benjhm

That's a pity, I had been expecting level or a slight decrease in fossil CO2 (due to economy in China which has 1/3 of emissions), so maybe I was wrong, or maybe it's just too soon to say (they give error range -0.3% to +1.9%). There's still 1/6th of 2024 to go, including part of the NH winter whose heating demand varies with weather, most of the raw data that goes into these calculations is likely not so fresh, and chinese economic projections tend to be 'optimistic'. The rise in LUC CO2 is mainly hangover from tail of El Niño early this year, leading to fires in southern hemisphere. So it's still possible, if we think monthly, that the global peak was early this year, i.e. in the past.
Of course, they release GCB before the end of the year to try to influence the COP, which makes more sense when the COP is in mid-December (as typical, but not necessary - iirc COP1 was April and COP2 July). But does projected bad news really help motivate the world? I'd emphasise mixed news - some trends up, others down, which shows what difference we can make.

Och some things never change ... at least Ed Uni had the same reputation when I was a student there from 1990, but in reality this mainly applied to humanities departments - in chemistry, geology, agric, etc. down at the 'King's buildings', it was mostly Scottish students. Overall a fine diversity.

Indeed there is huge momentum in renewable costs. I recall 20 years ago climate economists starting to model endogenous technological change, but they just had to invent ' learning curves' with magic numbers. Now it has happened.
On the other hand, I still wish heat pumps were cheaper. Where I live, the cost is inflated by the requirement for installation by people qualified with refrigerant gases.

Some sense to this - global emissions probably just peaked because China's housing bubble burst - responsible for much more CO2 than AI/crypto, and even a communist government can't effectively control such crashes. So no, we are not f****d, but not always saved for noble reasons.
Also regarding crypto - how much of that was sustained by russians evading sanctions - which new team in US is likely to remove ?

Makes sense. China holds a good hand now, as they have probably peaked emissions five years ahead of their promise, and are not yet obliged with financial contributions. Also they need to sell renewables, electric cars etc. - especially to southern countries while US and EU put big tariffs. And if you look at the numbers, US is no longer so important in the world.

Your first sentence is correct. But if you look at the historical data, the sharpest drop in chinese fertility rate was several years before they introduced the one-child policy, which also ended several years ago without apparently making any difference. Also, fertility rates in Taiwan, South Korea, Japan are even lower. As these rates are also lower than europe, that maybe related more to housing affordability and density, possibly combined with some common evolution of 'eastern' values.

In high latitude winters, snow provides light and contrast - without it the world is just shades of black brown grey. Some people there may think a little extra warmth could be welcome, but -2ºC with snow is much better than +2ºC with cold grey drizzle.

It's not necessary for world leaders (with all their entourage) to attend every year, and the total numbers should come down, it's a big waste of energy, especially regarding aviation emissions.
Only a handful of people in a few small rooms can actually change anything in the key decision texts - the other diplomats repeat old positions, and most other participants are just there to lobby for support for their projects.
I recall the early COPs - attended COP2 with only 2000 people, not 80k like last year. Also COP15 where world leaders did turn up, but didn't conclude.
The discussions leading to big decisions are are a multi-year process. COP30 next year in Belem, where new targets are expected, is more important than this year (fortunately, given weak choice of host government).

I'd say there might be an 'optimum' somewhere in between - on average slightly lower rate than replacement, aiming for sustainable decline without crisis, preserving cultural heritage - as human cultural diversity matters as well as biodiversity. But we lack intelligent discussion of this topic - partly as it’s hard for people to imagine intuitively how small annual changes integrate over time.I'd like to further develop my interactive model - designed for climate projections but including a demographic model, to help people experiment for themselves, including regarding potential changes in global migration fluxes.

As a kid, I learned to write i = i +1, before school maths taught me it can't. The point is, computers do iteration well, especially to model dynamics of real non-linear systems, while classical maths is good at finding algebraic solutions to equilibria - typically more theoretical than real. Calculus is great for understanding repeatable dynamics - such as waves in physics, also integrating over some distributions. But even without knowing that well you could still approximate stuff numerically with simple loops, test it, and if an inner-loop turns out to be time-critical or accuracy-critical (most are not), ask a mathematical colleague to rethink it - believe in iteration rather than perfect solutions.

Actually, if you swapped 'on' for 'by' (and cut 'US diminishment' etc.) you'd have a point there - Russian emissions per capita are among the world's highest and growing, while they decline in the rest of the north - most commentators don't notice as Russia has no NGOs left to shout about it.
(Note emissions fell since 1992 but from an even higher peak - while soviet industry produced that huge stockpile of missiles, tanks etc. now being used up). Also there are potentially huge climate feedbacks in Siberian forests and tundra, and we should be cooperating globally to help manage that. Maybe 'europe from lisbon to vladivostok' was a missed opportunity. I crossed siberia by train, helping local scientists attend COP3 in Japan, even studied many russian songs. Maybe one day we'll cooperate again. But now I and many others here think the only way to end these wars, is for russians to dump their crazy leadership which started them.

I'm not an expert on biodiversity, although I'd like to be. Of course extinction is forever, and habitat loss is exacerbated by climate feedbacks. But we have to accept change, making less fuss about protecting 'native species' (to me this feels rather like nativism wrt human immigration), and recognise that life on earth has suffered and survived worse calamities in geological history, so it will re-adapt to new situations, if we let plants and animals (including ourselves) move with the climate. We can't save all the old ecosystems (for example from considering thermodynamics of the symbiosis within coral reefs, I have little hope for their survival with combination of higher T and CO2 and SLR), but we might help create new opportunities for new ecosystems in new places. In this context, what matters is the rate of changes - as it takes time for trees to grow, soil to accumulate - rather than 'equilibrium' changes.
I don't know whether the OP was specifically reacting to lack of progress at the Biodiv COP16 in Cali, as well as US election and climate news, but as an old hand at COPs too, I hadn't expected much, at the end of these circuses the only certainty is that the show must always go on (or diplomatic teams would kill their own job). In my opinion both COP processes have got bogged down talking mainly about money, and the UN system as a whole has not been working for many years, so we need some radical rethinking about global cooperation. Nevertheless on a local and regional level plenty of positive things are still happening. Also human population growth is also peaking, or heading that way, on all continents except Africa, and in many countries there is reforestation recently.
In general, bear in mind that many big science consortiums publish reports around this time of year, with extra-worrying headlines, in a bid to influence the COP processes. This is just part of the new-normal seasonal cycle, like the grey skies where I live, but not a reason to lose hope - brighter days will follow.