Comment by alex_duf
3 days ago
>whether the growth of renewables outpaces the depletion of our carbon budget
I'm not sure I understand. There's no carbon budget, any carbon that we emit is carbon we'll have to re-capture somehow and the longer it stays in the atmosphere the longer it will have a heating effect.
I think renewable have accelerated to the point of matching the electricity growth worldwide: https://ourworldindata.org/grapher/electricity-production-by...
We've also passed the peak of CO2 per capita, but since the population is still growing we are still increasing carbon emitions worldwide. It's going to be a while before we stop emitting anything, and then longer before we start re-absorbing it...
Whenever I hear "carbon budget", I usually understand it as "how much CO2 we can still emit (net of sinks) before the warming passes a certain threshold (for example, some level of the Paris agreement.)
Is that a misunderstanding on my side ?
Shrinking? China is growing their coal capacity (1). What people mistake is China is not "for renewables". They are for maximizing absolute output. That means they are "for everything"
(1) https://www.reuters.com/business/energy/china-has-more-than-...
China ist still adding coal plants but their capacity factor is falling.
In fact Chinas emissions have probably already peaked.
https://www.economist.com/china/2025/05/29/chinas-carbon-emi...
https://www.carbonbrief.org/analysis-clean-energy-just-put-c...
https://www.sustainabilitybynumbers.com/p/china-coal-plants
I didn't mention any shrinking. I just said we'd passed the CO2 per capita peak.
https://ourworldindata.org/grapher/co-emissions-per-capita?c...
This means for any human being we are emitting less carbon than we use to. It's not a big win but I'll take any good trend at the moment.
I highly doubt that we will have global negative emissions (CO2 capturing) within the next decades-- maybe by the end of the century.
Even very rich nations have a handful of prototype plants for CO2 capture right now at best, and the budget for things like this is the first thing that gets slashed by Doge et al.
If we were on track for lots of CO2 capture by 2050, we would see the beginnings already (massive investments, quickly scaling numbers of capture sites, rapid tech iteration).
Fully agree with the rest of your point though. I consider CO2 emissions as basically "raising the difficulty level" for current and future humans (in a very unethical way, disproportionately affecting poor/arid/coastal nations).
I'm also highly confident that human extinction from climate change is completely off the table (and I think a lot of people delude themselves into believing that scenario for no reason).
The problem with carbon capture is volume. There is about 0.04% CO2 in air. So in order to remove a ton of CO2, you would need to process thousands of tons of air, depending on the efficiency of the extraction process.
It's just kind of infeasible to pull the entire atmosphere through these plants. The largest one we have is called mammoth, claimed to remove 36000 tons of CO2 per year, meanwhile our emissions are measured in billions of tons per year. Like over 30 billion.
We would need about 30 mammoths to get to a million tons per year, and 30,000 mammoths to get to a billion. Then multiply by another 30 and in total we would need almost a million mommoth plants just to undo what we are doing right now at the same rate. Carbon capture is like trying to empty the ocean with a bucket.
How are you so confident that extinction is off the table? I've stopped following this stuff because it's depressing but last time I checked we were in dire straits and I haven't heard any good news on this front. I'm just seeing ice caps disappearing, ocean currents changing, weather changing, pretty much everything that's been predicted is now happening and it's not going to slow down any time soon.
> How are you so confident that extinction is off the table?
Because even the worst-case scenarios (=> think RCP8.5) are just not enough to get rid of us.
I can totally see populous breadbasket states turning into unliveable deserts, billions of deaths from famines and heatwaves, iconic coastal cities being lost to the sea and a giant loss of biodiversity-- but I simply don't see this eradicating our species.
Humans are too adaptable, and warming is invariably gonna leave too many survivable holdout regions.
I think that an all-out global nuclear war would be much more threatening to humanity, and even that I'm very confident we would survive as species.
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>I highly doubt that we will have global negative emissions (CO2 capturing) within the next decades
Just to clarify what I wrote, I also highly doubt we'll get it at scale in the near future. We desperately need it though, as well as any other measure that will bend the trends in the right direction.
This may not be the right place for this, but I'm honestly getting very anxious about our climate. Some of the data such as the temperature anomaly is showing an exponential trend. See the scariest graph I've ever seen here: https://www.nytimes.com/2025/06/26/climate/climate-heat-inte...
"Even very rich nations have a handful of prototype plants for CO2 capture right now at best, and the budget for things like this is the first thing that gets slashed by Doge et al."
Might want to take a look at China, or at least what IEA writes about CCUS and the like there.
https://www.chinadaily.com.cn/a/202505/09/WS681d52e5a310a04a...
If electricity is sufficiently cheap it can be cheaper to capture carbon from the atmosphere for chemical industry than to use oil or coal there.
Do you have any source for this extraordinary claim? It's practically a claim of perpetual motion.
Carbon dioxide a tiny fraction of the atmosphere, even in concentrations which are immediately harmful to human life.
At the moment it's 400 parts per million. So in order to extract 1kg of Carbon Dioxide from the atmosphere you have to pump 2500kg of air through the system. This alone makes it unlikely we can do this profitability.
You then need to extract the carbon dioxide using some technique which will probably involve cooling or pressuring that volume of air. Before finally transforming carbon dioxide, a very stable chemical compound, into a reagent which is actually useful (probably carbon monoxide).
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If you actually use captured carbon for something productive like synthetic fuel (where CO2 gets re-emitted) you are kinda ruining the point though.
Thats what makes this even less attractive-- those plants are expensive to build and operate and you can't even really use the product in the most obvious ways.
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It never will be.
My apologies. By available carbon budget, I meant the carbon we can burn before we exceed 1.5 degrees, or 2 degrees etc.
I think 1.5°C is already basically impossible; scenarios between 2°C and 4°C by 2100 over pre-industrial levels seem achievable-- that would be a total remaining CO2 budget of ~3 Tera-tons of CO2 within 2100.
That is an average of 4 tons of CO2/person/year for 10 billion people. Americans are at 3x that right now, Europeans/Chinese 2x, and a few wealthy nations are already there (France, Switzerland, Israel). Poorer countries like India are significantly under that value (for now!).
Doubling that CO2 budget to 6000 Gt would make things significantly worse (5° expected temperature increase or more).
1.5 degrees was last year.
https://climate-adapt.eea.europa.eu/en/news-archive/copernic...
Oh, we're definitely going to need direct air capture, which consumes massive amounts of energy. Fortunately, it's only massive compared to things like global shipping, not compared to the sun that hits the Earth.
I see, thanks for clarifying I got confused there.