How would you measure the temperature of the earth from mars? Well you could measure the infra red spectrum of the earth and then fit it to a black body spectrum to derive T. If you did that you would get an answer of about 252K, unchanging with time. The greenhouse effect keeps the effective average surface warmer at 288K, but what does this actually mean and how can we measure if it changes? This is not a simple question.
The earth’s temperature at any location is never in equilibrium. It changes daily, seasonally and annually. Incoming solar radiation varies enormously especially near the poles which receive more energy per day in summer than the equator.
The earth cools primarily by moving heat from hot tropical regions towards high latitudes where net IR radiation loss cools the planet, thus maintaining a certain temperature profile.
Rising CO2 levels modify that radiation imbalance profile slightly. Surface temperatures in the tropics are not really warming at all. Any excess heat induces more clouds and more convection while surface temperatures remain constant. What really happens is that the meridional radiation profile changes. Slightly more heat is transported polewards so that hot places are shifting more heat to cold places which are doing the warming. If CO2 levels stop rising then a new temperature and radiation profile would rather quickly be reached. This is then called ‘climate change’ but any such changes are concentrated in colder regions of the world. The global ‘temperature’ itself is not changing, but instead the global distribution of temperature is changing.
Temperatures at the poles during 6 months of darkness would fall well below -150C if there was no atmosphere, similar to the moon. Instead heat is constantly being transported from lower latitudes by the atmosphere and ocean and so that temperatures never fall much below -43C. If more heat is transported northwards than previously, then minimum temperatures must rise, and this is exactly what we observe in individual measurements.
The main problem with all the existing observational datasets is that they don’t actually measure the global temperature at all. Instead they measure the global average temperature ‘anomaly’. This is because measuring any average global temperature is “biased” by the distribution of stations, whereas measuring an average anomaly ( ) is supposedly not. Each monthly station ‘anomaly’ is actually the difference between the measured monthly temperature and so-called “normal” monthly values. In the case of Hadcrut4 these normal values are the 12 monthly averages calculated from 1961 to 1990 at each station.
The basic assumption being made when using anomalies is that global warming is a universal, location independent phenomenon which can be measured by averaging all station anomalies together, wherever they might be distributed. So in principal this then implies that global warming could be measured by just one station alone, which is clearly nonsense.
The use of anomalies introduces a new bias because they are now dominated by the larger ‘anomalies’ occurring at cold places in high latitudes. The reason for this is obvious, because all extreme seasonal variations in temperature occur in northern continents, with the exception of Antarctica. Increases in anomalies are mainly due to an increase in the minimum winter temperatures, especially near the arctic circle. To take an extreme example here is the monthly temperature data and calculated anomalies for Verkoyhansk in Siberia.
Annual temperatures vary from -50C in winter to +20C in summer. That is a seasonal range of 70C each year, and a year to year anomaly variation of ~8C is normal. The only global warming effect evident is a slight increase in the minimum winter temperatures since 1900. That is not due to any localised enhanced greenhouse effect but rather to an enhanced meridional heat transport. Temperatures in equatorial regions meanwhile have only ~4C seasonal variations, and show essentially no warming trend.
Long term changes in temperature anomalies occur mainly in northern continents in winter months. This is not because the earth as a whole is warming up but rather that meridional heat transport from the equator to the poles has increased and the largest effect on ‘anomalies occurs in winter. The average absolute temperature of the earth’s surface is unknown. Basing the evidence for climate change on the 150 year trend in global averaged temperature anomalies still biases the result towards higher latitudes where most of the stations are located. Is it any wonder then that climate scientists are tempted to further amplify the impression of global warming by artificially infilling the Arctic, rather than say Africa or South America. For some reason they are not so keen to infill the much larger Antarctica, because surprisingly it isn’t warming
This is an animation of recent monthly temperature anomalies which demonstrates how most variability in anomalies occur over northern continents.
Note the El Nino’s in 1998 and 2015.
Interesting post. I think there is more support for what you are saying than you furnished.
For example, when you go the site where the RSS data are furnished I have notices that when you look at the slopes of the temperature change they are declining as you move down from the North Pole. The NP is the highest and the SP has no change. You did say this is prevalent in the NH. It sure seems that way.
Second, I used to look every week at Joe Bastardi’s updates. One of the graphs he would use commonly was this one.
It shows that the temperatures are above average but still very cold. Joe would say the thing to worry about were the summer months. If temperatures deviated from the green line in the summer months that would be a concern. Last summer it followed the green line. This supports your contention about the winter months.
I have not posted anything on my tracking of El Nino or Hadrut4 in a while. I have revamped things a bit and been more critical on myself thinks to some comments from Javier.
The Nino region data I analyze are now composed of the following:
Monthly data until 1990
Weekly data after 1990 until 2014
Pseudo daily data after 2014. What I mean by pseudo is I do linear interpolation between the weekly points to give me daily point.
I did the OFT over again with more recent data. The OFT serves as a foundation for the cyclic analysis. I think I am doing better in my projections. I don’t expect them to change as much now if things have been done right.
With just measured data here is how things look:
The projections for the new method are those dated 12/21 and 01/18. I am encouraged that those two lines are on top of one another. I hope it continues this way. The camel hump is there but has been mitigated.
I could not do quite the same for Hadcrut4 but I do think these results are better than what I had before.
The projections are more reasonable and do indicate declining solar activity which some predict.
That’s right. It is the coldest months that are warming in Europe, US and Russia. That is when net heat flow has increased due to GHE. Look at how the seasons change net radiative loss.
“Global temperature” is about as meaningful as “global telephone number”.
The global telephone number is ’42’ isn’t it ?
“Global temperature” is about as meaningful as “global telephone number”
I’ve been pointing out for years that the Earth system response to radiative gases is a circulation change instead of a surface temperature change.
That view is becoming more common.
I have read your theory and agree with 80% of it. I do think though that the CO2 greenhouse effect is real, and that it mainly causes a small rebalancing of the heat circulation on earth. This will lead to an increase in surface temperatures at high latitudes. The tropics already have an excess of heat which drives the earth’s weather. A rebalancing of circulation won’t change the temperature of the tropics but will move climate zones slightly, leading to some localised warming. The main effect is a rise in minimum winter temperatures in arctic regions. OK arctic ice may diminish causing eventually (100 years time) ~1m rise in sea levels.
The real mystery is why Antarctica shows no signs of warming or ice loss.
“The real mystery is why Antarctica shows no signs of warming or ice loss.”
It seems obvious to me Clive that the answer is the thermohaline circulation isn’t close enough to the southern pole to effect Antarctica. If there was similar geography, I’d expect that the South pole would behave as the north, with oceanic heat warming the pole with frigid air moving northward to replace the movement of heat.
Yes that must be the main reason. The circulating antarctic current drives the global circulation. Water upwelling in Antarctica has travelled from the Arctic where it descended to the deep ocean 1000 years ago.
That is a good point that I considered carefully over a long period and it is dealt with by the fact that at all times the atmosphere must remain in hydrostatic equilibrium if it is to be prevented from drifting off into space or falling to the ground.
If you try to increase surface temperature from GHGs (or any other radiative materials floating in the atmosphere) then that equilibrium is preserved by the affected layer of the atmosphere (in Earth’s case the troposphere) expanding until radiation to space from GHGs matches radiation to the ground from GHGs for a zero net effect. CO2 may block one narrow band of wavelengths but the energy just escapes at other wavelengths instead. CO2 will always be moved by convection until the net thermal effect on the average lapse rate slope is zero.
I went into the specific processes involved here:
For non condensing GHGs Fig 3 is the important one.
You will see that the ‘secret’ is in the way the GHGs distort the lapse rate slope differently at different heights.
The fact is that the tropopause is higher above low pressure despite the vertical column being taller because the air is less dense and thus lighter whereas the tropopause is lower above high pressure despite the vertical column being shorter because the air is more dense and thus heavier.
Furthermore the tropopause height distortions are greater for both higher and lower surface pressures so the NEGATIVE system response I describe is always proportionate to the amount of distortion of the lapse rate slope caused by GHGs.
Thus, taking the surface of the globe as a whole the net thermal effect is zero but you get BOTH warmer and cooler surfaces in different locations which also net out to zero globally.
That would also explain why there is no warming or long term net ice loss in the Antarctic as a result of our CO2 emissions.
There should be an effect in Antarctica from solar induced (in my opinion) global cloudiness/albedo variations but maybe not enough to reliably measure.
Amusingly, the alarmists are correct when they suggest that GHGs cause both warming and cooling, just in different places at varying times.
However, the primary GHE being due to atmospheric mass the additional effects of GHGs would be indiscernible even in the regions of the surface shifted to the warm side or the cold side.
Additionally, the Earth’s rotation jumbles it all up over time so no single location could ever notice.
A single global statistic is good for propaganda but useless for analysis of cause and effect.
My own investigations support what you have to say here Clive. The temperature increase occurs in winter mainly in the northern hemisphere. This increase in winter is due to enhanced meridional flows.as a response to an increase in the surface pressure differential between the equator (where surface pressure has increased slightly and the poles where surface pressure has fallen away due to enhanced polar cyclone activity generated at Jet stream altitudes. Its tied to change in the stratosphere.
Surface air temperature volatility increases with latitude and is greatest in January in the northern hemisphere and July-August in the bulk of the southern hemisphere. The variability from year to year is greater than the variation between the 1940’s and today. Climate variability is a fact of life that has nothing to do with carbon dioxide and a lot to do with the changing ozone content of the upper air peaking always in winter.
There has been no increase in the temperature of the entire southern hemisphere in the month of December for seven decades. The increase has occurred in winter.Paradoxically high southern latitudes have been cooling now in winter and spring for many decades giving rise to increased ice persistence about Antarctica..
Apart from the meridional distribution effect there is also of course a change in surface temperature due to change in cloud cover. In general, and particularly so in the southern hemisphere surface temperature increases in parallel with surface atmospheric pressure and geopotential height at all levels of the atmospheric column reflecting a warming atmospheric column where relative humidity falls away.This affects in particular areas that naturally support the formation of high pressure cells….the oceans. When more solar energy gets to the surface of the ocean the globe warms.
We fondly imagine that its all about ‘the science’. If only it were that easy.
So UHI has no affect on Lower temps in the NH then, only GHGs?
For a perverse reason involving temp-anomalies the effect of UHI is to cool the past ! https://clivebest.com/blog/?p=6678
I would like to tell you of my latest book and documentary.
‘The Deliberate Corruption of Climate Science’.
My latest documentary and video of my presentation.
My website is
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Thanks for this post. I reblogged at Science Matters entitled Temperature Misunderstandings
and added this question: Why in the world would we pay anything to prevent a little bit of warming in the world’s coldest places?
Thank you for your comment on Climate Etc. with link to this post.
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Thank you for this. I have a question you. Can you tell me if Scotese (2016) Phanerozoic Temperature is approximately correct and generally accepted by paleo climate scientists? If not, can you refer me to a more authoritative chart (with the same axes – i..e. global temperature , not temperature change versus years BP, both on linear scales).
Your post seems support Scotese (2016) explanation of how he estimated global temperature for the past 542 Ma, equator to pole temperature gradients and average temperature of the tropics for the past 542 Ma. His results (mostly from geological evidence) seem to suggest the equator to poles gradient flattens much more as GMST increases than the climate models project. He also says the global average temperature was 7C warmer than now for 70% of the past 650 Ma.
I had a quick scan of Scotese’s writing and it looks spot on to me. I am not a Paleo expert so can’t tell you if it is widely accepted. I am pretty sure he is right that tropical temperatures are limited to ~30C, so that it is just latitude profile temperatures that change when moving to ‘hothouse’ conditions. Enhanced CO2 GHE will never bring about such hothouse conditions because arrangement of land masses and in particular the Tibet plateau are not conducive. AGW will be a damp squid on geological scales.
Thank you for your comment. I’ve been asking the same question on many climate blog sites, including Gavin Schmidt at RealClimate. No one before you has been willing to make any comment at all.
I agree with your comment about the location of the tectonic plates and their influence on long term climate change. Icehouse conditions have occurred roughly every 150 Ma and, I understand, each has been when the plates have been aligned to prevent circulation of ocean currents around the world in low to mid latitudes and allowed circulation of cold currents around one or both poles.
By strange coincidence I was just debating this same issue on ATTP here after another commenter quoted Hansen and Sato(2012)’s inventory of causes for the initiation of the ice age. Of course, they discovered by elimination it was CO2 ocean uptake. But they never cited polar gradient, the meridonal sea currents that may have been interrupted by continental drift. Hansen and Sato is their main observational evidence to claim 3C ECS. Is the missing of polar gradient Hansen’s oversight?
I have a reference you might be interested in on the effect of plate tectonics and ‘ocean gateways’ on global temperatures over the Phanerozoic Eon. However, I won’t be able to access it for a few days.
There is a new paper which suggests that ice ages are triggered in Antarctica. When the earth’s precession moves perihelion to June, summer insolation falls in Antarctica but depends on eccentricity. The larger eccentricity is then the weaker summer melting occurs. This causes sea ice to expand around antarctica reducing the earth’s albedo, thereby cooling the entire planet. A new ice age is started. This does not happen in the Arctic because sea ice extent is restricted by nearby continents.
Ice ages start in Antarctica.
Ice ages end in the Arctic
I should explain the reason for my question and my interest in global temperatures over the Phanerozoic Eon – the period when multi-cell life flourished.
Richard Tol is one of the foremost authorities on estimating the impacts (i.e. biophysical) and benefits-damages (i.e. economic) of global warming. His Integrated Assessment Model (IAM) is the most sophisticated of all the commonly used and cited IAMs. Figure 3 here http://www.copenhagenconsensus.com/sites/default/files/climate_change.pdf shows interesting output of net benefits and damages by sector up to about 4 C warming. I am interested in understanding the assumptions and empirical evidence that has been used in deriving the impact functions and damage functions used in FUND (especially for energy consumption which is the only significant negative of global warming, according to this analysis). They are explained in the Technical Description and Tables downloadable from here http://www.fund-model.org/versions . I am looking at Version 3.9.
I notice a significant difference between Scotese’s and Tol’s temperature change by latitude. I want to understand the reason for the apparent discrepancy between Tol’s Regional Temperature Conversion Factors and Scotese’s Figure 12 https://www.academia.edu/12082909/Some_thoughts_on_Global_Climate_Change_The_Transition_from_Icehouse_to_Hothouse . This is very important because the justification for the belief that GHG emissions are a significant threat depends on the outputs from the IAMs.
Richard Tol, 2013 FUND 3.9, Technical Description, (p5) https://05f0e81c-a-5f9963c9-s-sites.googlegroups.com/a/fund-model.org/fund-model/Fund-3-9-Scientific-Documentation.pdf
Table RT ( FUND 3.9, Tables, p33, https://05f0e81c-a-5f9963c9-s-sites.googlegroups.com/a/fund-model.org/fund-model/Fund-3-9-Scientific-Tables.pdf ) says:
Most of the country groups/regions from CAM down (except CHI and NAF) are in the tropics. They have factors of 0.75 to 0.91. However, from Scotese Figures 12 and 13, I interpret the tropics warms by only about 1C for a 3C increase in GMST. That suggests the conversion factor should be around 0.33, not 0.75 to 0.91. Likewise, the higher latitudes would warm much more according to Scotese’s chart below; e.g., for a 3C GMST increase the average temperature at latitude 45 degrees would increase by around 4C and the poles from -36C to -7C, i.e. about 29C increase).
What is the explanation for the apparent discrepancy?
Which is correct, Scotese or Tol?
Is FUND significantly overestimating the damages and underestimating the benefits of increasing GHG concentration in the atmosphere?