by Willis Eschenbach, November 17, 2018 in WUWT
Let me start explaining the link from Picasso to climate science by looking at what Dr. Nir Shaviv called “the most boring graph I have ever plotted in my life”.
This is the graph of the changes in the best estimate of the range of what is called “climate sensitivity” over the last forty years or so.
What is climate sensitivity when it’s at home? To explain that, I’ll have to take a slight detour. First, downwelling radiation.
“Downwelling” in climate science means headed down towards the planetary surface. Downwelling radiation is the total radiation going downwards towards the surface. It is composed of sunshine (shortwave) plus thermal radiation from the atmosphere (longwave). In climate science, this quantity, total downwelling radiation, is called “forcing”, abbreviated “F”
The central paradigm of modern climate science is that if you change the amount of downwelling radiation (forcing), that the surface temperature perforce will change. The claim is that everything else averages out, and if the forcing increases, then surface temperature needs to change to maintain the global energy balance. It has to change. It must.
In short, the central paradigm of modern climate science is the following:
In the long run, global temperature change is proportional to global forcing change.
The putatively constant proportion between the two, which is the temperature change divided by forcing change, is called the “climate sensitivity”.
See also here
by Bob Tisdale, November 15, 2018 in WUWT
As you’ll soon see, there was an eye-catching uptick (+0.25 deg C) in the GISS global Land-Ocean Temperature Index (LOTI) data from September to October 2018. We’ll have to wait for next month’s update to see if it also appears in the NOAA and Met Office datasets.
There are numerous things to note in the trend comparison. First, there is a growing divergence between models and data starting in the early 2000s. The continued rise in the model trends indicates global surface warming is supposed to be accelerating, but the data indicate little to no acceleration since then. Second, the plateau in the data warming rates begins in the early 1990s, indicating that there has been very little acceleration of global warming for more than 2 decades. This suggests that there MAY BE a maximum rate at which surface temperatures can warm. Third, note that the observed 30-year trend ending in the mid-1940s is comparable to the recent 30-year trends. (That, of course, is a function of the new NOAA ERSST.v5 data used by GISS.) Fourth, yet that high 30-year warming ending about 1945 occurred without being caused by the forcings that drive the climate models. That is, the climate models indicate that global surface temperatures should have warmed at about a third that fast if global surface temperatures were dictated by the forcings used to drive the models. In other words, if the models can’t explain the observed 30-year warming ending around 1945, then the warming must have occurred naturally. And that, in turns, generates the question: how much of the current warming occurred naturally? Fifth, the agreement between model and data trends for the 30-year periods ending in the 1960s to about 2000 suggests the models were tuned to that period or at least part of it. Sixth, going back further in time, the models can’t explain the cooling seen during the 30-year periods before the 1920s, which is why they fail to properly simulate the warming in the early 20thCentury.
One last note, the monumental difference in modeled and observed warming rates at about 1945 confirms my earlier statement that the models can’t simulate the warming that occurred during the early warming period of the 20th Century.
by David Middleton, November 13, 2018 in WUWT
This story was previously discussed here at WUWT… But, why wasn’t this headline news in the Washington Post, New York Times, etc.? Yes… That was a rhetorical question.
Comparisons with nearby automated weather stations suggest that air temperatures during these events are near −94 ± 4 °C or about −138 F. Ultracold conditions (below −90 °C) occur more frequently when the Antarctic polar vortex is strong. This temperature appears to be about as low as it is possible to reach, even under clear skies and very dry conditions, because heat radiating from the cold clear air is nearly equal to the heat radiating from the bitterly cold snow surface.
by S. Lüning & F. Vahrenholt, December12, 2017 in FrontEarthSci
The Paris Agreement adopted in December 2015 during the COP21 conference stipulates that the increase in the global average temperature is to be kept well below 2°C above “pre-industrial levels” and that efforts are pursued to limit the temperature increase to 1.5°C above “pre-industrial levels.” In order to further increase public acceptance of these limits it is important to transparently place the target levels and their baselines in a paleoclimatic context of the past 150,000 years (Last Interglacial, LIG) and in particular of the last 10,000 years (Holocene; Present Interglacial, PIG). Intense paleoclimatological research of the past decade has firmed up that pre-industrial temperatures have been highly variable which needs to be reflected in the pre-industrial climate baseline definitions …
See also here
by J.C. Maurin, 12 novembre 2018 in ScienceClimatEnergie
L’IPCC (GIEC en français) fut créé en 1988 par l’UNEP (United Nations Environment Programme) et le WMO (World Meteorological Organization). Dans les principes régissant les travaux du GIEC (1) on lit : Le GIEC a pour mission d’évaluer … les risques liés au changement climatique d’origine humaine. Le GIEC respecte son propre principe fondateur : il attribue l’intégralité de la hausse du taux de CO2 depuis 1958 à une cause anthropique. Nous examinerons ici le modèle anthropique du GIEC et nous le confronterons aux mesures contemporaines, puis à un modèle mixte. Cet article fait suite aux deux précédents publiés sur le site SCE au cours des mois de septembre (1/4) et octobre 2018 (2/4).
C. Modèle anthropique GIEC
C.1 Les contraintes des modèles (Fig. 1)
Le paragraphe A (article 1/4) a montré qu’en 1980 le taux de CO2 atmosphérique était de 338 ppm et le δ13C de -7.6 ‰. En 2010 le taux de CO2 atmosphérique était de 388 ppm et le δ13C de -8.3 ‰. Il existe une modulation annuelle de ce taux, très marquée dans l’hémisphère Nord.
by Coles et al., November, 11, 2018 in CO2Science
In light of the above findings, Coles et al. state the obvious, that the corals “were able to withstand elevated temperatures (31.4 °C) for a longer period of time in the current 2017 experiment” compared to the 1970 study. Consequently, they conclude that their results “indicate a shift in the temperature threshold tolerance of these corals to a 31-day exposure to 31.4 °C,” which findings “provide the first evidence of coral acclimatization or adaptation to increasing ocean temperatures.” And that observational reality should hold great bearing on the status and health of coral reefs in response to future climate change. If temperatures rise in the future, clearly, as living organisms, corals can (and do!) adapt. Alarmist predictions of their fast and ensuing demise due to global warming should not be taken too seriously.
by University of Barcelona, November 9, 2018 in ScienceDaily
Regional differences regarding other reconstructions
The results of the study show a temperature rise in the beginning of the Holocene, reaching the highest values in the Holocene Climate Optimum (about 7,800 years ago). There are also high temperatures until about 6,000 years ago, when a decline of temperature started and led to the lowest values in the first stage of the late Holocene (about 4,200 and 2,000 years ago).
Last, researchers detected a rise of temperatures over the two last millenniums, but they state they have to be careful with these data. “We cannot guarantee the observed rise in the reconstruction results from a temperature rise only, we cannot rule out other variables that can influence at other levels, such as the gradual increase of the anthropic activity in the area, which can change the community of Chironomidae to species that adapt to higher temperatures, but there are also human influence indicators,” says Narcís Prat.
Although these conclusions can coincide with other paleoclimate reconstructions, results also highlight some divergences at a regional level. “These differences can occur due the fact that some indicators point out to different seasonal signs. Therefore, Chironomidae are indicators of temperature in summer, while others such as chrysophites or alkenones are related to winter/spring temperatures,” notes the researcher.
A tool to evaluate climate trends
by Anthony Watts, November 7, 2018 in WUWT
A new study, based on 27 years of data from Mana Pools National Park in Zimbabwe, suggests that temperature increases over the last three decades have already caused major declines in local populations of tsetse flies.
This analysis, published in the journal PLOS Medicine this week, provides a first step in linking temperature to the risk of sleeping sickness in Africa.
A model for fly population mortality is only as good as the temperature data used to run the model. It appears they only used one source of temperature data, the only one available to them, the Rekomitjie Research Station.
Interestingly, this helpful photo was also included in the press release from Eurekalert. It is the weather station used to monitor climate at the Rekomitjie Research Station, Zimbabwe. I provide it below, click for full-size. At the scale displayed above, you might not notice some important details about the weather station itself, but I did. Here it is, magnified: …
by Lüning et al., 2018 in NoTricksZone
Global warming alarmist scientists like claiming that the well documented Medieval Warm Period (MWP) was merely a regional phenomenon, and not global. However a new publication by Lüning et al adds yet another study that shows the warm period from 1000 years ago was indeed global.
by Norman Page, November 2, 2018 in WUWT
When analyzing complex systems with multiple interacting variables it is useful to note the advice of Enrico Fermi who reportedly said “never make something more accurate than absolutely necessary”.
My recent paper presented a simple heuristic approach to climate science which plausibly proposed that a Millennial Turning Point (MTP) and peak in solar activity was reached in 1991.
Zharkova et al 2015 DOI:10.10381/srep15683 says ” Dynamo waves are found generated with close frequencies whose interaction leads to beating effects responsible for the grand cycles (350-400 years) superimposed on a standard 22 year cycle. This approach opens a new era in investigation and confident prediction of solar activity on a millenium timescale. ”
Svalgaard concluded in his essay on WUWT 10/27 2018:
The temperature increase since about 1650 is clearly chiefly due to the up- leg in the natural solar activity millennial cycle as shown by Lean 2018 “Estimating Solar Irradiance Since 850 AD” Fig 5
by Albert Parker, November 2, 2018 in WUWT
A recent paper Trajectories of the Earth System in the Anthropocene (Ref.  below) claims that even if the CO2 emission reductions called for in the Paris Agreement are met, our Earth may still enter what they call “Hothouse Earth” conditions, a long-term stabilization at temperature 4-5 °C-higher than pre-industrial temperatures, and sea-level 10-60 m-higher than today. They conclude calling for an accelerated transition towards a CO2 emission-free-world-economy. There is, however, very little evidence that the apocalyptic prediction is scientific grounded. Where really measured, the temperatures haven’t increased dramatically, and similarly, the sea-levels haven’t risen dramatically. More importantly, any acceleration of the temperature warming, or any acceleration of the rate of rise of the sea-level, are hard to detect.
Figure 1 –sample long-term-trend thermometer results (Alice Spring, NT, Australia). The temperatures were recorded in the Post Office / City and Airport locations. Data downloaded from www.bom.gov.au/climate/data/.
by David Whitehouse, October 29, 2018 in GWPF
The IPCC appears to have secretly changed the definition of what constitutes ‘climate’ by mixing existing and non-existing data
The definition of ‘climate’ adopted by the World Meteorological Organisation is the average of a particular weather parameter over 30 years. It was introduced at the 1934 Wiesbaden conference of the International Meteorological Organisation (WMO’s precursor) because data sets were only held to be reliable after 1900, so 1901 – 1930 was used as an initial basis for assessing climate. It has a certain arbitrariness, it could have been 25 years.
For its recent 1.5°C report the IPCC has changed the definition of climate to what has been loosely called “the climate we are in.” It still uses 30 years for its estimate of global warming and hence climate – but now it is the 30 years centred on the present.
by Davis W.J., 2017 in CO2Science
Davis, W.J. 2017. The relationship between atmospheric carbon dioxide concentration and global temperature for the last 425 million years. Climate 5: 76; doi: 10.3390/cli5040076.
Writing by way of introduction to his work, Davis (2017) notes that “a central question for contemporary climate policy is how much of the observed global warming is attributable to the accumulation of atmospheric CO2 and other trace greenhouse gases emitted by human activities.” If you talk to a climate alarmist, the answer you receive from such an inquiry will likely be “almost all.” A climate skeptic, on the other hand, will likely respond that the answer is “likely none.”
Hoping to provide some crucial information on this topic, Davis analyzed the relationship between historic temperature and atmospheric CO2 using the most comprehensive assemblage of empirical databases of these two variables available for the Phanerozoic period (522 to 0 million years before present; Mybp). In all, 6680 proxy temperature and 831 proxy CO2 measurements were utilized, enabling what Davis described as “the most accurate quantitative empirical evaluation to date of the relationship between atmospheric CO2concentration and temperature.” Multiple statistical procedures and analyses were applied to the proxy records and the resultant relationship is depicted in the figure below.
Egalement voir ici
by Steve McIntyre, October 24, 2018 in ClimatAudit
The PAGES (2017) North American network consists entirely of tree rings. Climate Audit readers will recall the unique role of North American stripbark bristlecone chronologies in Mann et al 1998 and Mann et al 2008 (and in the majority of IPCC multiproxy reconstructions). In today’s post, I’ll parse the PAGES2K North American tree ring networks in both PAGES (2013) and PAGES (2017) from two aspects:
ex post screening based on recent proxy trends necessarily biases the resulting data towards a Hockey Stick shape – a criticism made over and over here and at other “ske;ptic” blogs, but not understood by Michael (“I am not a statistician”) Mann and the IPCC paleoclimate “community”;
the PAGES 2017 North American tree ring network has been severely screened ex post from a much larger candidate population: over the years, approximately 983 different North American tree ring chronologies have been used in MBH98, Mann et al 2008, PAGES 2013 or PAGES 2017. I.e. only ~15% of the underlying population was selected ex post – a procedure which, even with random data, would impart Hockey Stick-ness to any resulting composite
despite this severe ex post screening (in both PAGES 2013 and PAGES 2017), the composite of all data other than stripbark bristlecones had no noticeable Hockey Stick-ness and does not resemble a temperature proxy.
by S. Lüning, January 9, 2018 in WUWT
The climate of the pre-industrial past is of greatest importance to the ongoing climate discussion. Current climate can only be understood when interpreting it in the paleoclimatological context of the past few thousand years. Until not too long ago it was thought that the pre-industrial climate was monotonous and constant. This idea was e.g. promoted by Mann et al. whose famous hockey stick curve featured prominently in the IPCC report of 2001. Over the last 15 years, however, a large number of studies changed this view by providing robust evidence for the existence of significant natural climate variability. Of particular interest are the past 1000 years which commenced with the generally warm ‘Medieval Climate Anomaly’ (MCA, aka ‘Medieval Warm Period’, MWP), that eventually passed into the ‘Little Ice Age’ (LIA), before returning to the warm climate of the current ‘Modern Warm Period’ of the 20th and early 21st centuries.
There have been controversial debates about the existence of the MWP, …