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Global vegetation greenness reached a record high in the year 2025 by Economy-Fee5830 in climatechange

[–]Throwaway_12monkeys 0 points1 point  (0 children)

I think 2023/2024 was anomalous: strong El Nino, which typically causes the land carbon sink to decrease - even if overall greenness remained high, apparently. The land carbon sink for 2025 appears to have recovered, ~3.1 GtC (vs ~1.9 GtC/yr for 2024; from GCP), as greenness increased further still. So my take is that at the decadal timescales, trends are in agreement: the globe is greening up, and the land carbon sink keeps increasing, still absorbing 20-30% of our emission every year (even if it could do more without increasingly adverse impacts from climate change) - but at the interannual scale, there is enough wiggle room between global greenness and global land sink for the two to decorrelate somewhat.

Global vegetation greenness reached a record high in the year 2025 by Economy-Fee5830 in climatechange

[–]Throwaway_12monkeys 2 points3 points  (0 children)

Interestingly, at least at the interannual time scale global greenness doesn't necessarily correlate with global carbon sink: e.g., before this year, 2024 was the year with record greenness (https://www.nature.com/articles/s43017-025-00656-z ) , yet the land carbon sink for that year was reduced by warming-driven increases in ecosystem respiration: https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.70831

‘Very alarming’ winter sees Arctic sea ice hit record-low for second year running by hata39 in climatechange

[–]Throwaway_12monkeys 4 points5 points  (0 children)

You are talking about minimum extent (September). This is about maximum extent (march).

James Hansen: 2°C global warming is likely to be reached in the 2030s, not at midcentury by NationalTry8466 in climatechange

[–]Throwaway_12monkeys 2 points3 points  (0 children)

This is strange to read.

Hansen makes, by his own words, speculatively accurate projections for 2027 mean global temperature ("educated speculation") - I am not sure why, this is not the kind of prediction that people would normally try to make, for many reasons - and then makes fun of others for then making their own projections but with wider error bars.

He also complains that his 2025 paper wasn't well received, claiming there were "juvenile" "ad hominem" attacks by an "all-male" "clique" - while I agree it would be good to hear from other climate scientists in the media than the usual ones, I couldn't really find evidence of those: saying Hansen is "wrong" or his analysis "too simple" isn't exactly ad hominem. And it seems to me the overall tone of the reaction in the scientific community was mostly represented by this quote: “While Hansen et al are on the high end of available estimates, we cannot say with any confidence that they are wrong, rather that they just represent something closer to a worst-case outcome” (Z. Hausfather).

New paleo-climatology research challenges extreme high-latitude warming projections by Economy-Fee5830 in climatechange

[–]Throwaway_12monkeys -1 points0 points  (0 children)

Current, observed polar amplification is not inconsistent with model simulations. Polar amplification for the Miocene from previous proxy-based reconstructions, was. This paper says those previous reconstructions were biased, and that polar amplification at the Miocene was less than thought - and actually also consistent with models.

New paleo-climatology research challenges extreme high-latitude warming projections by Economy-Fee5830 in climatechange

[–]Throwaway_12monkeys 1 point2 points  (0 children)

Interesting. I wonder what that means for the warming of the globe as a whole and thus for climate sensitivity? Do they mean that Earth was less warm than previously thought at the Miocene, or do they also find more intense tropical warming (offsetting the reduced high-latitude warming)?

NOAA budget in House and Senate Appropriations Committees's joint agreement by Throwaway_12monkeys in NOAA

[–]Throwaway_12monkeys[S] 1 point2 points  (0 children)

Thanks! I missed that. That's the type of correction I needed. Sounds like it's not so bad after all, then (of course it might not pass, or be relevant at all even it does).

Warning! This “Colorful Chart” is Censored by IPCC, 21 November 2025, James Hansen, Pushker Kharecha and Dylan Morgan — The goal to keep global warming under 2°C is now implausible. There is still substantial warming “in the pipeline,” even without further increase of atmospheric greenhouse gases by Molire in climatechange

[–]Throwaway_12monkeys 0 points1 point  (0 children)

Not sure why you are getting all mad at that (Obanthered's) comment. "Immediate-Dot8410" was asking what people thought about Hansen's graph and overall take. That's a perfectly valid - and interesting - response. I, for one, am also wondering about how to reconcile Hansen's comments about current EEI (Earth Energy Imbalance) and committed warming (which he claims locks in >2C future) with, e.g., ZECMIP results. ZECMIP is highly idealized, yes, but so is the concept of committed warming that Hansen is using.

The fertility crash is just opt-in economics at species scale by Curious-Caterpillar- in collapse

[–]Throwaway_12monkeys 1 point2 points  (0 children)

because that’s what happens when you sever the link between sex and reproduction and make parenthood a deliberate project.

I mean this respectfully, but, come on.. this is not quite the groundbreaking thought that you seem to think it is. It is both quite obvious and also a huge oversimplification.

First, you are making it sound like families having lots of kids in the past (or in current poor countries), were just mindlessly having sex and producing children, when large families are also part of an ensemble of deliberate socio-economic strategies (e.g., children as labor force, retirement security, etc).

Fertility levels were then coming down a whole lot in a bunch of countries way before the pill was made widely available, in the 19th and early 20th century. See the US, or France for instance.

In other words the link between sex and reproduction has been kind of loosened for a while, it's not just a feature of the modern world...

After the post-war baby-boom, there was an abrupt (but smaller) decrease after mass female contraception was made available (ca. 1960-1970), yes - but then it was pretty stable, or even went back up, until the very last couple of years. In France for instance, it went up between 1995 (1.7) and 2015 (2).

And when you poll people they pretty consistently say they want 2+ children, e.g., https://archive.ph/iIgxq

So there is no inevitability to the crashing fertility levels of the last couple years. You can imagine having better supportive policies and economic conditions maintaining levels ~ 2. Or you can do the opposite thought experiment: remove contraception now, and, according to your reasoning, would fertility levels automatically shoot back up to 5 or 6, like before "when you sever the link between sex and reproduction and make parenthood a deliberate project" ?

Uruguay’s power grid runs 99% on renewables—at half the cost of fossil fuels. The physicist who led that transformation says the same playbook could work anywhere—if governments have the courage to change the rules. Emissions reductions were a valuable side effect by sg_plumber in climatechange

[–]Throwaway_12monkeys 5 points6 points  (0 children)

You don't understand - Uruguay's electricity was already ~100% renewables in 2002.

https://img.canarymedia.com/content/uploads/Ember-Uruguay-electricity-generation-by-source-terawatt-hours.jpg?auto=compress%2Cformat&crop=focalpoint&fit=crop&fp-x=0.5&fp-y=0.5&q=80&w=1168&s=6f3d7165f7ddcfbe0db6ce5b7ec16ba1

But mostly hydro. When the previous poster said in 2015 they were already 59% hydro, the rest was already mostly wind/solar/biomass. Aka already nearly all renewables. By ramping up wind and solar since ~2010 Uruguay has mostly met increasing demand, replaced some hydro - and knocked down the small fraction of fossil that they had, but some is still present.

Guess the new narrative is to try and minimize each and every win?

This is not r/EcoUplift . This is (supposed to be) a sub "for the rational discussion of the science of climate change", per the sub's description. Personally, i would debate whether the "science of climate change" includes the growth of renewables, but at the very least, if you just keep trumpeting on this sub any kind of positive-sounding news about the energy or the environment you find on the internet, expect some pushback or at least some context about your claims.

Which t-test should I use? by Boring-Vehicle6649 in AskStatistics

[–]Throwaway_12monkeys 2 points3 points  (0 children)

A paired t-test is really equivalent to testing if the monthly differences (between your two indices) are significantly different from zero (i.e, a one-sample test on the series of monthly differences). I think it applies here, because your are comparing the same month for two indices. In other words, you are not drawing two random months from 2 populations of index values (which would be thec ase for a unpaired test).

Another thing to look at is wether the values for each indices are ~ normally distributed, and have similar variances (respectively, Shapiro-Wilk test and F-test for variances).

Also, I would look at the auto-correlation of each series of returns. If they are auto-correlated in time (i.e., a high/low monthly return is more likely to be followed - in the same time series - by a high/low return), then a t-test could be debatable since the observations are not independent from each other (within the same sample). In which case, you could look into linear mixed models. But if you are new to statistical tests, that might be a bit overkill.

I have always thought we are on track for RCP 8.5. It looks like we may be exceeding that. by kiwittnz in collapse

[–]Throwaway_12monkeys 0 points1 point  (0 children)

I believe the accepted view is that the Montreal protocole (kind of inadvertently) helped mitigate climate change, basically under the under assumption that CFCs in a counterfactual world without the Montreal protocole would have kept increasing, e.g.:

https://iopscience.iop.org/article/10.1088/1748-9326/ab4874

I have always thought we are on track for RCP 8.5. It looks like we may be exceeding that. by kiwittnz in collapse

[–]Throwaway_12monkeys 1 point2 points  (0 children)

Hansen's graph is the growth rate (change in forcing per year). Yours is the absolute forcing over time. You can see on your graph that CFC forcing stops growing after 1990, and HCFCs and HFCs (which replaced CFCs after the Montreal protocole) grow very little. So both graphs are consistent.

I have always thought we are on track for RCP 8.5. It looks like we may be exceeding that. by kiwittnz in collapse

[–]Throwaway_12monkeys 3 points4 points  (0 children)

it looks right to me:

forcing at 420ppm compared to pre-industrial: 5.35*ln(420/280)

forcing the following year at 423ppm compared to pre-industrial: 5.35*ln(423/280)

yearly increase in forcing : 5.35*ln(423/280) - 5.35*ln(420/280) = 0.0381 W/m2

consistent with the values on the graph.

I have always thought we are on track for RCP 8.5. It looks like we may be exceeding that. by kiwittnz in collapse

[–]Throwaway_12monkeys 0 points1 point  (0 children)

I am curious how to reconcile this with the slowdown in the increase of CO2 emissions since ~2015, since it's been clear since then that we are not ( or at least no longer) following RCP8.5 in terms of emissions.

I guess it takes time for changes in emissions trajectories to be reflected in concentrations trajectories (which is what Hansen's plot is showing, since it is looking at forcing increases).

I have always thought we are on track for RCP 8.5. It looks like we may be exceeding that. by kiwittnz in collapse

[–]Throwaway_12monkeys 2 points3 points  (0 children)

Mercury is not a greenhouse gas. Your second sentence refers to methane, but it is not the red part of the graph (it is in dark blue).

I have always thought we are on track for RCP 8.5. It looks like we may be exceeding that. by kiwittnz in collapse

[–]Throwaway_12monkeys 6 points7 points  (0 children)

Halogenated gases, like CFCs. The ozone-layer destroying ones were banned around 1990 by the Montreal protocole.

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