Comment by Biologist123
3 days ago
This was a great positive start to the day. Thanks whoever posted that.
One point curious in its omission is whether the growth of renewables outpaces the depletion of our carbon budget. Presumably that’s the critical metric in all of this.
[Edit: I ran this question through ChatGPT and the initial (unvalidated) response wasn’t so exciting. This obviously put a dampener on my mood. And I wondered why people like McKibben only talk about the upside. It can sometimes feel a bit like Kayfabe, playing with the the reader’s emotions. And like my old man says: if someone tells you about pros and cons, they’re an advisor. If someone tells you only about pros, they’re a salesman.]
>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.
5 replies →
>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.
22 replies →
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.
Even if, for sake of argument, one outright denies the evident exponential growth in solar, a purely linear extrapolation of 2024's rate from [1] puts solar equal to today's coal output by 2042. Solar is fundamentally a factory product, so this is a wildly pessimistic case, just enough interest in the product to keep the lines running. If you believe solar will grow for even a few more years, but still declare that it should level off, it's the mid 30s. If you're willing to just fit the established trend, even that's a vast underestimate. The difference between which of these to believe is just how brave you are.
[1] https://ourworldindata.org/grapher/electricity-production-by...
Solar and wind are booming, but fossil fuels aren't shrinking nearly as fast in absolute terms
There's an article a while ago about the solar boom in a poor country that had unreliable electricity network. The result was, solar wasn't treated as a replacement, but as a new source of energy, which enabled them to do more industrious things. Of course that doesn't help with the carbon budget...
Countries are placing their bets. Fossil fuels will be a massive waste of investment in a decade. Anyone who can extrapolate a graph sees where this is headed.
Usually old energy sources don't go away until there's an economic contraction of some sort.
The rollout of renewables is the main factor in climate predictions for 2100 reducing over time.
They're still bad, but better than they would have been with business as usual or if solar, wind and batteries hadn't plummeted in price:
https://climateactiontracker.org/global/emissions-pathways/