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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BBD I suspect that the only links that would get you in trouble are links to porno sites.
@ur momisugly Rhoda R
Well, that’s a relief.
But seriously, I believe with some sites you can get blocked for posting links if you are new… Just being cautious.
Dominic
Robuk says:
August 23, 2010 at 3:20 am
“All these temperature graphs are total crap, the weather stations measure the micro climate around them, if they are situated at airports they are measuring the temperature of the tarmac at the airport, in cities they measure the temperature of the buildings. There are hundreds of pristine rural stations with long records world wide that can be used to verify the accuracy of this suspect warming, ever wonder why the warmers dont want to go down that road. If you are trying to measure the temperature of the natural environment, you dont go to an airport or a city to do that.”
Go to the late John-Daly’s website “Still Waiting for Greenhouse” at:
http://www.John-Daly.com.
On the home page scroll down and click on “Station Temperature Data”. There you can find many temperature-time plots from mostly rual ( i.e, remote) weather stations from all over the world.
In particular, check out the plots for Death Valley and other desert locations such the stations in Utah and Alice Springs, Australia.
The seasonal plots for Death Valley are almost flat since 1922. Thus CO2 had no influence on warming local air at the Furnance Creek weather station which is about 280 ft below sea level. Death Valley is a good field site to test the AGW hypothesis because the are usually no day or night time clouds and little water vapor to effect temperature.
Analysis of monthly Tmax and Tmin would probably show even flatter time-temperature plots since there would be less weather noise.
Looks like you really hit a nerve here Steven.
Harold, Death Valley thermometer data would be good ones to check. Death Valley is less directly and immediately affected by oceanic inputs. However, the juxtaposition of the jet stream can cause weird weather once in a while in that place. Fortunately, the weird weather is so rare that it does not significantly change the average. Still, I would look at oceanic/atmospheric neutral years as the best measure/extent of CO2 AGW.
I wonder why CO2 stabilized during the period of WW2 even though we know that industry ramped up during this time, massive fires on a global scale were around, massive amounts of dust and debris sent up in to the atmosphere….. yet CO2 stabilized?
Interesting.
J. Knight says:
August 23, 2010 at 6:57 am
“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?”
I think my point was that once the subject has become politicised (as climatology after the late seventies) no database is trustworthy any more; once it’s on a computer, it can be altered, and the reader has no way of knowing what has been done to it. He can only trust that somebody is telling the truth. The AGW crowd certainly aren’t. But how can he be certain that the skeptics aren’t lying too? The only way to be sure would be to look at the original hand-written readings, on the paper met forms or lab notebooks. So, yes, somebody could perhaps trawl through the old records and recompile a sound history. Yet quis custodiet custodes? Nevertheless, one can also use the temperature charts from old books and academic publications, stored in public reference libraries, or one’s own personal library. Those are still reliable – they may not be perfect, but they have not been deliberately biased or manipulated. Remember, though, once the document has been scanned onto a computer, it can be altered; even facsimiles are not completely secure.
Right. It is an easy enough thing to do. Determine the slope/increase for each one’s linear regression. Break all the stations into population ranges. Also have a separate category for airports, possibly broken into population center size, also.
Then simply average the increase in each group.
If the cities and large airports don’t show the most rise, I am a monkey’s uncle. Rural will have the lowest slope.
But I will make this argument, also:
If there is a GLOBAL warming, then that should show up in the rural locations. If it does not, then it isn’t global – it is only local, with the cities and airports being the “arm” places. “Global warming” would mean that the warm spots have warmed up all the locations to some degree. The argument is that it is global, meaning “it” has warmed up all over the place – allowing for local variations – therefore the rural stations’ average slope should be the true warming slope.
Dispersal in the short term will show up as a cooling toward the rural spots, with the rural being the coldest. However, over the long term, it will all have evened out, except for steep isotherms in the vicinity of the warm locations. THE RURAL – AND ONLY THE RURAL – IS THE TRUE “GLOBAL WARMING” LEVEL. Taking measurements anywhere but rural makes no sense.
Pamela –
If nothing else, a worthwhile exercise to see what falls out.
Kudos.
Well, this week is climatically the end of summer here in upstate New Hampshire. We have a pretty simple guage for this: we leave our windows open all summer to let the air flow through (see, we don’t cotton to any o’ that new fangled Aich Vee Ay Cee up here in Grouse Hollow), while simultaneously leaving the gas heater set to come on when the temperature goes below 64. When that happens, we shut the doors and windows til it warms up again.
The added benefit of leaving them open all the time is I can be sitting on my La-Z-Boy watching the Red Sox game inside in the shade on my wide screen LCD tv, and shoot tree rats (otherwise known as red squirrels) trying to raid the bird feeders with my high power, noise suppressed, 10x scoped pellet gun. I’ve got some nice snapshots of the local red foxes swinging by the house each day to pick up the squirrel corpses to feed their kits.
This week, the windows and doors have been closed the entire time due to cold. Hence the squirrels have been going gangbusters on the bird feed (they have learned that the sound of the deck door sliding open is the squirrel version of the Jaws theme, and scram as soon as I crack it open).
It’s a good day – my comment was deleted at Closed Mind http://tamino.wordpress.com/2010/08/23/antrhopogenic-global-cooling/
What I said was: if mid-century aerosol cooling is real, why does Los Angeles, which should be a poster child for aerosol cooling, look more like the Southern Hemisphere:
than the Northern Hemisphere:
??
This might have some application here, as a general guide. Steve is talking about comparing the earlier warming period to the 1975-2000 one.
States represent temperature areas, more or less like 5° or 2° regions do, though the states are not uniform in size (but neither do 5° or 2° regions on a globe, either). And they are to single met stations more or less as climate is to weather.
So, if we look at record temps in light of claims of “highest decade ever” or “hottest period ever”, we should expect to see a large number of record temperatures since 1975. I broke down the record highs for the 50 US states, to see which decades had the most record high temperatures. Weather is not climate, but when looked at statewide and decade-wide, it begins to approach climate.
Let’s see how the 1990s or 2000s stack up:
Period . . . . . State Record Highs
Pre-1900 – 3
1900-1909 – 1
1910-1919 – 4
1920-1929 – 2
1930-1939 – 23
1940-1949 – 0
1950-1959 – 5
1960-1969 – 1
1970-1979 – 2 (both in 1975)
1980-1989 – 2
1990-1999 – 5
2000-2010 – 2
* The first amazing thing that jumps out is those 23 state records in the 1930s.
* The 2000s, supposedly the hottest decade ever, had only 2 state record highs.
* The cool period 1950 thru 1975 had 8 record HIGHs.
* The “hottest” period 1975 thru 2000 had 9 record highs, only 1 more than 1950-1975.
* The entire 1879-1929 period was cooler than ANY later time period. It had 7 record highs.
* The period 1900-1920 was the coldest period of the 20th century. It had 5 record highs.
What does all this mean?
It states very clearly that even in very cool periods record high temperatures occur.
It does not “prove” anything. It is evidence that suggests the 1990s and the 2000s were not the hottest decades. It strongly suggests the 1930s were the hottest decade.
* The 1950s – at the low point of the 1940-1975 cool period – had 5 record highs – the same as the 1990s.
Feet2theFire says:
August 23, 2010 at 3:20 pm
It does not “prove” anything. It is evidence that suggests the 1990s and the 2000s were not the hottest decades. It strongly suggests the 1930s were the hottest decade.
Very, very strongly. However, this is just the US. Do we have any data from other countries on the record highs?
WordPress ate my tags – I forgot I shouldn’t try to outsmart.
Southern Hemisphere: http://img844.imageshack.us/img844/1567/junksh.gif
Northern Hemisphere: http://img840.imageshack.us/img840/6697/junknh.gif
The CO2 graph is spliced from different sources. Mauna Loa monitoring started in 1959 … it’s no coincidence that the graph turns up at this point.
David Middleton says:
August 23, 2010 at 11:18 am
Your links/graphs are excellent – do you have any more stuff like this?
The cooling due to particulates is kinda like the pot at the end of the rainbow. As long as you can’t find it, it can be as large as you want it to be.
Heh!
So then, the propagandists are wont to blame ‘carbon,’ eh?
Well, how about this: There’s TWICE as much OXYGEN in the CO2 molecule, than there is carbon.
THINK about that.
It’s not carbon that’s causing the ‘warming.’
Rather, it’s the OXYGEN!
QUIT BREATHING, YOU BREATHERS!!!
JR says:
August 23, 2010 at 3:19 pm
Excellent post! I would actually argue that it can be refuted, but it shows how sad the warmists are to just delete your comment rather than to argue against it scientifically.
-Scott
Harold Pierce Jr says:
August 23, 2010 at 12:15 pm
With regards to Death Valley temperatures, shouldn’t it be one of the places MOST affected by CO2 warming? At below sea level, it is under higher pressure and thus (a) higher CO2 partial pressures/concentrations and (b) subject to more collisional broadening of the CO2 absorption bands. Additionally, and perhaps more importantly, there is little H2O to absorb IR, so the absolute (and certainly the percentage) effect of CO2 should be more here than in humid areas.
Can anyone confirm my line of reasoning here?
-Scott
In the CRU emails Cook to Mann: ““I think that most researchers in global change research would agree that the emergence of a clear greenhouse forcing signal has really only occurred since after 1970. I am not debating this point, although I do think that there still exists a signficant uncertainty as to the relative contributions of natural and greenhouse forcing to warming during the past 20-30 years at least.””
The IPCC AR4 report indicates the warming prior to 1970 was natural. The two cycles are identical in shape, so they can’t have two different causes (natural before 1970, CO2 since) – see: http://www.appinsys.com/GlobalWarming/GW_Summary.htm for the details on this.
Steve,
Can you add the delta in the CO2 onto the annotated chart for the period 1940 to 1975? I think it would improve the usefulness of your annotated chart.
Regards
Gnrnr
Harold Pierce Jr says:
The web link you provided for the Russian article is not working. Could you please fix it? Thank you.
Yuba Yollabolly:
August 23, 2010 at 8:53 am
It is not purely cyclic. It is a cyclic pattern with an overall linear warming of 0.6 deg C per century. As a result, during the warming phase, the cyclic warming and the linear warming components are additive; while during the cooling phase, the cyclic cooling and the linear warming components are subtractive.
This is why “the cooling phases” are no “equal the warming phases”
Look at the following graph:
http://wattsupwiththat.files.wordpress.com/2010/04/orssengo3.png