If you actually stayed on the topic of arctic temperatures in the 19th-21st centuries instead of resorting to poorly constructed strawmen arguments about how I'm appealing to consensus/authority, etc, this discussion would certainly be a lot more pleasant.
I think it is best if we both follow the advice of the mods here and keep this a pleasant discussion
Pot meet kettle. Your subjective, heavily biased approach and attitude to this problem is very evident in every single one of your posts, even Larry (GaWx) is picking up on this, take a good hard look in the mirror.
I always appreciate Larry's questions and his probing into the data. He has some fantastic observations and is far more knowledgeable than I am on a lot of things, especially weather and statistics. His question was a terrific one and I have since answered
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The HadCRUT4 data series has improved high latitude data coverage (compared to the HadCRUT3 series) the individual 5x5 grid cells has been weighted according to their surface area. This is in contrast to Gillet et al. 2008 which calculated a simple average, with no consideration to the surface area represented by the individual 5x5 grid cells.”
You're completely oblivious to the larger point I was trying to make. First of all, I actually was talking about the HADCRUT4 timeseries earlier so this argument about it's better than HADCRUT3 is entirely mute from the beginning. Second of all, their improved coverage still only means about a third of the grid cells at best are covered by HADCRUT4 during the 1930s, you can easily check this using the KNMI Climate Explorer, what about the other two-thirds of the arctic that weren't measured, again apples-oranges, cling to this all you want but the reality is all the datasets show the 2000s are warmer and likely so.
The quote I posted was straight from the climate4you website explaining the data methodology used in the HadCRUT4 graph. It was their comparison to HadCRUT3 and mention that it was not a simple average and are weighted according to surface area. I think the data posted shows that prior to 2005, the 1990s and early 2000s have experienced similar levels of warmth as that seen in the 1920-45 period and post 2005 there has been additional warming which varies in extent by the dataset and methodology used. The graph you posted shows a spike around roughly 2005 but prior to that the warming in the late 90s and early 2000s was similar to the 1930s and 40s.
It doesn't matter if I used 1971-2000, 1951-1980, or 1961-1990, the anomalies in the 2000s are still higher than the 1930s-40s in all the datasets I showed, no matter how you want to try & twist it. If the 2000-2010 anomaly is +2C, and the 1930-40 anomaly is +1.5C for example w/ 1951-1980 base period, then they both cool and warm at the exact same rate if you change the base periods, again the relative anomalies are what we actually care about here, whether the 2000s are warmer than the 1930s, which most would agree is the case. The few papers you've linked don't make a strong case for that and the Francis (2006) study is using data that ended in 2000, the arctic has warmed even more since then, the case for the 1930s being warmer would be even weaker.
I would agree that the Arctic has warmed a bit since 2005 but also make note that the original point I was trying to make, although it may have been a bit unclear, is that stating the 2000s are warmer than the 1930s isn't entirely accurate. If you're talking about 2005-present then yes there has been some additional warming (the extent of warming varying based upon the dataset used) that is warmer than the 1930s. If you are looking at the early 2000s the data I posted along with your chart indicate that the early 2000s and 1930s-40s experienced similar levels of warmth. My apologies if this was not clear in my original statements.
As for the climate4you graphs, they were presented here with the y axes being very large and deceivingly compressed because it's hard to pick out even a 1C long-term temperature change in each of those, which is very important here in the context of whether the 1930s were warmer than the 2000s. The reality is they're not, and most of those stations, especially Svalbard are in fact warmer, in some cases by a longshot. As Larry alluded to above, this certainly gets in the way of being able to provide evidence the 1930s & 40s were warmer than the 2000s & especially the 2010s.
I have since posted graphs for 5 of the 6 stations that the climate4you graph cites in my response to Larry. I pulled the graphics straight from the GISS website and used the option to remove only suspicious records from the data. I think the GISS graphs I posted indicate the warming even recently isn't unprecedented for most of the stations. Unfortunately, the Svalbard dataset only goes back to 1977 when I try to pull the dataset, I assume they changed to a newer station since records only go to 1977 now.
The glaring problem with this argument is that natural forcing suggests we should have cooled in the midst of lower solar activity, the lowest in over a century in fact, a -PDO that's dominated most of the post 1998 era, and now a cold AMO to boot, global temperatures shouldn't have continued to rise but they have, and practically every year since the 2015-16 NINO is warmer than the 1998-2014 era, a clear sign that the globe is warming. Using mostly variations in natural forcing to explain ongoing temperature variability doesn't get you anywhere close to the answer.
I have no doubt the globe is warming. The question is what is causing the warming. Is it all anthropogenic, partly natural cycles/variability, or entirely natural? The two most popular that I've seen are that it is all/primarily man-made and then the other side where man has contributed to magnifying these cycles but the underlying drivers are natural cycles. Here is some interesting data surrounding this.
"However, the proposition that the world should be cooling absent an anthropogenic effect, contradicts our knowledge of Holocene climate cycles. One of the main cycles is the ~ 1000-year Eddy cycle found in climate and solar activity proxy records of the Early and Late Holocene (see:
Centennial to millennial solar cycles). The periodicity of this cycle is maintained from Early to Late Holocene, and reflected in the Bond events of increased iceberg activity in the North Atlantic (
figure 81). The start of the Medieval Warming ~ 700 AD, and the start of the MGW at ~ 1700 AD are separated by ~ 1000 years. The peak of the MWP at ~ 1100 AD and the trough of the LIA at ~ 1600 are separated by ~ 500 years (figure 103). Based on this cycle it can be projected that the period ~ 1600-2100 AD should be a period of net warming, to be followed by a cooling period ~ 2100-2600 AD, if the cycle maintains its beat (figure 105).
Figure 105. Warming and cooling periods of the past 1500 years, fitted to known climate cyclic behavior. Moberg et al., 2005, reconstruction of Northern Hemisphere temperature anomaly for the period 500-1978 AD (grey curve), and its low frequency component (black curve). The 980-year Eddy cycle is shown in red, with a declining Neoglacial trend of –0.2 °C/millennium. As Moberg’s reconstruction ends in 1978, the dotted line represents the 1975-2000 warming, that is similar in magnitude to the 1910-1945 warming. DACP, Dark Ages Cold Period. MWP, Medieval Warm Period. LIA, Little Ice Age. MGW, Modern Global Warming. Peak natural warming is expected in 2050-2100 AD."
"Physics shows that adding carbon dioxide leads to warming under laboratory conditions. It is generally assumed that a doubling of CO2 should produce a direct forcing of 3.7 W/m2 (IPCC-TAR, 2001), that translates to a warming of 1°C (by differentiating the Stefan-Boltzmann equation) to 1.2°C (by models taking into account latitude and season). But that is a maximum value valid only if total energy outflow is the same as radiative outflow. As there is also conduction, convection, and evaporation, the final warming without feedbacks is probably less. Then we have the problem of feedbacks, which are unknown and can’t be properly measured. For some of the feedbacks, like cloud cover we don’t even know the sign of their contribution. And they are huge, a 1% change in albedo has a radiative effect of 3.4 W/m2 (Farmer & Cook, 2013), almost equivalent to a full doubling of CO2. So, we cannot measure how much the Earth has warmed in response to the increase in CO2 for the past 70 years, and how much for other causes.
Looking at borehole records and proxy reconstructions (figure 103), it becomes very clear that most of the acceleration in the rate of MGW took place between 1700 and 1900, when very little human-caused GHGs were produced. The rate of warming has changed little in the 20th and 21st centuries, despite the bulk of GHGs being emitted in these past 70 years. However, if the increase in global average temperature over the past 7 decades was mainly a consequence of the rapid increase in CO2, the rate of temperature change should show dependence on the rate of change of the natural logarithm of CO2 concentration. This is because the proposed link between CO2 and temperature is based on a molecular mechanism where every added molecule has slightly less effect than the previous. Even accounting for the logarithmic response of global average temperatures to CO2, the curves for proposed cause and effect are clearly diverging (figure 111). The global temperature anomaly between 1950 and 2017 is not significantly different from a linear trend. On the other hand, atmospheric CO2 increase has been so fast over the 1958-2017 period that the rate of change of its logarithm displays a pronounced acceleration (figure 111).
Figure 111. The difference between temperature increase and CO2 increase. Thick black curve, HadCRUT4 13-month centered moving average surface temperature anomaly, relative to 1961-1990, from 1950 to 2017 (November). Source: UK Met Office. The thin continuous line is a linear trendline of the temperature data. Thick red curve, the natural logarithm of the 1958-2017 annual atmospheric CO2 concentration (ppm). Source: NOAA. Thin black dotted lines, visual aid showing the effect of the rapid increase in CO2 concentration on its logarithm. It is proposed that the increase in the logarithm of CO2 is causing the increase in temperature, yet the curves diverge."
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The lack of MGW acceleration despite the rapid increase in CO2 over the past 7 decades only has two possible explanations. The first is that the ongoing increase in the proposed anthropogenic forcing exactly matches in magnitude and time an ongoing decrease in natural forcing (figure 104). The second is that MGW responds more to natural causes, and only weakly to anthropogenic forcing.
The first explanation constitutes an “ad hoc” match of hypothesis to evidence, requires an unrelated coincidence of decadal precision within a multi-century process (natural cooling started just when we started our emissions), and it is disavowed by the IPCC, that considers natural forcing over the 1950-2010 period too small to have contributed to the observed temperature change in any direction (figure 113). That natural forcing has had no role over a 60-year period is hard to believe.
Figure 113. IPCC proposed contributions to observed surface temperature change over the period 1951-2010. IPCC assessed likely ranges (whiskers) and their mid-points (bars) for warming trends over the 1951–2010 period from well-mixed greenhouse gases, other anthropogenic forcings (including the cooling effect of aerosols and the effect of land use change), combined anthropogenic forcings, natural forcings and natural internal climate variability. The observed surface temperature change is shown in black, with the 5 to 95% uncertainty range due to observational uncertainty. The attributed warming ranges (colours) are based on observations combined with climate model simulations, in order to estimate the contribution of individual external forcings to observed warming. Source: IPCC. 2014. AR5. Synthesis Report. Summary for policymakers. Figure SPM.3 p. 6.
The second explanation requires only an insufficient knowledge of the response of the climatic system to CO2, and an insufficient knowledge of natural forcings and climate feedbacks. That our knowledge is insufficient is clear and demonstrated every time the “argumentum ad ignorantiam” that “we don’t know of anything else that could cause the observed warming” is used. New research into solar variability mechanisms (see: Climate change mechanisms) has produced hypotheses that indicate that solar forcing is probably not adequately represented in models, and the cloud feedback is essentially not understood yet."
"The CO2 hypothesis proposes that changes in atmospheric CO2 levels are the main driver of Earth temperature changes (Lacis et al., 2010). It is based on the spectral absorption and radiation properties of certain gases, of which water vapor is by far the most abundant, and CO2 is a distant second. Water vapor levels are locally determined and highly variable due to condensation. CO2 levels are global, as it is a well-mixed gas that does not condense, and before industrialization it changed very slowly over time from natural causes. CO2 hypothesis considers that water vapor changes are not the driving factor, but a feedback, proposing without clear evidence that the relevant causal relationship is CO2 –> temperature –> water vapor. Past water vapor levels cannot be determined, but in the distant past, cold periods of the planet (Ice Ages) were associated to lower CO2 levels than warm periods, and this is the supporting evidence offered by proponents of the CO2 hypothesis. The interpretation of this evidence, however, is far from straightforward, as changes in temperature also lead to changes in CO2, from huge ocean carbon dioxide stores, because the gas solubility is dependent on temperature, and in well resolved records, changes in temperature generally precede changes in CO2 by hundreds to thousands of years.
Another problem with the hypothesis is that it is generally accepted that a progressive decrease in CO2 levels has taken place for the past 550 million years (the Phanerozoic Eon), from ~ 5000 ppm in the Cambrian to ~ 225 ppm in the Late Pleistocene. This decrease does not appear to have produced a progressive decrease in temperatures, that display a cyclical range-bound oscillation (Eyles, 2008; figure 115), alternating between icehouse and hothouse conditions over the entire Phanerozoic.
Figure 115. Phanerozoic Eon conditions don’t support the CO2 hypothesis. Schematic representation of glacio-epochs during the past 550 million years in Earth history, and their relationship to phases of supercontinent assembly and break up. Glaciations are indicated and represented by the blue area above the scheme. Estimated global temperature trends (red graph), and variations in atmospheric carbon dioxide (green graph), are indicated, with their general trend as a dashed line. Surce: N. Eyles. 2008. Palaeo3 258, 89–129."
Finally, here is a summary of the article as presented below.
The CO2 hypothesis is not new, and can be traced to Arrhenius in 1896, however it did not become the dominant hypothesis to explain temperature changes until the last warming phase of MGW started in the late 1970’s, and temperature and CO2 were both increasing.
In the 20th century, while MGW was taking place, humanity embarked in the ultimate experiment to determine the validity of the CO2 hypothesis and set about to burn huge fossil fuel natural stores while industrializing, to raise CO2 levels beyond what the world has had in perhaps millions of years. After 70 years with CO2 levels increasing faster than ever recorded, and above any previously recorded level for the Late Pleistocene, it is time to analyze the results.
- The world has continued warming as before. The warming during the 1975-1998 (or 1975-2009) period is not statistically significantly different from the warming during the 1910-1940 period (Jones, 2010).
- The temperature increase since 1950 shows no discernible acceleration and can be fitted to a linear increase. The logarithm of the CO2 increase, however, displays a very clear acceleration (figure 111). A linear relation between supposed cause and effect cannot be established.
- Sea level has continued rising as before. Its acceleration is not responding perceptibly to the increase in anthropogenic forcing (figure 114).
- The cryosphere shows a non-cyclical retreat in glacier extent with evidence of acceleration (figure 107; Zemp et al., 2015). The reduction of the size of ice shelves is also unusual (figure 109). The evidence supports a cryosphere response to the CO2 increase.
- Despite CO2 levels that are almost double the Late Pleistocene average, the climatic response is subdued, still within Holocene variability, below the Holocene Climatic Optimum and below warmer interglacials.
Lack of support for the CO2 hypothesis from Antarctic ice cores (figure 110), and from results 1-3 has forced the proponents of the hypothesis to make numerous new unsupported assumptions. They assume that all warming since 1950 is anthropogenic in nature (IPCC-AR5, 2014, figure 113). That past recorded temperatures must be cooler than previously thought (Karl et al., 2015). That the oceans (Chen & Tung, 2014), and volcanic eruptions (Fasullo et al., 2016), are delaying the surface warming and SLR. And essentially concluding that more time is required to observe the warming and SLR acceleration. All these might be true, but the simplest explanation (Occam’s favorite) is that an important part of the warming is due to natural causes, and CO2 only has a weak effect on temperatures.
If after 70 years of extremely unusual CO2 levels, a lot more time is required to see substantive effects, then the hypothesis needs to be changed. As proposed it does not call for long delays, due to the near instantaneous effect of the atmospheric response to more CO2. The CO2 hypothesis is at its core an atmospheric-driven hypothesis of climate. There is a significant possibility however that the climate is actually ocean-driven, directly forced by the Sun, and mediated by H2O changes of state.
The high sensitivity of the cryosphere to the CO2 increase might actually be an argument for a reduced sensitivity by the rest of the planet. The air above the cryosphere is the coldest of the planet, as it is not warmed much from below, and therefore it has the lowest humidity of the planet. The ratio of water vapor to CO2 in the air above the cryosphere is the lowest and the one that changes the most with the increase in CO2. There is the possibility that air dryness, and the low capacity to produce water vapor in response to warming might be the reasons why the cryosphere is particularly sensitive to CO2, but it implies the rest of the planet is less sensitive. If CO2 sensitivity is highest over the cryosphere (except Antarctica), and lower over the rest of the planet, this points to a negative feedback by H2O response, in its three states, to temperature changes. Antarctica doesn’t show increased sensitivity because it has not been warming through the entire MGW, regardless of CO2.
There are multiple possible H2O temperature regulatory mechanisms, and the proposition that H2O only acts as a fast-positive feedback to CO2 changes is too simplistic. The huge water mass in Earth’s oceans and its slow mixing, add a great thermal inertia that resists temperature changes. Atmospheric humidity determines how changes in energy translate into changes in temperature, as humid air has a higher heat capacity and responds to the same energy change with a lower temperature change than dry air. Atmospheric humidity responds very fast to temperature changes through evaporation and condensation. This mechanism is proportional to water availability, and works better above the oceans than over land, and very little over the cryosphere, inversely correlating to MGW temperature changes, that are highest in the Arctic (polar amplification), and lower over the oceans than over land. To that we must add other region-specific temperature-regulating mechanisms by H2O. Deep convection is a tropical atmospheric phenomenon that takes place when the surface of the tropical ocean reaches 26-30 °C. The ocean flips from absorbing energy to releasing it, and convection takes the energy very high in the troposphere, cooling the ocean (Sud et al., 1999) and effectively limiting its maximum temperature. Polar sea ice is a negative feedback that releases heat when it forms in the autumn, then absorbs heat, when it melts in spring, and it acts as an insulator preventing ocean heat loss during winter. Ice-albedo effect is a positive feedback, in that a decrease in ice reduces albedo, driving further ice loss. But ice-albedo feedback is ameliorated because ice extent moves opposite to sunlight (maximum ice coincides with minimum albedo when it is darker), and by the high inclination of the Sun’s rays at polar latitudes, making water more reflective. So the albedo effect is not driving Arctic sea ice melting as demonstrated by the 10-year pause in summer Arctic sea ice loss, after losing 30% of its extent the previous 10-year period.
Due to its huge thermal inertia, changes in its three states, cloud condensation, humidity regulation, and effective saturation of IR absorption, H2O is a good candidate to explain the observed resistance of planetary temperatures to increasing CO2 forcing. Only in the cryosphere, where humidity is very low and sublimation a very ineffective change of state, CO2 increase, helped by the albedo effect, is likely driving a non-cyclical melting that affects sea level rise.
Conclusions
1) Modern Global Warming is one of several multi-centennial warming periods that have taken place in the last 3000 years.
2) Holocene climate cycles project that the period 1600-2100 AD should be a period of warming.
3) A consilience of evidence supports that Modern Global Warming is within Holocene variability.
4) Modern Global Warming displays an unusual non-cyclical cryosphere retreat. The contraction appears to have undone most of the Neoglacial advance.
5) The last quarter (70 yr) of Modern Global Warming is characterized by extremely unusual and fast rising, very high CO2 levels, higher than at any time during the Late Pleistocene. This increase in CO2 is human caused.
6) The increase in temperatures over the past 120 years shows no perceptible acceleration, and contrasts with the accelerating CO2 forcing.
7) Sea level has been increasing for the past 200 years, and its modest acceleration for over a century shows no perceptible response for the last decades to strongly accelerating anthropogenic forcing.
8) The evidence supports a higher sensitivity to increased CO2 in the cryosphere, which is driving unusual melting and a small long-term sea level rise acceleration. The rest of the planet shows a lower sensitivity, indicating a negative feedback by H2O, that prevents CO2 from having the same effect elsewhere.
For additional reading of the entire data analyzed see here.
https://judithcurry.com/2018/02/26/nature-unbound-viii-modern-global-warming/
