The 1,5 C "target" has now become the firm foothold for legal action against large corporations. Latest example: with the support of NGOs four native residents of a tiny Indonesian island are suing the world's largest cement producer Holcim at the Cantonal Court of Zug/Switzerland (https://callforclimatejustice.org/wp-content/uploads/Climate_Analysis_FINAL.pdf). The lawsuit won against Shell seems to have served as a template. NGOs play a leading or supporting role in these legal actions, trying to circumvent democratic processes and creating more and more precedents.

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Feb 2Liked by Roger Pielke Jr.

Roger, I don't know if you still read comments here but I'll give it a try.

Under the 2 degree target the available carbon budget is large enough that there is a real discussion to be had about who needs to cut emissions to zero and who can retain some emissions beyond 2050. Under the 1.5 target everyone needs to get to zero emissions, and it also opens for an industry to capture CO2 from air (negative emissions).

I believe one of the factors behind the drive for the 1.5 degree target was actually to avoid discussions on the necessity to go to zero emissions.

Do you have any thoughts on this?

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You have written extensively on the topics of misuse of scenarios and the different emission reduction targets (including the temperature targets). I have seen the links you give to papers addressing these things. Currently there seems to be more papers and stories coming out saying that we will miss the 1.5 degree target. Some stories say that we were never on track to meet it anyway (and I believe they are right).

At some point reality always comes back to smack you with your assumptions and/or prejudices in the back of your head. Seasoned travellers in science and research are therefore careful about the weight of assumptions and prejudice in their work.

What do you think will be the fallout for climate science eventually having to drag itself out of the 1.5 degree mud and climb back to the 2 degree target?

What about the story on scenarios, if I read you correctly you are saying we are on track for something like 2.1-2.9 degrees (or at least that is what GCMs are saying based on the realistic emissions scenarios). Would that also mean going back to the 2 degree target makes it possible to argue 2.4 won't be so bad?

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There are many thousands of scientists who work under the general umbrella of “climate science”. Some build instruments, some use instruments to make observations, some monitor the state of things, some collect various data, but only a very few attempt to develop the big picture of how the earth’s atmosphere responds physically to changes in atmospheric composition, and even fewer run the big computers at the National Center for Atmospheric Research (NCAR)* in an attempt to model the entire earth’s atmosphere. Conclusion: Most “climate scientists” don’t have a clue how the atmosphere responds to greenhouse gases, and the few that do attempt this are befuddled by complexity.

* In 1976 I went to NCAR to use their “little big machine” to model atomic collisions with a deck of 3,000 IBM cards. LOL

Roger mentioned Jim Hansen as an early advocate to control greenhouse gases. Jim Hansen was an outstanding climate scientist with numerous important publications. He had a remarkable ability to focus on the key issues in climate, and see the big picture without gigantic computers. He was famous for his quote that believing governmental plans for reducing emissions was like believing in the easter bunny or the tooth fairy – especially without a major role for nuclear. Jim couched all his discussions in terms of CO2 ppm, not temperature.

In terms of atmospheric concentration of CO2 (ACCO2), one can easily approximately trace out the growth of ACCO2 from now to year 2100 based on any arbitrary future scenario for annual emissions. Right now, with ACCO2 at something around 415 ppm, there does not seem to be any way to transition from the present to the future (year 2100) without exceeding 500 ppm. If we can hold the line at 500 ppm in 2100 that might be all we could hope for but it will not be easy. The world is driven by economic pressures and as long as the UN believes that the developing nations are entitled to emit, we won’t get there.

As Roger said:

“Because climate policy target setting was shifting from carbon dioxide concentrations targets to global temperatures, to keep pace, the discourse needed to change as well. So, 450 ppm became recast as 2 degrees Celsius and 350 ppm became 1.5 degrees Celsius, even though 350 ppm had never really been studied and the previous IPCC assessment associated 450 ppm with temperature outcomes of 1.4C to 3.1C.”

Along with this transition in the rhetoric from ACCO2 to global average temperature (GAT), the advocates also adopted the belief system that solar and wind can do it all, there is no role for nuclear, and immediate draconian reductions in emissions is possible. The war on natural gas is totally crazy. At the same time, China, India and Russia continue to dominate uncontrolled emissions.

By relying on annual emissions and the ACCO2, we can pinpoint each year, which nations are dominating emissions, and use this data to project forward how ACCO2 might change in the future. If the world is serious about combatting climate change, it must change its rhetoric and focus, reign in the outliers, introduce widescale nuclear, and get rid of the easter bunny and tooth fairy. If the world allows ACCO2 to continue to rise at present rates, we’ll exceed 500 ppm in 2100, and despite the world’s biggest computers, nobody knows what that will imply.

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don't we have enough evidence that policy making based on models is deeply flawed, anti-scientific and often damaging because the models are damn wrong? From macroeconomics to Covid modelling the evidence about model failures is overwhelming. should we throw them in the bin? no but they need to be put back in their place. they might support decision making subject to the decision makers being able to understand the assumptions, the limitations and the lack of flexibility. you can't bet the farm on models.

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Jan 24Liked by Roger Pielke Jr.

This piece in the German newspaper Der Spiegel calls Hans Joachim Schellnhuber "the father of the two degree target": https://www.spiegel.de/international/world/climate-catastrophe-a-superstorm-for-global-warming-research-a-686697.html (you have to scroll 3/4 down)

A bit different perspective, but mostly in line with what you write. Do you have any comment?

The quote is: "For this reason a group of German scientists, yielding to political pressure, invented an easily digestible message in the mid-1990s: the two-degree target. To avoid even greater damage to human beings and nature, the scientists warned, the temperature on Earth could not be more than two degrees Celsius higher than it was before the beginning of industrialization.

It was a pretty audacious estimate. Nevertheless, the powers-that-be finally had a tangible number to work with. An amazing success story was about to begin.

'Clearly a Political Goal'

Rarely has a scientific idea had such a strong impact on world politics. Most countries have now recognized the two-degree target. If the two-degree limit were exceeded, German Environment Minister Norbert Röttgen announced ahead of the failed Copenhagen summit, "life on our planet, as we know it today, would no longer be possible."

But this is scientific nonsense. "Two degrees is not a magical limit -- it's clearly a political goal," says Hans Joachim Schellnhuber, director of the Potsdam Institute for Climate Impact Research (PIK). "The world will not come to an end right away in the event of stronger warming, nor are we definitely saved if warming is not as significant. The reality, of course, is much more complicated."

Schellnhuber ought to know. He is the father of the two-degree target."

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I have always wondered about whether the election of Trump also pushed the IPCC to 1.5 given that its adoption of 1.5 occurred after the election.

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2ist Century temperatures are very likely to remain below 1.5°C since 1850- ie increases over the next 80 years will probably aggregate less than 0.4°C. Exceeding this target will only happen if ECS exceeds 2.0 – which now seems improbable.

At COP27 the UNFCCC position was that temps would reach 2.5±0.7°C by 2100. The lower bound is just above the 1.5°C target – and all past UN estimates have "run hot".

On the other hand, the 'carbon budget' that the IPCC associates with the 1.5°C target will certainly be exceeded. The China and India projections alone guarantee this will happen

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So the IPCC is as political as NOAA. The leaders of the UN tell the leaders of the IPCC what answers they want and the "scientists" tweek their models or fudge their data or pick different cherries to come up with the right answer and assure continuance of funding. What kind of "scientists" are these? They're just hacks who know what side their bread is buttered on, or maybe they're progressive activists who are willing to manipulate the science to force the policy makers to do what is "right".

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Biomass Bill, after his appearance in Jeff Gibbs' "Planet of the Humans" crowing about the new biomass energy plant at Middlebury College, decided it would be a good idea to be against biomass after said documentary cornered him.

We can think of a bunch of reasons why 1.5 deg C isn't in the cards. CAVEs (citizens against virtually everything, the 21st century version of NIMBYs) rejecting spinning green crucifixes and sun catchers, as Robert Bryce documents at his "Renewables Rejection Database" is the least of it.

Think Simon Michaux's analysis of what's required in terms of metals mining in order to make ONE generation of wind/solar/battery storage/EVs to replace fossil fuels. Think what fuels that metals mining.

We could go on with other examples but we won't here. You get the picture.

We believe future science historians will document more examples of the abrogation of science in this arena than any to this point in human history.

Keep up the great work, Roger.

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Truth is always and everywhere what policymakers need to hear and what they deserve to hear. Clearly, it is not always what they want to hear, which explains the process of developing the IPCC Summary for Policymakers (Summary by Policymakers). It is admirable that you and a few others speak out; and, you have paid the price. The majority of the "consensed" climate science community has been notable in its silence. A few have even chosen to affirm and promote falsehood. This situation persists at our great peril.

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Jan 23Liked by Roger Pielke Jr.

This is fascinating, thanks for digging into it, Roger! Here's my thought. I bet the modellers didn't think it was their job to push back.. they were doing what they were asked to do. Perhaps the problem is that the concept of "science" and "results of modelling" have become problematically entertwined so that the invisible hand of assumptions are no longer visible, nor accessible to the public. Before the "make it so" request came to the modellers, there should have been a panel of reality checkers for the target. Actually there should always in the chain of policy somewhere be a panel of reality checkers, IMHO. Not just scientists, but people who understand the technologies involved.

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I said this in previous posts and I will say it again.

It is really crazy to set policy according to standards of global average temperature (GAT). First of all, the definition of GAT is elusive. Does it include the oceans? How are the different measurement stations weighted? How is averaging done? At what elevation above ground are the measurements made? What about surrounding structures? What about urban warming? What about distribution of stations and quality thereof? What about satellite observations?

From the point of view of setting policy, how is one to know that a given level of CO2 will produce a given level of temperature? In fact, over the last 100 years, the comparison of CO2 to temperature is quite bumpy.

The only thing that is measurable is the atmospheric concentration of CO2 (ACCO2), not the GAT. All policy should be addressed to goals for ACCO2.

A simple way to predict the annual increase in ACCO2 is to (1) estimate the increase if 100% of the CO2 ended in the atmosphere, and (2) estimate the fraction of the increased CO2 that ends in the atmosphere. It is found that each 16.3 Gt of CO2 emitted amounts to the equivalent of 2 ppm of CO2 emitted, but slightly less than half ends up in the atmosphere while the remainder is stored in the biosphere. Thus, the net addition to the atmosphere is roughly 1 ppm per 16.3 GT of CO2 emitted.

Now if the policy makers set limits on emission, that puts limits of ACCO2, and that is the only thing we can measure, and the only thing we can try to regulate.

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Jan 23Liked by Roger Pielke Jr.

I also believe in providing truth, even though it is uncomfortable. Unfortunately many Politicians do not believe in providing truth, and I think that there are now many scientists who no longer seek the truth.

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