By Steve Goddard
My friend Tamino says that “the modern global warming era starts in 1975.”
He goes on : “It’s an estimate of the time at which the trend in global temperature took its modern value.”
As you can see in Phil Jones’ HadCRUT graph above, the 25 year period from about 1975 to 2000 did warm about half a degree C.
You can also see that the 30 year period from 1910 to 1940 similarly warmed about half a degree C. At that time, atmospheric CO2 averaged about 305 ppm, well below Dr. Hansen’s suggested “safe level” of 350 ppm. See the graph below for that period:
Here’s an annotated HadCRUT graph to help you see the relevant periods and the changes of temperature versus changes in global CO2 concentration during the same period:
The video below superimposes the 1975 warming (blue line) on the 1910 warming (black line.) Note the similarity in slope, duration and patterns. It would be difficult to explain the 1910 warming as being due to CO2, because CO2 was barely above pre-industrial levels and rose only 10 ppm during that period.
Given the similarity between the 1975 warming and the 1910 warming, it is irrational to blame the 1975 warming entirely on CO2. The practice of good science tells us to look for a hypothesis which can explain both similar warming periods.
If there is an influence of CO2 in the recent warming, it appears small. And the warming stopped ten years ago, as shown in the HadCRUT graph, despite rapid increases in CO2.
Or perhaps one might conclude that climate sensitivity has decreased as CO2 levels have risen. In 1910, with CO2 at 300 ppm, it only took ten additional ppm to raise temperatures by 0.5°C. By contrast, in 1975 it took about fifty ppm more to produce the same 0.5°C warming by the year 2000.
There were also periods of time with rising CO2, and little or no rise in temperature. From 1940 to 1980, there was no net warming while CO2 rose by 30 ppm. Since 1998, there has been no warming – as CO2 levels have risen 30 ppm.
I feel a chill of La Niña coming on.
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David Gould,
If you took a murder case to grand jury, and your only evidence was that your suspect was in the same city at the same time – it wouldn’t get very far.
Unless you were in Fort Collins, where Tim Masters spent ten years in jail for a murder with zero physical evidence linking him to the crime.
http://www.cnn.com/2010/CRIME/07/29/tim.masters.police.perjury/index.html
Likewise the ~1940 to 1977 cooling – see John Finn’s important comment above (Aug 23 1:57 am). It DOES NOT appear to have been aerosols, as the consensus would have it. Too small, too local and no arctic haze to warm the pole.
C20th climate change has not been explained.
Dominic
Julian Flood says:
August 23, 2010 at 1:25 am
To my knowledge, no one cared about aerosols back then. They started caring after the London smog episode of 1952 killed a bunch of people. Thus, I doubt anyone can make good estimates of aerosols from back then, and there likely isn’t any sort of data that’s even close to useful.
In general, human-caused aerosols probably went down per person as we got cleaner/more efficient, but at the same time the population went up, so…?
-Scott
http://www.dilbert.com/strips/comic/2010-08-23/
Sorry folks, whenever I see one of these temperature graphs, I ask myself, “is this the original raw data, or the adjusted, homogenised, value-added data?”.
Sorry, but sometimes my BS indicators are stretched a little too far
son of mulder,
I also saw the butterfly wings flap and failed to understand the significance of the event. The threat of nuclear winter and the doomsayers forecasting an ice age made it hard to sift the chaff from the wheat. Chaos theory { not Maxwells nemesis } saw the beginning of understanding in chaotic systems. Thus far however the mainstream scientific endeavour has failed to incorporate this basic universal mathematics, that powers all of creation. The non linear equations that ultimately will give sense to climate are way beyond the linear thinking of the AGW scientists.
Coterie consensus in science is costing billions and the results are BS. It is not only climate science that is degraded, the standard model of the universe and quantum physics have gone nowhere, except for more complications and new explanations. They also will not accept new ideas. Savour your cherries, for real science has always lagged the accepted truth, some times for centuries, we can hope that this endeavour of AGW can be banished, some-what more quickly. Wayne
David Gould says:
August 23, 2010 at 1:13 am
Stevengoddard,
“So you are saying that unless I know who killed person A, I cannot possibly know who killed person B? I think that there might be something in error about that logic …”
The only thing posting this kind of nonsense brings are concerned smiles. Think it through prior to posting!
I’m not convinced there’s anything significant here (other than to show, yet again, the worthlessness of the whole AGW pseudo-theory), because the similarity in slope is appearing in what is already a dataset deliberately fudged to show as close to a continually rising trend as its inventors can manage. It’s not even a coincidence; it’s an artefact. If you look at the original data – preferably using old printed literature which can’t be edited away – the slopes do not really match; the earlier period had a steeper rise (and bigger subsequent fall) and the later period should have had a shallower rise. On the other hand, the absolute temperatures were a lot closer.
Robert,
Tamino (as usual) missed the point of my hockey stick argument. If the hockey stick was an accurate representation of temperature trends, it would be impossible to find a cooling trend from 1930 – or any other date in the past.
It is basic math, but he diverted attention with his sociological straw man argument.
David Gould says:
August 22, 2010 at 9:55 pm
If the argument was that CO2 was the only driver of global temperature, the ups, downs and flatlines would show that argument to be false. But, given that that is not the argument …
So, sometimes C02 forces the temperatures up, and sometimes it doesn’t. Got it.
“There were also periods of time with rising CO2, and little or no rise in temperature.”
From about 8,000 years before 1950, there was no net warming while CO2 rose by 30 ppm (about 255 to 285 from Vostok data as shown in Engelbeen’s recent post).
http://wattsupwiththat.files.wordpress.com/2010/08/engelbeen2-2.jpg?w=550&h=435
John M Reynolds
‘David Gould says:
August 23, 2010 at 1:13 am
Stevengoddard,
So you are saying that unless I know who killed person A, I cannot possibly know who killed person B? I think that there might be something in error about that logic …”
True, but if the only wounds on Person A and Person B are gunshot wounds to the head, by what logic would you conclude A had been shot to death but B must have been stabbed to death?
Michael Hauber says:
August 22, 2010 at 11:37 pm
“Giss model E forcings suggest that the warming between 1910 and 1940 was caused by roughly equal parts of increase in solar activity, increase in Co2, and reduction in aerosols (i.e. volcanos early in the period, and an increase to no volcanos late in the period).”
At least choose a GOOD climate model to base your conclusions on…no one knows (or cares to show) what model E is solving…
Yes, the simplest reasonable hypothesis is that total forcings increased for both periods, causing net warming.
The simplest reasonable hypothesis might be that the up-down-up is an artifact in the data.
Robert says:
August 23, 2010 at 12:16 am
Why didn’t you put up GISS or NOAA?
You must have been joking, or you were new. Mosher’s work isn’t the best in the world either.
Peter Jones,
Excellent Dilbert!!
http://www.dilbert.com/strips/comic/2010-08-23/
John: August 23, 2010 at 5:23 am
True, but if the only wounds on Person A and Person B are gunshot wounds to the head, by what logic would you conclude A had been shot to death but B must have been stabbed to death?
Whoa! A and B are dead? Geez, I had breakfast with them just last Monday!
When’s the funeral? I’ll have to send flowers…
Basically, the climate models use the big three other forcings to try to match up to the record (in addition to adjusting the record to match up to the theory).
Aerosols is just guesstimated. Volcanic impact is overstated. The latest solar forcing estimates say it is has not changed much at all (at least the solar minimums haven’t).
Since 1998 as well, these big three are flat (and zero in the case of volcanoes).
The math really only works if one assumes there are, indeed, natural cycles in the climate AND the GHG impact is less than assumed. Two things climate science works very hard to avoid coming to grips with. The current La Nina will make this avoidance even more awkward.
Our friends argue that GISS is nearly identical to HadCrut -until HadCrut shows something which they don’t like.
pat said:
“The stupidity of this is beyond belief. How can the global average always be under the average until Warmists decide it is over? This is not science. It is not real. It is some sort of game.”
The zero anomaly line isn’t an average for the entire ‘data’ period. The basis period which anomalies are compared to is 1961-1990.
Assume the CO2 effect is true. If 10ppm 1910-1940 caused a 0.5C increase and another 50ppm caused the 1975-2000 0.5C increase, another 0.5C increase would require how much more CO2? 250ppm?
Paul Birch,
Do you know where all the original data might be catalogued? Is it in one place, or would one have to search different databases maintained by various nations and their weather services? Robuk brought up the subject of using rural, pristine databases to check the accuracy of the temperature record. Could such a thing even be possible?
As I look around, life goes on just as I remember it from previous years, and I remember well before 1975. Reading information and debate on the topic of MMGW, all I can detect is a detachment from reality: where are the changes happening? And don’t say in the temperature records, I mean where I can go and look and see the effect. Any examples, not could-be & might-be but something tangible? Just asking.
I think that everyone knows that AGW is an acronym for “Anthropogenic Global Warming,” as it is often used in this blog to describe a theory of climate change. After reading many of these posts, ABC or “Anything But Carbon” might be a good fit to define this site’s opposing view.
I think it urbane to point out (again) that Skeptics do not argue that an increase in CO2 would not have 0% affect on the climate, rather that the affect of said increase is no where near catastrophic in nature and that the increase in temperature over short periods of time ( anything less than a couple centuries ) is in many ways meaningless as there is too much natural ‘noise’ to be of any use.
Add to this that the only thing that people talk about in reference to Global Warming is doom and gloom and you have skeptics of such prophesying ( cause that is what it is ) sitting back and trying to separate the facts from the fiction.
For instance when it comes to an increase of Carbon Dioxide are there no beneficial affects? Of course there are. An increase in temperature? No Beneficial affects? Once again of course there is. But that is not what we hear over and over again from those studying the phenomenon.
I enjoy this site because it questions and this is a perfectly valid question that Steve Goddard has brought to the fore. Explain the warming in other time periods. The truth is that you can’t easily do so…. In fact some of the hypothesis that I have heard trying to down play this really cause more questions then answers.
Being able to point to one place and say it was caused by nature and another and say it was caused by man without being able to really justify the first and simple discounting the second as possibly being natural is in my mind the ravings of a fanatic with an agenda. Just as not being able to suggest good along with ill when it comes to increased CO2 and Global temperatures causes me to question if people are able to think through the Global Warming Debate or are trapped within their own ignorance.
Regardless of the answer I believe that CO2 does contribute to a warmer world ( though how much warmer… I know not ) Just as I believe CO2 contributes to a greener world ( and that I do know the answer to because it has been fairly well documented what an increase in CO2 does to plants )
Here in Western Washington we’ve been well below average all Spring and Summer. Apart from a literal handful of hot days, 60s and low 70s has been the norm. I had to wear a sweatshirt while mowing my lawn yesterday, since it didn’t hit 70f. There’s no global anything going on, except hysteria, in both directions.
However, an ice age will come eventually, unless the configuration of the continents drastically changes, or the sun suddenly puts out significantly more energy, or drastic orbital changes occur…