By WUWT Regular “Just The Facts”:
Note: This article builds upon a previous article, When Did Global Warming Begin?, which offers highly recommended background for this article.
There appears to be some confusion as to when humans might have begun to influence “Earth’s Temperature”. For example, “Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century primarily due to the greenhouse gases released as people burn fossil fuels.” NASA Earth Observatory “Ninety-seven percent of climate scientists agree that climate-warming trends over the past century are very likely due to human activities, and most of the leading scientific organizations worldwide have issued public statements endorsing this position.”
NASA Climate Consensus page “‘Global warming started over 100 years ago‘: New temperature comparisons using ocean-going robots suggest climate change began much earlier than previously thought”. The Daily Mail “The temperature, they pointed out, had fallen for much longer periods twice in the past century or so, in 1880-1910 and again in 1945-75 (see chart), even though the general trend was up. Variability is part of the climate system and a 15-year hiatus, they suggested, was not worth getting excited about.” Economist “Our Earth is warming. Earth’s average temperature has risen by 1.4°F over the past century, and is projected to rise another 2 to 11.5°F over the next hundred years.” EPA
However, there is not compelling evidence that anthropogenic CO2 was sufficient to influence Earth’s temperatures prior to 1950, i.e. “Climate model simulations that consider only natural solar variability and volcanic aerosols since 1750—omitting observed increases in greenhouse gases—are able to fit the observations of global temperatures only up until about 1950.” NASA Earth Observatory “The observed global warming of the past century occurred primarily in two distinct 20 year periods, from 1925 to 1944 and from 1978 to the present. While the latter warming is often attributed to a human-induced increase of greenhouse gases, causes of the earlier warming are less clear since this period precedes the time of strongest increases in human-induced greenhouse gas (radiative) forcing.” NASA Geophysical Fluid Dynamics Laboratory / Delworth et al., 2000 “Internal climate variability is primarily responsible for the early 20th century warming from 1904 to 1944 and the subsequent cooling from 1944 to 1976.” Scripps / Ring et al., 2012: “There exist reasonable explanations, which are consistent with natural forcing contributing significantly to the warming from 1850 to 1950”. EPA
So how to clear up this confusion? Let’s take a look at the data…
If you look at Global CO2 Emissions from Fossil-Fuels;
Global CO2 from Fossil-Fuel Emissions By Source;
and Cumulative Anthropogenic CO2 Emissions from Fossil-Fuels,
you can see that Anthropogenic CO2 Emissions from Fossil-Fuels did not become potentially consequential factor until approximately 1950, and then grew rapidly thereafter. Per the Economist, “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.’” The large increase in Anthropogenic CO2 Emissions from Fossil-Fuels since 1950 is quite clear in this Global Per Capita Carbon Emissions graph:
There have also been claims made that Land Use Changes measured as Annual Net Flux of Carbon to the Atmosphere were a significant source of Anthropogenic CO2 i.e.:
However, when you look at the Net Flux of Carbon to the Atmosphere from Land-Use Changes from 1850 to 1990;
it is apparent that the majority of the increase occurred after 1950, and the change between 1900 and 1950 was de minimis. Furthermore, the Houghton data these graphs are based upon is highly suspect, i.e. from IPCC AR4: “Although the two recent satellite-based estimates point to a smaller source than that of Houghton (2003a), it is premature to say that Houghton’s numbers are overestimated.” Houghton’s method of reconstructing Land-Use Based Net Flux of Carbon appears arbitrary and susceptible to bias; i.e. “Rates of land-use change, including clearing for agriculture and harvest of wood, were reconstructed from statistical and historic documents for 9 world regions and used, along with the per ha [hectare] changes in vegetation and soil that result from land management, to calculate the annual flux of carbon between land and atmosphere.” Furthermore Houghton’s findings have varied significantly over time, i.e. in Houghton & Hackler, 2001 they found that, “The estimated global total net flux of carbon from changes in land use increased from 397 Tg of carbon in 1850 to 2187 Tg or 2.2 Pg of carbon in 1989 and then decreased slightly to 2103 Tg or 2.1 Pg of carbon in 1990“. However, by Houghton, R.A. 2008 he found, “The estimated global total net flux of carbon from changes in land use increased from 500.6 Tg C in 1850 to a maximum of 1712.5 Tg C in 1991“.
Given Houghton’s overestimations, arbitrary reconstruction method and highly variable results, his Net Flux of Carbon to the Atmosphere from Land-Use Change data is not credible. However, even if it was, Net Flux of Carbon to the Atmosphere from Land-Use Change was inconsequential prior to 1950;
and it appears that Land and Ocean Sinks would have absorbed any increace, along with much of the minimal pre-1950 Anthropogenic CO2 Emissions from Fossil-Fuels. This is supported by the findings of Canadell et al., 2007 that, “Of the average 9.1 PgC y −1 of total anthropogenic emissions (F Foss + F LUC) from 2000 to 2006, the AF was 0.45; almost half of the anthropogenic emissions remained in the atmosphere, and the rest were absorbed by land and ocean sinks.” Furthermore, they found “increasing evidence (P = 0.89) for a long-term (50-year) increase in the airborne fraction (AF) of CO2 emissions, implying a decline in the efficiency of CO2 sinks on land and oceans in absorbing anthropogenic emissions.” Thus absorption rates of Land and Ocean Sinks were likely significantly higher prior to 1950.
As such, since there is not compelling evidence that Anthropogenic CO2 was sufficient to have ab influence Earth’s temperatures prior to 1950, Anthropogenic CO2 cannot be the cause of the warming that occurred before 1950. However, this doesn’t mean that CO2 based Anthropogenic Global Warming began in 1950, because 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. However, this doesn’t mean that CO2 based Anthropogenic Global Warming began in 1975, because as Phil Jones noted during a 2010 BBC interview, “As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different.” As such, the warming from 1910 – 1940, before Anthropogenic CO2 became potentially consequential, is “not statistically significantly different” from the warming during the period from 1975 – 1998 when the IPCC AR5 claims to be ” extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century”. Given that “causes of the earlier warming are less clear“, our understanding of Earth’s climate system is rudimentary at best, and our historical record is laughably brief, it is confounding how the IPCC can be so “extremely” sure “that human influence has been the dominant cause of the observed warming since the mid-20th century”, which is “not statistically significantly different” from the natural warming that occurred between 1910 – 1940.
Regardless, claims that “Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century” are erroneous and indicative of either ignorance or duplicity on the part of NASA’s Earth Observatory, NASA’s Climate Consensus page, The Daily Mail, the EPA and many others. So what do you think? When Did Anthropogenic Global Warming Begin?
Human induced global warming began in 1988 when the IPCC was formed.
Bill Parsons says: March 29, 2014 at 2:42 pm
William F. Ruddiman: Plows, Plagues, and Petroleum – Click the pic to view[/caption]
Plows, Plagues, and Petroleum: How Humans Took Control of Climate, by William F. Ruddiman
Yes, that’s interesting stuff, I particularly like Ruddiman’s “Human Impact on Climate” graphs;
[caption id="" align="alignnone" width="542"]
which appear to have been drawn and offer no indication that any actual data was used in their development…
The graph showing CO2 by source is suspicious. Before the 1950s, it was all flaring. They did very little recovery of natural gas. So any oil extraction would involve an enormous amount of fairing. The graph shows none.
Steven Mosher says:
March 29, 2014 at 1:07 pm
Humans have “influenced” the climate from day 1.
Sorry, Mr. Mosher.
With all respect, your AGW is modelled AGW only.
Even the IPCC admits in AR4, that models are flawed.
Please explain to me, why, at the end of the last glacial period 12000 years ago, we had ~180 ppmCO2 followed by an increase to ~270 ppmCO2 at the beginning of the holocene, BUT there was an increase of ~7° C in temperature!
If I apply those 100 ppmCO2 difference to modern times, the world must be ~10° C warmer since 2 centuries, than in the holocene… and this with the far-fetched culprit “industrial aera”, AGWs often use as an explanation.
If you look at the temperatures form icecores, temperatures have decreased(!) by ~ 0.3° C since 12000 years, despite of actually ~400 ppmCO2 and despite of your ridiculous “AGW” theory hypothesis.
Would you please explain that to me?
Anthropogenic global warming began when the Cold War ended. Just gotta have something to fight.
There is two things that coincide with the 1950 date: 1. It is when atmospheric testing of the abomb began in earnest and 2, its when USDOD began its geo-engineering of the atmosphere. Has anybody examined the geo-engineering of the ionosphere and increases in temperature? How about the US DOE ARM program and its cloud formation program in the Arctic, which ran roughly from the mid 1980s to the late 1990s and the apparent warming of the Arctic?
When Did Anthropogenic Global Warming Begin?
There are two answers to this question: one is ‘never’ and the other answer is ‘When they realized that there was a lot of money to be made from this huge scam’.
I agree entirely with Steven Moshers post. It’s true that as a consequence of any organism interacting with the chemistry of its surroundings it’s going to affect it, and that will have a knock on effect, from day 1, and in perpetuity. In the context of the global warming debate, we might say that is “trivially true”. The rest of his post outlines how the debate should be framed, but the problem with the debate is that it is not.
The sum total of the answers to the questions he has posed is that it is entirely possible that there is no consequence of great significance or that they maybe consequence of net benefit….just as much as there might consequences that are detrimental. The problem is there is an automatic assumption that any influence we have will be negative.
It is just all so foolish. Human inputs have virtually no effect on CO2 concentration anyway. It’s essentially a temperature dependent, natural process.
Many of the graphs are labeled “Global carbon dioxide emissions”. Such as label is horribly misleading, as the graphs actually are supposed to represent “Global carbon dioxide emissions attributable to humans”. The actual global carbon dioxide emissions are not well-know, but are roughly 20 times those due to humans. We don’t have a good handle on either the natural (e.i., non-human) sources or the natural sinks.
Mosher states: “we can be somewhat confident that the climate of the earth with humans would be different than the climate without humans” based on the premise “butterfly wings and all that.” [sic]
Nonsense.
Is “somewhat confident” the IPCC 97% version?
Climate sensitivity (to CO2 and indeed to the butterfly wings remain undetermined and in the case of the latter, probably unknowable).
Wikipedia states: “Some scientists have since argued that the weather system is not as sensitive to initial condition as previously believed.[6] David Orrell argues that the major contributor to weather forecast error is model error, with sensitivity to initial conditions playing a relatively small role.[7][8] Stephen Wolfram also notes that the Lorenz equations are highly simplified and do not contain terms that represent viscous effects; he believes that these terms would tend to damp out small perturbations.[9]”
(C)AGW remains a theoretical construct based on ideologically dependent models reliant upon apparently inexhaustible funding.
But, like your vaunted butterflies, any effect is quickly overcome by local conditions.
When Did Anthropogenic Global Warming Begin?
————————————————————–
When Prometheus brought fire to man…perhaps Zeus was a CAGWer, that’s why Prometheus was punished!
🙂
Robin
“I think it began in 1972 at the UN Conference on the Human Environment”
Pushed along by Margret Thatcher war on the coal miner union and giving huge amount of money to “study of problem”.
There might be said to be two start points, one leading directly to the other, a million years apart.
The first was mans ability to control fire at will, the second was putting that fire under the boiler in a steam engine
It has been stated here and elsewhere that the Global Warming campaign was designed as a means to reduce the impact of humans on the Earth. The Club of Rome along with Erlich were concerned that increasing population would destroy the planet so a method should be developed to limit growth. Since then we have observed a decrease in populations in Europe as those countries became richer and healthier. Likewise in other Western nations. Even in places like India the better educated families are having fewer children. It would appear that the way to curb population growth is not by stifling rich countries but by encouraging prosperity in poor countries.
We do best by having trickle down prosperity than by trickle up poverty.
It is obvious that the members of the Club of Rome and the UN would know this so why do they perpetuate the myth that preventing access to cheap power will save the world? It seems the ones making the biggest noise are already very rich whether they be film makers, financiers or ex vice presidents. They all want to be even more rich and few if any want to share their wealth with the poor. They are fighting hard now because they know the game is up but I am bemused that the President of the US is now pushing the AGW barrow even harder as his less than successful term comes to an end. This scam has nothing to do with the health of the planet and everything to do with the health of the bank balances of the self appointed saviours. What’s in it for Obama? that is the question you folk in the US need to ask.
GW ended before 2001. http://endofgw.blogspot.com/
AGW never existed. http://agwunveiled.blogspot.com/
@ur momisugly JustTheFacts
You asked above for input on when anthropogenic global warming began.
My position is that the entire “warming” is a statistical fluke, created by a series of colder-than-normal winters centered around 1980.
In January, 2010, I wrote:
“The climate alarmists maintain that man’s emissions of CO2 caused such a rapid increase world-wide, and further increases in CO2 will create additional catastrophic global warming. Yet, the data for Abilene [Texas] shows the same pattern from . . . above, that is, much colder winter temperatures from 1976 to 1985, but not warmer summers. These colder temperatures are circled on Figure 3. These circled winter temperatures were not colder than those recorded since the 1880’s. The unique aspect is that several winters in succession were colder than normal. The succession of cold winters “tipped the see-saw” downward on the left, and upward on the right, thus creating the appearance of a rising temperature, or warming trend, when there clearly was none. The maximum summer temperatures for Abilene are no greater than for previous years, and the most recent winter temperatures are actually colder than several earlier periods during the previous 120 years “
For the full article, see
http://sowellslawblog.blogspot.com/2010/01/cold-winters-created-global-warming.html
– Agnostic says:
March 29, 2014 at 3:51 pm
I agree entirely with Steven Moshers post. It’s true that as a consequence of any organism interacting with the chemistry of its surroundings it’s going to affect it, and that will have a knock on effect, from day 1, and in perpetuity. In the context of the global warming debate, we might say that is “trivially true”. The rest of his post outlines how the debate should be framed, but the problem with the debate is that it is not.-
Yes, it not a debate, rather it political campaign of powerful corporate and state controlled media.
It’s propaganda. The purpose of propaganda is not to have debate. Just as bulldozer is not having a debate by plowing earth into heaps,
As a political campaign, and a political campaign which so much in a fever swamp that does even want something like the attraction of “presidential debate”, and it explains the slogan, the “science is settled”. Which a hopelessly stupid thing for any scientist to claim, but is the stuff a troglodyte politicians can be expected to say.
But the propaganda war mongers lost their war.
For a numbers of reasons. First their generals were all incompetent in managing their massive army.
And the “weather changed”- so it’s Napoleon assaulting Russia in early winter all over again- btw, would have been lost war had it been summer.
And a large global recession that politicians which media supported, created, also dampen the appeal of even more excessively wild government spending- hundreds of billions or trillions depending how want to measure it, which of course involved massive government fraud and waste which obviously created too much unemployment and poverty in general. And such things as there are too big to fail. So if the politicians had sunk the ship, whereas otherwise the ship may have continued to float for a longer time.
A measure of he scale of corruption can seem in endless studies, which “had” to be related to “global warming”, so a thick phone book of how everything imaginable is caused by global warming.
Quite – but a departure of, say, 5 deg from the “normal” on a graph using the Kelvin scale wouldn’t appear particularly alarming either. However, the last time the earth’s average temperature was 5k lower than to-day mile-high ice sheets covered much of northern Europe and America.
Global warming began its recovery after the last Snowball Earth, was halted a few times by the ice ages (big and little), and for the past 150 or so years has been slowly been returning to NORMAL. As if there is such a thing. Snowball earth bad, warm earth good.
Speaking on a side topic from the main thrust of the article:
This reminds me of how implied figures for non-combustion human CO2 emissions can be junk.
The reported net flux of carbon from land use change makes no mention whatsoever of considering the enormous effect of carbon fertilization, let alone doing so accurately, in the abstract linked of the paywalled paper.
The other link, to a PDF not paywalled, mentions in passing that their computer modeling “does not account for” “environmental factors, such as CO2 and climate, that affect vegetation.” They technically covered their rear ends but in practice produced misleading results which are utter junk compared to proper observations: a huge missing variable fallacy
Those few quoted words matter more than the other 74 pages, but superficial impressiveness is effective on the naive falling for a formal writing style.
If someone tries to defend such by saying “land use change” doesn’t have to consider carbon fertilization, by definition, I’d practically laugh at the worthless cop-out: arguably technically true but irrelevant to how much such misleads readers in practice.
As human fuel combustion amounts to an annual gigatonnage of CO2 emissions near double the measured rate of net CO2 rise in the atmosphere and since the net amount going into the oceans isn’t enough to cover all the remainder, there is the “missing sink.” It isn’t really a missing sink, though.
CO2 doesn’t magically cease to exist. By process of elimination, there is net flow of CO2 into vegetation/land (with emissions from them being overall negative aside from fuel combustion), which is unsurprising in contexts ranging from a multitude of studies on co2science.org to how satellite-measured global net terrestrial primary production increased by several percent per decade during the period of global warming (Nemani et al. 2003, for instance). However, calling it by its proper name, carbon fertilization, would be like discussing global warming predictions while using the specific term CAGW rather than “climate change” and so admitting that global cooling is contradictory: not sufficiently dishonest.
The missing variable fallacy of neglecting a factor entirely, implicitly treating it as 0% effect, minimizing mention to quickly skip on (except when the target audience unavoidably already has heard of it), is common when something is so extraordinarily dangerous to the CAGW movement as to be he-who-must-not-be-named to them, a distinction which belongs to the magnitude of beneficial effects of CO2 (several tens of percent rise in plant growth rates under a more extreme scenario of CO2 doubling, plus as huge a rise in water usage efficiency, if the plants aren’t underfertilized meanwhile) and to the dominating influence of cosmic rays on climate as in the link in my name.
And, on another topic, as the obligatory note when an article publishes solely false temperature data from CRU / their ilk: There was no mere temperature plateau in the 1950s-1970s but far more cooling then, as the plots of the time showed, like those illustrated in my link.
link fix
And when will the warming re-start?
When the two main guys looking after the satellite records are replaced with CAGW apologists. !
In the sense the climate obsessed mean the question, “When did AGW begin?”, which is “When did the cliamte catastrophe begin?”, the answer is never.
In the sense of when did humans influence the climate. the answer is, “Ever since we influenced land cover and discovered fire.”