to the right, toward heavier vehicles traveling longer distances, the need for a dense form of energy storage starts to increase – until, at the far end, non-fossil hydrocarbons are the only option we currently have to power long-haul aviation. For several of the cases in the middle, there is a third possibility: hydrogen, and hydrogen-derived fuels.

Hydrogen has many advantages as a carbon-free chemical fuel. For a start, it is the most abundant element in the universe. H2 gas can be produced without any carbon emissions by using electricity from renewables to electrolyze (run an electric current through) water (H2O), causing the oxygen and the hydrogen to separate. Hydrogen produced in this way is often called “green hydrogen.” There are other ways of producing carbon-neutral hydrogen, which we’ll discuss in the sections on Carbon Capture and Storage (CCS) and Carbon Dioxide Removal (CDR), but for now we’ll focus on green hydrogen to keep things simpler. Compressed H2 is very energy dense by weight (Wh/Kg) – about 2.8 times more energy dense than jet fuel.  It can be combusted to power an engine with no carbon emissions.1Combusting H2 in the atmosphere does produce Nitrous Oxide (NOx), which is both a greenhouse gas and a pollutant dangerous to health, but the NOx emissions nonetheless have lower warming potential than the CO2 and NOx emissions from burning fossil fuels. Or it can be run through a fuel cell to produce electricity. (A fuel cell works like an electrolyzer in reverse: it combines H2 with Oxygen from the air to produce electricity and pure water.)

Let’s take a look at how hydrogen competes as a solution for the different uses on our transportation continuum, starting again at the left end of the continuum and then moving right.

Fuel Cells vs. Batteries

A Fuel Cell Electric Vehicle (FCEV) is basically an electric vehicle with a hydrogen tank and fuel cell providing electricity instead of a battery. For many years, major automakers like Toyota thought that FCEV passenger cars were more likely to succeed than Battery Electric Vehicles (BEV) cars, and bet heavily on their development while largely ignoring BEVs. In part, this was because the costs of lithium ion batteries were initially very high, and automakers assumed they would remain prohibitively expensive. But it was also because, if a network of hydrogen filling stations were built, drivers could quickly refuel their FCEVs in the same way that they now fuel-up at gas stations, whereas BEVs need to be recharged, which takes more time.

It’s now clear that this was a bad bet. Battery prices have declined dramatically, and will continue to do so. As batteries have become cheaper and more energy dense, the distance that a BEV can go without recharging has steadily increased, so that many newer models can go more than 300 miles and can charge to 80% in around 20 minutes. FCEVs are much more complicated than BEVs, and so they cost more to maintain.

Credit: Michael Leibreich

The most important difference between FCEVs and BEVs is one that applies wherever batteries and hydrogen (or hydrogen-derived fuels) are in competition, across the transportation continuum. In the process of using electricity to produce hydrogen through electrolysis, then to compress, transport, and store the hydrogen, and then (with a fuel-cell) to convert the energy contained in the hydrogen back to electricity, most of the initial energy is lost, as the diagram below shows.

(The diagram is from the 2017 Transport and Environment report “Roadmap to climate friendly land freight and busses in Europe.”)

Electrolyzers have gotten more efficient in the time since 2017, so the final numbers in a similar diagram today might be somewhat better for hydrogen. Even if that’s the case, the diagram is helpful in showing the general shape of the inefficiencies that are unavoidable in using hydrogen. (Even more energy is lost when hydrogen is converted into e-fuel and then combusted in an engine, because engines waste most energy as heat.) The end result is that FCEVs require something like three times more initial electrical energy than BEVs do to go the same distance.

These facts explain why, despite initial hopes for hydrogen, electrification is already winning and is destined to dominate on the left-hand side of our transportation continuum – not just for cars, but for urban delivery trucks, for local ferries, and for small airplanes, including the Vertical Take Off and Landing (VTOL) flying taxies that many companies are developing.

But what about as we move further to the right?  The limits on battery energy density are real, and they may matter for long-haul trucking (more than 500km), because long stops to recharge are expensive for trucking companies. So, trucking companies may be willing to accept the lower efficiency of hydrogen fuel (and thus higher fueling costs) in order to gain extra range. For this reason, the competition between batteries and hydrogen fuel-cells is more real in this space. Some truck manufacturers are betting on fuel cells, some are betting on batteries, and some are developing both, waiting to see how technologies and the market will develop.

⇒ Read this article for an overview of the competition playing out right now between hydrogen FCEV trucks and BEV trucks.

⇒ There are other possibilities, too. Germany is testing the use of overhead catenary wires on highways, like those used on trains and some buses, so that trucks can get power as they drive, without stopping to refuel.

Credit: New York Times

Our bet is that electrification (with batteries and in some locations catenary wires) will end up dominating long-haul trucking – but it’s also possible that BEV trucks and FCEV trucks will co-exist for a long time.

A similar contest is shaping up in short-haul aviation, with some businesses pursuing electrification and others developing hydrogen fuel-cell driven electric turboprops. (As with cars, these are essentially electric planes, but with a hydrogen tank and a fuel cell in place of a battery.)  You might think that this is a case in which the energy density of hydrogen should make it a clear winner: since hydrogen gas is much more energy dense than batteries (and even more energy dense than jet fuel), shouldn’t we be able to use hydrogen to fly planes of all sizes for the same distances that they now fly on jet fuel?  Unfortunately not.  Hydrogen gas is very energy dense by weight (because H2 molecules are very light). But, even when heavily compressed, H2 takes up a lot of space. Even when super-cooled into a liquid at -253°C, hydrogen occupies four times more volume than jet fuel does per unit of energy stored – and that’s before you count the space and weight for the special tanks required to hold hydrogen in liquid or compressed gas form. So, in order to fly hydrogen-powered aircraft for much longer distances than battery-powered aircraft, planes will have to be redesigned to allow much more space for fuel storage. For short-haul planes, this might be done with existing fuselages by sacrificing some passenger seating and cargo capacity in order to make room for fuel tanks, as in this concept from Universal Hydrogen:

For medium-haul planes, this might require creating brand new designs from scratch – a process that can take more than a decade from the drawing board to safety testing and final certification. Even with radical new designs, like the “flying wing” hydrogen plane idea that Airbus is studying, the fact that hydrogen is so much less energy dense by volume than jet fuel means that it will not work for the long-haul flights at the right end of our continuum.

Ammonia and Methanol

As we move right along our continuum, there’s one more step before we get to biofuels and e-fuels. Hydrogen can be used to create ammonia or methanol. Both of these molecules are much easier to store than hydrogen, because they are liquid at much higher temperatures; and both are more energy dense than hydrogen by volume, though still much less energy dense than hydrocarbons. These can be combusted in engines, or used in fuel-cells. Ammonia emits no carbon dioxide when combusted (though it does emit NOx); methanol emits much less carbon dioxide than fossil fuels when combusted and no NOx. Both are being considered for trans-oceanic shipping. Large ships are like long-haul jets in that they need to carry tremendous amounts of energy with them, but they are unlike long-haul jets in that they have more space to store fuel, so a fuel that is less energy dense by volume is less of a problem. Because both methanol and ammonia each emit some greenhouse gasses, neither is a perfect decarbonization solution for shipping, but either would be a tremendous improvement over the dirty “bunker fuel” (the very most polluting grade of oil) by which ships are powered now. They might win out in this space.

Read about Amogy, a start-up trying to scale up the use of green ammonia for transoceanic shipping

In thinking about the continuum, you could group green ammonia and green methanol together with hydrocarbon e-fuels, since they are all “hydrogen-derived fuels.” You need to use energy to turn hydrogen into ammonia or methanol, and you need to use more energy to turn it into hydrocarbon e-fuels, but in all these cases, you’re working on hydrogen to turn it into a more useful fuel. However, because hydrocarbon e-fuels are “drop-in” replacements for fossil fuels, and because they emit as much carbon when combusted (though not over their whole life cycle, taken on net) as fossil fuels do, whereas ammonia and methanol are not and do not, it’s helpful to think of them as a separate categories.

How far can electrification go?

Let’s look back at the continuum one more time. Electrons in a battery are a far more efficient way to store energy than molecules in a tank: they give much more of the energy that you put in back to you as useful work. That, together with the simplicity of all-electric systems, makes them the favorite in any contest where the weight or volume of your energy storage aren’t the most important factors. The fact that electric systems can be so much cheaper, simpler, and cleaner than fuel-driven systems prompts the question: how far can electrification get, in its march from the left side of the transportation continuum to the right? Maybe further than we think, if we’re creative.

Batteries will not power the huge cargo ships, as long as four football fields, that transport 20,000 shipping containers across the Pacific ocean. But they might not have to. Fleetzero has designed much smaller, battery powered ships that take 3,000 or 4,000 shipping containers and break a trip from China to L.A. with a few stops at coastal ports (for instance, in Japan, then Alaska, then Seattle) along the way. This makes the trip a little longer, but the added cost that brings is made up for by the fact that simpler electric ships need a much smaller crew, because they require less maintenance, and they can stop at smaller, less crowded, lower-cost ports that can’t accommodate the biggest ships.

⇒ Check out this My Climate Journey podcast interview with the co-founders of Fleetzero.

“Hey, wait! Aren’t we just assuming that ‘the market’ will determine how we decarbonize… when actually we need more radical changes than ‘the market’ will bring?”

If you’ve read this far… wow, you’re dedicated! But also, maybe an objection has been coalescing in your head as you’ve read. We’ve been talking about whether or not different solutions will be “economical.” Are we assuming that we should leave decarbonizing transportation to the decisions that business people make about what will maximize their profit? That’s crazy! The planet is on fire, so we need to do whatever it takes to decarbonize as fast as possible, even if it increases costs, or means that we no longer fly nonstop from London to Sydney, or that we retire huge cargo ships in favor of small, electric ones from Fleetzero.

We agree! We need public policies, at levels from local to international, to force rapid decarbonization, and we need a strong climate movement to force politicians to adopt those policies. But technological and economic factors can make that much easier – or much harder. Fifteen years ago, when wind and solar power were much more expensive than coal and gas power, no US state had a plan to eliminate greenhouse gas emissions from electricity generation. It was too politically difficult to ask energy consumers to pay more. But in the last few years, as the cost of renewables has plummeted, twenty one states have adopted plans to reach zero emissions in their electricity sectors. Likewise, twenty five years ago, when the only electric car available was GM’s clunky, low-range, lead acid battery-powered EV1, it was hard to get public support for electric vehicles. But now that Tesla (thanks to a $465 million loan from the US federal government in 2010) and others have produced BEVs that are better to drive than ICE cars and comparable in cost, it’s easy to generate public support for policies like California’s that will prohibit ICE cars from being sold in the state after 2035. Making decarbonized options better and cheaper than fossil fuel options will help us win.

“Wait, I’ve heard that in order to switch from fossil fuels to electric vehicles, we’d need huge amounts of new minerals to make all those batteries. And mining is really, really environmentally destructive (and in some parts of the world, there are human rights abuses too). If we just swap out ICE cars for EVs, won’t we just be making things worse (or at least, not that much better)?”

It’s true that decarbonizing transportation (and the whole economy) will require that we extract many minerals from the earth in quantities much larger than we do now.  For batteries, we’ll need lots of lithium, as well as some cobalt, nickel, and other metals, and we’ll need boatloads more copper for wires to carry electricity, and steel to construct giant wind turbines. And it’s absolutely true that pulling things up out of the earth is almost always environmentally destructive – and that in many parts of the world it’s done by people working in unsafe conditions, subject to human rights abuses. We should do everything possible to make sure that, in developing the mining industry to power transition to clean energy, we don’t replicate the bad practices in much existing mining.

Here’s the thing to keep in mind as we consider this transition.  Right now, we extract an enormous quantity of material from the earth, the vast majority of which is fossil fuel.  It is a very, very dirty business, with terrible environmental costs and human costs – even before we reckon the toll of climate change. Air pollution – the vast majority of it from burning fossil fuels – kills ten million people each year. Almost everyone is affected by fossil fuel pollution, but the burdens do not fall equitably. In countries from Nigeria to Ecuador, the people who live where oil and gas is extracted suffer both from intense air and water pollution in their communities and from human rights abuses. All over the world, the people who live in “fenceline” communities closest to fossil fuel refineries are almost always the poorest and most marginalized people, and they suffer terrible and disproportionate health burdens from air and water pollution. And poor, marginalized communities (in the US, that means mostly communities of color) live closest to the commercial and industrial facilities with heavy truck traffic, and so again suffer disproportionately from air pollution.  This is the status quo, and it is grossly unjust.

⇒ For a powerful accounting of the toll of fossil fuel pollution, read this column by David Wallace Wells.

So, how would a decarbonized world, where we extract lots more minerals, but have stopped extracting fossil fuels, compare to the status quo? Here’s one way to think about it: an average ICE car will use 16,000 kg of oil over its lifetime. All of that has to be extracted, transported, refined… and then it is burned, releasing pollution into the air and warming the planet.  An EV requires about 200 kg more minerals than an ICE car requires, and these have to be mined.We got these figures, and the more general point, from the energy analyst Kingsmill Bond, in his Volts Podcast interview. When the car reaches its end of life, those minerals can be recycled and used again.

David Roberts offers an illuminating treatment of this topic in this great article.  In it, he quotes Saul Griffith, who compares the amount of waste we’d produce in a decarbonized world to the status quo:

Assigning all 328 million Americans equal share of our fossil fuel use, every American burns 1.6 tons of coal, 1.5 tons of natural gas, and 3.1 tons of oil every year. That becomes around 17 tons of carbon dioxide, none of which is captured. It is all tossed like trash into the atmosphere. The same US lifestyle could be achieved with around 110 pounds each of wind turbines, solar modules, and batteries per person per year, except that all of those are quite recyclable (and getting more recyclable all the time) so there is reason to believe it will amount to only 50-100 pounds per year of stuff that winds up as trash. That is a huge difference: 34,000 pounds of waste for our lifestyles the old way versus 100 pounds the new, electrified way.

We can add one more number to this picture of the difference between the status quo and a decarbonized future, which we got from the same article by David Roberts: right now, close to 40% of global shipping is devoted to moving fossil fuels around – contributing not just carbon emissions, but also large amounts of air pollution (especially NOx and SOx) in the process.

Mining is destructive, and it can have a social cost if we don’t do it in a just way.  (We must do it in a just way!)  But a world in which we mine lots more minerals, but stop extracting, transporting, and refining fossil fuels is both a more just world, and a world in which humanity walks with a much lighter footprint on the whole earth.

“OK, this is kind of exciting. What work needs to be done?”

A lot!

We already mentioned that we need public policy, at every level of government from local to international, to accelerate the transition to decarbonized transport.  We discuss that here.

On the technology side, every area we’ve discussed is a site of intense innovation by scientists and engineers.

There are also technology companies designing smart “bridge” solutions, to help us decarbonize existing trucks and ships, before the next generation of electric or hydrogen trucks and ships rolls out.

As cool as all the technologies are, technological innovation alone will not decarbonize transportation. In order for these technologies to be adopted, creative entrepreneurs will need to build the infrastructure to support them. Here are two, great examples.

Here are some more articles and podcasts on transportation topics we’ve found helpful.  This is a long list.  We’re not recommending you listen to or read all of these.  But they’re there as resources, in case you want to explore and dive deeper.

Learn about about startups innovating in transportation by searching our startup database, here.