How Will US Eliminate All Greenhouse Gas Emissions by 2050?

Achieving a net-zero emissions economy by 2050 involves aggressively restraining emissions from all sectors including transportation, which is the largest source of U.S. greenhouse gas emissions. It is crucial to make meaningful reductions in emissions during every decade along the way to 2050. To achieve this the blueprint focuses on three categories: increasing convenience, efficiency improvements, and transitioning to clean options.  

Increasing convenience entails supporting community designs and land-use planning that ensure job centres, shopping, schools, and other essential services are located nearer to where people live, thereby reducing commute times and improving walkability and bikeability. The design of our cities, towns, and suburbs heavily impact travel behaviour and mode choices, which in turn impact total miles travelled and the resulting emissions.  

Efficiency improvements focus on the incorporation of highly efficient travel options, while also improving the energy efficiency of all vehicles. The use of more efficient transportation modes might also result in the reduction of vehicles on the road and congestion, improving travel time and traffic flow.

Increasing convenience and efficiency are the foundation for the deploying clean vehicles and fuels. With renewable electricity and sustainable fuels becoming available and affordable, there are more ways to transition from petroleum fuels (95% of transportation energy use) to zero-carbon technologies. The cornerstone of the new transportation will be highly efficient zero-emission EVs that can leverage clean electricity. Hydrogen fuel cell vehicles can complement battery EVs for cases requiring longer ranges and faster refuelling times, for example in long-haul trucking. To archive the 2050 goals, most new vehicle sales will need to be zero-emissions by the mid-2030s and the legacy stock of fossil-based vehicles must be transitioned to EVs. To enable this transition, there must be support for technology development and cost reduction across different stakeholders. Moreover, the replacement of older vehicles must be accelerated. However, some applications such as long-haul aviation have range and power requirements that are beyond the limits of current electric technologies. In this case, sustainable fuels will be necessary.

Finally, for the success of these strategies they must apply across all transportation options. Light-duty vehicles produce about 49% of current transportation emissions, medium and heavy-duty trucks and buses are the second largest category with 21%, and aviation is in third place with 11%.  Each of these travel modes presents unique technological challenges for the transition to clean technologies.

Personal Comment:

Let’s look at the decarbonization pathway of Europe and compare it with the strategies of the U.S. The largest source of the greenhouse gas emissions in the EU is also transportation, which accounts for 28%. The emphasis of the EU’s strategy for reducing emissions falls mainly on the adoption of EVs. Their main argument is that it will take ten more years to set up supply chains to support a transition to 100 percent EV sales. Urban buses are the first transport mode where electrification is having a significant impact today. Another part of this strategy is to decrease the use of legacy combustion energy vehicles before 2035 and ban them completely by 2050.  

It seems to me that one missing, or at least under emphasized, part of the puzzle is shared mobility. Achieving carbon-free city travel depends a lot on the availability and acceptance of shared mobility options, as well as new transportation modes like micromobility and mini-vehicles. Well-functioning and integrated shared mobility can limit the excessive use of private vehicles. However, the transition from private cars to shared mobility requires significant changes in travel habits and behaviours. These are behaviours that people have had for decades and which our infrastructure is built to support. Making this transition, I think, is a more difficult challenge than the transition to the EVs, but it is also a critical step.

Written by Kateryna Melnyk,
RISE Mobility & Systems