Carbon emission reduction: News and technology

[L'Emmerdeur]

I found at least six different theories on the etymology/origin of 'taking the piss' but nothing I consider authoritative. I don't have access to the Oxford Dictionary of Modern Slang, but it seems clear to me that nobody is certain.

[Brian Peacock]

lol

[pErvinalia]

Piss off!

[Brian Peacock]

It's old, dated and it's irrelevant.

Why do you think three years old is too old to be relevant? Do you believe the figures or the trend are significantly different to three years ago - particularly given projected sector growth (link & link)? If so please provide a cogent argument (and some reputable sources if you don't think the IPCC is reputable enough).

...

[macdoc]

The IPCC is not a scientific body - it does no science or research and is rather a political organization.

The IPCC, or Intergovernmental Panel on Climate Change, is not a science institute that conducts its own research. It is an intergovernmental body that assesses the scientific information relevant to understanding human-induced climate change. The IPCC synthesizes and summarizes existing, peer-reviewed scientific literature to provide comprehensive reports for policymakers

It is inherently laggy and conservative because of its very nature and subject to political winds.

The IPCC also has some notable weaknesses — its reliance on out-of-date scenarios most obviously. The Synthesis Report was written by a small group of people. For better or worse, the work of this small group of people reflects upon the entire IPCC and the years of effort leading to this week's report

Even this is a year old

The UN’s climate science advisory group, the Intergovernmental Panel on Climate Change (IPCC), is currently meeting in Bulgaria to decide on a timeline for its next “cycle” of reports over the rest of this decade. That decision should have been taken in January, but government divisions arose over aligning IPCC outputs with UN climate negotiations, at a meeting that the IPCC chair described as “one of the most intense” he had experienced.

Political struggle over the final wording of IPCC reports is well known, but this division at the start of the process reflects the organisation’s achievements. The more successful it becomes in disseminating climate knowledge, the more deeply imbued in climate politics it becomes.

I have studied the IPCC for 15 years and think these political factors are often overlooked. For instance, though the reports are written by scientists, governments play an integral role throughout the process. The IPCC is after all an intergovernmental body – it’s governments that decide to produce the reports and give the final approval, not scientists.

Most notably, this involves the final line-by-line approval of a report’s key findings in the “summary for policymakers” (the only bit most people read). Media reporting and accounts by IPCC authors frequently reveal the extent of negotiation over how the latest knowledge of climate change is presented to the public. This has lead to whole sections being deleted and open conflict between scientists and government delegates.

more
https://theconversation.com/inside-the- ... nce-235608
by contrast ...climate scientists discussing the science
https://www.realclimate.org/index.php/a ... over-time/

[Brian Peacock]

OK mac. So you believe the IPCC's synthesis of the science on the extent of and trends in aviation C/GHG emissions are too laggy and conservative, and that the conclusions of the IPCC on the subject suffer from too much political wrangling. Good. That's something we can agree on. The IPCC is laggy and conservative and the conclusions of its reports are prone to the kind of political dilution that results from electoral short-termism, ministerial incompetence, and of course the undue influence of special-interest lobbying.

Though the various IPCC committees and sub-committees examining the scientific literature are populated by some of the top people in their fields, you are clearly better informed than the IPCC on this matter and presumably abreast of the most up-to-date data. For this reason I'm very interested in tapping into your expertise here as I am part of a team producing teaching programmes and materials that promote group- and active-learning projects for Scottish secondary school students focused around climate change and sustainability, implemented across the curriculum. It's important that the team ground our resources in the best possible science available, so I'm particularly eager to find out from you the most reputable and relevant scientific sources showing the current state of aviation's global emissions profile, how this really sits within the broader historical context, and, taking into account the sector's projected growth, what the actual emissions trends are.

[macdoc]

I gave you the links and have many times over the years ....I never claimed I was better informed than the IPCC members - I claimed that the the IPCC was laggy and conservative which you agree with....
So go directly to the key scientists for your project.
Either post up on Real Climate bog, use their resources which exist there all ready in Getting Started or email Gavin.
gavin.a.schmidt@nasa.gov

[Brian Peacock]

I gave you the links and have many times over the years ....I never claimed I was better informed than the IPCC members - I claimed that the the IPCC was laggy and conservative which you agree with....

Well, you were apparently informed enough to feel confident in dismissing the aviation emissions data and to dispute the trend. It really isn't my job to research your assertion for you. So are you going to provide a cogent argument and some reputable sources to support your assertion or are you going to just rely on "because, that's why"?

[Brian Peacock]

Best-case aviation sector fuel use, NO, particulate and CO2 emissions projected to double by 2050.
.

.
International Civil Aviation Organisation, working paper 93 (2022) (PDF).

The ICAO actually frame these increases as net reductions when measured against the 'technological freeze with no operational improvements' line. Interesting how a doubling can be spun as a c.25% reduction eh?

[Brian Peacock]

Political cowardice hindering Europe’s climate efforts, says EU’s green chief

Political cowardice is hindering European efforts to face up to the effects of the climate crisis, even as the continent is pummelled by a record-breaking heatwave, the EU’s green transition chief has warned.

In an interview with the Guardian, Teresa Ribera said that although the effects of the climate emergency were becoming increasingly obvious, they were still not translating into proper action.

“When you see the map of Europe, it’s dreadful,” said Ribera, speaking amid a heatwave with unprecedented June temperatures from Spain and Portugal to the UK.

“We saw it in [the southern Spanish province of] Huelva, where it was 46C on Saturday. It’s 36C in Brussels and 38C in the east. They are absolutely terrible temperatures that have a very serious impact on ecosystems, on the economy and on health. And I think that there hasn’t yet been a real shift from the headlines about extreme meteorological phenomena to preparing people and understanding what needs to be done in the case of certain events.”..

But surely The Invisible Hand of The Market has this covered, once it's accounted for the various negative externalities and confounding variables ... right?

[Brian Peacock]

Best-case aviation sector fuel use, NO, particulate and CO2 emissions projected to double by 2050.
.



.
International Civil Aviation Organisation, working paper 93 (2022) (PDF).

The ICAO actually frame these increases as net reductions when measured against the 'technological freeze with no operational improvements' line. Interesting how a doubling can be spun as a c.25% reduction eh?

Cat got your tongue mac?

I fear you were trying to have it both ways. You can't imply the IPCC data on aviation emissions is exaggerated (an implication I took from your link to an article explaining refinements in sea-ice modelling) AND then say that the IPCC's reports are too conservative.

YOU asserted the IPCC's projected emissions for the aviation sector were "irrelevant" - but you didn't explain why their projections are either too high or too low, even though you've given the impression your think they are both, or how the science has moved on and/or where it has got to.

I see from your posts elsewhere that you're an aviation aficionado. Perhaps you might even go as far as to say you're a bit of an aviation nerd! You seem to know a lot about the engineering involved, and the history of passenger flight, and even the amount of leg room one can expect on this-or-that aircraft with this-or-that carrier. You project a certain excitement about flight and an enthusiastism about the technology and the very idea that we can take to the air and travelling to far-away places at all. I mean, flying is pretty cool isn't it?

But, as much as you love flying, surely you recognise that aviation is a dirty, significantly polluting sector, and one that contributes disproportionately to Global Heating? Aviation accounts for c.2.5% of global CO₂ emissions but has contributed c.4% to global warming historically. In terms of emissions alone, if aviation was a country it would be in the World's top-10 emitters, sitting somewhere below the US, Japan and Germany and somewhere above Brazil, Mexico, and the UK.

Then we have the Sector's own projected growth to figure in (quoted above), which even with new tech and efficiency expectations is still projected to increase its already high share of global CO₂ emissions - emissions that threaten to wipe out the gains from the emission reduction plans of developed economies...

While global oil consumption rose by 0.8% in 2024, oil-related emissions increased by only 0.3%. This was despite aviation emissions surging by approximately 5.5% amid record global air passenger demand. The modest overall rise in emissions from oil use is largely due to the fact that petrochemical feedstocks accounted for 70% of the total volumetric increase in oil use.

Emissions trends between regions diverged in 2024. CO₂ emissions grew in emerging market and developing economies and international aviation and marine bunkers, outweighing reductions from advanced economies led by the European Union, Japan and the United States.

IEA: Global Energy Review 2025 (PDF)

Addressing the sector's growth through to 2050, researchers in a 2023 paper accounted for the emissions reduction factors (ERF) the sector itself suggests are possible to mitigate the projected c.430 million tonnes (MtCO2) that would be emitted to 2050 if nothing changed between now and then. The paper estimates that up to 17% of that total could be saved by the natural replacement of old aircraft with new stock. Up to 11% could be saved through the introduction of 'advanced technologies'. And c.2-4% could be saved by operational improvements. That still leaves c.70% of projected 2050 emissions unaccounted for.

To reach net-zero by 2050 the sector needs to source its fuel feedstocks from 100% carbon-neutral sources - so-called SAFs (sustainable aviation fuels). As the paper notes: "Meeting a net-zero emissions goal by 2050 with SAF would require an increase in SAF production by 57% annually from 2022 to 2030 and 13% per year thereafter, reaching 100% emissions reductions factor by 2050." (my bold) This is only one of a number of papers in this area. Notably however, SAFs are not emission-free, so carbon neutrality will inevitably mean the sector's emitting will have to be offset elsewhere in the carbon economy. The question is: what level of priority should be given to aviation in a net-zero world, and who or what offsets that priority?

As I've mentioned before in our similar 'debates', the issue here is not the theoretical doability of achieving net-zero by 2050 - it's technically possible, in theory - but the scale of the problems the sector faces and the scale of the actions needed to address them. At the moment whatever solutions are being discussed and may eventually be settled on, apparently they have to guarantee sectoral growth and year-on-year investment returns, even when that growth and investment is ultimately underwritten by further heating the atmosphere and degrading the biosphere.