Any thoughts on the validity of using the IPC reports as predictions? I.e., if they are predictions of what would have happened otherwise in the absence of interventions, but there were interventions? ¯\_(ツ)_/¯?
Is there a reason you are just testing the buisness as usual scenario? My impression of IPCC reports is that is merely one scenario among many, and by no means the most likely.
BOU is to do with how much CO2 we emit, we now know how much CO2 we emitted up to 2023.Up to present day we have pretty much perfectly followed business as usual emissions. So if you want to test projected warming to 2020 then you have to use business as usual. Once we fall off the BOU emissions path (very likely) you would have to test future projections against the other IPCC scenarios.
I wasn't even aware this was controversial. I'm not paying £30 to read that article, but as far as the title says it doesn't contradict what I said. We have, up until now, being globally emmiting pretty much on par with the IPCC's business as usual pathway. https://wattsupwiththat.com/2023/05/04/introducing-the-realitometer/ is a quick source, but if you distrust that website I can almost certainately find a more reliable source.
"Under this [Business-as-Usual] scenario, the equivalent of a doubling of preindustrial CO2 levels occurs, according to Working Group I, by around 2025"
that says we are only halfway to being on track for 2025, which is to say, we are not on the buisness as usual track, and "the anticipated doubling of atmospheric CO2, which is likely by the year 2060".... well if you look at the report i citied, that puts us in line with not senario A, but Scenario C
"Scenario С (Control Policies Scenario) assumes that a shift towards renewable energies and safe nuclear energy takes place in the latter part of the next century, CF C gases are phased out and agricultural emissions (methane and nitrous oxide) are limited; an equivalent doubling of pre-industrial carbon dioxide will occur in about 2050."
so yeah, I need a better source cause a quick check says your source doesnt match the reports
Why do you feel your attempts to pull out numbers are more accurate than the fairly simple "take the explict claims and evaluate them" approach?
Even if your tools are accurate, then by your logic we have
1. One strong[1] data point showing we are close[2] to business as usual [3]
2. One strong [4] data point showing we are close[5] to scenario C
Which isn't strong evidence for claiming "we obviously are on scenario A", it's strong evidence for claiming "Scenario A and C are insufficiently distinguishable".
So why on earth are you pretending otherwise?
1. how confident are you in your tools ability to extract values?
2. Is that close??
3. I am assuming you are differentiating it from the other scenarios but nothing in that comment clearly stated it.
4. I'm fairly confident the doubling of atmospheric co2 holds a constant meaning to distinguish the scenarios, and holds that same meaning in the article I shared
5. It clearly differentiates the scenarios with clear times (2025, 2040, 2050), and lines us up closely (in terms of the gap between the scenarios) with C
Just to be silly about it, the simplest model I'd really try to fit to that data would be autoregression, a bit more comple, than linear but far more plausible as an underlying mechanism.
I think we’re going to learn a lot about how accurate the IPC reports are in the next few years if we have another El Nino event. Some people claim the last 3 years of La Nina have obscured the actual rise in temperature. I have no idea whether that’s true, but I suspect we will soon.
The IPCC should provide (maybe does, I don't know) a *median* of prediction, because (legitimate) climate change worries are about *tail risk*.
So, if reality diverges from the *mean*, that's not super concerning, given that understanding feedback-riddled climate systems is just really hard---I'd only care much if reality diverged significantly from the median prediction of what IPCC said were the best models... I do expect those to diverge as well though (due to bias at every level, since it's a hot-topic/politically-entangled issue).
Any thoughts on the validity of using the IPC reports as predictions? I.e., if they are predictions of what would have happened otherwise in the absence of interventions, but there were interventions? ¯\_(ツ)_/¯?
Is there a reason you are just testing the buisness as usual scenario? My impression of IPCC reports is that is merely one scenario among many, and by no means the most likely.
BOU is to do with how much CO2 we emit, we now know how much CO2 we emitted up to 2023.Up to present day we have pretty much perfectly followed business as usual emissions. So if you want to test projected warming to 2020 then you have to use business as usual. Once we fall off the BOU emissions path (very likely) you would have to test future projections against the other IPCC scenarios.
Did I miss the part of the post where "Up to present day we have pretty much perfectly followed business as usual emissions"
If he? claimed that, then, well, I'd like to see evidence because that is isn't true, as far as I'm aware
https://www.nature.com/articles/d41586-020-00177-3
If you are claiming that, please provide some evidence to back your claim, cause it sounds redicious
I wasn't even aware this was controversial. I'm not paying £30 to read that article, but as far as the title says it doesn't contradict what I said. We have, up until now, being globally emmiting pretty much on par with the IPCC's business as usual pathway. https://wattsupwiththat.com/2023/05/04/introducing-the-realitometer/ is a quick source, but if you distrust that website I can almost certainately find a more reliable source.
I could use a more reliable source. I assume you are referencing this graph? https://i0.wp.com/wattsupwiththat.com/wp-content/uploads/2023/05/image-45.png?ssl=1
which is presented entirely without context so i have no idea if it actually supports your claims or not.
However it seems real easy to assess this:
1. look at an IPCC report: https://www.ipcc.ch/site/assets/uploads/2018/05/ipcc_90_92_assessments_far_overview.pdf
2. See if we are on the buisness as usual track:
"Under this [Business-as-Usual] scenario, the equivalent of a doubling of preindustrial CO2 levels occurs, according to Working Group I, by around 2025"
here is a meh washington post article: https://www.washingtonpost.com/weather/2021/04/05/atmospheric-co2-concentration-record/
that says we are only halfway to being on track for 2025, which is to say, we are not on the buisness as usual track, and "the anticipated doubling of atmospheric CO2, which is likely by the year 2060".... well if you look at the report i citied, that puts us in line with not senario A, but Scenario C
"Scenario С (Control Policies Scenario) assumes that a shift towards renewable energies and safe nuclear energy takes place in the latter part of the next century, CF C gases are phased out and agricultural emissions (methane and nitrous oxide) are limited; an equivalent doubling of pre-industrial carbon dioxide will occur in about 2050."
so yeah, I need a better source cause a quick check says your source doesnt match the reports
edited for formatting
Good source. I've taken figure 1 of that report. And used https://apps.automeris.io/ to grab projected Carbon emissions for 2019 (to ignore strange COVID effects). I got out 10.57, multiply that by 3.67 (to convert between carbon and CO2 https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator#:~:text=To%20convert%20a%20quantity%20of,carbon%20dioxide%2C%20multiply%20by%203.67.) That comes out at 38.79 Billions of tonnes of CO2. This compares to 2019 reality of 37.08 https://ourworldindata.org/co2-emissions. I had a bit of a crude go at overlaying the Our world in data data onto the IPCC figure: https://ibb.co/dmjK57w
Why do you feel your attempts to pull out numbers are more accurate than the fairly simple "take the explict claims and evaluate them" approach?
Even if your tools are accurate, then by your logic we have
1. One strong[1] data point showing we are close[2] to business as usual [3]
2. One strong [4] data point showing we are close[5] to scenario C
Which isn't strong evidence for claiming "we obviously are on scenario A", it's strong evidence for claiming "Scenario A and C are insufficiently distinguishable".
So why on earth are you pretending otherwise?
1. how confident are you in your tools ability to extract values?
2. Is that close??
3. I am assuming you are differentiating it from the other scenarios but nothing in that comment clearly stated it.
4. I'm fairly confident the doubling of atmospheric co2 holds a constant meaning to distinguish the scenarios, and holds that same meaning in the article I shared
5. It clearly differentiates the scenarios with clear times (2025, 2040, 2050), and lines us up closely (in terms of the gap between the scenarios) with C
I'd be interested in pairing this with estimates of CO2 growth. I'm too lazy to do it myself.
Just to be silly about it, the simplest model I'd really try to fit to that data would be autoregression, a bit more comple, than linear but far more plausible as an underlying mechanism.
I think we’re going to learn a lot about how accurate the IPC reports are in the next few years if we have another El Nino event. Some people claim the last 3 years of La Nina have obscured the actual rise in temperature. I have no idea whether that’s true, but I suspect we will soon.
The IPCC should provide (maybe does, I don't know) a *median* of prediction, because (legitimate) climate change worries are about *tail risk*.
So, if reality diverges from the *mean*, that's not super concerning, given that understanding feedback-riddled climate systems is just really hard---I'd only care much if reality diverged significantly from the median prediction of what IPCC said were the best models... I do expect those to diverge as well though (due to bias at every level, since it's a hot-topic/politically-entangled issue).
Nice article.
"The solution is to test the model against data that not used" should be "data that were not used."
Thank you. It’s very strange that yours was the only article I’ve seen that assessed the predictions out of sample like this.