Global Warming XVI: The Breadth of Evidence


Greg Tomlinson and I have been discussing global warming in a series of comments and replies to a blog post of mine from April 2017. Readers can review this discussion here1, here2, here3, here4, and here5. This back and forth primarily deals with the evidence that Earth’s average surface temperature has been increasing for many decades as the result of humans burning fossil fuels. As our discussion focuses, for the most part, on the details of the global average surface temperature record derived from thermometer measurement records, readers might get the impression that this is the single key data record that shows the Earth’s warming and that it is a close question as to whether the globe is warming or not. In fact, the results of analyzing temperature records are fully consistent with many other lines of evidence that the globe is warming. These other lines of evidence do not involve the detailed analysis of world-wide temperature records. I’ll describe a few of these, but there are, literally, dozens of such striking demonstrations that the globe is warming.

These examples are point measurements that suggest but do not tell us about global climate. Therefore, the professional researchers go through the immense trouble to produce a global average surface temperature. Even that is not the only global climate measure they produce. Indeed, the temperature record at each weather station is a point measurement.

Here’s a proxy temperature record from Japan that goes back to 800 AD. The graph is from an article in the Economist, but the data points are from a publication by a Japanese researcher. He and his colleagues investigated records of cherry blossom viewing going back 1200 years, nearly to the beginning of Japanese civilization. The vertical axis shows dates in April, except for a few early in May or late in March. The Economist writers have graphed the Japanese researchers’ data and averaged it. The date at which the blossoms reach their peak is a proxy for the temperature: earlier warm temperatures produce earlier peak blossoms. Dots lower on the chart are earlier in the season and reflect warmer springs. Of course, over the centuries there are wide variations. To my eyes, the peak blossom dates have moved earlier by about two weeks since the early or mid-1800s. What do your eyes see? Climate fluctuations known to scholars as the medieval warm period, around 1000 to 1200 AD or the little ice age around 1400 are European climate phenomena, not world-wide ones. The movement of the most recent 100 years or so is larger than any of the earlier fluctuations, in 12 centuries, and shows no sign of moderating.


Cherry blossoms tell us about the arrival of spring warmth. It’s getting warmer earlier. What about the arrival of fall’s chills? They are arriving later.

Gingko trees lose most of their leaves shortly after, indeed often during the night of, the first autumn freeze. People have been recording the date on which a gingko tree at the University of New Hampshire drops its leaves since the 1970s. Evidently the biology student amuse themselves with a betting pool. The school in Durham is close to New Hampshire’s short Atlantic Ocean coast. Here’s the data. Julian day, the vertical axis, is the day of the year beginning with January 1 as Julian Day 1. This year’s leaf fall was the second latest in this record. It looks to my eyes as if the trend line is now about 10 days later than it was in the late 1970s.

The Great Ginkgo Leaf Dump



This interesting chart is from a New York Times article: How Much Warmer Was Your City?

You enter your city in the window. They have data from many cities around the world. I’ve just put in the Tampa data because I live and teach here.

The horizontal axis shows the days of the year, grouped by month. The vertical axis shows temperatures for each day in Fahrenheit degrees. For each day, the black vertical bar shows the high and low temperature for that day. The dark gray shows the normal temperatures for that day, and the lighter gray shows the record high and the record low for that day. By the way, you can see that last December was unusually warm in Tampa. You can see the general sweep of the seasons from temperate to steamy hot to temperate.

If the climate in Tampa were stable, you’d expect to see a few record highs and a few record lows throughout the year. The records could, just randomly, come at any time. So, an unusually hot winter day or an unusually cold summer day. Perhaps, you’d see 4 record lows and 6 record highs one year, then 5 record lows and 5 record highs the next, and so on. But in 2016 Tampa had 15 record highs and 0 record lows! The small vertical arrows mark the records. This suggests that the climate has warmed relative to the long term historical climate.

I encourage you to visit this site and enter your own city.



Alaskan rivers freeze during the long cold winters, and the ice breaks apart in the spring as weather warms. People have been recording, and betting upon, the breakup date for more than a hundred years. Here’s the data for two rivers in Alaska: Ice Breakup on Two Alaskan Rivers.

This is from the still worthwhile EPA site: Climate Change Indicators, which has many similar records from distinctive sources, all of which are broadly consistent with a warming climate.

Notice that in the graph, upward is earlier in the year, which is also presumed to mean warmer earlier. To my eyes, it looks as if the breakup is about 0 days later than it was a hundred years ago.

The figure figure shows the date each year when ice breaks up at two locations: the town of Nenana on the Tanana River and Dawson City on the Yukon River.

Data sources: Nenana Ice Classic, 20164; Yukon River Breakup, 20165
Web update: August 2016


Here is data about arctic sea ice coverage from the excellent National Snow and Ice Data Center: Arctic and Antarctic Sea Ice News.

This data arises from systematic recording from satellites in polar orbits that have been collecting data since the 1970s. You can see the line for the 1981-2010 median. The two shades of gray show plus and minus 25% and plus and minus 45%. The year 2012 was the record low, but you can see that recent years have all been outside the usual range. Indeed, in recent years cargo ships, with strengthened hulls but no accompanying ice breakers, have traversed the famous Northwest Passage over the top of Canada, and over the tip of Russian and Siberia. These are much shorter routes Asia to Europe and the eastern US.

There is much more useful material at this site, about Antarctic sea ice, for example.

Figure 2a. The graph above shows Arctic sea ice extent as of November 2, 2017 along with daily ice extent data for five previous years. 2017 is shown in blue, 2016 in green, 2015 in orange, 2014 in brown, 2013 in purple, and 2012 in dotted brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center

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Go-ing: Gone


In March 2016 Google’s AlphaGo program defeated one of the top Go players in the world, a breakthrough for so-called artificial intelligence. AlphaGo learned the game starting from records of thousands of Go games played by masters around the world – mostly in Japan, Korea and China – for the past few hundred years.

The latest version of AlphaGo, named AlphaGo Zero, started learning last year with only the rules of Go and no input whatsoever from humanity’s history of the game. Zero learned by playing millions of Go games against another instance of itself, remembering what worked well and what did not. Then it played one hundred games against last year’s AlphaGo. Score: Zero 100 wins, AlphaGo none.

From an article in the MIT Technology Review: “The most striking thing is we don’t need any human data anymore … By not using human data or human expertise, we’ve actually removed the constraints of human knowledge…” [italics added].

Game over, for humans.


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Carbon Dioxide Control Knob Discussion V


Greg Tomlinson and I have been discussing in comments a blog post from last April:

Global warming XIII – The Carbon Dioxide Control Knob . I think that his comments and my replies will be informative to our readers, who aren’t likely to notice items from six months ago. Therefore, I’m going to create new blog posts each of which contains a comment and a reply with titles The Carbon Dioxide Control Knob I, II, III, and so on.

Here’s the fifth:

October 7, 2017 at 3:19 am Edit

I’m afraid there is strong evidence that most of your statements in this comment are based on “corrected” (ie. falsified) temperature data. Several indisputable facts point in that direction. As you probably remember, NOAA presented a paper by Thomas R. Karl et. al. in 2015 which basically rewrote the entire temperature record from 1880 onward, allegedly to help eliminate data “biases”. On several occasions, NASA did similar doctoring of their data. How can they possibly know if their adjusted data in any more accurate that the original readings taken over 100 years ago? Nowadays, however, you can’t go to the NOAA or NASA websites and pull up data for the year 1995 and expect to get actual measurements taken in 1995. Instead, you will get “corrected” data that was probably calculated sometime after 2010. If you want 1995 data taken in 1995, you will need to go the NASA archives, assuming they still exist. Since most climate researchers are not aware of this, they use the currently posted NASA and NOAA data without question. If you ask them “Where is the data that convinced the IPCC we are in a warming hiatus?”, they will probably respond with “WHAT warming hiatus?” since the new “corrected” data eliminates all level and downward temperature trends. Unfortunately, our government agencies have become extremely deceitful in this manner. Is this any way to do science?

Suppose one of your graduate students gathered data for his/her thesis, and then “corrected” that data to fit the original hypothesis. Would you or your university accept that thesis? If not, then please don’t expect me, the Trump administration, nor the American people in general to buy these NASA/NOAA arguments when they would most likely be used to justify economy destroying carbon taxes and regulations.

Greg Tomilinson

Mr. Tomlinson,

You are thoroughly informed about global warming denier debating points. Unfortunately, these arguments or assertions are misleading or mistaken. Your argument also falsely impugns the integrity not just of the climate scientists involved, but of the scientific enterprise.

NOAA, NASA, and the British Hadley group do not “doctor” their data. They all adjust and correct it however. You can read a description of what they do here:

No climate conspiracy: NOAA temperature adjustments bring data closer to pristine

This is written by a climate scientist involved in the research and published in the Guardian.

Thorough, not thoroughly fabricated: The truth about global temperature data: How thermometer and satellite data is adjusted and why it must be done.

This is written by a scientist who is also a science journalist.


Explainer: How data adjustments affect global temperature records.

This one is written by one of the climate scientists involved in the global temperature research.

You are correct that the scientists go back to the original raw data records and recalculate corrections as more data become available. The corrected data sets are labeled, for example, HADCRUT1, HADCRUT2, and so on.

You are mistaken that climate scientists are unaware of this, and you are mistaken that the original raw data sets are not available. Here you can find the raw data that researchers used to produce HADCRUT4. The raw data for the NASA and NOAA datasets are also available and easy to find.

The new corrected data does not “eliminate all level and downward temperature trends.” Indeed, comparing a century’s data, the corrected data reduces the warming between the first half of the 20th century and the second half. Here’s the data for you to see for yourself.

“The figure below shows the global surface temperature record created from only raw temperature readings with no adjustments applied (blue line). The red line is the adjusted land and ocean temperature record produced using adjusted data from the US National Oceanic and Atmospheric Administration (NOAA), with the difference between the two in grey.” This is from the third link above.

Neither our government agencies nor the world’s academic climate researchers have been deceitful. Their methods and data have been and are open for all to review in the best traditions of the scientific enterprise.

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The Carbon Dioxide Control Knob Discussion IV


Greg Tomlinson and I have been discussing in comments a blog post from last April:

Global warming XIII – The Carbon Dioxide Control Knob . I think that his comments and my replies will be informative to our readers, who aren’t likely to notice items from six months ago. Therefore, I’m going to create new blog posts each of which contains a comment and a reply with titles The Carbon Dioxide Control Knob I, II, III, and so on.

Here’s the fourth:

October 1, 2017 at 3:43 am Edit

What you pointed out about aerosols increasing from human industry and volcanic eruptions demonstrates my point. There are factors other than CO2 that affect earth temperatures just as much or more. These aerosols caused a net cooling trend for about 30 years despite increased CO2 levels during those times. It is probably the sun, however, that is the most important driver of temperatures. The “warming hiatus” noted by the IPCC in 2005 was well correlated with a drop in solar activity that started within the first few years of the 21st century.

Greg Tomlinson

October 3, 2017 at 7:25 pm Edit

Mr. Tomlinson,
No one asserts that CO2 is the only, or even the most important, factor that contributes to the Earth’s climate or temperature. Indeed, you are correct that the Sun is the most important factor. Climate scientists investigate both the sizes and changes in the various factors when they assess changes in the climate. It happens to be the case, that humans have grabbed the CO2 control knob and are turning it strongly to the right, increasing CO2 levels to ones not seen for millions of years.
There has been no hiatus in global warming. Variations in the Earth’s global average surface temperature are larger than the annual change in the underlying temperature trend caused by warming. In addition to aerosols, produced by volcanoes and humans burning fossil fuels, there are also fluctuations in ocean currents and temperatures known popularly as El Nino that contribute to short term global temperature fluctuations. It happens that 1998, a strong El Nino year, produced a record high average global surface temperature. For several years after this as the El Nino weakened, temperatures did not exceed 1998. Each of the last three years, 2014, 2015, and 2016 have exceeded 1998, each setting a new record. This year looks as if it will again set a record.
While global warming deniers declared that the Earth was now cooling, global warming continued unabated. Indeed, most of the increasing heat energy goes into the world’s oceans.

Here’s a temperature chart that shows, on the right, a short horizontal line that exhibits the supposed hiatus to which you refer. Indeed, you can see that by picking each local maximum global average surface temperature going back 50 years, that we have an uninterrupted string of hiatuses. Hmmm.



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The Carbon Dioxide Control Knob Discussion III

  • Wayne,

    Greg Tomlinson and I have been discussing in comments a blog post from last April:

    Global warming XIII – The Carbon Dioxide Control Knob . I think that his comments and my replies will be informative to our readers, who aren’t likely to notice items from six months ago. Therefore, I’m going to create new blog posts each of which contains a comment and a reply with titles The Carbon Dioxide Control Knob I, II, III, and so on.

    Here’s the third:

  • I’m afraid CO2 is not the best “insulation” for the atmosphere as indicated by the cooling trend that occurred between the early 1940s and 1970s. In fact the fear of global cooling persisted into the late 1970s. During this entire cooling period, however, CO2 levels continued to rise as they did throughout the entire 20th century. This indicates to me that, all else being equal, the earth may well be cooler without CO2, but there are other factors much more important in determining earth’s temperature. What worries me much more than the greenhouse warming resulting from anthropogenic CO2 emissions is how our government and others (including the UN) are going to react to this “crisis”. We simply cannot afford any more economy-crippling taxes and regulations that our last president tried to impose on us. Fortunately, it appears our current president and EPA director are working to undo the damage.

    Greg Tomlinson

September 30, 2017 at 4:08 pm Edit

Mr. Tomlinson,
No one claims that CO2 is the best insulation or the only one. Water vapor is a more important greenhouse gas, for example. It happens, however, that CO2 is the control knob that humans have rotated to the right and are continuing to turn.
Researchers believe, based on substantial evidence, that the cooling you cite was the result of increased atmospheric aerosols, which are one of the other factors that influence the extent to which incoming solar radiation reaches the surface. These aerosols increased as industrial production returned to normal and then grew after World War II, and they increased because of several major volcanic eruptions. World-wide efforts in the 1960s and 1970s to reduce poisonous pollution from coal burning led to a decrease in aerosols and an increase in solar energy reaching the Earth’s surface. Once these aerosols lessened, CO2 induced warming resumed.

As for your political and economic concerns, economists call costs that one economic actor imposes on others an externality. For example, a manufacturer who takes clean water from a river to use in production, and then returns the contaminated water to the river is imposing costs on downstream water users. They must spend to clean up the water before they use it. The water-polluting upstream manufacturer imposes costs upon downstream manufacturers who require clean water.Economists usually prescribe taxes on the polluter with revenues used to clean up the dirty river water or regulations to require that the polluter clean up the water. These government interventions are necessary because the polluter’s products do not reflect the actual costs of their production, a market failure.
President Obama, and presidents going back to Richard Nixon, who created the EPA, have been putting in place sensible regulations to protect Americans health.
EPA Administrator Pruitt, an industry shill and known enemy of the EPA’s mission, is systematically working to destroy the EPA. He is pushing out public-spirited knowledgeable scientists and replacing them with polluters.
Regulations that require coal mine owners to provide safe working conditions for their miners and to protect nearby streams and rivers, and regulations that power plants that burn coal not spew acid rain causing sulfur dioxide, low levels of mercury and radioactive uranium, and micro-particles of soot into the atmosphere have significant and measurable benefits to our health and the health of the environment. They are not the cause of the decline of employment in the coal industry, which economists tell us arises from increasing mechanization and competition from less expensive fuels such as natural gas.
Delusional Donald Trump, who has asserted that global warming is a hoax perpetrated by the Chinese to destroy American business, will cause great harm, not just to the citizens of the United States, but to all humans living today and to come.

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Global Warming Control Knob Discussion II


Greg Tomlinson and I have been discussing in comments a blog post from last April:

Global warming XIII – The Carbon Dioxide Control Knob . I think that his comments and my replies will be informative to our readers, who aren’t likely to notice items from six months ago. Therefore, I’m going to create new blog posts each of which contains a comment and a reply with titles The Carbon Dioxide Control Knob I, II, III, and so on.

Here’s the second:

September 28, 2017 at 7:34 pm Edit

There is an important difference between the work of Svante Arrhenius and the earth’s surface/atmosphere. Namely, Arrhenius’s laboratory was in thermal equilibrium whereas the earth and its atmosphere was not — never was and never will be. Therefore, Arrhenius could read and report the temperature and pressure of his gases whereas it makes no sense to even talk about a single temperature or H2O vapor pressure of the earth’s atmosphere. Hence, most of those physical chemistry laws with which we have become familiar (including the Clausius-Clapeyron equation) do not apply on the global scale because they assume thermal equilibrium. These laws, however, can be applied locally over a region small enough to be characterized by a single temperature and pressure, which makes them an excellent for meteorologists. But to extend them to a global scale is mathematically invalid. Therefore, while Arrhenius may have made some great contributions to our understanding of the greenhouse effect, his conclusions apply only to the laboratory and not the entire atmosphere.

Greg Tomlinson

September 29, 2017 at 6:53 pm Edit

Mr. Tomlinson,
I believe that Svante Arrhenius was, for the most part, a theoretical scientist. His ideas about what he called the hot-house effect arose from the observations and measurements of others.
He did not create a “hot-house” in his laboratory and figure out why they kept their interior warmer than their surroundings. Indeed, hot-houses, glass enclosed volumes, work for two main reasons. Incoming visible radiation from the Sun passes inward through the transparent glass, but the radiated infrared energy from the house’s interior cannot pass outward through the glass. Hot-houses also work by stopping convection. Winds do not blow past and cool the plants, and the warm air does not rise away from the plants drawing in cooler surrounding air.
Arrhenius showed, using measurements of CO2 and H2O infrared absorption made by others, that those gases take the role of the glass in a hot house.
His model, created as equations, that he and his assistants had to solve or estimate by hand were much simpler than today’s models. His model of the atmosphere designed to elucidate the effect of CO2 and H2O did not consider the role of convection in transporting energy upward through the atmosphere. He knew, of course, about convection. But he intended his model to illustrate the effect of those two gases. Today’s weather and climate models take convection and other effects into account along with those of CO2 and H2O.
These modern models, and all modern scientific thought confirm Arrhenius’ insights.
Climate scientists know that the physical and chemical properties of the atmosphere, oceans, and continents change from second to second, from one altitude to the next, from one latitude to the next, between day and night, from one season to another, and from year to year. The technical term that they use to describe these changes is the weather. That is why they take averages of things. Climate scientists research the long-term and large-scale variations in the key properties of the atmosphere and oceans.
Consider the temperature. The global average surface temperature cited by climate researchers is an average over the many time and space scales I mentioned. The same could be done for pressure, water content, and any other important property. As you know, normal human body temperature is about 37 C (or 98.6 F). Human body temperature varies throughout the body, cool at the skin, high in working muscles, and throughout the day, lower in the morning, higher in the late afternoon. According to your argument about the meaning of temperature, the concept of human body temperature would be meaningless.
In equilibrium thermodynamics, a closed system with no energy or material flowing in or out will eventually reach a stable state in which no changes occur. This is an equilibrium. The Earth, for the purposes of meteorologists and climate researchers is not a closed system. Energy flows into the system from the Sun primarily in the visible and near infrared regions of the spectrum, and energy flows out of the system from the Earth’s surface and atmosphere in the far infrared. As you say, this is not an equilibrium, it is a stationary state, for most purposes.
The flow of energy through the Earth’s environment is stationary over long scales, but it does change. Thus, researchers today believe that tiny roughly periodic changes in the Earth’s orbit over thousands of years lead to changes in the incoming flow of radiation from the Sun. The averaged properties of the Earth’s environment adjust to this, warming or cooling. This is thought to be a key cause of ice ages.
The flow of energy through the Earth’s environment also depends upon the properties of that environment. For example, snow reflects some of the Sun’s radiation back into space. Less snow, in the summer, or from a warming climate, means less radiation going back into space. Less sea ice in the Arctic or Antarctic means less reflected into space and more absorbed by the polar seas. (The official term for this property is the albedo.)
Another property of the atmosphere that is stationary for many purposes but that changes for natural and human-caused reasons is the CO2 content. You could think of this property as changing the insulation that the atmosphere provides to the surface. Since pre-industrial times, humans have changed the CO2 content of the atmosphere from about 280 parts per million to more than 400 parts per million. In my opinion, those who deny that the climate is warming have the burden of proof to explain why adding significant insulation does not cause the surface to warm.
Look at the famous Keeling curve. (Look at my blog post, Global Warming VII — Carbon Dioxide History , for example.) You will see, in addition to the decades-long slightly concave upward swoop, that the CO2 concentration at the Mauna Loa Observatory shows seasonal wiggles. According to your criticism of global temperature averages, researchers should not use this data to represent properties of the atmosphere over continents, near urban areas, or close to volcanoes. What they do, rather than follow your advice to abandon their efforts, is to check whether these other factors significantly change their conclusions, and take these variations into account where necessary.
Scientists use equilibrium thermodynamics when the systems they study are in or near to equilibrium, and they use non-equilibrium thermodynamics when they deal with energy flows. Climate science is an applied branch of non-equilibrium thermodynamics and non-linear fluid mechanics.



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The Carbon Dioxide Control Knob Discussion I


Greg Tomlinson and I have been discussing in comments a blog post from last April:

Global warming XIII – The Carbon Dioxide Control Knob . I think that his comments and my replies will be informative to our readers, who aren’t likely to notice items from six months ago. Therefore, I’m going to create new blog posts each of which contains a comment and a reply with titles The Carbon Dioxide Control Knob I, II, III, and so on.

Here’s the first:

September 28, 2017 at 5:53 am Edit

You give no arguments as to what makes CO2 a primary “control knob” for the earth’s temperature, except for saying that this is what “knowledgeable people” believe. Well, the knowledgeable people I know realize this “climate change” fraud for what it is worth.

Greg Tomlinson

September 28, 2017 at 3:50 pm Edit

Mr. Tomlinson,
I’m afraid that the “knowledgeable people” you know have misinformed you.
Here’s how climate scientists and other researchers know that carbon dioxide is a key “control knob” for the Earth’s temperature. They have known this since Svante Arrhenius published research on the greenhouse effect in the 1890s.  Svante_Arrhenius and the Greenhouse effect.

The greenhouse effect is not a new phenomenon caused by human fossil fuel use. It is a natural effect, and is the reason why the Earth’s average surface temperature is about 60 F instead of 20 F, which is what it would be if there were no water vapor or carbon dioxide in the atmosphere.
The basic idea is this: The flow of energy into the Earth must balance for the temperature to be stable. The flow in comes from the Sun. The flow out comes from the Earth and appears in the far infrared. The atmosphere is transparent to most of the Sun’s radiation, which is in the visible and near infrared. But the atmosphere absorbs and re-emits substantial parts of the Earth’s upward flowing far infrared radiation. Water vapor and carbon dioxide absorb upward moving far infrared radiation and re-emit it in all directions. This reduces the amount flowing to space. Therefore, the Earth’s temperature must increase to increase the amount of upward flowing radiation leaving its surface until the flow outward equals the flow inward from the Sun. To increase its radiation, the Earth’s surface temperature must increase. That is, the globe must warm.
Natural fluctuations in the amounts of water vapor and carbon dioxide in the atmosphere produce fluctuations in the Earth’s surface temperature, as when there have been massive volcanic eruptions.
Thus actual knowledgeable people, and not your “knowledgeable people” know from fundamental principles, the 1st Law of Thermodynamics, and the detailed properties of water and carbon dioxide, that carbon dioxide is a key “control knob.”



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