Chapter 1: Introduction to Aviation's Climate Goals

During the first quarter of 2022, I embarked on a sustainability reading initiative focused on climate change, diligently documenting my insights along the way. Now that it's April, I've completed that project, which was so fruitful that I’m diving straight into my next endeavor. This post delves into the U.S. 2021 Aviation Climate Action Plan (AAP).

What I Discovered

First and foremost, the primary objective is clear:

U.S. Aviation Climate Goal:

Achieve net-zero greenhouse gas (GHG) emissions from the U.S. aviation sector by 2050.

Note: This includes life cycle emissions of carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4).

In my previous post regarding the 2021 Emissions Gap Report, I discussed the necessity of reducing GHG emissions by 55% by 2030 and reaching net-zero carbon dioxide by 2050 to limit global warming to 1.5°C by the year 2100. The goal outlined in the AAP appears to align with this overarching objective, although it doesn’t explicitly mention the 2030 target.

Pathway to Achieving Net-Zero

A significant revelation was that a staggering 97% of the aviation sector's GHG emissions stem from jet fuel combustion. While I was aware that this was a major contributor, the extent was surprising. Consequently, most mitigation strategies focus on enhancing aircraft design and fuel efficiency.

Key measures include:

• Developing more fuel-efficient aircraft
• Utilizing Sustainable Aviation Fuels (SAF)
• Optimizing flight routes for efficiency
• Collaborating with international organizations to establish stricter emission standards
• Purchasing offsets for unavoidable emissions

The Importance of Timelines

I found the report's approach to establishing timelines particularly intriguing. By analyzing historical data, the authors estimated the typical duration for implementing new technologies, underscoring the urgency for innovation.

With investments from the aviation industry and the U.S. government, new aircraft with significant fuel efficiency advancements could be introduced. Narrow-body planes might enter service in the 2030s, while wide-body models could follow in the 2040s. The anticipated improvements will directly result from research and development investments made over the next five years, as it usually takes around seven years for a technology to transition from flight demonstrations to service entry.

Chapter 1.2: Understanding Sustainable Aviation Fuels (SAF)

SAF are liquid hydrocarbon fuels that match the performance and safety of conventional jet fuels derived from petroleum. They are fully compatible with existing fuel infrastructure and can be produced from renewable or waste materials. According to the action plan, SAF can reduce life cycle GHG emissions by at least 50% compared to traditional jet fuel.

While some SAF still emit gases when burned, they could potentially achieve net-zero lifecycle emissions by capturing CO2 during their production phase. However, there is currently no indication that such SAF are available, making this projection seem more aspirational at this stage.

Why SAF Instead of Electric or Hydrogen Planes?

The report suggests that electric and hydrogen-powered planes are unlikely to be ready by the net-zero deadline. In the transportation sector, various decarbonization strategies are under evaluation, including electrification, hydrogen fuel, and sustainable liquid fuels. Current battery technologies are limited in energy density, restricting them to low-speed aircraft with limited passenger capacity and range.

Although these technologies may play a role in decarbonizing short flights in the future, they are not expected to address the medium- and long-haul flights responsible for the majority of aviation carbon emissions by 2050. This raises questions about whether prioritizing investment in SAF is the best course of action.

Key Takeaways

What do these developments mean for us?

For those intrigued by these advancements, it's beneficial to stay updated on the AAP, as the U.S. plans to review progress annually and will update the overall document every three years.

Moreover, engineers, researchers, and students interested in sustainable technology have a wealth of research opportunities available, such as:

• Efficient trajectory planning for flight paths
• Investigating the effects of contrails on climate
• Exploring various aerospace innovations under NASA's Sustainable Flight National Partnership (SFNP)

Aviation is an industry marked by incredible achievements and rapid innovation, but it also significantly contributes to GHG emissions. Observing how governments, industries, and innovators navigate the challenges ahead is fascinating.

While I cannot definitively assess the effectiveness of this plan, its notable omission of a suggestion to reduce flight frequency raises questions. Cultural shifts regarding air travel should be part of the broader dialogue on sustainability.

I would love to see more industries adopt a similar approach in defining their expected timelines for innovation and consider where to allocate their investment and efforts.

Videos for Further Insight

In this video, titled "How Will Air Travel Hit Net Zero Emissions? | The Extra Mile, With Boeing, Airbus & United," experts discuss the challenges and strategies for achieving net-zero emissions in aviation.

The second video, "How can global aviation reach net-zero CO2 by 2050," provides insights into the specific actions needed to meet the ambitious goal of net-zero emissions in the aviation sector.