JetZero A One-Way Ticket To Climate Hell; Efficiency Gains In Past 50 Years Around 1%/Year

[hatrack]

EDIT

The UK Government's Jet Zero report predicts that efficiency improvements will account for the largest share - a quarter to a third - of aviation carbon savings by 2050. Alas, this forecast is based on wishful thinking, with no historical empirical evidence to support it. Efficiency savings over the last 50 years have increased at most by an average of one percent per annum (pa), and they stalled from 1995 to 2005.

Even the International Civil Aviation Organisation projects 1.37 percent pa as the most optimistic long-term projection of fuel efficiency. The 1.4 percent pa efficiency gain on which Jet Zero relies, Finlay Asher, a former aircraft engine designer at Rolls Royce, told us, is “wildly optimistic.” There are “no large step-changes in efficiency around the corner and it takes 10-15 years to certify a significant new aircraft and engine design. So, anything we do see in 2035 - e.g. new designs entering service - will not be the predominant aircraft in service in 2050, due to the 20-30 year lifetime of aircraft.”

A deeper problem with efficiency improvements are their rebound effects. Improvements reduce costs which spur demand, leading to more miles flown. Historically, the global aviation industry has grown at approximately three percent pa, far exceeding the efficiency gains of about one percent. According to the Climate Change Committee (CCC), if demand is not constrained, Britain’s aviation industry will grow at an average rate of over two percent pa over the next few decades. Earth’s systems care little that less kerosene is required per passenger if more in total is being burnt due to air travel’s overall growth.

EDIT

The offset hopes of Jet Zero and Sustainable Aviation are mostly pinned on trees. We can agree: trees should return. Half of them - three trillion - have been removed by humans; a better balance should be restored. Yet there are caveats. Trees are not interchangeable units. Old forest is a complex ecosystem with dense understories; it cannot be ‘replaced’ by plantation silviculture. And people inhabit the places where aviation firms wish to site plantations. What of their fields, livestock, and lives? Bioenergy with carbon capture and storage (BECCS) would have to grab an area one or two times the size of India to achieve a 50 percent chance of staying below 2C. Offsetting through afforestation could threaten food security, if global agriculture is not radically reformed. Offsets, in Sustainable Aviation’s definition, are processes that ensure a permanent reduction of emissions that cannot be reversed. Frankly, this is a con. Afforestation is a moment within the carbon cycle in which reversal is guaranteed—when the trees die and rot, or burn. This summer has seen the forestry offsets of blue-chip corporations go up in smoke. The ideology of offsetting ought to go the same way.

EDIT

https://theecologist.org/2021/aug/31/jet-zero-one-way-ticket-climate-hell

[hunter]

1. Sustainable air travel probably isn't possible without nuclear power and synthetic fuels

Switching to biofuels would be an environmental disaster.

Agriculture for ordinary food already has a huge environmental footprint. Don't add fuel to that.

We know how to make jet fuel using carbon dioxide extracted from the ocean or atmosphere using nuclear power. We just have to do it.

There's no other technology on the horizon that could power trans-oceanic air travel approaching the speed of sound.