Climate signals detected in global weather

ETH Zurich

North American surface temperatures for Dec. 26, 2017-Jan. 2, 2018: even if it is extremely cold in a region, this does not mean that climate change has stopped.  Credit: Source: NASA Earth Observatory, ETH Zurich

North American surface temperatures for Dec. 26, 2017-Jan. 2, 2018: even if it is extremely cold in a region, this does not mean that climate change has stopped. Credit: Source: NASA Earth Observatory, ETH Zurich

In October this year, weather researchers in Utah measured the lowest temperature ever recorded in the month of October in the US (excluding Alaska): -37.1°C. The previous low-temperature record for October was -35°C, and people wondered what had happened to climate change.

Until now, climate researchers have responded that climate is not the same thing as weather. Climate is what we expect in the long term, whereas weather is what we get in the short term – and since local weather conditions are highly variable, it can be very cold in one location for a short time despite long-term global warming. In short, the variability of local weather masks long-term trends in global climate.

A paradigm shift

Now, however, a group led by ETH professor Reto Knutti has conducted a new analysis of temperature measurements and models. The scientists concluded that the weather-is-not-climate paradigm is no longer applicable in that form. According to the researchers, the climate signal – that is, the long-term warming trend – can actually be discerned in daily weather data, such as surface air temperature and humidity, provided that global spatial patterns are taken into account.

In plain English, this means that – despite global warming – there may well be a record low temperature in October in the US. If it is simultaneously warmer than average in other regions, however, this deviation is almost completely eliminated. “Uncovering the climate change signal in daily weather conditions calls for a global perspective, not a regional one,” says Sebastian Sippel, a postdoc working in Knutti’s research group and lead author of a study recently published in Nature Climate Change.

Statistical learning techniques extract climate change signature

In order to detect the climate signal in daily weather records, Sippel and his colleagues used statistical learning techniques to combine simulations with climate models and data from measuring stations. Statistical learning techniques can extract a “fingerprint” of climate change from the combination of temperatures of various regions and the ratio of expected warming and variability. By systematically evaluating the model simulations, they can identify the climate fingerprint in the global measurement data on any single day since spring 2012.

A comparison of the variability of local and global daily mean temperatures shows why the global perspective is important. Whereas locally measured daily mean temperatures can fluctuate widely (even after the seasonal cycle is removed), global daily mean values show a very narrow range.

If the distribution of global daily mean values from 1951 to 1980 are then compared with those from 2009 to 2018, the two distributions (bell curves) barely overlap. The climate signal is thus prominent in the global values but obscured in the local values, since the distribution of daily mean values overlaps quite considerably in the two periods.

Application to the hydrological cycle

The findings could have broad implications for climate science. “Weather at the global level carries important information about climate,” says Knutti. “This information could, for example, be used for further studies that quantify changes in the probability of extreme weather events, such as regional cold spells. These studies are based on model calculations, and our approach could then provide a global context of the climate change fingerprint in observations made during regional cold spells of this kind. This gives rise to new opportunities for the communication of regional weather events against the backdrop of global warming.”

The study stems from a collaboration between ETH researchers and the Swiss Data Science Center (SDSC), which ETH Zurich operates jointly with its sister university EPFL. “The current study underlines how useful data science methods are in clarifying environmental questions, and the SDSC is of great use in this,” says Knutti. Data science methods not only allow researchers to demonstrate the strength of the human “fingerprint”, they also show where in the world climate change is particularly clear and recognisable at an early stage. This is very important in the hydrological cycle, where there are very large natural fluctuations from day to day and year to year. “In future, we should therefore be able to pick out human-induced patterns and trends in other more complex measurement parameters, such as precipitation, that are hard to detect using traditional statistics,” says the ETH professor.

###

Reference

Sippel S, Meinshausen N, Fischer EM, Székely E, Knutti R: Climate change now detectable from any single day of weather at global scale. Nature Climate Change 2019, 2 January, DOI: 10.1038/s41558-019-0666-7

From EurekAlert!

79 thoughts on “Climate signals detected in global weather

  1. Wow, so climate change signals only show up clearly in the examination of weighted average global measurements. Yet:

    “This information could, for example, be used for further studies that quantify changes in the probability of extreme weather events, such as regional cold spells. “

    But of course:

    “These studies are based on model calculations, and our approach could then provide a global context of the climate change fingerprint in observations made during regional cold spells of this kind. This gives rise to new opportunities for the communication of regional weather events against the backdrop of global warming.”

    And I would assume there will be no days when evidence of global climate change is NOT detected by their daily data crunching model. And that the main purpose is “communication” about climate change.

    • Isn’t this all just a fancy way of averaging global temps over a decade to say decade is on average warmer then some 30 year period 60yrs pior? Then saying it proves cold weather is not cooling? Or in other words saying “climate is not weather”. Wow they just made a model to show globe has warmed instead of using existing data that shows same. Lipstick meet pig.

      • If it includes models (they say it does), then it is not an experimental result, regardless of whether it incorporates actual data. Just more “just so” modelling garbage.

        • The fact that they used models to test the method does not make the method garbage. They are not drawing conclusions about existence of global warming in the real world from model data, they are developing a method.

          This is not a “new paradigm” it has always been false to claim local regional variation prove or disprove global climate change.

          Next time there is an intrusion of warm saharain winds into continental Europe due to a stalled weather system in the Atlantic , we point out this has nothing to do with global warming and they need to take the global average.

          • “This is not a “new paradigm” it has always been false to claim local regional variation prove or disprove global climate change.”

            It can be, and has been argued that the notion of a global average temperature and a global anomaly is as equally flawed. There is no compelling reason to believe that this average value provides any useful information. Its usefulness is defined by the fact that it is “somewhat measurable” and that it varies.

            A trillion dollars (hyperbole) spent trying to verify the bogeyman (CO2) and apportion blame (humans) has meant an equal amount not spent doing useful research. I remain unconvinced that this will add to knowledge.

      • It’s worse than that. They cherry picked a cooling trend and then compared that to a warming one to make their conclusions.

      • It’s one thing to say the globe is warming somewhat. I doubt anybody disputes that fact. It’s quite another thing to conclude that it is anthropogenic.

    • That is the ‘beauty’ of the climate crisis narrative. It cannot be falsified with observations. Of course, this makes it a faith based narrative, not a science based narrative. The EPA endangerment finding is actually unconstitutional because it violates the separation of church and state!

    • Exactly, James! You can and do get a mix of hot places and cool places, but setting all time cold temperatures these past two winters, no, with 150 years of so-called catastrophic Global warming and supposed tripley enhanced polar temperature enhancement on the Arctic. The Illinois all time cold record of -41C+ last winter swooped down from a frigid air mass more than 10 C colder in the Arctic Basin! WUWT?

      And a Russian giant icebreaker that took paying passengers ($120,000 a ticket) to the N Pole in August this year ran into continuous ice up to 9m thick as soon as they passed Svalbard. It took 2 days longer each way because the ship had to back up so often (a WUWT article).

      Besides, a fingerprint of warming is not automatically a “signal of Anthropo GW” that is one of the most disingenuous assumptions of alarmist science.

  2. Comment from CC skeptic: I’d give studies like this more credence if they didn’t use climate models and temperature data that has been repeatedly “adjusted.”

    • Yes, when the numbers being shuffled bear no resemblance to the original actual measurements, the exercise becomes a nonsense.

      Are there any actuaries here that would care to comment?

      • Not an actuary by any measure, but this seems to me to at least rhyme with the “hockey stock” shenanigans.

        I wonder, if you applied their “statistical methods” to random data (say, red noise) would you be able to detect the warming signal?

        • Yeah and strange that the national met bureaux of Canada, USA, Australia, UK etc determined that actual temps measurements recorded prior to 1910 or even 1950 are unreliable, yet they accept that tree rings interpretations from centuries ago can be taken as undeniable representations of temps records.

          Color me skeptical.

          • They kind of have to say that. If you look at unadjusted temperature measurements going back 100 years at any station that you like from around the world, there is no trend to be found (that I can see) – except for the giant metropolises like Sao Paolo or Calcutta. Everywhere else is basically flat.

  3. Really, you can determine the source by examining the output. It was the sun or it was man. Impressive programming indeed.

  4. For a daily precise root-mean-square of global temperature you need dense equally distributed thermometers using a sensible sampling rate of say 10 min.
    Do we have such instrumentation? Certainly not Earth surface bound thermometers. Satellites may be an option, but will the sampling be dense, concurrent and equally distributed enough? I don’t think so, even remotely. A few thermometer on the poles and virtually non on the oceans!

    I understand, to a low degree, the idea behind the study, but apparently they have a rather limited understanding of measurement and the precision needed for such a technique.

    The long term average global temperature may be somewhat close to a reality, as errors drown somewhat in the quantity of data, but on a daily bases – forget it it is absolutely and utter nonsense.

    • ..and then you have to adjust for lapse rate of measurement device altitude, phase change correction for relative moisture content and so on and on, then correctly integrate it all instantaneously over the planet for the period in question for land sea and air from the depths of the oceans to the top of the atmosphere.. Sure. Great idea. Lets do it.

  5. This will win a Nobel for the first application of AI to fudge the data to support Climate Change.

    If my model says that I can only see aardvarks, then that is all I will find in the data.

    • exactly….this is all such total BS

      In order to claim CO2 is making it warmer….they would have to know exactly what the temperature is supposed to be right now

      ..they have no clue what the temp is supposed to be

      • The don’t even know what the temperature is. Whatever they report today, will be adjusted tomorrow.

  6. The problem– not sufficient or accurate enough data to reach reasonable conclusions but enough to establish a narrative that suits your needs. Politics in action.

  7. Comparing spatial statistics of weather data seems sensible, and in fact I think it’s long overdue.

    But then this “climate change fingerprint” appears to be nothing but a product of models and the paper seems mostly concerned with issues of “climate change narrative”, which does not appear very scientific to me.

    I fail to see how this work can be earth-shattering.

  8. UAH showing +.56C for December. To me probably the “closest” estimate to whether the planet air temps are a little warmer or a little cooler, but the temperature estimates are still taken from low earth orbit satellites that don’t pass over the same patch of earth but once a day.

    • They pass over the same spot on the earths surface once per fourteen days!! See NASA A-train constellation of satellites.

  9. I read this as carefully as I could, trying to grasp what might be new and genuinely useful for diagnosing climate trends. No success. Word salad.

    • Furthermore, try looking for anything indicating what the CAUSE of any such “climate” change is. You won’t find any, of course – they just ASSUME what that is, as usual.

  10. As They report:
    “According to the researchers, the climate signal – that is, the long-term warming trend – can actually be discerned in daily weather data, such as surface air temperature and humidity, provided that global spatial patterns are taken into account.”

    So “Spatial Patterns”, which are dependent on local measurements__ ie. weather,.. must be taken into account, and yet without taking into account local measurements. or in other words irrespective of that which makes up “spatial patterns”.

    I could not help but be reminded of the infamous statement attributed to Bill Clinton, which to many people torpedoed his defense: ‘That depends on what the definition of “is” is.’

    These people are cornered and are beyond desperate for their next infusion of grant money, much like a crack or fentanyl addict no matter what the cost to their self or others including the entire world.

    These people are dangerous to themselves and others. They can no longer keep track of their life of lies.

  11. Full stupidity and impossibility for chaotic systems: “the study concludes that the long-term climate trend in global average temperature can be predicted if you know a single day’s weather information worldwide”. I can’t be done. Period.

  12. If it is beyond are ability to perceive without the aid of new-fangled statistical models and computers, why is it such a dire problem? It’s like going to your doctor for a check up and being told that they didn’t find anything wrong but they need to operate immediately, because their new statistical model says something should be wrong.

    “Prep him nurse. We are going to take out his ability to use fossil fuels, a large portion of his freedom and an equally large portion of his wallet. Now relax. We just need you to remain unconscious and this won’t hurt a bit! Trust me.”

    • Socialism doesn’t take a large portion of your freedom. It takes it all. In National Socialist Germany, you couldn’t move or rent an apartment without permission from the State. You needed your identity card to buy groceries and other documents to buy gasoline. Control was total. There was a reason that in East Germany, the suicide rate was a State secret. It was the only thing the Communists couldn’t control.

  13. I was surprised by the temperature at Peter Sinks on that October morning. We were something like -25F in Laramie during that cold snap, but if I were to look around at all the temperature monitoring sites in Laramie, like down along the Laramie River, I might have been able to find a -35F and perhaps a -20F at some other spot. Peter Sinks looks like an ideal location if one were looking for record low temperatures; so, the pertinent question is, how long has temperature been monitored at Peter Sinks? If it a recently established site, then what does this measurement mean?

  14. Can I metaphorically apply this kind of reasoning to the stock markets. The weather, the daily behaviour of prices holds important information about the long-term performance of the climate, eh market. Wow! The perfect recipe for becoming very rich.

    Somehow I am not convinced.

  15. As a starting point attribution of this kind could only be valid if all the measures are unbiased and without error… … …

  16. “If the distribution of global daily mean values from 1951 to 1980 are then compared with those from 2009 to 2018, the two distributions (bell curves) barely overlap.”

    Other people tinkering with climate think that there was a cooling period from 1945 to 1975. Hardly surprising that this group would find a difference between temperatures inside and outside that period.

    • SSSsshhhh! You’ll let them know they just unintentionally confirmed that the 1970s cooling scare was based on REAL cooling (that they have been trying to “erase” from the temperature record), and that atmospheric Co2 (which was rising) is therefore not the driver of the Earth’s temperature!

      They may need treatment when they find out what they have done! Or be sent to the Gulag!

  17. NASA needs to recalibrate their Earth Observatory. They show southern Arizona as above average for December 26 to January 2. I live in Tucson and the temperature here has been well below average since before Christmas. Typical highs in the low to mid 50’s, normal 64. Lows in lower 30’s, normal being 42.

  18. ”If the distribution of global daily mean values from 1951 to 1980 are then compared with those from 2009 to 2018, the two distributions (bell curves) barely overlap. The climate signal is thus prominent in the global values but obscured in the local values, since the distribution of daily mean values overlaps quite considerably in the two periods.”

    The “barely overlap” of the 1951-1980 relative to 2009-2018 range is simply the result of cherry picking.
    Let them try to do to the 1920-1950. Or to take every 30 year period in 10 year increments.
    For example, 1911-1940, 1921-1950, 1931-1960, 1941-1970, 1951-1980 (which is the one they showed us), 1961-1990, 1971-2000. Then try to tell us its climate change and not the AMO or some 60-80 yr cycle.

    The foundation of the climate scam started by Hansen in his 1988 Senate testimony rests on the cold 30-yrs of 1951-1980. Hansen saw an opportunity for an environmental agenda with the correlative rising CO2 record, the post-WW2 global CO2 emissions growth, and a fortuitous “peak oil” projection for early in the 21st Century. It all came together to enable a “correlation masked as causation” sleight of hand to pursue his personal environmental agenda (and many others like GreenPeace with the collapse of the USSR and end of the Cold War) that co-conspiring Democrats seized on for a simultaneous political power agenda.

    All they needed then was the climate computer model cargo cult science community to assist them. Al Gore no doubt found his man in DoE’s Ben Santer in 1995 with the SAR being drafted and the political need for anthropogenic attribution. The rest of the scam we all since we all know too well.

    • Yes Joel. Knutti is cherry-picking, as follows:

      “If the distribution of global daily mean values from 1951 to 1980 are then compared with those from 2009 to 2018, the two distributions (bell curves) barely overlap. The climate signal is thus prominent in the global values but obscured in the local values, since the distribution of daily mean values overlaps quite considerably in the two periods.”

      Their period from 1951 to 1980 corresponds closely to the global cooling cycle from ~1945-1977 when the PDO was negative, in cold mode, which occurred even as fossil fuel consumption accelerated strongly starting circa 1940, at the beginning of WW2. That cooling period, btw, is a credible falsification of the CAGW hypothesis.
      __________________________

      The PDO went negative and the world cooled from about 2008-2014, and then the PDO went positive again culminating in the ~2017 El Nino. The PDO appears about to go negative (cold mode) again.

      The PDO correlates well with global average temperature. Major volcanoes El Chichon (1982) and Pinatubo (1991+) disrupt the relationship.

      http://woodfortrees.org/plot/jisao-pdo/from:1979/plot/uah6/scale:4

      The PDO correlates even better with detrended global average temperature – detrending is used here only to demonstrate the correlation.. As stated above, major volcanoes El Chichon (1982) and Pinatubo (1991+) disrupt the relationship. The effect of volcanoes can be compensated using the Sato optical air index and then the correlation is almost perfect. As expected, the PDO leads temperature.

      http://woodfortrees.org/plot/jisao-pdo/from:1979/plot/uah6/scale:4/detrend:1.0

  19. This all goes right to the point I always try to make which is that Climate is not a scientific concept. Other ideas can be switched in and out of what Climate is supposed to be when convenient. It’s never been anything other than a vehicle for thought manipulation.

    Andrew

  20. Here is some more, some would say ‘junk science’.
    We are only 3 days into 2020 and sunspot count (SC25 signature) is almost as high as it was for some 50 preceding days at the end of 2019.
    Can we say the SC24 minimum is over?
    I don’t know about anyone else, but at the and of 2013 (6years ago, one year before SC24 hit its peak) I made a bold prediction that SC24 min will end in early January 2020 (actual number is 2020.0), “on what bases?” You might ask.
    Simply “observe, calculate, postulate prognosticate and falsifate” or at list what I have done here
    http://www.vukcevic.co.uk/J-S-a.htm
    Provenance: Someone who runs Weathercycles blog, has reproduced my graph here
    https://weathercycles.wordpress.com/2014/05/15/schwabbe-triplets-and-earths-climate/comment-page-1/#comment-2000
    If the above comes to be true, I will be as surprised as anyone else, as indeed I was when the SC24 SSN amplitude hit within a decimal point, calculated some 11 year earlier
    http://www.vukcevic.co.uk/SSN.htm
    … as always time will tell.

  21. Implicit in the idea that climate can only be understood globally rather than regionally is the underlying point of it all – global governance is needed to save the world from regional states with their chaotic and conflicting policies.

  22. “Uncovering the climate change signal in daily weather conditions calls for a global perspective, not a regional one,”
    Regional temp changes, especially in populated crop growing areas during planting/harvesting periods (or populated cold areas with fuel poverty) are the ONLY important conditions. “Global” changes mean squat.

  23. “Your card was the 🃊! Ta-DAAAA!” I guess the Little Ice Age is really over. But we already knew that. No congratulations are in order. There’s no end to the tricks you can do if you already know the answer.

    As far as being able to detect global warming from daily data by the use of novel statistical methods, if that is true, what is the global forecast for tomorrow? Separating annual variation from the mammoth diurnal variation is not a trivial process. “And for my next trick, I will saw this hockey stick in half.”

    🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊🃊…

  24. “In future, we should therefore be able to pick out human-induced patterns and trends” says what this ‘study’ was all about.

  25. Until every method ceases to be designed to specifically prove AGW, by researchers who set out with that primary goal, all this conclusion-first research is pretty much done to support/enable/provide propaganda.

    • When the article started talking about “…machine learning techniques…” I had visions of a nun with ruler in hand standing over a monitor, “Bad! Bad machine! The correct answer is Global Warming! Bad!” *smack*

  26. It always seems that every year is warmer than the last, based on that weather station in the Arctic with the running snow vehicle next to it.

  27. I had to check the header twice when I got a paragraph or two into this article, I thought I had wound up on The Onion by accident.

  28. >>> the climate signal – that is, the long-term warming trend – can actually be discerned in daily weather data, such as surface air temperature and humidity, provided that global spatial patterns are taken into account.

    In plain English, this means that – despite global warming – there may well be a record low temperature in October in the US. If it is simultaneously warmer than average in other regions, however, this deviation is almost completely eliminated. <<<

    So if it is cold as my ex wife's heart someplace that must be offset by warming elsewhere, but of course it doens’t work the other way: if it is hot in one location that can’t possibly be offset by cold somewhere else, it must be global warming.

  29. There are distinctions here between climate change, CO2 and human involvement. We know climate changes and I agree that changes are best viewed globally. I also agree that it should be using undoctored temperatures that are collected in a consistent manner. A conclusive finding that climate is warming or climate is cooling doesn’t prove that the only cause is CO2, or even that CO2 contributes in the first place. And finally, the mere existence of proof that the climate is changing, and the direction, i.e. hotter or cooler, doesn’t prove human activity is a cause to any degree.

  30. Climate and weather are two different subjects…climate is only driven by the Sun…not humans or pollution. Weather is locally driven and recently (last 80 years) made worse by technology used by stupid scientists who cow tow to the negative Cabal for funding. Therefore most papers or people like Al Gore and who ever joins the global warming bs are pure evil in action…meaning they lie and lie continuously to keep the lie going. Tim Ball and a few others have proved this beyond a shadow of a doubt in Supreme Court. End of story for the lies. We are headed into a very long ice age. Get over it and get prepared because no government is going to tell you the when the SHTF and what to do about it. You have approximately 2 years before there is no food growth on the planet unless you are prepared. Can not get any simpler a message…get cracking on learning how to survive because this year is the beginning of the Ice packs and the North pole will never be ice free for another 100,000 year cycle. The Northwest Passage has been frozen over for two years now..impossible to pass with ships and ice breakers. You must have heard the news about University students having to be rescued because they were NOT TOLD it was frozen over.!!! Sick lying shills of scientists who would cow tow to this lying to the public.

  31. I think this study touches on an important issue about patterns. I’m beginning to suspect that regional patterns of warm and cold, wet and dry, may be more important than global averages that are unnaturally smeared over different continents. There may be characteristic spatiotemporal global patterns of particular types of climate transition or change.

  32. Obviously, these people are paid too much and/or don’t have much to do.
    Gotta look busy! What about if we…..

  33. “In future, we should therefore be able to pick out human-induced patterns and trends in other more complex measurement parameters, such as precipitation, that are hard to detect using traditional statistics,” says the ETH professor. – They’re self-deluded.

    Physically what do they mean? You can’t know with their thought system.

    Their way claims the ongoing regional variations are simply expected (why? how?) from within a statistical regionally balanced data field, w/o considering net incoming energy changes, just extremes emerging out of the data field that balance out in the end, nothing to see here. In other words, it’s a theory that explains everything without direct attribution to specific forcings for specific events – the latter is what I do in my solar-weather attributions.

    It’s warm or cold somewhere for physical reasons, down to physics, not probabilities and regional climate averaging/balancing. Probabilities don’t provide direct attributions, and weather doesn’t cause weather.

    If they didn’t know the right attributions before they sure won’t now. The authors’ method has already missed the following real solar attribution from just a few months ago, so why expect them to get anything else right down the road?

    The F10.7cm solar flux for a period during October 2019 was the lowest in many decades, perhaps indicating the lowest activity in a century, which was then immediately followed by century-class cold and snow records in the NH. This should inform everyone as to the abruptness of low solar influence in concert with the season. They missed this proper attribution by a mile.

    They claim it happened because it was warm somewhere else… statistics made it cold…

  34. Exactly, James! You can and do get a mix of hot places and cool places, but setting all time cold temperatures these past two winters, no, with 150 years of so-called catastrophic Global warming and supposed tripley enhanced polar temperature enhancement on the Arctic. The Illinois all time cold record of -41C+ last winter swooped down from a frigid air mass more than 10 C colder in the Arctic Basin! WUWT?

    And a Russian giant icebreaker that took paying passengers ($120,000 a ticket) to the N Pole in August this year ran into continuous ice up to 9m thick as soon as they passed Svalbard. It took 2 days longer each way because the ship had to back up so often (a WUWT article).

    Besides, a fingerprint of warming is not automatically a “signal of Anthropo GW” that is one of the most disingenuous assumptions of alarmist science.

  35. “This information could, for example, be used for further studies that quantify changes in the probability of extreme weather events, such as regional cold spells.”

    That’s all about short term indirect solar variability driving Arctic Oscillation anomalies, that drives climate change. The occurrence of regional cold spells has nothing to do with probabilities or the mean state of the global climate. Forecast 2019-2020 cold spells. second half of October, second week of November, middle third of December, and late January through February.

    https://www.linkedin.com/pulse/2019-2020-cold-season-arctic-oscillation-forecast-ulric-lyons

  36. “climate signals”

    They clearly don’t understand math.

    Climate is what happens when you put terrain in the way of weather.

  37. The explanation of the statistical method is as follows:

    ” Statistical detection of externally forced climate change involves three steps. (1) A fingerprint γ^ of external forcing on climate is extracted, using regularized linear regression, that relates model simulated spatial patterns of daily temperatures (Xmod) and a defined univariate target variable used as test statistic (denoted Ymod in the figure: for example annual global mean temperature, AGMT, or decadal-scale Earth’s Energy Imbalance). (2) Spatial patterns of daily temperatures (Xobs) are projected onto the fingerprint γ^ to predict the target variable (denoted Y^obs). (3) A statistical significance test is used to infer whether external forcing on the climate system can be detected from the observed daily temperature pattern against the distribution of the test statistic under natural variability (denoted here P[Y^mod∗]). ”

    It seems to be completely dependent on climate models, and thus unable to extract a signal from the noise with as little bias as possible, but only to compare observations with what is supposed to happen given a certain set of assumptions used to build the model(s).

  38. Professor Knutti and his policy-driven “pseudo-science” is going to slowly but surely ruin the ETH’s reputation.
    Unfortunately since the Swiss ministry of Environment, Traffic, Energy and Communication (UVEK) has decided to follow Merkel’s footsteps towards the “alternative energy dream”, policy driven science is unfortunately the only way to get research money in Switzerland these days…
    Modelled rubbish in = modelled “politically correct” rubbish out.

  39. Some sixty years ago I was having a technical education and was told that the average for the world was 14.7C@1013 Millibars. I posed the question recently what is the temp of the world now and was told it was 15.1C so for me the world has warmed .4C in about 100 years,very frightening.

    I had a career in aircraft and engines were rated for power @ 14.7C @1313millibars and probably still are.

  40. I didn’t realize that a “warming signal” was at all controversial – it seems pretty straight forward that the Earth has been warming since the coolest state of the last Ice Age (I guess officially we are still in it) and also since about 1850 since the “Little Ice Age” blip. So detecting that it is warming seems kind of silly?

    Now when they mean they can detect the effects of CO2 in the atmosphere – forget it. That is laughable. The data is not of high enough quality to support such a finding, not is our understanding of the atmosphere and its dynamics. They would have to distort and abuse the data in order to demonstrate a biased finding – oh wait, that is already happening. So again, this article is just silly.

  41. https://wattsupwiththat.com/2020/01/03/climate-signals-detected-in-global-weather/#comment-2885524

    Yes Joel. Knutti is cherry-picking, as follows:

    “If the distribution of global daily mean values from 1951 to 1980 are then compared with those from 2009 to 2018, the two distributions (bell curves) barely overlap. The climate signal is thus prominent in the global values but obscured in the local values, since the distribution of daily mean values overlaps quite considerably in the two periods.”

    Their period from 1951 to 1980 corresponds closely to the global cooling cycle from ~1945-1977 when the PDO was negative, in cold mode, which occurred even as fossil fuel consumption accelerated strongly starting circa 1940, at the beginning of WW2. That cooling period, btw, is a credible falsification of the CAGW hypothesis.
    ___________________________________

    The PDO went negative and the world cooled from about 2008-2014, and then the PDO went positive again culminating in the ~2017 El Nino. The PDO appears about to go negative (cold mode) again.

    The PDO correlates well with global average temperature. Major volcanoes El Chichon (1982) and Pinatubo (1991+) disrupt the relationship.

    http://woodfortrees.org/plot/jisao-pdo/from:1979/plot/uah6/scale:4

    The PDO correlates even better with detrended global average temperature – detrending is used here only to demonstrate the correlation.. As stated above, major volcanoes El Chichon (1982) and Pinatubo (1991+) disrupt the relationship. The effect of volcanoes can be compensated using the Sato optical air index and then the correlation is almost perfect. As expected, the PDO leads temperature.

    http://woodfortrees.org/plot/jisao-pdo/from:1979/plot/uah6/scale:4/detrend:1.0

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