Image Credit: Marathon Nation – Soft Pixel
By WUWT regular “Just The Facts”
There have been a number of statements made recently about “Global Warming Deniers”, e.g. “White House: Global Warming Deniers Wrong to Reference Polar Vortex” US News, “Watch The Daily Show mock Trump and other global warming deniers” The Week and “Global warming denier Jim Inhofe: ‘Fewer and fewer’ senators believe in climate change ‘hoax’”. The Raw Story
Given the apparent prevalence of “Global Warming Deniers”, it seems prudent to take a look at the data so that everyone is clear when Global Warming began and what is undeniable. As such, from the following EPICA Dome C Ice Core record from Vostok, Antarctica, over the last 450,000 years Earth has experienced numerous Glacials, commonly referred to as Ice Ages, and Interglacials, like the Holocene Interglacial we are experiencing today:
“The Last Glacial Maximum (LGM) refers to a period in the Earth’s climate history when ice sheets were at their maximum extension, between 26,500 and 19,000–20,000 years ago, marking the peak of the last glacial period.” As such, one could argue that Global Warming began about “19,000–20,000 years ago”.
However, there was “the Late Glacial Maximum (ca. 13,000-10,000 years ago), or Tardiglacial (“Late Glacial”)” which was “defined primarily by climates in the northern hemisphere warming substantially, causing a process of accelerated deglaciation following the Last Glacial Maximum (ca. 25,000-13,000 years ago)”. “As such, one could also argue that Global Warming began about “13,000-10,000 years ago”.
Now looking at the GISP2 Ice Core record from Greenland, over the last 10,700 years, you can see the rapid warming that occurred at the end of last Glacial and that the current Holocene Interglacial reached it’s maximum peak between 8000 – 7500 years ago:
Since the peak of the Holocene Intreglacial, Earth has experienced several additional descending peaks, including the Minoan Warm Period between 3500 – 3000 years ago, the Roman Warm Period between 2250 – 1500 years ago and the Medieval Warm Period between 1250 – 750 years ago. The Medieval Warm Period and subsequent Little Ice Age can be seen clearly on the following temperature reconstruction based upon Alexandre, 1987 and Lamb, 1988, found Page 250, Figure 7.1 of IPCC Assessment Report 1:
The Little Ice Age “has been conventionally defined as a period extending from the sixteenth to the nineteenth centuries, or alternatively, from about 1350 to about 1850, though climatologists and historians working with local records no longer expect to agree on either the start or end dates of this period, which varied according to local conditions. NASA defines the term as a cold period between AD 1550 and 1850 and notes three particularly cold intervals: one beginning about 1650, another about 1770, and the last in 1850, each separated by intervals of slight warming.” As such, one could argue that Global Warming began in “about 1850”.
However, generally when referring to “Global Warming Deniers” there is an implication that the “Global Warming” that’s being denied is caused by anthropogenic carbon dioxide emissions. Anthropogenic CO2 emissions were de minimis in 1850. In fact, anthropogenic CO2 Emissions from Fossil-Fuels did not become potentially consequential until approximately 1950:
This is why the IPCC only claims to be;
“95% certain that humans are the “dominant cause” of global warming since the 1950s” BBC
As such, one could argue the Global Warming began in “the 1950s”.
However, if you look at the Met Office – Hadley Center HadCRUT4 Global Surface Temperature record for the last 163 years you can see that temperatures didn’t warm during the 1950s, nor the 60s:
In fact it was not until approximately 1975 that temperatures began to rise. As such, one could argue that Global Warming began in approximately 1975.
However, in 2010 Phil Jones was asked by the BBC, “Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?” Phil Jones responded that,”Temperature data for the period 1860-1880 are more uncertain, because of sparser coverage, than for later periods in the 20th Century. The 1860-1880 period is also only 21 years in length. As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different. I have also included the trend over the period 1975 to 2009, which has a very similar trend to the period 1975-1998. So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other.”
The warming during the periods of “1860-1880” and “1910-1940”, before anthropogenic carbon dioxide emissions became potentially consequential, is “not statistically significantly different” from the warming during the periods “1975-1998” and “1975 to 2009”. Thus there is no indication that the warming between “1975-1998” and “1975 to 2009” is unnatural, unusual and/or caused by anthropogenic carbon dioxide emissions. Global Warming may have started in 1975, but there is no observable evidence [of] anthropogenic CO2 emission based Global Warming began in 1975. As such, one could argue that anthropogenic CO2 emission based Global Warming began sometime [after] 1975.
However, if you look at following UAH Satellite Lower Atmosphere graph for the last 34 years;
and this NASA GISS Mean Monthly Surface Temperature Anomaly graph for the last 17 years;
you can see that Global Warming stopped in the late 1990s or early 2000s, which has been referred to as “The Pause” in Earth’s temperature. In fact, looking at the Werner Brozek’s recent article, the Pause in each major temperature data set is as follows:
For GISS, the slope is flat since July 2001 or 12 years, 6 months.
For Hadcrut3, the slope is flat since July 1997 or 16 years, 6 months.
For Hadcrut4, the slope is flat since December 2000 or 13 years, 1 month.
For Hadsst3, the slope is flat since December 2000 or 13 years, 1 month.
For UAH, the slope is flat since October 2004 or 9 years, 3 months. (goes to December using version 5.5)
For RSS, the slope is flat since September 1996 or 17 years, 4 months.”
Shown graphically, that looks like this:
As such, one could argue that for the last 17 – 9 years Global Warming hasn’t been occurring, and thus Global Warming began in 1975 and ended between 1996 and 2004.
However, this would not resolve the question of when the “Global Warming” that’s being caused by anthropogenic Carbon Dioxide emissions began. If you look at Global CO2 Emissions from Fossil-Fuels and;
and Cumulative Anthropogenic CO2 Emissions from Fossil-Fuels, you can see that emissions have been growing rapidly in the last few decades:
In fact the Economist noted in 2013 that “The world added roughly 100 billion tonnes of carbon to the atmosphere between 2000 and 2010. That is about a quarter of all the CO₂ put there by humanity since 1750. And yet, as James Hansen, the head of NASA’s Goddard Institute for Space Studies, observes, ‘the five-year mean global temperature has been flat for a decade.'”
Thus, while anthropogenic CO2 emissions are the highest they’ve ever been, and growing rapidly, Earth’s temperature has been in a 9 – 17 year Pause. And the only period of warming that anthropogenic CO2 emissions could have had a significant influence on, 1975 – 1998, is “similar and not statistically significantly different from” the periods of 1860-1880 and 1910-1940 when there is no evidence of anthropogenic CO2 emission influence. As such one could argue that “Global Warming” due to anthropogenic Carbon Dioxide emissions may not have begun, that Earth’s sensitivity to CO2 may be low, that natural processes may be large enough to outweigh the effects of anthropogenic CO2 emissions, and/or that preparing for a period of rapid and catastrophic Global Warming, when there is no observational evidence that it is in fact occurring, may be a historic folly.
Anyway, what do you think, when did Global Warming begin?
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Then, of course, there is this:
http://www.metoffice.gov.uk/hadobs/hadcet/
(Hadley Centre Central England Temperature (HadCET) dataset, a/k/a Mean Central England Temperature Anomalies, 1772-2013)
What global warming?
Frans Franken asked:
“What drives the rate of convection and how, in relation to increased atmospheric CO2?”
The basic rate of convection is determined by the response of atmospheric density at the surface to an unevenly irradiated surface.
Because of the unevenness of surface energy distribution one inevitably (via conduction) gets parcels of air at different temperatures and densities alongside one another at the same height.
That situation is inherently unstable because lighter parcels must rise above denser parcels and that starts the process of convective overturning. That inherent instability can never be removed for a rotating rough surfaced sphere illuminated by a point source of energy. All references to containers stabilising at an even temperature distribution (isothermal) are invalid.
The decline in density with height inevitably gives rise to a lapse rate even in the absence of radiative gases and the convective overturning is self sustaining because the heat used in uplift (KE becomes PE) is returned on the descent (PE becomes KE).
The convective overturning is effectively a closed adiabatic loop.
If one then introduces radiative gases then any radiation from them back to the surface seeks to increase the temperature and density differentials in the horizontal plane at the surface.
But as we have seen it is the size of those differentials in the horizontal plane that determines the rate of vertical motion in the form of convection so increase the differentials and one must increase the convection for a complete or near complete negative system response.
So, radiative gases have a zero or near zero effect on surface temperatures but do have an effect on the global air circulation.
If GHGs try to slow down the flow of energy through the system then the speed of convection increases to negate the thermal effect at the surface by increasing the flow of energy through the system again by an equal and opposite amount.
There is some debate as to the net effect of GHGs due to their ability to radiate to space from the atmosphere but that need not concern us here.
The whole process is the result of temperature and density differentials in the horizontal plane at the surface being mechanically converted into vertical convective motion via conduction from surface to air.
Meanwhile for Earth the variations in global air circulation caused by solar and oceanic changes makes any effect from our CO2 emissions completely imperceptible.
Convection is the process whereby the combination of conduction and radiation is constantly adjusted so as to maintain radiative balance for the system as a whole.
If the balance of conduction and radiation goes out of equilibrium then the rate of convection changes so as to deliver the right amount of kinetic energy to the effective radiating height to match radiative energy in with radiative energy out once more.
Jimbo says:
January 25, 2014 at 10:42 pm
I´ve tried to come up with a phrase comparable to Ike’s Military Industrial Complex to tag today’s government-funded Climastrology. I’ve seen Climate Industrial Complex (unfortunately not pronounced SIC) , which works only partly, to describe Green Energy boondoggles. Climate Academic Complex (CAC) is similarly not inclusive enough for the whole range of crony scientivism with which the world is presently afflicted.
Maybe younger, more agile brains here than mine can coin the needed term.
AGW- the idea that humans are causing a climate catastrophe- is 100% man made. It is yet another manifestation of what happens to many people when they stare into the abyss too long. The abyss starts to stare back.
FWIW, everytime some government hack uses the term “denier” to dismiss skeptics and hide the failure of AGW predictions, it is clear at that our government ill serves us.
J. Philip Peterson says:
January 25, 2014 at 5:37 pm
…t if man is only causing 3% of the CO2 rise why is it increasing so steeply? Is there any proof that the 3% is what is causing the CO2 rise?
>>>>>>>>>>>>>>>>
800 years ago was the Medieval Warm period. CO2 lags temperature by 800 years.
Of course that all depends on whether or not you agree that CO2 is well mixed in the atmosphere (I don’t) and that the measurements of CO2 are reliable.
http://www.rocketscientistsjournal.com/2006/10/co2_acquittal.html
http://www.rocketscientistsjournal.com/2007/06/on_why_co2_is_known_not_to_hav.html#more
http://www.greenworldtrust.org.uk/Science/Scientific/CO2-ice-HS.htm
http://www.greenworldtrust.org.uk/Science/Scientific/CO2-flux.htm
When did Global Warming begin?
When scientists/researchers, politicians, big corporations, the media, Green organisations, NGOs, bureaucrats, realised there was money and/or power, prestige, privilege in it for them.
The only long term trend I can glean from the above graphs is that of declining temperature against Co2 rise on the Greenland ice-field history. It is a conductor of heat even if reluctantly so.
Eric, the seasonal swings of CO2 are greater than what man contributes in that same time period…
…what man contributes can not be cumulative
Since the planet is capable of reducing CO2 levels to limiting for plant growth….etc
John Tillman says:
January 26, 2014 at 6:02 am
Doesn´t spell anything, but makes kind of a gagging sound: Government-Academic-Industrial Climate Scam (GAICS).
“Anyway, what do you think, when did Global Warming begin?”
In 1972 I heard during a UNEP meeting in Nairobi a discussion on CO2 as a pollutant. I found it remarkable that several of the discussing team were bankers. Therefore 1972 is the date for me.
Stephen Wilde
I believe there is a very straight forward and simple answer to your question of why changes in CO2 concentrations have so little impact.
1) compare the absorption spectrum of CO2 and H2O. Not the relatively minor portion where there is no overlap and CO2 could have an impact
2) compare the abundance of water vapor (H2O) and CO2 in the atmosphere (approx 3% to 0.4%)
Conclusion: due to the minimal absorption bandwidth allotted CO2, and its minuscule concentration in our atmosphere, there is no logical reason to believe changes in the CO2 concentration will have any measureable impact on Earth’s heat retention or mean temperature!
But accepting this by the AGW crowd would end their “research” funding gravy train. Not going to happen until skeptics or Mother Nature jams it down their throats.
Bill
Bill,
I agree.
The so call greenhouse effect is a result of atmospheric mass held within a gravitational field and irradiated from outside resulting in conduction and convection with the radiative characteristics of CO2 coming pretty much nowhere in the scheme of things.
Your point about the absorption spectrum supports that diagnosis by pointing out that even if radiative characteristics of CO2 did have a significant effect they would be marginalised by the water cycle in any event.
The water cycle most certainly accelerates radiative loss to space by lifting vapour to height and condensing it out where radiation to space from the condensate can occur more easily so a faster or larger water cycle will make it easier for the system to shed energy when necessary for the maintenance of radiative equilibrium.
More convection is obviously involved in a faster water cycle so we come full circle and your point meshes with mine perfectly.
Negative system responses rule and Willis E. has always been right about that and about the role of convection but he (along with many others) has a mental block about conduction and convection involving non-radiative gases being the cause of the mass induced greenhouse effect. It is that mechanical process together with its freely variable nature which provides the only possible mechanism for any thermostat hypothesis.
Radiative physics cannot achieve system equilibrium in the face of internal system forcing elements such as CO2 without insisting on a higher surface temperature.
That higher surface temperature then offends the purely radiative S-B law and potentially causes the atmosphere to be lost.
One has to supplement the radiative physics with a negatively varying mechanical process to allow changes in internal system forcing and yet maintain radiative equilibrium without a rise in surface temperature.
In that way one can have a surface temperature higher than the S-B law would predict without upsetting radiative equilibrium for the system as a whole.
The reason being that one can then transfer radiative or mechanical energy excesses or deficits to and fro between the radiative and mechanical processes in order to maintain overall radiative equilibrium with space.
Convection achieves the necessary effect by ‘mediating’ between the processes of conduction (between surface and atmosphere) and radiation (between surface and atmosphere on the one hand and space on the other).
hn robertson says: @ur momisugly January 25, 2014 at 7:37 pm
…But what is the beginning?
The plotting at the UN?…
>>>>>>>>>>>>>>>>>>>>>>
Dr. Ball talks of that HERE – The Fallacy Behind The Fallacy Of Global Warming
Correction:
One has to supplement the radiative physics with a negatively varying mechanical process to allow changes in internal system forcing and yet maintain radiative equilibrium DESPITE a rise in surface temperature.
Bob Weber says: @ur momisugly January 25, 2014 at 8:31 pm
Why won’t the media fact check Al Gore?
>>>>>>>>>>>>>>>>>>>>
The reason is in this article and my comment. (It’s the first one)
Don’t forget Walter Duranty, the New York Times, Stalin Apologist. “Walter Duranty played a key role in perpetrating some of the greatest lies history has ever known.”
http://www.amazon.com/Stalins-Apologist-Walter-Duranty-Timess/dp/0195057007
The most recent warming clearly began in the mid 1600s at the depth of the LIA. We are likely at or near the top of this latest cycle in global temperature and will start heading back down some time relatively soon (within a couple of centuries).
I like to think of it like a spinning top. As the top spins down it starts to wobble but regains its balance a few times until the final wobble when it falls to the floor. This is what I see happening in the climate. The “force” that warms the planet is slowly dropping. We are currently back into the spin state but the next wobble may be the last one before we drop into the next glaciation event.
What is causing the loss of “force”? Well, that force is probably solar energy and the loss could a combination of Earth’s tilt and Antarctic sea ice. Since a higher percentage of solar energy is now directed at the SH, the amount of sea ice reflecting away that energy reduces the planetary total. When we see more upwelling cold water, the ice increases and the Earth cools. At some point this initial cooling allows the NH to maintain land snow year round and this feedback sends the GAT plummeting.
RoHa says: @ur momisugly January 25, 2014 at 9:09 pm
…I don’t know who said that, but the Industrial Revolution was well under way by 1850….
>>>>>>>>>>>>>>>>>
It was a bit gradual but the end of the 1700’s and beginning of the 1800’s is where I would put it. If you wanted to you could push it further back and pin point Gutenberg and his use movable type printing around 1439 giving us the Renaissance and the scientific revolution as the precursor of the Industrial Revolution.
On the farming front – you have to free people from farm work to have a scientific and industrial revolution.
Without coal/oil/natural gas you do not have modern farming and you are back to 90% of the labor force trying to feed themselves and a select few elite.
I wish the anti-CO2 types would get that through their thick skulls. No CO2 generating fuels AND no CO2 generating livestock (like oxen) means YOU get hitched to the plow! IMAGE
(Might make a good t-shirt) with
Tractors? – Too much CO2
Oxen? – Too much CO2
We already ate the horses
At the risk of being naïve here – presumably none of the GCM’s can replicate the historical temperature record if they can’t model natural variation sufficiently well to account for the current pause? Isn’t that an easier means to invalidate them with politicos?
First, over a period of billions of years multiple stars lived and died, Some were big enough to supernova. That material formed into our sun and the planets in our solar system. It took billions of years for the earth’s surface to become cool enough to form a solid crust.
And before all that, it all started with a big bang! I say global warming never started, we’ve been cooling for billions of years.
Village Idiot says: @ur momisugly January 26, 2014 at 12:35 am
Could you do an article on what arguments we can use to prove ‘rapid and statistically significant cooling’ when the temperatures start going up again?
>>>>>>>>>>>>>>>>>>>
It is not the short term up and down squiggles that matter:
The melting of Arctic ice and increase in Antarctic ice is the bipolar seesaw.
Twentieth century bipolar seesaw of the Arctic and Antarctic surface air temperatures
http://onlinelibrary.wiley.com/doi/10.1029/2010GL042793/abstract
Reposted, and linked back to this here original. Excellent presentation and I believe those who read it (and can Think for themselves) shall come away Edified.
more soylent green!:
re your post at January 26, 2014 at 8:35 am.
Yes, as you say, we are at a point in time from the Big Bang to the Heat Death of the Universe when all heat will be uniformly distributed and everything will stop.
But that is cosmic cooling which started at the Big Bang. And that continual loss of entropy does not preclude local warming; e.g. wood gets warmer when it burns.
The Earth is a small locality in cosmic terms. We are discussing global warming of the Earth.
Richard
richardscourtney says: @ur momisugly January 26, 2014 at 5:23 am
….Global warming is also a political issue which from its start was independent of physical reality. And the start of the political issue of global warming was in early 1980 when Margaret Thatcher began her campaign to create the political issue….
>>>>>>>>>>>>>
And then moved to the USA.
However you could go back to Al Gore’s Earth in the Balance in 1992
Or you could go all the way back to Maurice Strong and the UN First Earth Summit in 1972.
The UN and the First Earth Summit in 1972, is where I would peg the start of the campaign.
The Club of Rome was founded in 1968 and its first report The Limits to Growth, was published in 1972. It is about the computer modeling of exponential economic and population growth with finite resource supplies. Five variables were examined in the original model. These variables are: world population, industrialization, pollution, food production and resource depletion. WIKI
Among the alleged members are: Al Gore, Maurice Strong, Mikhail Gorbachev, (The Chicago Climate Exchange) Anne Ehrlich, Stephen Schneider, Bill Clinton, Bill Gates are among the members link
Just after the first man (or woman) discovered how to make fire a few others didn’t like it, that’s when “global warming caused by man” began. [;)]
@Stephen Fisher
The basic mechanism for atmospheric water vapor convection is:
Ocean surface water receives (radiative) heat which promotes evaporation; the evaporated water vapor is lighter than the surrounding air which makes the vapor rise.
Adding CO2 to the atmosphere theoretically increases IR back radiation from the atmosphere, which promotes evaporation and convection. Convection thus provides an inevitable negative feedback to radiative surface forcing. Nevertheless, this mechanism alone does not necessarily annihilate all radiative surface forcing from CO2.
The mechanism you describe might enhance the negative feedback; can you please give a reference for this mechanism?
(I’m a mechanical engineer, graduated from Technical University of Eindhoven, the Netherlands; would you care to share your educational background?)