My apology for the unwieldy title. But I chose the long title to highlight one thing: Although there are many decarbonization opportunities with large impact, road transportation offers the clearest path forward.
Let me elaborate.
First, let’s examine the areas where we need to reduce our carbon footprints. There are lots of high-quality research and data available, but the trick here is to look at the data at the right level of granularity. For example, we know as a fact that the energy sector produces the most GHG emissions – in fact it is a whopping 76% (I am using data Climate Watch, but data from other sources are similar). But that does not help much if we want to identify where the decarbonization opportunities are. Then we need to drill down and see where those emissions come from.
It turns out within the 76% emissions, here are the major sources:
- Heat and electricity (31.9%)
- Transportation (14.2%)
- Manufacturing and construction (12.6%)
But we can do even better by looking at how those energy categories are actually being used. If we do so, the breakdown for all the sources into end-use activities is the following (the top 6):
- Road transportation (12.5%)
- Residential buildings (11.4%)
- Commercial buildings (6.7%)
- Livestock and manure (5.9)
- Other industry (4.5%)
- Agricultural soils (4.2%)
Ourworldindata.org publishes a fantastic article (and visualization) on this. Its data are slightly different (likely because they were a little old), but here is its breakdown by all sectors (sorted and bars added by me for visualization):
Next comes the exciting part. Road transportation technology is overwhelmingly homogenous across the world: they all use fossil fuel, i.e., mostly gasoline! Compare that to residential buildings emissions, which not only include burning fossil-fuel for heating, but also using electricity, or even bio-mass for cooking for many parts of the world.
(Someone may say the agriculture sector emits a lot of GHGs as well (e.g., see this article by Bill Gates). True. But agriculture means a lot of things: livestock, soil, crop growing, crop burning, deforestation. And they each needs a very different technology/system to decarbonize. They also differ dramatically by geographical regions. Too big a nut to crack!)
Such a remarkable homogeneity means that the path forward in decarbonizing road transportation is clear: Replace nonrenewable fossil fuel with renewable ones.
Now the hard part. It is definitely not easy to decarbonize transportation. The major hurdles are:
- The base is large. It is reported that there are now 1.2 billion vehicles in the world.
- They last a long time. A car could be kept running for many (5-10) years. Many cars in developed countries are shipped to poorer regions of the world, where they are used much longer (and pollute a lot more).
- The renewable fuel technology in transportation is relatively new. Although electric cars are making headway, they are still in their early adoption cycle. There are also other promising alternatives, such as hydrogen fuels, but they are even more nascent.
But we should not underestimate the power of innovation and entrepreneurship. We have already witnessed the tremendous transformation brought by innovations in solar photovoltaic technology, battery-powered electric vehicles, and hydrogen fuel cells. Smart transportation systems are being imagined and designed, where vehicles run on clean energy and are driven automatously. Operations researchers are designing algorithms to minimize travel waste and maximize transport efficiency.
This is also an area government policy can play a pivotal role. The implication for public policy is extremely clear: Invest more in green transportation. This may include:
The implication for public policy is also extremely clear: Invest more in green transportation. This may include:
- Encourage innovations in technologies that can decarbonize all modes of road transportation: cars, trucks, railroads.
- Invest in green transportation infrastructure.
- Provide incentives for consumers to make greener transportation choices, such as buying electric vehicles, driving less and taking more public transportation.
Now back to the good news. Decarbonizing our world economy is never easy. In fact, it is extremely challenging. But ground transportation is one area where the target is clear and singular. It also happens to be one of the largest culprits in global warming. We need to prioritize and exert great collective efforts to decarbonize road transportation.
Acknowledgement: The author thanks David Steven Jacoby of Boston Strategies International for inspirational discussions.