Is sustainability in aviation sustainable?

Aviation and sustainability are funny frenemies.  By one measure, the activity an individual can do to emit the most carbon is to travel by air.  However, by another measure, the percentage of global carbon emissions by aviation is less than 2.5% (increases to roughly 5% of the greenhouse effect when you consider the altitude of the emissions and even contrails).

The technological progress in aviation relating to reduced fuel burn has been impressive over the decades.  In the past two decades alone, the fully-developed United States market decreased fuel burn per passenger by 40%.

But then, a funny thing happened.  It’s a thing that’s been happening for centuries.

Introducing William Stanley Jevons.  Jevons has a paradox.

William Stanley Jevons

It’s called Jevons Paradox (because when you make it, you get to name it), and the paradox focused initially on coal in its 1865 genesis.  Jevons noticed that with the increasing efficiency of coal furnaces, the expected effect of lower coal consumption did not materialize.  In fact, coal consumption largely remained unchanged, not because the efficiencies weren’t real, but because with efficiency comes lower cost.  With lower costs comes increased usage.  With increased usage comes… you get the picture.

But the furnaces were more efficient, so if the amount of emissions did not decrease, what benefited?

Quoting political strategist James Carville over 125 years later, “It’s the economy, stupid.”

The efficiency of coal furnaces did not result in lower emissions because the industry grew into the new efficiencies.  More stuff was made.  More jobs were created.  More people were pulled out of poverty.  More leaders were elected.  Emissions continued.

Aviation has long been subject to Jevons Paradox.  Looking back at twenty years in the United States, the 40% reduction in fuel burned per passenger has been swallowed up by increased growth.

And this is a fully developed market, growing at lower rates than the developing markets worldwide, where economic travel is being introduced to a whole new population.  Travel grows.  Economies grow.  Carbon emissions grow.

We approach our analysis objectively, focusing on the likely direction of the market rather than wading into a direction it should take.  I suspect we’ll direct several responses to this paragraph specifically, but the distinction is critical.

The reality for aviation is that it cannot reduce carbon emissions AND continue to grow.  Jevons noticed this in 1865, and it holds today.  Growth rather than lower aggregate emissions offset any improvement in emissions.

But Jevons also arrived at another logical conclusion; the way out was for governments to create policies to short-circuit the paradox – effectively forcing the market not to take advantage of the efficiencies.

In aviation, the clearest example is carbon taxes… well, kinda.  By increasing the cost of fuel through carbon taxes, you reset the economic benefits of efficiency.  Burn more, pay more.

But the same Paradox is still in effect, only more powerful now.  With carbon taxes in addition to the price of fuel, the advantage of gaining fuel burn efficiencies will result in even more competitive room for growth.

How did Jevons Paradox play out in coal?  Not well, at least not as well as you may think.  While many suggest the way out of Jevons Paradox is to switch the fuel source entirely, that’s exactly what happened and is continuing to happen with coal.  The world switched to oil and gas.  You know, those things that emit less carbon than coal, but that we use exponentially more today than in 1865.

So while we technically reduced coal consumption, from a carbon perspective, we are still firmly within Jevons Paradox.

Alternative fuels in aviation have suggested paths out of the paradox, however, this is where the new paradox arrives.  Aviation will not be able to reduce emissions AND continue to grow.  We’ll call it the Sherlock Paradox for its obvious nature and role in the saying “No s*$t, Sherlock.”

Those alternative fuels have serious drawbacks:  Batteries can’t match longevity for over 90% of air travel.  SAF still puts carbon into the atmosphere and competes with agricultural needs.  Hydrogen tends to go boom.

Not insurmountable problems, necessarily, but also not without higher costs.  Considering the higher costs are demanded by developed regions at the expense of growth in other regions, and the dilemma continues.  Also consider that the aircraft built today will still be in service in 2050.

Further complicating matters is the S of ESG (Environmental, Social, Governance).  While aviation focuses on its Environmental impacts, the Social impacts are often overlooked.  What is the social benefit of global travel?  When it comes to aviation, the E and the S are often in direct conflict.  Restricting travel to entire generations reduces the environmental impact but also damages the social.  Real life is complicated.

As we look into the future, we see these paradoxes playing out.  Chief among them for aviation is the paradox of reduced emissions and growth. With holistic industry solutions still decades away, the ugly logic of Jevons Paradox leaves aviation with a critical decision:

Sustainability or growth;  pick one.

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