this post was submitted on 09 Jul 2024
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Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.

As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades: Graph of temperature as observed with significant warming, and simulated without added greenhouse gases and other anthropogentic changes, which shows no significant warming

How much each change to the atmosphere has warmed the world: IPCC AR6 Figure 2 - Thee bar charts: first chart: how much each gas has warmed the world.  About 1C of total warming.  Second chart:  about 1.5C of total warming from well-mixed greenhouse gases, offset by 0.4C of cooling from aerosols and negligible influence from changes to solar output, volcanoes, and internal variability.  Third chart: about 1.25C of warming from CO2, 0.5C from methane, and a bunch more in small quantities from other gases.  About 0.5C of cooling with large error bars from SO2.

Recommended actions to cut greenhouse gas emissions in the near future:

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....neither a Biden presidency nor Trump presidency would put the U.S. on track to achieving net zero emissions by 2050, the benchmark needed to prevent catastrophic warming of over 1.5 degrees Celsius

As alarming as that is, however, it does not mean that Biden and Trump are the same...

...a Trump administration would still add an additional 4 billion tons of greenhouse gas emissions to the atmosphere by 2030 compared to a Biden administration, according to Carbon Brief’s analysis.

That additional 4 billion tons could add more than $900 billion in global climate damages compared to Biden, the study’s authors claim.

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[–] 50 points 2 days ago (1 children)

neither a Biden presidency nor Trump presidency would put the U.S. on track to achieving net zero emissions by 2050, the benchmark needed to prevent catastrophic warming of over 1.5 degrees Celsius.

My guy, we’re at 1.5 now

There’s a fiction that it’s far away, because all the pleasant theories that meant we were going to avoid the catastrophic outcomes put it far away

But it’s not. It’s here now. And things will get much, much, much worse from this point forward. As the author points out, we’re still setting a new record for how much fossil fuel we are burning, every single fucking year.

Yes, Biden is better, by a significant-fraction-of-the-federal budget amount. He spent a trillion dollars on the problem, and how he got the current government to be okay with that much, I have no idea.

But compared to what’s required, it’s pitiful. It’s turning on the seat belt sign when the plane’s engines are off, and you’re over the ocean. It’s moving the steering wheel around when your car is already sliding down the embankment towards the high cliff-face.

The problem is, we’ve still got our foot hard on the gas, even though we’re clearly going to go over the edge, while we keep congratulating ourselves on hitting our targets, because we lifted up on the pressure by a fraction of a fraction of an inch.

[–] 6 points 2 days ago (1 children)

I see this misconception a lot and it's really unfortunate. We aren't at what climate scientists call 1.5°C. Being at 1.5°C in the means the average anonomly being over 1.5 for a period of decades. It isn't just a case of scientists being cautious it a completely different impact in the climate. It implies different amounts of impacts and different levels of heat energy in the whole system.

Yes we have hit 1.5°C over the last 12months partly down to el nino which is expected to subside shortly. Though there is some discussion about whether this year was an expected randomly anonomly or whether it suggests some feedback loop that's been underestimated but we can't know until enough time has passed (maybe a year).

All that just means both that the impacts we are already saying are less worse than you'd expect at long term 1.5°C and therefore we should be extremely worried but also that we have factored that in in our estimates of what outcomes are possible (though the 1.5°C window is increasingly narrow because as you say we still have our foot on the gas). So there is still time to make an impact and every fraction of a degree and kg of CO2 matters.

[–] 5 points 2 days ago* (last edited 2 days ago) (1 children)

I find it unlikely that the average temperature year on year is going to go down now, and bring the average over a period of decades back down below 1.5.

Yes I know about El Niño. I don’t think the drop in temperature is going to bring us back down below 1.5 for any significant length of time. Certainly not for decades. Maybe for a single year. I am not a climate scientist, so maybe I’m missing something, but I can look at the graph and understand that (1) they are clearly using a baseline that includes some amount of increase already baked in, for whatever reason, (2) we are roughly 1.5 degrees above the real baseline, and (3) the idea that the trend will suddenly reverse or even hold steady now that we’re at 1.5 seems like pure fantasy since the direction of all human activity year by year is still to increase the slope of the line, not decrease it.

So there is still time to make an impact and every fraction of a degree and kg of CO2 matters.

This is a good point. The sheer apocalyptic magnitude of the problem means that every tiny amount of change matters. Billions will die. There probably isn’t a way to prevent that completely anymore. But if we can tick things down by a fraction and save a few hundred thousand people, preserve a species of food crops that would have gone extinct, IDK what the exact outcomes are but the point is tiny changes will have a massive impact and they’re important even if the situation is dire.

[–] 3 points 2 days ago (1 children)

The answer to your questions are: yes it's a different baseline to the one chosen by the Paris agreement, different baselines are chosen for relevant to different elements of the issue. Likely the baseline chosen in your link is down to what reliable data they have and so they choose a baseline from a region of data they have rather than going to other sources. This website provides the latest years official record in Paris Terms I would expect the next one (2024) to be much closer to 1.5°C. On (2) I agree that current measurements suggest an instantaneous/yearly temperature around 1.5°C against the relevant baseline. On (3) you are right that the trend is unlikely to change because it comes from radiative forcing (emissions) that have already occurred so even with sudden zero human emissions we would see an increase or best case a leveling (before maybe long term it can decline as CO2 is naturally removed from the atmosphere or faster if humans find a way of doing so at scale). A trend however is already an average of several time points and you can see in the link you said that year on year variation on that number can be as high as say ~0.3°C. This comes about from non-GHG forcing elements of the system (such as El Niño) that add natural variation. So already you could see 2019-> dropped by 0.2°C even though the trend is up. So you could expect us to potentially drop back down to say 1.2°C for a few years before it goes up again. The link above suggests the best data we have we would likely breach 1.5°C by 2031 so not long at all.

This sounds like a pedantic point but it's actually quite important for the climate and the confusion stems back to how the problem and climate science was chosen to be communicated. Temperature was chosen in part because it's a proxy variable of other parts of the system that are what control the system impacts and it was felt that Temperature would be "naturally understandable" by the general population (and politicians...). This had a bit of a backfire because 1.5°C is not a lot of different when considered in say a room and it highlights why this variable is different and why it matters that it's decadal average rather than a yearly. So if temperature is only a proxy then what are the variables that control the outputs? One key one is the total heat energy stored in different earth systems and there the size of the storage medium matters (so the reason 1.5°C on the world is a lot but on a room isn't is because the sheer volume of the earth you have to have a huge amount more energy). The other place where Surface Temperature adds confusion and complexity is because of the oceans: the oceans have been absorbing some of the heat and that hasn't always been visible to us (as we don't live in the ocean) so if we stopped emitting today the ocean may then deposit some of that heat energy back into the atmosphere so it's a complex interaction. What we really need to know is what the additional level of radiative forcing and how much additional heat energy swimming about in Earth's systems - that is what will control the experience we have of the climate. Greenhouse gases act to stop Earth cooling back down by radiating out to space which is why the effect is cumulative so the difference between a sustained year on year 1.5°C and something that averages less but has a few years of 1.5°C is quite high because they will be different amounts of total energy in the system as a result.

So, the short answer is that the Paris agreement targets are set on the basis on what a decadal rise of 1.5°C by 2100 (i.e the average 2090-2100) means in terms of the excess heat energy and radiative forcing in the system. The limit itself is somewhat arbitrary driven in part by the fact we were at ~1°C when it was agreed and 2°C seemed like a reasonable estimate of something we might be able to limit it to. The origin of 1.5°C rather than 2°C is actually quite interesting and highlights a lot about how climate change policy has been decided but this post is long enough.

This is a good point. The sheet apocalyptic magnitude of the problem means that every tiny amount of change matters. Billions will die. There probably isn’t a way to prevent that completely anymore. But if we can tick things down by a fraction and save a few hundred thousand people, preserve a species of food crops that would have gone extinct, IDK what the exact outcomes are but the point is tiny changes will have a massive impact and they’re important even if the situation is dire.

Agreed, I think this is the right way of thinking about it and the risk of having communicated it to the world as a binary target of 1.5C/2C we risk people completely switching off if/when we finally confirm we've breached it when the reality is it should embolden us further not demoralise us. This is my number one concern at the moment. I would also add that what we doing is "pushing" a system away from it's natural equilibrium and if we push hard enough we might find that we find changes in the system itself which are very hard or impossible to undo. So it's more than just more increase more damages it's also about risks of fundamentally and permanently changing the system.

A potential energy surface with local and global minima to demonstrate how forcing can shift the fundamental equilibrium the system operates in

As an analogy think of the ball in the well of this local minima and we push it back and forth. If we hit it hard enough rather than come back it goes and finds another minima which is just a whole different system than we are used to. These are sometimes called tipping points and the frustrating thing about the complexity of the systems is we don't and can't know for sure where those points are (although we do know they increase heavily as you move above 1.5C upwards). They by definition are hard to model because models are built up from prior experience (data) and these are in part unprecedented changes in the atmospheric records.

A slide about tippings showing how it's like a game of minesweeper where each layer we "dig" down (more temperature increase) the more "mines" (tipping points) we risk hitting.

I haven't mentioned "negative emissions" technologies but it is worth saying in principle you could have a situation where we are able to do significant negative emissions and that might mean we could end up with 1.5C in 2100 whilst having a period of time above it but negative emissions technologies could be a whole other rant. Worth noting though that lots of the pathways that show we could just about keep to 1.5C do rely on negative emissions to different degrees (though also the pathways are limited in how much they think we might be able to push our economic systems).

[–] 2 points 1 day ago* (last edited 1 day ago)


I sorta stand by my statements. Looking over the main graph in your link and doing some sloppy math, it looks like if the 10 year average temperature keeps following its linear line up, it’ll hit 1.5 C / 2.7 F above pre industrial instantaneous three years from now (that’ll be the result of averaging 2022-2031 if things keep going up the way they are, I.e. a smoothed graph will show an instantaneous +1.5 C value in 2027).

Of course, the other side of that is that there’s a strong argument that recent indications are that we’ve hit at least some of those tipping points you’re talking about, with implications that aren’t yet understood by anybody, and so it makes more sense to talk about instantaneous values now, than it does to assume that everything will definitely continue linearly from now until 2031 and so we can smooth the big spikes we’ve been seeing since 2023 back into that linear path because they won’t continue. That’s possible, but to me the probability of it is less than 50/50.

The one encouraging thing I will say is that the leveling off of emissions since 2018 or so is palpable on the emissions graph. It’s not just going aggressively up every year anymore, which is, no joke, to be celebrated a little bit. We’re starting to cope with the problem. I thought it was still shooting up every year. But, of course, even if we’re lucky and there are no tipping points involved, the huge sustained level value on the emissions graph still translates into a steady slope up on the temperature graph, which means we hit 1.5 instantaneous in 2027 or so by this data.

I like your explanation of total heat in the atmosphere, and temperature as an easy proxy for the more accurate numbers in the model… a lot of this stuff is new to me and you gave a lot of detail so thank you.

Honestly, I think the small appearance of 1.5 C in the public mind is overstated. There are quite a lot of people who understand on some level the size of the catastrophe; that’s why people like Greta Thunberg who speak plainly about it get popular. To them, they tie 1.5 to the catastrophe and measuring the scope, not to turning up the thermostat in their house. The people who are saying who cares about 1.5 degrees are mostly operating on denial and bullshit anyway; I think the number of people who are coming at it from an honest perspective but then can be swayed back to thinking it’ll be okay because 1.5 is a small number is less than it would seem.

But yeah, we fucked. Doesn’t mean stop doing everything we can for better outcomes (which, I will fully admit I am not doing on a personal level), but the outcome is gonna be real real bad.

[–] 0 points 2 days ago (1 children)

This is precisely why I don’t like either of them. I suspect trump is worse for our environment. One of trump’s admin, Betsy was also bad for student loan debt, which also was a government fuck up.

[–] 11 points 2 days ago (1 children)

You SUSPECT the guy who told everyone at a fossil fuel conference that he'd roll back environmental protections if they gave him money is worse than the guy who passed some of the strongest climate policies in US history?

[–] -2 points 2 days ago

Any one with their take is a troll.