From the AMERICAN GEOPHYSICAL UNION and the Australian “ARC Centre of Excellence for Climate System Science” (you know, that outfit that gave “Ship of Fools” Chris Turney an award) comes this exercise in climate modeling numerology. From the introduction in the paper:
In this study we use the well-established Fractional Attributable Risk (Allen, 2003; FAR) framework to investigate the changing influence of anthropogenic forcings on record-breaking hot seasons and years for different regions around the world. The probability of record hot events is compared between climate model simulations with both natural and anthropogenic forcings and simulations forced by natural climate influences only.
They also go on to say they have detected emergence of AGW driven heat waves in the Central USA in recent years. From Figure 3. “FAR timeseries of record-breaking hot summers for the globe and five regions” here is the panel for the Central US:
They suggest that from 2000 onward, heat waves should be anywhere from 2 to 10 times more common. By that reasoning, this graph of record high temperature should also be increasing during that period, but it isn’t:
![STATE_RECORDS[1]](https://wattsupwiththat.files.wordpress.com/2012/06/state_records1.jpg?quality=83)
As should this one:
Note the dust bowl period in the 1930’s mainly affected the Central US.
In short, the entire study is an attempt to pull a desired result out of a set of data. Reading the paper, it seems clear to me that the conclusion existed before the paper was written. Here is the press release for what it’s worth.
WASHINGTON, DC — Humans have triggered the last 16 record-breaking hot years experienced on Earth (up to 2014), with our impact on the global climate going as far back as 1937, a new study finds.
The study suggests that without human-induced climate change, recent hot summers and years would not have occurred. The researchers also found that this effect has been masked until recently in many areas of the world by the wide use of industrial aerosols, which have a cooling effect on temperatures.
“Everywhere we look, the climate change signal for extreme heat events is becoming stronger,” said Andrew King, a climate extremes research fellow at the University of Melbourne, Australia and lead author of the study. “Recent record-breaking hot years globally were so much outside natural variability that they were almost impossible without global warming.”
The researchers examined weather events that exceeded the range of natural variability and used climate modelling to compare those events to a world without human-induced greenhouse gases. The study was accepted for publication yesterday in Geophysical Research Letters, a journal of the American Geophysical Union.
According to the new study, record-breaking hot years attributable to climate change globally are 1937, 1940, 1941, 1943-44, 1980-1981, 1987-1988, 1990, 1995, 1997-98, 2010 and 2014.
“In Australia, our research shows the last six record-breaking hot years and last three record-breaking hot summers were made more likely by the human influence on the climate,” King said. “We were able to see climate change even more clearly in Australia because of its position in the Southern Hemisphere in the middle of the ocean, far away from the cooling influence of high concentrations of industrial aerosols.”
Aerosols in high concentrations reflect more heat into space, thereby cooling temperatures. However, when those aerosols are removed from the atmosphere, warming returns rapidly. The researchers observed this impact when they looked at five different regions: Central England, Central Europe, the central United States, East Asia and Australia.
There were cooling periods, likely caused by aerosols, in Central England, the central United States, Central Europe and East Asia during the 1970s before accelerated warming returned, and aerosol concentrations also delayed the emergence of a clear human-caused climate change signal in all regions studied except Australia, according to the study.
“In regards to a human-induced climate change signal, Australia was the canary in the coal mine for the rest of the world,” King said.
###
The paper: http://onlinelibrary.wiley.com/doi/10.1002/2015GL067448/abstract
Emergence of heat extremes attributable to anthropogenic influences
Authors
Andrew D. King, Mitchell T. Black, Seung-Ki Min, Erich M. Fischer, Daniel M. Mitchell, Luke J. Harrington, Sarah E. Perkins-Kirkpatrick
Accepted manuscript online: 7 March 2016
Abstract
Climate scientists have demonstrated that a substantial fraction of the probability of numerous recent extreme events may be attributed to human-induced climate change. However, it is likely that for temperature extremes occurring over previous decades a fraction of their probability was attributable to anthropogenic influences. We identify the first record-breaking warm summers and years for which a discernible contribution can be attributed to human influence. We find a significant human contribution to the probability of record-breaking global temperature events as early as the 1930s. Since then, all the last 16 record-breaking hot years globally had an anthropogenic contribution to their probability of occurrence. Aerosol-induced cooling delays the timing of a significant human contribution to record-breaking events in some regions. Without human-induced climate change recent hot summers and years would be very unlikely to have occurred.
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Such studies must first look in to the precipitation patterns — droughts and floods. Without such study, the results can be interpreted as preconcieved by the uthors. This is a bad research.
Dr. S. Jeevananda Reddy
It’s no interpretation Dr. These results are absolutely pre-conceived. And yes, it is bad research.
“The researchers examined weather events that exceeded the range of natural variability …”
So how could they do that? Where is the ‘range’ of natural variability quantified?
I suspect this is just a way to try and remove the valid sceptical objection to the claims that recent hot weather is outside norms by asking ‘what about the 30’s?’. By claiming them now as ‘man-made’ they try to remove a glaring objection to the alarmism.
Just been reading ‘1984’, this is classic Big Brother rewriting history…
The great heatwaves and droughts in the Dust Bowl were due to a combination of one or more multidecadal oscillations and the farming practices during and before the mid 1930s.
Australian “ARC Centre of Excellence for Climate System Science” reminds me of this;
Surely, this claim is at its root, circular.
Surely they are now testing their assumptions using simulations – which are already simulations of what would happen if this set of assumptions are assumed to be true.
We already know that models will show that anthropogenic greenhouse gases will cause most of the warming and that very little of the warming will have its origin in natural variability – because that’s the assumption upon which the models are based.
The modellers effectively told the model to do this. Now the model is telling climate scientists that this is what the model does…
Shouldn’t someone be predicting something and then testing something against reality?
Have I missed something?
..I have a model of my model that proves that my model is better than your model ! So there !
I’ll see your model and raise you 8 models. it’s risky I know, how can we lose? Hahaha
I decided to let my Scientific American subscription expire many years ago when they declared that the last ice age ended because of agriculture.
CO2 must have been the cause of early 20th century warming because the modelers cannot find another reason.
Step forward the great Dana Nuccitelli at Sks on the settled science.
We can all eagerly await Dana’s corrective Guardian article.
If you want to look for human effects on the climate look at something other than CO2. From what I remember reading, the USDA went to great lengths to teach farmers dry land farming after the dustbowl. They publicized planting wind breaks of trees, putting trees around housing. Planting cover crops immediately after plowing. Using contour plowing to prevent excessive run off. Raising cattle instead of farming. Crop rotation, etc. It was pretty well accepted from the 50’s on that the dustbowl was primarily due to the wrong farming practices in the early part of the century. But it was a fairly localized problem and made worse by the recurring drought conditions that were known to happen fairly periodically.
Now almost all farmers/ranchers in the area go to great lengths to preserve and improve the soil and use good practices.
The 1930’s dustbowl occured during a warm period in earths recent history, trying to cool the past again? Farmers back then didn’t know how to farm?
Trying not to fucken swear so hard…
The 1930’s dustbowl occured during a warm period in earths recent history, trying to cool the past again? Farmers back then didn’t know how to farm?
See, it all goes back to the discovery of fire. All those campfires added up. Who invented the match anyway?
…. not sure – was it Al Gore ? He invented all kinds of stuff.
Notably he invented:
1. climate change as a tool for electoral popularity.
2. climate change as a tool for getting very rich by making carbon marketable
It’s all well and good that they don’t live in small cold countries, winters are just as cold as the state they vote to rule them.
I can’t see any basis for declaring that these events exceed natural variability or to assume that the comparison with a theoretical world is valid unless the models have been thoroughly validated. Which they haven’t, and to do so would take a hundred years or so.
Notably, Mr.Gore invented:
1. the use of Global Warming hysteria as a tool for getting elected and
2. the use of Global Warming hysteria as a tool for getting rich by marketing fictitious carbon quotas.
You could shorten that to Al Gore is a tool. But then that would be an insult to tool makers who do real, useful, work.
“The researchers also found that this effect has been masked until recently in many areas of the world by the wide use of industrial aerosols, which have a cooling effect on temperatures.”
Sounds like, if we really try hard, we could induce a GGS (Goldilocks Global Stasis) … but I guess that would also rate as “still happening and even worse than we thought!”
They should try that for the years 900-1000. I’m sure their models will find that the human-emitted carbon dioxide at that time has a much greater effect than previously thought. Success!
The AGU played a role in this piece of horse pucky? How does the AGU retain it’s membership? I would be embarassed. to say that I was a member.