As the nice graph shows, predictions (based on the laws of physics) not only foresaw warming, but got the amount of warming right--actual numbers are the gold standard for science. And the paleoclimate evidence gives essentially the same number (viz. sensitivity of three degrees C for doubled CO2). When you get the same number from two fundamentally different methods, you are in touch with reality.
Based on data that was from 2006 (note 20 years ago) "The IPCC Fourth Assessment Report (AR4), released in 2007, declared that warming of the climate system is "unequivocal". It concluded with high confidence that most global warming since the mid-20th century is "very likely" (over 90% probability) due to human-produced greenhouse gas concentrations. "
Summary for Secretary Scott Bessent - "... due to human-produced greenhouse gas concentrations."
“Yes, the climate does change,” Mr. Bessent said, adding that “we are going through cycles, and I believe that it is very difficult to deconstruct the reasons around why anything changes.”
Thanks Andrew. Your whodunit framing and my diagram are actually making the same argument from two different directions. You eliminate the alternative suspects using modern instrumental evidence. The diagram shows what 66 million years of geological data demands.
Here's the hypothetical that I find most compelling: if you came to the paleoclimate data as a pure empiricist — no knowledge of Tyndall, Foote, or Arrhenius — and plotted CO₂ and temperature across wildly different continental configurations, solar luminosities, and ice sheet extents, you would be forced to conclude there is a hidden variable that explains R=0.97 across all of it. It must be present throughout, independent of geography and orbital state, and logarithmic in its effect on temperature. You would have to invent CO₂ radiative physics from the data alone.
The detective doesn't just find CO₂ guilty. The data makes it the only possible suspect.
It’s hard to imagine Bessent, in his role as a hedge fund guy, telling Soros or any of his other bosses or shareholders, “It is very difficult to deconstruct the reason around why any company generates profits or losses.”
The way to reduce atmospheric carbon at scale is to stop burning fossil carbon, i.e. decarbonize the global economy. That requires national government intervention to eliminate the price advantage fossil fuels enjoy over renewable alternatives. The previous US Administration and Congress took a step in the right direction, but the DJT kakistocracy is gleefully rolling back all decarbonization policies. Please vote Democratic in coming elections, because it's now the de facto party of collective intervention for public good in this country.
Life on the planet is being destroyed by human cynical greed, consumerism, overpopulation of homo magister sapiens stupidus, and commerce.Life on the planet is being destroyed by human cynical greed, consumerism, overpopulation of homo magister sapiens stupidus, and commerce.
The impact of CO2 on our planet is dwarfed by the sun, clouds, and the water cycle. But this is not an excuse to keep using the atmosphere as a trash can.
The climate has been warming in fits and starts since the depths of the Little Ice Age around 1700AD
Why did global temperature cool down to the chilly temperatures of the Little Ice Age?
No one knows, including Andrew Dessler.
Why did it stop cooling around 1700AD instead of just heading into a new glaciation?
No one knows, including Andrew Dessler.
Why didn't it just stay cold after 1700 AD?
No one knows, including Andrew Dessler.
Why did it start warming around 1700 AD?
No one knows, including Andrew Dessler.
But we do know the first two centuries of that current warming can't be from CO2, it hadn't risen enough.
Given our lack of understanding of the reasons that the climate cools and warms, claiming that we know that humans are the sole cause of the current warming is hubris of the highest order.
At best we can say that humans likely contributed something to the last century of warming. But even the scientists Andrew claims understand the climate can't say how much the contribution is.
Estimates from a host of different scientific studies put the warming from a doubling of CO2 at somewhere between 1/2°C and 8°C … and the uncertainty of that number has only INCREASED in the last 50 years we've been studying it.
And when the uncertainty about that critical central value is increasing over time, when climate models with climate sensitivities differing by a factor of 3 are able to reproduce the historical period, that's clear evidence that no, Andrew … we don't know what drives the climate.
"Given our lack of understanding of the reasons that the climate cools and warms, claiming that we know that humans are the sole cause of the current warming is hubris of the highest order."
You're overpluralizing again. Your lack of understanding is solely your problem. It's a commonplace that while climate science doesn't know everything, it knows more than nothing. Among other things, it knows that humans are the sole (i.e. >100%) cause of the current warming trend. The explanation will be wasted on you, but lurkers should see Dr. Hausfather's analysis on CarbonBrief: https://www.carbonbrief.org/analysis-why-scientists-think-100-of-global-warming-is-due-to-humans/. It's your narcissistic belief that if you reject the consensus knowledge of peer climate scientists, then they're the ones who are fooling themselves, that's "hubris of the highest order".
completely false ....temp increase has been proven to be at least 3 degrees C for the TCR ....unfortunately the long term increase is probably between 8 - 9 degrees
"there is a mountain of evidence supporting that explanation and no plausible alternative suspects" ... the extreme scenarios for RCP 8.5 are now deemed implausible. Go climb the mountain and check your data again. Your gold standards might be tarnished.
Good post, but here's a point worth adding:
As the nice graph shows, predictions (based on the laws of physics) not only foresaw warming, but got the amount of warming right--actual numbers are the gold standard for science. And the paleoclimate evidence gives essentially the same number (viz. sensitivity of three degrees C for doubled CO2). When you get the same number from two fundamentally different methods, you are in touch with reality.
Great post, Andy!
And on the same "Whodunnit" theme:
https://www.sigmaxi.org/news/keyed-in/post/keyed-in/2019/11/11/how-do-we-know-that-human-activities-have-affected-global-climate
Thanks, Ben. I liked your post. “Great minds think alike!”
Based on data that was from 2006 (note 20 years ago) "The IPCC Fourth Assessment Report (AR4), released in 2007, declared that warming of the climate system is "unequivocal". It concluded with high confidence that most global warming since the mid-20th century is "very likely" (over 90% probability) due to human-produced greenhouse gas concentrations. "
Summary for Secretary Scott Bessent - "... due to human-produced greenhouse gas concentrations."
Global warming is exacerbated by the heat from Hell the diabolical POTUS brings to the world.
You guys are doing a great job.
Thank You Andrew
Another excellent post, even if it is technically a re-post. Please keep up the great work!
Thanks for sharing Andrew!
A much needed article, Andrew -- thank you for reposting it.
“Yes, the climate does change,” Mr. Bessent said, adding that “we are going through cycles, and I believe that it is very difficult to deconstruct the reasons around why anything changes.”
My head nearly exploded when I read this.
He hasn’t seen your plot :)
Thanks Andrew. Your whodunit framing and my diagram are actually making the same argument from two different directions. You eliminate the alternative suspects using modern instrumental evidence. The diagram shows what 66 million years of geological data demands.
Here's the hypothetical that I find most compelling: if you came to the paleoclimate data as a pure empiricist — no knowledge of Tyndall, Foote, or Arrhenius — and plotted CO₂ and temperature across wildly different continental configurations, solar luminosities, and ice sheet extents, you would be forced to conclude there is a hidden variable that explains R=0.97 across all of it. It must be present throughout, independent of geography and orbital state, and logarithmic in its effect on temperature. You would have to invent CO₂ radiative physics from the data alone.
The detective doesn't just find CO₂ guilty. The data makes it the only possible suspect.
It’s hard to imagine Bessent, in his role as a hedge fund guy, telling Soros or any of his other bosses or shareholders, “It is very difficult to deconstruct the reason around why any company generates profits or losses.”
What the heck does Bessent know? He thinks there are climate epicycles?
This is settled; how to reduce atmospheric carbon at scale is not; without that, we can only slow global warming.
Yes, that's settled too. POTUS and friends don't like that answer. We don't need incantations.
The way to reduce atmospheric carbon at scale is to stop burning fossil carbon, i.e. decarbonize the global economy. That requires national government intervention to eliminate the price advantage fossil fuels enjoy over renewable alternatives. The previous US Administration and Congress took a step in the right direction, but the DJT kakistocracy is gleefully rolling back all decarbonization policies. Please vote Democratic in coming elections, because it's now the de facto party of collective intervention for public good in this country.
The biggest risks to the global system aren’t loud
They’re slow.
And that’s what makes them dangerous.
Climate change isn’t just an environmental issue anymore.
It’s a supply chain issue.
An economic issue.
A stability issue.
Because when temperatures rise and water becomes scarce
Food becomes uncertain.
And when food becomes uncertain
Everything else follows.
Prices rise.
Regions destabilize.
Migration increases.
This is how pressure builds quietly over time.
Experts have been warning about this shift for years
But now it’s no longer theoretical.
It’s measurable.
Crop yields under stress.
Water systems reaching limits.
Entire regions becoming harder to sustain.
And here’s the part most people underestimate:
These risks don’t stay isolated.
They stack.
Climate pressure + economic instability + conflict = systemic risk.
That’s why global organizations are no longer treating these as separate issues
They’re calling them interconnected threats.
Because the future risk landscape isn’t about one crisis.
It’s about multiple slow-moving ones
Hitting at the same time.
No single breaking point
Just rising pressure across the entire system.
And just like in markets
The biggest disruptions don’t come from what you see coming.
They come from what builds quietly
Until it can’t be contained anymore.
Life on the planet is being destroyed by human cynical greed, consumerism, overpopulation of homo magister sapiens stupidus, and commerce.Life on the planet is being destroyed by human cynical greed, consumerism, overpopulation of homo magister sapiens stupidus, and commerce.
The impact of CO2 on our planet is dwarfed by the sun, clouds, and the water cycle. But this is not an excuse to keep using the atmosphere as a trash can.
The climate has been warming in fits and starts since the depths of the Little Ice Age around 1700AD
Why did global temperature cool down to the chilly temperatures of the Little Ice Age?
No one knows, including Andrew Dessler.
Why did it stop cooling around 1700AD instead of just heading into a new glaciation?
No one knows, including Andrew Dessler.
Why didn't it just stay cold after 1700 AD?
No one knows, including Andrew Dessler.
Why did it start warming around 1700 AD?
No one knows, including Andrew Dessler.
But we do know the first two centuries of that current warming can't be from CO2, it hadn't risen enough.
Given our lack of understanding of the reasons that the climate cools and warms, claiming that we know that humans are the sole cause of the current warming is hubris of the highest order.
At best we can say that humans likely contributed something to the last century of warming. But even the scientists Andrew claims understand the climate can't say how much the contribution is.
Estimates from a host of different scientific studies put the warming from a doubling of CO2 at somewhere between 1/2°C and 8°C … and the uncertainty of that number has only INCREASED in the last 50 years we've been studying it.
And when the uncertainty about that critical central value is increasing over time, when climate models with climate sensitivities differing by a factor of 3 are able to reproduce the historical period, that's clear evidence that no, Andrew … we don't know what drives the climate.
Best to all, including Andrew,
w.
"Given our lack of understanding of the reasons that the climate cools and warms, claiming that we know that humans are the sole cause of the current warming is hubris of the highest order."
You're overpluralizing again. Your lack of understanding is solely your problem. It's a commonplace that while climate science doesn't know everything, it knows more than nothing. Among other things, it knows that humans are the sole (i.e. >100%) cause of the current warming trend. The explanation will be wasted on you, but lurkers should see Dr. Hausfather's analysis on CarbonBrief: https://www.carbonbrief.org/analysis-why-scientists-think-100-of-global-warming-is-due-to-humans/. It's your narcissistic belief that if you reject the consensus knowledge of peer climate scientists, then they're the ones who are fooling themselves, that's "hubris of the highest order".
Thanks, Mal. I note that you didn't point out one scientist that knows what I said they don't know about the climate.
Instead, you accuse me of narcissism, lack of understanding, and fooling myself.
Why do so many alarmists resort to ad hominem arguments instead of quoting what I said and showing it's incorrect?
w.
completely false ....temp increase has been proven to be at least 3 degrees C for the TCR ....unfortunately the long term increase is probably between 8 - 9 degrees
Thanks, Dave, but there is no such agreement about either the TCR or the ECS. See below.
w.
https://i0.wp.com/wattsupwiththat.com/wp-content/uploads/2021/08/knutti-ECS-estimates.png?w=936&quality=75&ssl=1
you have referenced a well known global warming denier .....enough said
Dave, I wrote the post in question. Attacking me as a "denier" instead of attacking my ideas is an "Ad Hominem Fallacy".
Anyone calling someone a "denier" is trying to discredit their opponent by attacking the person WITHOUT dealing with their scientific claims.
The only valuable use of the term is to reliably identify people like you whom anyone can ignore without remorse or error.
w.
"there is a mountain of evidence supporting that explanation and no plausible alternative suspects" ... the extreme scenarios for RCP 8.5 are now deemed implausible. Go climb the mountain and check your data again. Your gold standards might be tarnished.