RealClimate logo

Two graphs show the path to 1.5 degrees

Filed under: — stefan @ 21 April 2021

In the Paris Agreement, just about all of the world’s nations pledged to “pursue efforts to limit the temperature increase to 1.5 degrees Celsius above pre-industrial levels”. On Saturday, the top climate diplomats from the U.S. and China, John Kerry and Xie Zhenhua, reiterated in a joint statement that they want to step up their climate mitigation efforts to keep that goal “within reach”.

But is that still possible? Here are two graphs.

Global temperature trend (relative to mean 1880-1910, NASA data). The colored curve shows the moving average over 12 months, the black line the linear trend over the last 50 years. Transient warmth following two strong El Niño events in the tropical Pacific is indicated by arrows. If everything continued like this, the 1.5 degree limit would be exceeded around 2040.

The first graph shows the global temperature trend. Warming has progressed essentially linearly for fifty years in response to increasing CO2 emissions. Although the latter accelerate the rise of CO2 in the atmosphere, on the other hand, radiative forcing (which causes warming) increases only with the logarithm of CO2 concentration, and therefore roughly linearly since the 1970s. Any acceleration of warming over the last decade is not a significant trend change. It is linked to two El Niño events in recent years, but that is part of natural variability. Does anyone remember the discussion about the supposed “warming pause” in the early 2000s? It also never was statistically significant, nor did it signify a trend change.

Therefore, if emissions continue to grow, we expect a further roughly linear increase in temperature, which would then exceed 1.5 degrees around 2040. If we lower emissions, the trend will flatten out and become roughly horizontal as we reach zero emissions. Therefore, these observational data do not argue against the possibility to still keep warming below 1.5°C.

Exemplary emission trajectories with CO2 emission budgets that, according to the IPCC, correspond to limiting warming to 1.5 °C with 50% probability (solid) or limiting it to 1.75 °C with 67% probability. The same emissions as in 2019 were assumed as the starting point in 2021, assuming the “corona spike” in 2020 is likely to be temporary.

The second graph shows global CO2 emission trajectories with which we can still limit warming to 1.5 °C, at least with 50:50 probability. This means: given the uncertainties, this could also land us at 1.6 degrees, but with a bit of luck, it could land us a bit below 1.5 degrees. The core conclusions:

  •     It is not yet impossible to keep warming below 1.5 °C.
  •     This requires roughly a halving of global CO2 emissions by 2030 (as already stated in the IPCC 1.5 degree report).
  •     If the world dithers for another ten years before emissions fall, it will no longer be possible (red curve).

It should be noted that I have not assumed net-negative emissions here. Many scenarios assume that we first emit too much and that our children then have to pull CO2 out of the atmosphere after mid-century – I think this is not very realistic and also ethically questionable. I think we will probably not be able to achieve more than reducing global emissions to net zero. Even that would require CO2 sinks to compensate for unavoidable residual emissions, e.g. from agriculture.

Conclusion: The limitation to 1.5 degrees is still possible and from my point of view also urgently advised to avert catastrophic risks, but it requires immediate decisive measures. I am curious to see what the climate summit scheduled by US President Joe Biden will bring in the coming days!


Fact check by Climate Analytics to the claim that we can no longer limit warming to 1.5°C.

This article originally appeared in German at KlimaLounge.

166 Responses to “Two graphs show the path to 1.5 degrees”

  1. 1
    Richard Yates says:

    Posts like this only further reduce the scope of the meaning of the word “possible,” a disturbing trend in climate science. Here “possible” means only whether warming has continued beyond the point that the IPCC’s CO2 emission budgets even apply.

    In the real world, “possible” must also include an evaluation of whether those sample emission budgets can be achieved given the social and geopolitical realities and vastly disparate levels of resources across the globe.

    When half the politicians of the richest country do not even think that climate change is a problem, then the extraordinary conclusion that it is possible to follow those IPCC budgets requires extraordinary evidence. I have not seen that evidence.

    [Response: The argument here is not about politics, and not about whether we can cut emissions to zero by 2040. To understand the background to this, have a look at the Climate Analytics document linked below. It is a response to the claim that even if the world cut emissions to zero by 2040 we would certainly breach the 1.5 °C limit. That is simply not consistent with the evidence and it is based on flawed reasoning, as the colleagues from Climate Analytics detail on 10 pages with all the references to the scientific literature you need. -Stefan]

  2. 2
    Killian says:

    1. Assuming the ENSO effect is limited to those two events in effect and will not affect future warming doesn’t fit with what happens when you goose systems. El Nino tends to accelerate effects long-term because it increases the amplitude of extreme events.

    2. We have signs of accelerations all over the climate map. Downplaying that overall reality is maybe not the best idea. For example, in the last five years we’ve had years with no El Nino yet very low ASI levels.

    There is little or no hysteresis in the system, so each “goose” of the system is a potential trigger of tipping points. Bear in mind the Texas corals…

  3. 3
    Solar Jim says:

    I am also disappointed in this post. Is it not possible for the planet to reach 1.5C increase from pre-industrial just with our present 500 ppm,equivalent or even the actual 420 ppm or so concentration of carbonic acid gas? We are now at about 1.25C.

    I think some climate scientists, whom I wholeheartedly support as a category, get too far ahead of themselves and can be found to contradict, disregard or be unaware of other considered analyses (such as life sciences).

    It is the year 2021 and we are still only talking about global reductions, while financiers, corporations and nation-states are constructing massive fossil buildout or otherwise proping up the status quo. Temperature is only one indication of our peril (and the trend is very bad).

    Regards, Solar Jim

  4. 4
    Dan Miller says:

    it was +1.2ºC in 2020 with a cooling La Niña and the Sun near the minimum of its 11 year cycle. Part of the high temperature during the COVID year may be due to reduced manmade aerosols cooling the planet. This points to the important but still relatively unknown amount of “Faustian” warming we will get when we eliminate fossil fuel burning. Another important factor is the Earth Energy Imbalance (warming in the pipeline) as well as warming from the emissions between now and whenever we stop burning fossil fuels & creating land use changes that contribute to warming.

    On the good side, we can also greatly reduce short-term GHG such as methane, NOx, CFCs, etc. and that should contribute to a lower temperature. But that is countered by emissions from permafrost, shallow Arctic clathrates, soils and forests, as well as Arctic albedo changes, etc.

    And I’m talking about the literal definition of “possible”. I agree with Richard (#1) that possible should also include what is practically possible. But in either case, it seems we are past +1.5(C) and likely +2ºC as well.

    And even if we can avoid going much over +2ºC, the question is is that even an “acceptable” outcome for our children or is it a catastrophic outcome that we should be avoiding at all costs. I come to the conclusion that we should be investing heavily in NET R&D right now.

  5. 5
    Mr. Know It All says:

    Thomas Sowell summarizes government efforts to combat climate change:

  6. 6

    Thanks for this post Stefan.

    In regards to the criticisms already posted, it is important that people working for positive change don’t engage in a ‘circular firing squad’ against others doing or thinking things differently.

    It is clear your post is focused on the physical science, not the immense political and social challenges to achieving the 1.5C goal.

    As a lawyer working on climate litigation (and not a climate scientist), I found your snapshot analysis helpful and thought-provoking in the context of the current public and policy debates.

    Thank you for your ongoing research and public education on RealClimate.

  7. 7
    Henry says:

    I think the most disheartening thing is seeing the amount of decrease in CO2 emissions because of covid. We shut large portions of the world economy down, massively changed how we live and work, and the CO2 emissions decrease is only a blip to where the world was 5 years ago. Now we’ll have to do that every year for a decade. I’m feeling like the guy who starts training the week before the marathon.

  8. 8

    “Possible” is a somewhat detouched word, I would prefer “success probability for a certain action by a certain set of determined people”.
    If this set of people are not homogenous in their will, as is the case for “mankind”, i.e. they are, as a group, not determined, “possible” or “impossible” is not the right term.
    What remains is a success probability 0 < p < 1 for those who really want us to stay below +1.5°C. That means act in spite of uncertainty.

  9. 9
    Piotr says:

    Re: Richard Yates(1) and Solar Jim(3).
    You seem to imply that the authors somehow accept, or even provided cover for, the further emissions. I, on the other hand, read it the same way as Gavin did, i.e. the opposite – as a statement about the cuts and timeline that NEED TO BE IMPLEMENTED IF we are serious to stay within +1.5C.

    And it counters the claim that it is already too late ( is physically impossible to achieve it), which is used, among others, by the deniers who
    smoothly transit from “there is no need to do anything” to “it’s already too late to do anything, so let’s concentrate on the adaptation”, or, in effect, go full Mme Pompadour: “After us, Deluge!”, just without putting it in such honest way.

  10. 10
    Donald Condliffe says:

    I get that this is a theoretical discussion of what is physically possible based on physics. I very much appreciate the author’s stellar credentials and clear thinking. Unfortunately this analysis is purely theoretical and not applicable to the real world. You cannot leave human needs and politics out of the analysis of reducing emissions without eliminating reality from the analysis.

  11. 11
    b fagan says:

    #5 Mr. KIA – here’s a better one from the “public intellectual” at Stanford’s Hoover Institution:

    Title: “Thomas Sowell: Global Warming Manufactured by Intellectuals?”
    Opening statement from the Hoover Institution interviewer mentions that the demand for public intellectuals is manufactured, then he unintentionally demonstrates why a libertarian think tank manufactures theirs.

    He lobs a “What do you think about global warming?” to Public Intellectual Thomas Sowell.

    Within two or three sentences, Mr. Sowell demonstrates he does not understand the science at all, but instead, glibly spouts a misunderstanding about warming, where he confuses extremely specific conditions at the start of interglacial periods with the overall mechanism. He then ignores the evidence of CO2 driving warming during the rest of interglacials, as well as the abundant science erasing any doubt based on little events like the PETM.

    People paying attention will note that a Public Intellectual is calling climate researchers “intellectuals” rather than “working scientists” who use peer review and things Sowell is free to ignore these days.

    Why not instead let Sowell research and publish (after peer review) some studies that look into why NOT regulating tends to produce abuses of the global commons by “free” entities. You know – have him explain why time and again, the evidence shows that regulation follows irresponsible behavior when regulations are lacking.

    That would be a service the Hoover Institution studiously avoids on big problems where lack of regulation fails.

    Remember, Nixon created EPA, not some Democrat. Because he realized we really needed it. And the first Bush signed us into the UNFCCC, not Carter or Clinton.

  12. 12
    Dan Miller says:

    I read the “Fact Check” analysis and it did not give me comfort that +1.5ºC is still possible in a real-world way. But putting aside the details (such as do the models really include all appropriate Earth system feedbacks?), the real issue, as I see it, is the question is framed incorrectly.

    The authors of the Fact Check say since the Australian authors stated it was “impossible” to avoid +1.5ºC, that the onus was on them to show there was zero probability of staying below +1.5ºC. Well, OK, but I think the Fact Check authors are missing the point.

    Since we are literally talking about the lives of our children, we should instead be asking:

    1) What is the temperature that has a 95% chance of not being exceeded under each scenario? Who would put their child on an airplane that only had a 50% or 66% (or even 95%!) chance of reaching its destination without crashing? Why is the 50%/66% temperature even being discussed?

    If the 95% temperature even under the most optimistic plausible emissions scenarios is greater than +1.5ºC (which I’m sure it is), then we must *assume* we are going to breach +1.5ºC and act accordingly.

    2) Is +1.5ºC an “acceptable” outcome for our children? What is the societal outcome of a +1.5º and +2ºC world? How many people would die? How many failed states would there be? How many cities destroyed by SLR? Again, apply a 95% (or 99%) confidence of safety to these estimates.

    When I ponder these questions, I come to the conclusion that we must push for immediate reduction in emissions *plus* massively scale up R&D on carbon dioxide removal (CDR) techniques of all types. No matter what temperature we reach when we finally stop emitting, it will be a better world if we *also* remove massive amounts of excess CO2 from the atmosphere.

  13. 13
    Mike Roberts says:

    I’d support the opening comment and go further. It seems incredible that Stefan make two almost opposite points:

    – It is not yet impossible to keep warming below 1.5 °C.
    – This requires roughly a halving of global CO2 emissions by 2030

    A halving of emissions by 2030 is impossible, given the way humans have behaved since the science clearly showed a serious problem 30 years ago. It is pointless to say that, if humans did everything needed to stay within 1.5C then that goal would be achieved. We’ve seen that humans will not do what is needed so it would be better to say that 1.5C is not achievable but we must at least try to limit global heating as much as we can.

    A dose of realism is required by climate scientists.

    This also doesn’t factor in any estimate of warming between 1750 (the start of industrialization) and 1880 (the start of global temperature records). Michael Mann estimated, several years ago, that the northern hemisphere warmed 0.2C in that time. I haven’t seen an estimate of a global figure but, if it were 0.2C, then that drastically reduces the time before we see 1.5C globally. Nor does it factor in the extra short term heating likely with reduction in the aerosol effect.

    The sooner we stop pretending that limiting heating to 1.5C is possible, the better because we can then concentrate on limiting heating to well below 2C (which I also have serious doubts about).

  14. 14
    MA Rodger says:

    Solar Jim @3,
    You ask “Is it not possible for the planet to reach 1.5C increase from pre-industrial just with our present 500 ppm,equivalent or even the actual 420 ppm or so concentration of carbonic acid gas?”
    The 500ppm(eq) value is indeed the 2019 value given by the NOAA AGGIndex and that is 86% of the forcing of a doubling of CO2 which has an attached ECS = ~3ºC. While this AGGI measure concerns only positive GHG forcings and there are negative forcings from the likes of aerosols, the net value is usually not seen as halved when the net forcings are totted up (eg here).
    However it does take many decades for the equilibrium entailed in the ECS to be achieved and only 40% of these positive GHG forcings are more than 40 years old. This would suggest there is some measure of time available because once we stop emitting the GHGs, their concentrations will drop reducing that AGGI number, hopefully quickly enough to prevent serious warming. Whether a +1.5ºC is achievable will depend on humanity getting its act together to cut those emissions, although this is something we have entirely failed to manage so far.

  15. 15
    AdamR says:

    Anybody polled Kevin Anderson on “possible” lately? That’s where I go for my Doom ‘n’ Gloom anytime hope strikes me.

  16. 16

    I completely disagree that it would be in some way unethical to pull CO2 out of the air–am I misinterpreting what you said here? I think we have to do that, and as soon as possible.

  17. 17

    KIA 5,

    Nobody, outside the circle-jerk of right-wing politics in this country, cares what Thomas Sowell has to say about a science issue.

  18. 18
    Spencer says:

    What I like about this post is the 1.75 degree scenario.

    Every sensible and informed person (a minority to be sure) knows that 1.5 degrees is posturing, it won’t happen. So it’s good to have a subtle reminder that there are scenarios that are actually possible. Realistically to even stop at 2 degrees will need either political miracles or technological miracles (which do happen) plus good luck in not being in the upper range of model sensitivities. But we need to avoid thinking, Oh we can’t hit 1.5 so let’s not think about it.

  19. 19
    Ray Ladbury says:

    I think a few folks are expecting a bit too much from two charts. However, the post is quite useful in terms of presenting the magnitude of the task before humanity. If you add two additional trends for context, it’s pretty easy to see that the best we can hope for is the red curve.

    First, the past 40 years of inertia have left us sorely lacking in the infrastructure required for sustainability. Decarbonizing just the energy sector of our economy would require massive spending in a very short time to make up the deficit. And making up the deficit will not be cheap in terms of greenhouse gas emissions, either. Steel and concrete are going to be needed to build out energy infrastructure, whether the solution is renewable, nuclear or fusion. Charging stations are going to be needed in much higher numbers than at present. R&D is going to have to increase and probably become more directed for the foreseeable future. All of that is going to require us to use lots more energy, not less.

    We can perhaps offset some of the increase through regenerative agriculture, low-hanging fruit (e.g. capping methane leaks and sources), allowing more telecommuting… All this does, though is buy a little additional time.

    The recent COVID pandemic has also revealed some important truths. Left-leaning governments and societies, even fairly authoritarian ones, such as China, were much more effective at doing what was needed to contain the pandemic. Right wing and conservative regimes failed miserably at this–as illustrated by the huge case numbers and death tolls in India, the US, Brazil, Turkey etc. The US provides an illustration of both trends–failing miserably under the right wing previous administration and vastly improving the situation when the left-center Biden administration took over. Left and left-center governments responded with effective strategies, while rightist regimes responded with conspiracy theories and snake oil. This should not be too surprising to those of us who have been following the climate wars over the past 40 years. And then there are the kleptocracies (Russia, N. Korea…), who will not only fuck up things for their own countries but for everyone else as well.

    On the other hand, market economies were more effective at generating treatments, vaccines and other innovations–viz. the differences in the success of the Pfizer, Moderna and J&J vaccines and mixed-at-best results for the Sinovac and Sputnik vaccines. This suggests that perhaps public-private partnerships may be an effective mechanism.

    And then we have the fatigue factor. Less than 18 months after the onset of the pandemic, fatigue is leading folks to do really stupid things even as workable solutions are being realize. Even during the crises of global wars, 4 years of concerted effort were about all the world could muster. Here, we are talking about efforts that could take 4 decades. And it is inevitable that people are going to resent the fact that with an effort of this magnitude, some folks are going to get filthy, fricking rich out of this, even as the rest of us endure hardship

    Maintaining public support is going to take the promise of something more than survival. People are going to want to know that the world that comes out of this will be better than the one we currently live in. The war to end all wars didn’t. The war to make the world safe for democracy made the world more dangerous. What will we have to promise the world’s population to retain their support for decades?

  20. 20
    Thomas Fuller says:

    Bart Verheggen made the point a decade ago that the idea of a ‘tipping point’ is misleading, in that we must carry on our efforts if we pass a tipping point and we must carry on our efforts if we avoid passing it.

    I think the same applies to concepts ranging from 2C (which morphed into the current 1.5C), 350 ppm and other lines in the sand that were drawn without analysis of impacts accepted and avoided.

    Don’t worry about the goals set by politicians. Keep your head down, do your part and encourage others to do theirs.

  21. 21
    Richard Colombe says:

    It seems to me if you scientists knew how to read charts (try, you would know that with every 100 ppm increase of CO2, there is a corresponding 5 – 10 degrees C increase in temperature. Since the current CO2 level is more than 100 ppm higher than previous peaks (over the past 500k years), the “normal” position for temperature is around 5 – 10 degrees C above previous peaks of around 2 degrees. The ONLY force that is capable of holding the temperature down like this is the amount of ice held in the polar ice caps, and as the ice slowly melts, the temperature is slowly increasing, and the faster the ice melts, the faster the temperature will increase. If we cannot stop the ice from melting, we cannot stop the temperature from rising. Therefore, it is a delusional fantasy to believe we have ANY chance of keeping the temperature rise below 2 degrees — it’s lunacy to think we have any chance of keeping the temperature increase under 5 degrees, which will be disastrous for humans.

  22. 22
    C. Wesley Dingman says:

    Dear Real Climate, I respect and have no quarrel with your latest report on the possibility of our being able to hold down the current increasing global mean temperature to about 1.5 degrees Celsius. However, I still see no consideration of the impact (if any) of the Milankovitch cycles on the Earth’s warming (or cooling) over the next few thousand years. My understanding of the impact of these cycles over the next several thousand years would normally be to cool (and thus counter the heating from our rising CO2 levels) our planet(although perhaps???? not sufficiently to prevent catastrophic warming. I would appreciate your thoughts regarding this possibility.
    C. W. Dingman

  23. 23
    Malte Meinshausen says:

    in the second graph, the label “67% chance < 1.5C" should instead probably read "33% chance < 1.5C".

  24. 24
    Susan Anderson says:

    It really doesn’t matter that we all know it’s problematical to enact appropriate action while the evidence mounts up and reality breaks in. It’s pretty simple if you look at it this way:

    It’s only all our lives. We can because we must &
    Despair and apathy are laziness in disguise.

    We can write and write – and write and write – about how bad things are, but that’s a substitute activity for what must be done, which is to get a grip.

    Showing that things can be done is worthwhile. A gold star to Stefan for putting this out there.

    Antivaxxing has the same problem of excessive false information and lack of universal quality education: people prefer what comforts them or confirms their bias, and there’s far too much false information out there. But we must soldier on regardless. I give you Mike Mann and the other great folks here at RealClimate as leaders in action.

  25. 25
    Susan Anderson says:

    Mr. Dingman, this is a quality science site. Time to educate yourself and wake up. You really mustn’t think that you and your preferred distractionalists have the holy grail while people who give their lives and considerable intelligence and skilled, hard work to these problems – which threaten all of humanity’s future – are ignorant of the obvious historical data. Also, try checking out world weather lately, if you don’t like “the science” and think you are uniquely well informed. Reality does not lie.

    Here’s a good place to start:

  26. 26
    Piotr says:

    R. Colombe (21) It seems to me if you scientists knew how to read charts (try, you would know that with every 100 ppm increase of CO2, there is a corresponding 5 – 10 degrees C increase in temperature.

    It seems to me that if you non-scientists (?) knew how to read you own graphs you would not be so arrogant to ridicule scientists for their presumed imagined inability to do what … you failed:

    You lecture the scientist on their inability to read graphs by claiming that in the graph you were able to see that “ with every 100 ppm increase of CO2, there is a corresponding 5 – 10 degrees C increase in temperature

    Your fallacy is in the words “ with every“: there is no “every” in your graph: the 5-10 C increase for 180-280 does not carry over even to the next “100 ppm increase” – the 277 to 377 ppm increase in pCO2 is associated with the temperature increases by some 0.8C.

    There could be several reasons for that: the saturation of the absorption windows of CO2, different strength of feedbacks at different pCO2 levels and v. different timescales, but these are not excuses for _you_, since you implicitly decided to IGNORE, in favour of just “reading the graph“. In other words – you failed even WITHIN your own argument.

    0.8C INSTEAD of “5-10C”, in your own graph. “It seems to me if you scientists knew how to read charts ….” eh? The bigger their ignorance, the more galling their arrogance.
    (Although, I would be careful with extrapolating _your_ slope of arrogance vs. ignorance onto the slopes of others …. ;-))

    So while you heart might have been in the right place: the real concern about the human impact on the climate, but it is all undone by your arrogance, and in fact you may be giving the fossil fuel lobby a tool to dismiss all environmentalists and climate scientists – through guilt by association – by painting them all with the single ignorance/dishonesty brush you have just provided.

    In fact, if ignorant, arrogant “alarmists” like you didn’t exist, the fossil fuel lobby would have to invent them.

  27. 27
    Piotr says:

    C. Wesley Dingman (22): However, I still see no consideration of the impact (if any) of the Milankovitch cycles on the Earth’s warming (or cooling) over the next few thousand years.

    Two reasons.

    First, wrong time-scale – the glacial cooling stage usually takes of order of 100,000s of years to fully develop so if our civilization collapses in the next 100 or 200 years, it would not be much of a consolation, that 10,00 later Milankovitch cycle + feedbacks reduced the temp, by say, 1C from the human-made highs.

    Even that rest on the assumption that Milankovitch would work – which is far from sure, see:

    The second reason why we don’t care about Milankovitch is that it works NOT by changing the total amount of solar radiation reaching Earth, but by making the summers in the Arctic warmer or colder ENOUGH that some of the last years ice/snow does or does not survive the summer. This then translates into changes in the albedo, which then starts the multiplication of the initial small change by the cycles of the positive feedbacks of CO2, CH4, albedo and water vapour.

    However, in the world with a lot of heating in the pipeline – the Milankovitch dropping the summer radiation in the Arctic would not change much: in the hot world the slight cooling from Milankovitch would not be enough to let ice and snow to survive summer, and therefore it would NOT be able to start the vicious cycle of positive feedbacks that the glaciation cycles require. So with the current CO2 and heating, we may have postponed the ability of Milankovitch to trigger planetwide cooling for 10,000s (?) years.

    To sum it up: “Milankovitch?” “Meh: too little too late, if anything at all.”

    P.S. And if you insist on the really long-term look – we still should stop burning fossil fuels short-term, so if humans were to survive to the NEXT Milankovitch cycle – they would still have some accessible fossil fuels left for them to avert THEIR ice age…

  28. 28

    RC 21: with every 100 ppm increase of CO2, there is a corresponding 5 – 10 degrees C increase in temperature.

    BPL: This is completely wrong. Please read a book on climate science.

  29. 29

    CWD 22,

    I’m afraid the Milankovic cycles operate too slowly to be of much use in the time scale we have to deal with. The main cycles are about 40,000 and 100,000 years in wavelength.

  30. 30
    Victor Grauer says:

    The steadily increasing trend from 1970 through 2020 implied by your first graph is misleading. Other assessments of the data offer a very different picture, as illustrated in the following graphs:


    Note the contrast between the steep rise from 1970-1998 and the leveling off from 1998 to 2015. And if, as you yourself noted, the two peaks in the years that follow cannot represent “a significant trend change” as they are “linked to two El Niño events in recent years” that are “part of natural variability.”

    A similar picture for the 21st century is presented by this GISTEMP graph:

    Clearly there is little to no trend during this period, especially if we discount the El Nino events.

    Here’s the picture from the RSS satellite data for the years 1998 through 2015 (prior to the two El Nino episodes):

    Once again the picture is very different from that depicted in your graph.

    A similar representation, courtesy of UAH:

  31. 31
    J4Zonian says:

    I’m immensely thankful for the work scientists have been doing on climate, but it strikes me as retreating into over-intellectualized narrowness to claim that there’s any chance in the world we can stay under 1.5° over pre-industrial temperature—even physically/numerically. We’re already above 1°. Unavoidable aerosol decline alone will bring us past 1.5°, and these other factors (and more) mean it will be virtually impossible to stay under 2°:

    The roughly 40 year pipeline of already emitted GHGs that haven’t reached their full warming potential; feedbacks; carbon cost of construction of the necessary clean safe renewable energy; the odds (trusting the existence of civilization to a coin toss is hardly sane).
    Decreasing EROEI of fuels is accelerating warming even of the same level of energy use, which is increasing faster than efficiency and clean safe renewables are being built. Because of small state bias, gerrymandering, voter suppression, etc. half the political power in the US either still outright denies warming is happening or denies the severity or the solutions.
    The huge gaps between Paris goals, NDCs, and effects; between need, the pitiful amounts pledged for the international green climate fund, and the even more pitiful amounts paid; between goals, means, politicians’ tendency to procrastinate, and the area-under-the-curve problem.

    The Republicans are insane, but ”Dems make chicken-shit (and out-dated) short-game political calculations while the worst planetary crisis humanity has ever faced accelerates.”
    —Alex Steffen

    Virtually no one in US politics is even considering the only solutions that will work at this point:
    Nationalizing fossil fuel, ICEV, agrochemical, banking, and other corporations to shut them down in an orderly and compassionate fashion.
    Based on decades off experience with the lunatic right, a lotta stick, a little carrot: mandating a transition to sustainability in energy, buildings, transportation, industry, agriculture, forestry. The crucial solution of a national high speed rail network and local and regional commuter networks to replace flying and driving is being ignored in favor of much-too-slow progress on personal EVs—which is also opposed by enormous political and corporate forces and fortunes. Meanwhile, supply chains of sufficient lithium to make enough personal EVs happen are also being stalled. The lithium exists but only government foresight and action, including rationing, can meet our needs in time.

    Every aspect of the transition faces the same problems, and even more important, denial in all its forms even by those scientists and others somewhat aware of the crisis feeds the refusal to consider solutions. Most current discussions about solutions involve side debates that are little more than further delaying tactics—the resort to too-low too-slow carbon prices, the projective hatred of blaming poor people of color for a problem that’s overwhelmingly caused by rich people of mostly white; nonexistent technologies like CCS etc; dead end technologies like nukes; and likely disasters like geoengimagicalism; all designed to slow implementation of the only solutions that will work in time.

    More people imagine the end of civilization than imagine the end of capitalism, which while not the root problem (that’s psychological) is an insane way to organize our relationships to each other and the rest of nature, and is stunting our ability to even think about solutions, let alone implement them. The forces of denial and delay are in charge in the US, and the rest of the world will never move fast enough without a truly democratic, motivated US pushing the actual solutions. The only solution to the whole problem is a massive, immediate, peaceful revolution. People who aren’t part of that are part of the problem.

    Mother Jones: “Don’t mourn; organize.”

    Judith Lipton: “The therapy for despair is action.”

    I think the therapy for despair is therapy, but action is a great way to put therapy’s lessons into practice.

  32. 32
    Russell Seitz says:

    Happy Earth Day from CFACT and the Heartland Institute

  33. 33
    J4Zonian says:

    To Mike Roberts, #13

    I agree that we are not going to stay under 1.5°C under preindustrial temp. or even 2°C. But the US and most of the world can not only reach 50 by 30, but can and must reach 100% clean safe renewable energy by 2030, and sequester carbon through permaculture and forestry to reach significant net negative emissions by then as well.

    People who assume we can’t do this are also making other assumptions:

    —that we continue with BAU instead of declaring a national and global emergency and acting on it;

    —that the rich must keep profiting, IOW we use only market “solutions” that are not solutions at all but more problems;

    —that the US and other governments don’t take charge, coordinating mandated solutions that actually are solutions, etc.
    Above all, all that amounts to the assumption that capitalism must continue as is, despite the obvious fact that it’s one of the main problems (itself caused by psychological problems).

    —they may also be making false assumptions or at least making false arguments about clean safe renewable energy, which can indeed provide all the energy we need by 2030.

    Numerous studies have shown various pathways to the goal; at least 65 countries are already providing most of their electricity with RE. 23 of them are providing 100% of it or nearly so, and several have already gotten near 100% renewable energy, not just electricity. All it takes is will, and government action.

    If we want civilization and most life on Earth to survive, we have to abandon those assumptions and move on with the political action needed to make the solutions happen.

  34. 34
    Solar Jim says:

    In support of my #3 above. EEI is Earth Energy Imbalance (see J. Hansen)
    This is from Solar Jim, Oct 2020 Unforced Variations:

    “Although the value of EEI in the first decade of this century was about 0.6 Watts per square meter, it is now measured during 2010-2018 as 0.87 W/m2. Since this applies to the entire surface, whcih is 5.1 x 10 E14, the total heating is 4.4 x 10 E14, or 440,000 Gigawatts (GW). (an astounding value) With an estimated 3% going into icemelt this means 13,200 GW, or the equivalent of more than thirteen thousand large 1000 MW power plants running 24/7/365, is the cause of some one trillion tons of ice converting to liquid water around the globe each year.

    The preferred value of EEI for the continuance of civilization is zero, implying “negative emissions.”

    NOW! Planetary heat flux has since increased to about 1.0 W/m2, which seems to me to be a tremendous acceleration.

  35. 35
    Richard Colombe says:

    Piotr (26) – My Dearest Piotr, thank you so very much for your very kind and generous response, it provided me with much laughter.

    “….with every 100 ppm increase of CO2, there is a corresponding 5 – 10 degrees C increase in temperature.” That is not a fallacy, but a scientific fact. (btw: the reason I indicate 5 – 10 degrees is because some of the graphs have it at 5 degrees, and others have it at 10 degrees increase, and I have no way of knowing which are more accurate.) As I explained, perhaps not as well as I should have, the temperature did not follow CO2 and methane increases, because of the ice that persists in the polar ice caps and high mountain glaciers, but that does not indicate the temperature increase did not find its way into the system, it just indicates climate scientists haven’t been measuring heat properly.

    Here’s the way I see it: roughly every 100,000 years, or so, over the past 800,000 years, CO2, CH4, and global atmospheric temperature have climbed, more or less in tandem, to a peak, then declined and meandered up and down until the process started all over again. When they reach their peak, they always reach close to the same peak, and when they bottom out, it’s again always near the same trough. The peaks seem to be regulated by how much ice has accumulated during the previous glacial periods, and the troughs seem to be regulated by how much of the Earth’s surface north and south of the equator is ice-free.

    Then, somewhere around twelve to fourteen thousand years ago, they peaked, and began to go back down, but when humans invented agriculture, around ten-thousand years ago, and began to alter the land and the climate, CO2 and methane began to climb again. With clearing the land for farming, domesticating animals, and planting rice fields, methane levels in the atmosphere rose higher and higher to where it is now more than double where it peaked previously. However, during this period the global atmospheric temperature has not followed suit, but has remained relatively steady (note I do not say stable, but steady. The temperature of the global system has NOT been stable, but the atmospheric temperature has remained steady, there’s a difference.) There has to be a reason for the atmospheric temperature to remain steady while CO2 and methane continue to climb, and I do not believe “…the saturation of the absorption windows of CO2,” or “different strength of feedbacks at different pCO2 levels and v. different timescales,” adequately explain the situation.

    It has been my experience that long before a system reaches its saturation point, the absorption rate begins to decrease, and the closer the system gets to the saturation point, the slower the absorption rate becomes. But that didn’t happen here. You would have me believe the the temperature would increase at 5 to 10 degrees between 180 to 280 ppm, and then not taper off, but instead come to a screeching halt, stopping on a dime, as it were, to begin creeping up at a meager 0.8C from 280 to 420 ppm, due to the saturation of the absorption windows of CO2. Nope. Nunca. Нет.

    The fallacy you speak of comes from the belief that the increase in atmospheric temperature describes the amount of heat the planet’s climate system has absorbed over the past ten-thousand years. The temperature increase that corresponds to the 280 to 420 ppm of CO2 is in the system, but it has been forced into the ocean, not absorbed into the atmosphere. The atmosphere and surface of the oceans are much easier to heat then are the deep ocean waters, so they were the first to heat up; however, due to the amount of ice that has survived since the last glacial period, the atmosphere is not able to absorb more of the heat, so almost all of that heat has been forced into the ocean. The heat has to go somewhere, and since it cannot go back out into space, due to the greenhouse gasses in the atmosphere, it goes into wherever part of the system is easiest to absorb it, and right now that is in the ocean, and at deeper and deeper depths. As the ice melts, the atmosphere is able to absorb more heat, and the faster the ice melts, the faster the atmospheric temperature will increase.

    Could you please show me how “…the saturation of the absorption windows of CO2,” or “different strength of feedbacks at different pCO2 levels and v. different timescales” invalidates my polar ice cap theory? It seems to me that all of that falls nicely within my theory; therefore, the ice theory remains nicely intact, thank you very much.

    You accuse me of “just ‘reading the graph’;” however, I believe that is more projection. What I’m doing is analyzing the graph and trying to determine the most plausible explanation of the cause for what is taking place. It looks to me that most climate scientists are the ones who are just reading the graph. What you see as arrogance I see as confidence and self-assuredness, mixed with more than a bit of impatience.

    Twice in your response, you refer to a 0.8C INSTEAD of 5-10C increase in temperature, completely ignoring my reference to the polar ice caps being responsible for the apparent temperature lag, and I say “apparent” because, once again, the majority of the 5-10C increase has gone into the ocean, and that is why the temperature increase has not been measured in the atmospheric temperature readings, but, once again, that does not mean the increase has not gone into the system, it just means the climate scientists have not measured the global temperature increases properly.

    You imply that I am ignorant and arrogant – well we are all ignorant; if that weren’t the case, there would be no need to study climate change, as we would have all the answers already. As to my arrogance, I am more than willing to accept I am wrong, if that case can be demonstrated with more than some vague notions of “absorption windows of CO2” and the “different strength of feedbacks.” I encourage you to respond to this response and let me know where my thinking is in error, as I don’t like being in error of the facts.

    As to my being an “alarmist,” well, when a building is on fire, we have a tendency not to dump on the person who pulls the fire alarm in the effort of trying to save as many lives as possible. The way I see it is that climate scientists have been feeding the public a lot of false hope that if we curtail our carbon emissions soon, we will still have enough time to keep global temperatures under 1.5 or 2C. I believe all of this false hope is what will lead to panic, once the public realize they have been lied to regarding the severity of the situation; whereas, I believe the public is much more likely to face what is coming more calmly, if they are gradually brought up to speed with an honest assessment of climate change and our prospects of a future. I have faith in the ability of people to do the right thing, as long as they are given accurate, complete, and honest information, but the politicians and climate scientists seem to believe the people need to be “managed,” as one would do with herd animals to keep them from stampeding. Now which one of us sounds more arrogant?

    You are right in saying it was wrong of me to imply scientists don’t know how to read charts, they obviously do; the problem seems to be in their ability to properly analyze some of the charts they do read. If you can demonstrate how your theories of differential absorption windows or differential feedbacks and timescales, or some other theories are superior explanations to my polar ice cap theory, I would love to hear about them. XOXOXO.

  36. 36
    John Monro says:

    Stefan, some queries in the fuller article by Carl-Friedrich Schleussner and Bill Hare you refer us to.

    “iIt is highly unphysical that the rate of anthropogenic warming should double without emissions doing so.” Is this a logical statement? It would be true, perhaps, if the physical controls on our climate proceeded in a linear fashion, but isn’t the whole discussion about “tipping points” predicated on the likelihood that the climate could quickly change due to positive feedback loops once these “tipping points” have been passed? I look at Arctic Ice and the reduction of summer time ice are and the consequent changes in the planet’s albedo could well cause a non-linear increase in global temperature. So I think this statement can be questioned and that’s even if one accepts that, at present, there’s no statistically significant increase in the rate of global temperature increase. As to that latter statement, it only remains true if the next five years or so of global temperature rise prove it, and that we don’t know. There is a fundamental logical difference in the claim that the planet’s temperature hadn’t risen for many years post 1998 and the claim that global warming might be accelerating. One is a simple and egregious denial of global warming, the other is more nuanced debate about the speed at which it’s happening.

    The graph “Rate of global warming over the next 20 years” appears to include outlying modelling results of below 0°C – indeed two at greater than -0.1°C. So do we really accept modelling results that suggest this might be reality? You suggest it’s physically impossible that the rate of warming will double, but what about the physical impossibility that the globe will so substantially cool from now? Obviously if we were to exclude outlying results on both the lower and upper figures, you might still end up with an average or mean much as they are now, but has anyone done this exercise?

    “Concentrations will not stay constant once net zero emissions are reached. The authors rightly cite the state-of-the-art literature showing that there is “no warming in the pipeline” once net zero emissions are reached.” I truly don’t understand this. It would be nice for you to provide a figure as to what will happen to our atmospheric CO2 levels, and to global warming, once zero effective emissions has been achieved. And your wording is open to misinterpretation, what you should be saying is “there is no further warming in the pipeline”, surely, a heated planet will remain heated as long as CO2, and other global warming gases, remain above their natural level.

    “Lastly, the authors cite a study that claims that the world is currently on a RCP8.5 trajectory. While historic emissions have been following this scenario most closely, there is a well-established understanding in the scientific literature that this view is incorrect, and that while the world is nowhere near doing enough to achieve the Paris Agreement goals, it is also very far away from building the fossil infrastructure implied by RCP8.5.10 COVID-19 has strongly accelerated that trend.” Here we come to the whole crux of the matter. These “trajectories” have absolutely nothing to so with global warming science per se, they are trajectories dreamed up by economists and others of that ilk that might or might not accurately reflect the thoughts that our humanity might collectively achieve them. So you’re back to square one. The idea that it is “possible” to limit warming to 1.5°C depends entirely on the idea that it is “possible” that humanity might be able to do so, and the physics of the matter is basically now irrelevant. It was much more “possible” that we’d be able to keep temperatures under 1.5°C twenty years ago, and the course to achieve this was multiple times easier, but we didn’t.

    It’s really hard for most of us to get our heads around the idea that our climate will stabilise relatively quickly, perhaps within 20 years, after achieving net zero emissions, since the almost all the prior information we were getting was that it would take a “long” time to do this. It could almost be reassuring, but what we are not being told yet is how quickly the temperature of the planet will fall from this higher, stabilised, level, nor what a persisting 1.5°C global rise in temperature will do so sea level rise, Arctic and West Antarctic ice, forest cover, permafrost etc. etc. A 1.5°C warmer world could still contain some very nasty surprises and the Arctic is likely to be the key player here, an ice free Arctic in summer might prove an irreversible tipping point. Obviously keeping our global temperature rise as low as possible, aiming for the “possible/impossible” 1.5°C, is still existentially important, but…..…for instance, Nico Wunderling et al paper from 2020 suggests with a CO2 level over 400 (it’s now approaching 420) the melting of ice in the polar and other glaciated regions could contribute to an additional 0.4°C global temperature rise, so if accurate, your 1.5°C rise is not just a socially impossible goal, but perhaps a physically impossible one too.

    Whilst the newspapers have published similar information, perhaps from this paper, or from Prof Mann, actually the second graph you provide surely is the lie to the claim that we can now avoid a temperature rise above 1.5°C. The graph show on the orange line the small notch in emissions due to Covid but the predicted rebound in the next year or two. So follow this orange line, we halve emissions by 2030, but we have to reach net zero by 2040, fully ten years before the commitments made by a number of nations. Failing nuclear war, a pandemic of Ebola or the biggest economic crash in human history, can anyone, even a climate scientist truly suggest, with a straight face, that this is “possible”?

    And as to 1.5°C of warming in itself? `How “reliable” a figure is this that makes climate scientists suggest this is actually a tolerable figure for our present ecosystems? When, without predicating any global warming at all, so many vital ecosystems are under such stress by unrestrained human activity and population, how can we be sure that a “mere” 1.5°C temperature rise won’t be the straw that breaks the planet’s back?

    Global warming is not merely the pure science of our atmosphere, it’s the behavioural, social sciences of sociology, politics, economics, population, ecology. Indeed global warming would not even be a subject of scientific analysis without these other underlying human phenomena to cause it. So I believe it’s fundamentally flawed to analyse global warming only on the basis of the understood physics. It might have been “possible” for Donald Trump to have managed his presidency without telling a lie, but in human terms, it was never possible, because telling lies defined who he was. It’s the same with wider humanity, I believe our behaviour up to now is a rather more reliable predictor of our future than any amount of advanced computer modelling. It’s not a reassuring understanding, is it?

    Thanks for your time, and keep up the good work on these pages. Keep well everyone.

  37. 37
    John Monro says:

    ….and perhaps this could be added to my prior posting. Yes, Covid has shown a temporary dip in emissions, but what happens next? Many are predicting a rebound. I think that’s very likely, and this rebound, particularly in flight, might last some time. We now have a globally dispersed population, where hundreds of millions of people have migrated to far flung lands, leaving family behind. I live in New Zealand, I emigrated here with my NZ wife 34 years ago. I have an ageing, loved, family in the UK, and not just that, but three daughters who migrated back to the UK and have lived in London for up to 15 years. I and my wife are desperate to get back to the UK to see our daughters and see my own family in the UK. I have friends in Europe I want to catch up with. Multiply my deepest and perfectly understandable desires by the hundreds of millions of others in the same position, grandchildren or grandparents they’ve never seen, unwell family members, bereaved relatives, new partners or spouses, life-time friends, the demand for such travel will be huge, even if prices rise considerably, which they’re likely to do. Hopefully, there will be a lower demand for tourism and business travel to counteract this. We have got very used to the idea that the world has become a lot smaller, it’s going to be distressing to realise that this is no longer the case, and like our ancestors, have to accept that emigration comes with a permanent cost in family ties – and that’s not just because of Covid, but is has shown us what might happen if we were to take our responsibility for aviation’s contribution to global warming seriously. .

  38. 38
    Pete Best says:

    Kicking the can down the road is still the course of action favoured by – well everyone who has a say in what to do.

    If I was a climate scientist and was giving a realist view of the state of the climate situation I would also say that 1.5C was still within reach as technically it is. However, the reality of the past 40 years of climate reports, meetings, and assessments say otherwise but we cannot be pessimistic now can we. Only optimism will be tolerated.

    Lets take life style changes, no lets not. Economics since the end of the World Wars has been growth. 2-3% per year to pay for everything going forward, pensions, stock market – everything. Its a massive Ponzi scheme essentially and it looks like due to the amount of money being created out of thin air (QE) since 2008 (the last crash)_it is coming to and end. However life style changes are not on the agenda at all so its all down to technology instead.

    Solar, Wind and storage. Hydrogen, paint buildings white along with heat pumps and a lot of other brilliant but not yet implemented at the scales required ideas. So lets move onto sequestration (CCS). Initially it was bury the carbon from existing coal plants, failed technology that never happened. Then we touted BECCS, grow plants on an areas the size of India and then cut it and transport it to existing coal plants and burn it, then capture the co2 and bury it in the ground somehow. Negative emission technology as is it known and its no known in reality yet but maybe come some future date we will do it. Last but not least is Geoengineering. this is a fundamentally last ditch effort to stave off the worse effects of ACC but also once again we drift into dreams and fantasy technology.

    so where are we, emissions continue to go up, we buy SUV because our kids needed to transferred safely etc. It is all a big mess and the emission cuts promised by governments are seemingly at odds with reality.

  39. 39
    Mike says:

    “If we lower emissions, the trend will flatten out and become roughly horizontal as we reach zero emissions.”

    I think this sentence is misleading at best and I would suggest the following is more accurate:

    The increase trend is expected to be reduced to the extent that we lower emissions and is expected to become roughly horizontal as we reach zero emissions as long as the natural carbon sinks and sources perform as we expect.

    Let’s say that we could show that we have lowered emissions by 0.1 ppm per year through our efforts. It will be true to say that “we lowered emissions” but flattening of the trend in increase will be barely perceptible.

    I appreciate the post and the effort that goes into presenting climate change science.

    for reference, see: Why Has a Drop in Global CO2 Emissions Not Caused CO2 Levels in the Atmosphere to Stabilize? from May 2016



  40. 40
    Karsten V. Johansen says:

    “The threshold for dangerous global warming will likely be crossed between 2027 and 2042—a much narrower window than the Intergovernmental Panel on Climate Change’s estimate of between now and 2052. In a study published in Climate Dynamics, researchers from McGill University introduce a new and more precise way to project the Earth’s temperature. Based on historical data, it considerably reduces uncertainties compared to previous approaches.”

    As far as I can see, the rather great “covid-drop” in Stefans curve over emissions 2020 is completely fictional: there is no trace of this in the CO2 measurements at Mauna Loa etc.:

    There isn’t even the shade of a microscopic drop in the relentlessly growing CO2-levels in the troposhere. Why? Of course because most emitters and their states are lying as much as they possibly can about their emissions: there are lots and lots of loopholes with false “negative emissions” etc. just as is done concerning taxes etc.

    I agree with #1 above: “In the real world, “possible” must also include an evaluation of whether those sample emission budgets can be achieved given the social and geopolitical realities and vastly disparate levels of resources across the globe”, if you add

    a) that these “budgets” are so hypothetical that they in fact are mostly science fiction: the reality is that mankind almost certainly already have moved the global situation past several dangerous tipping points given the enormous inertia in the evolving processes concerning the big icesheets in Antarctica and Greenland, the seas and most big ecosystems on land and

    b) that the speed in the emission-cuts needed is completely unrealistic given 1) the economic powers and their logic and 2) what we know from the recent history: relentlessly fraudulent “agreements” like the last in Paris, precisely called “pure bullshit” by James Hansen already early in december 2015, and even that has since then been proven to be an understatement: all promises are broken even before they are written down, the whole shitshow is just pathetic.

    Just consider the simple fact that almost all wars and military conflict since the Vietnam war has taken and takes place in regions with big oil and gas resources:×501/

  41. 41
    Karsten V. Johansen says:

    Just to make that clear, I have read this: but I don’t find it completely convincing. Nevertheless it makes it impossible for me to understand why Stefan includes a grossly overestimated drop in emissions due to covid in his curve, I mean just look at the “drop” from the 2008- financial crisis productions drop: there is none! And that drop in production was much bigger than this one. Further this: “It is not yet impossible to keep warming below 1.5 °C” from Stefan above is formally correct, but is it relevant? I think not, because it is fx. like saying on the 22. june 1941: “It is not yet impossible to achieve peace in our time”. That also would be formally correct, you could imagine that Hitler had died from a heartattack or some traffic accident together with the japanese emperor etc. some day during 1941, even if I doubt that would have changed things very much. The probability for that happening was just negible, as is the possibility that the global imperialist and financial power system will suddenly begin rolling back itself in the next decade. And that is what it will take to just get the UN to decide a global treaty where all countries adopt a policy as proposed by James Hansen called carbon fee and dividend: a modest and realist approach to *begin* cutting the use of fossil fuels efficiently.

    I agree with PBL above that it will be necessary to pull out CO2 from the troposphere. It can probably be done by spreading ironpowder in the southern ocean thereby stimulating the photosynthesis there, and by spreading rock powder containing silicates and CaCO3 over the farmlands and thereby stimulating chemical weathering. But I don’t believe for a second that neither this nor carbon fee and dividend will be implemented before the climate catastrophe is wreaking havoc all over the globe like the world wars. That will probably be some time after the global temperature has passed 1,5 degrees above pre-industrial level, around 2030, and probably even after the beginning collapse of the ice shelves in Western Antarctica etc. which I think they will by then. It’s even very probable that WW III will get going before that.

    Just to ignore the historical and physical facts before our eyes is no solution, it’s not science, it’s just ignoring reality, it’s just silliness. As the last thirty years have overwhelmingly demonstrated: continuing this silliness will achieve exactly the opposite as intended. As George Monbiot has written: *the socalled optimism is exatcly what has resulted in nothing at all happening until now, except business as extremely usual*. Remember Chamberlain and the optimism that resulted in WW II…

    The scientists have to man up and tell the politicians and the corporations financing them plainly that time is up and has been so for a while now, and that they are tired of all their lies. They have instead to speak directly to the people. Of course that will result in them being censored and probably worse (but that is already happening – just without resistance from the scientists…), but then at least we will have drawn a line and made things clear. The responsability will be clear.

  42. 42
    Al Percival says:

    One area where I am still confused is the confidence expressed about the time taken to reach equilibrium once emissions are stabilised and the resulting levelling off of global temperature rises. In the Australian Climate Council report, Section 2.4, it points out that in the mid-Pliocene, when CO2 levels were in the ~390 ppm range, global temps were approx 2.5 – 4.8 C above pre-industrial levels. In response, the rebuttal paper has really nothing useful to say on this point, simply stating that “…However, none of the evidence provided links to the question of whether 1.5°C will be exceeded.”

    So – I would really like to understand or be pointed to sources which can detail why the mid-Pliocene is such a poor model for current conditions, and why we should be so confident of a de-linking of atmospheric CO2 and long term warming when the historical record which, we are repeatedly told, provides a strong correlation demonstrating the connection?

  43. 43
    Oscar Anton Wehmanen says:

    About Carbon Capture

    1) For every Ton of carbon that you burn, you create about 6 tons of CO2. The volume of the CO2 is larger than the volume of the burned coal. At least for any normal state of matter.

    2) If the atmosphere is in equilibrium with the ocean CO2 content,
    About half of the removed CO2 will be replaced by CO2 exhaled by the ocean.

    Oh – Micro Black Holes. We could make the CO2 into a micro black hole! A practical application of Cosmology !!

  44. 44
    Piotr says:

    Re: Richard Colombe (35)(36)(39)
    Piotr: I’d assume these are identical, right?

    R. Colombe (35)(36)(39): “ Dearest Piotr, thank you so very much for your very kind and generous response, it provided me with much laughter.

    Dearest Richard Colombe, that’s what aim for. And it’s most funny, when the subject of the well-deserved laughter – is so full of himself that he is convinced that the joke is … on others, e.g.:

    Richard Colombe(21): “ seems to me if you scientists knew how to read charts (try, you would know that with every 100 ppm increase of CO2, there is a corresponding 5 – 10 degrees C increase in temperature.

    To which I have shown that …. it is was our “Richard Colombe (21)” who wasn’t capable of reading HIS OWN graph:
    Piotr (26): “in your graph your “5-10 C” increase for 180->280ppm does not carry over even to the next “100 ppm increase”: the 277->377ppm increase in pCO2 is associated with the temperature increases by some 0.8C.”

    And, no, you won’t save your face with claims that …. make your (21) even more absurd:

    Richard Colombe (35)(36)(39): “the temperature increase that corresponds to the 280 to 420 ppm of CO2 is in the system, but it has been forced into the ocean, not absorbed into the atmosphere. The atmosphere and surface of the oceans are much easier to heat then are the deep ocean waters

    If the recent heat stays in the atmosphere and surf. ocean because it didn’t have time to go into the deep ocean – wouldn’t it make the recent temp. increase HIGHER than your “5-10C” warming during deglaciation, when air and surface ocean had THOUSANDS of years (read your own graph!) to move the heat into the deep ocean? yet INSTEAD being HIGHER THAN “5-10C” it is … 0.8C ????

    Now let’s laugh together at the genius who thought that bringing in the deep ocean would save his face.

    P.S. * given your lecturing scientists to learn reading graphs – POINT WHERE IN YOUR GRAPH – you have READ your “ 5–10 C increase in temperature“?
    I ask because I see in it only: 4C-5.5C. For better rhetorical effect you have …. rounded “4-5.5C” to “5-10C”?

  45. 45
    nigelj says:

    J4Zonian @31 &33, the UK tried nationalising large parts of the economy in the 1970s and it was a disaster economically and environmentally, probably because politicians and bureaucrats aren’t good at running commerce and industry. You have to learn from history. Nationalisation is also unlikely to ever have enough support to get turned into legislation. Biden has some good ideas that might have more of a chance. Governmnets can exert control without nationalisation.

  46. 46

    J4 33: we use only market “solutions” that are not solutions at all but more problems;

    BPL: A cap and trade system got rid of the acid rain problem in the United States, and effluents taxes are used to great effect in Germany. Market-based solutions work just fine.

  47. 47

    RC 35: “….with every 100 ppm increase of CO2, there is a corresponding 5 – 10 degrees C increase in temperature.” That is not a fallacy, but a scientific fact.

    BPL: The fallacy lies in the “with every” statement, which extrapolates outside the range of observations–something they always and everywhere tell you not to do in every data analysis course. In a natural deglaciation, CO2 is being released from the ocean due to solubility changes with temperature; the CO2 then amplifies the warming started by Milankovic cycle insolation changes. Please read a book on climate science. You are taking your own individual “analysis” of a single chart and extrapolating physical principles from it, and your conclusions are wrong–definitely wrong, known to be wrong.

  48. 48
    R. Colombe says:

    BPL 28 — if you have a defensible position on the issue, why wouldn’t you state your evidence? It seems like you don’t have any evidence, and are merely praying that I’m incorrect. You sound like a religious fanatic who says “please read the Bible.”

  49. 49
    Richard Colombe says:

    In “David Attenborough: A Life on Our Planet” (2020), David offers the following explanation for why the Earth’s climate has been “stable” over the last 10,000 years:

    Phytoplankton at the ocean’s surface and immense forests straddling the north have helped to balance the atmosphere by locking away carbon. Huge Herds on the plains have kept the grasslands rich and productive by fertilizing the soils. Mangroves and coral reefs along thousands of miles of coast have harbored nurseries of fish species that, when mature, then range into open waters. A thick belt of jungles around the equator has piled plant on plant to capture as much of the sun’s energy as possible, adding moisture and oxygen to the global air currents. And the extent of the polar ice has been critical, reflecting sunlight back off its white surface, cooling the whole earth. The biodiversity of the Holocene helped to bring stability, and the entire living world settled into a gentle, reliable rhythm . . . the seasons.
    The rhythm of seasons was so reliable that it gave our own species a unique opportunity. We invented farming.

    This all sounds very plausible, as long as you don’t analyze it too carefully. I don’t know whether Dr. Attenborough compiled this list from his own knowledge, or if he was given this from climate scientists, but it seems to me like most of what is on the list have been around for millions of years, yet they were only able to “stabilize” the climate just at the time when humans invented agriculture and animal husbandry – what timing, right? Also, while most, if not all, of these systems are in distress, severe decline, and/or dying out all together, they still maintain the same ability to “stabilize” the climate – WTF! If I were a religious fanatic, or climate scientist, apparently, I might believe this was due to divine intervention. This sounds more like Zombie-science than climate science.

  50. 50
    Piotr says:

    Re: Richard Colombe (51)
    While it’s impressive that you on the first name basis with Sir Richard Attenborough, or for you: “ David” – I am not sure why would you drag him here, since neither he nor anybody in this thread has claimed that the human emissions of CO2 are OK BECAUSE … in the pre-industrial 10,000 yrs the climate was relatively stable.

    So, you are going “WTF?” about an argument that exists … only in your head????

    And while ridiculing Richard Attenborough for the argument he didn’t make, you
    have no clue about even simple arguments that were made in _this thread_ in RESPONSE TO YOUR claims. So, why exactly are you here?

    P.S. your “David” is right about climate being unusually stable in the last 10,000 yrs before recent changes – see your own graph ( – compare THE SLOPE of T in the last 10,000 yrs with the slopes in most of the 10,000 yr periods in the last 425,000 yrs … Now, if there only was somebody to lecture us about the value of the ability to read graphs…