UPDATE: a response to this paper has been posted, see below.
From McGill University , who blows the credibility of their science by putting the word “deniers” in it.
Statistical analysis rules out natural-warming hypothesis with more than 99 percent certainty
An analysis of temperature data since 1500 all but rules out the possibility that global warming in the industrial era is just a natural fluctuation in the earth’s climate, according to a new study by McGill University physics professor Shaun Lovejoy.
The study, published online April 6 in the journal Climate Dynamics, represents a new approach to the question of whether global warming in the industrial era has been caused largely by man-made emissions from the burning of fossil fuels. Rather than using complex computer models to estimate the effects of greenhouse-gas emissions, Lovejoy examines historical data to assess the competing hypothesis: that warming over the past century is due to natural long-term variations in temperature.
“This study will be a blow to any remaining climate-change deniers,” Lovejoy says. “Their two most convincing arguments – that the warming is natural in origin, and that the computer models are wrong – are either directly contradicted by this analysis, or simply do not apply to it.”
Lovejoy’s study applies statistical methodology to determine the probability that global warming since 1880 is due to natural variability. His conclusion: the natural-warming hypothesis may be ruled out “with confidence levels great than 99%, and most likely greater than 99.9%.”
To assess the natural variability before much human interference, the new study uses “multi-proxy climate reconstructions” developed by scientists in recent years to estimate historical temperatures, as well as fluctuation-analysis techniques from nonlinear geophysics. The climate reconstructions take into account a variety of gauges found in nature, such as tree rings, ice cores, and lake sediments. And the fluctuation-analysis techniques make it possible to understand the temperature variations over wide ranges of time scales.
For the industrial era, Lovejoy’s analysis uses carbon-dioxide from the burning of fossil fuels as a proxy for all man-made climate influences – a simplification justified by the tight relationship between global economic activity and the emission of greenhouse gases and particulate pollution, he says. “This allows the new approach to implicitly include the cooling effects of particulate pollution that are still poorly quantified in computer models,” he adds.
While his new study makes no use of the huge computer models commonly used by scientists to estimate the magnitude of future climate change, Lovejoy’s findings effectively complement those of the International Panel on Climate Change (IPCC), he says. His study predicts, with 95% confidence, that a doubling of carbon-dioxide levels in the atmosphere would cause the climate to warm by between 2.5 and 4.2 degrees Celsius. That range is more precise than – but in line with — the IPCC’s prediction that temperatures would rise by 1.5 to 4.5 degrees Celsius if CO2 concentrations double.
“We’ve had a fluctuation in average temperature that’s just huge since 1880 – on the order of about 0.9 degrees Celsius,” Lovejoy says. “This study shows that the odds of that being caused by natural fluctuations are less than one in a hundred and are likely to be less than one in a thousand.
“While the statistical rejection of a hypothesis can’t generally be used to conclude the truth of any specific alternative, in many cases – including this one – the rejection of one greatly enhances the credibility of the other.”
“Scaling fluctuation analysis and statistical hypothesis testing of anthropogenic warming”, S. Lovejoy, Climate Change, published online April 6, 2014. http://link.springer.com/search?query=10.1007%2Fs00382-014-2128-2
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Christopher Monckton has posted a rebuttal to this paper, see here
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“An analysis of temperature data since 1500”
– He *can’t* be serious. Can he?
Indeed, their Figure 5 shows the whole story. As I learned in college, when giving a seminar in front of people who don’t know as much about the topic as you do, if you can’t dazzle them with brilliance, baffle them with BS. They use a period of 500 yrs worth of cherry-picked flat-line data to derive their NATURAL temperature variation and of course the 1900-2000 temperature rise doesn’t fit with natural causes. Didn’t need to do any of the math in the rest of the paper to see that.
the killing fields is what happen under the regime of pol pot.Where anybody with classes were sent to die because the might be smart.
[Think, proofread, edit first. Mod]
“We’ve had a fluctuation in average temperature that’s just huge since 1880 – on the order of about 0.9 degrees Celsius”
Before or after adjustments? In the US, the 30’s is still the hottest decade. But the adjustments try to hide that away. Much talk of odds. These are mostly on models and flawed reconstructions. How about cold hard facts from measurements?
james says:
April 11, 2014 at 6:51 pm
yeah… no that they may be smart, but because the only reason for glasses was to read, which was unnecessary.
point well made.
One of the serious problem and flaw with Lovejoy’s analysis is that it starts in 1500 (!), the middle of the Little Ice Age.
To test how much the warming since 1880 was natural and how much it is human-induced, one needs to see much older records. At least there is a need of starting with the medieval warm period or the Roman Warm Period.
One this is done, according modern global surface temperature proxy records, about 50% of the warming since 1880 is natural and the left over may be human induced.
Everything is already published in my papers many times.
E.g. look here:
http://people.duke.edu/~ns2002/#astronomical_model
and here for the latest update of the models
http://people.duke.edu/~ns2002/#astronomical_model_1
If Lovejoy’s model is extrapolated in the past before 1500, it will never recover the medieval warm period.
He must be looking at the first graph here:
http://wattsupwiththat.com/2009/12/09/hockey-stick-observed-in-noaa-ice-core-data/
May he should look at the rest and apply his “stats” to them …..
PS. That link is one of (if not THE) all time favourite WUWT posts by the way.
McGill University should have its charter to grant degrees revoked.
““This study will be a blow to any remaining climate-change deniers,” Lovejoy says.”
Lovejoy references MBH 1998 as one of his canonical sources of ‘natural’ temperature changes.
MBH 1998 is an incompetent exercise in mining stick-shaped noise from noise.
In fact, this study is a blow to any remaining credibility of Lovejoy’s climate science.
I’ll have to take a closer look at their write off of the pause and the complete lack of skill shown by the models. The good news is reality does not agree with them.
” It was therefore replaced by the [Ammann and Wahl, 2007] update of the original [Mann et al., 1998]”
So their idea of assessing natural climate variability is to re-use the discredited Mann hockey-stick.
Volcanoes are regarded as being statistically “stationary” which is hardly the case for the 20th c.
I was curious as to why the selected 1880 as the starting point but then found the answer in fig 3b. It allows misleading the reader by distracting from the fact that the early 20th rise was just as strong as the late 20th c. rise.
Had they run it further back we would have seen that the CO2 “forcing” diverges from the temperature record, so they cropped it at 1880. The data also gets conveniently cropped at around 2000 so as to hide the pause.
This is just a wild mix of spurious assumptions, discredited proxies and cherry picked time intervals all hidden behind a bit statistics that is suppose to impress and confuse the reader enough that he doesn’t argue.
Frankly bullshit.
OT sorry, but why isn’t the Nevada land grab by the BLM not reported on WUWT since it centers around installment of a solar farm?
[Because it IS off-topic in this thread. Mod]
It is publish or perish out there.
The weak lexicon pays in the short run.
“This study will be a blow to any remaining climate-change deniers,” Lovejoy says.
What is a “blow” is that we have to waste time reading this kind of garbage and that it get printed in the first place. However, that comment clearly displays bias of the author and his intent to mislead. He says “any remaining” like there are fewer and fewer people questioning AGW alarmism, when polls clearly show less and less people regard it as problem.
He misleads in his press comments as he misleads in his published work.
Yet more abdication of scientific objectivity in a crusade to “save the planet” . The end justifies the means.
“Does anybody want to be a coauthor?”
Count me in. Let’s send it to the same journal.
you are our white knights fight with everthing you have because they would turn us into serfs and you into corspes
Oh, my…
Post hoc ergo propter hoc…
We’re witnessing the death of logic, reason and science…
More leftist fallacies based on this logic fallacy: US taxes were high during the 50’s, GDP grew in 50’s, ergo, higher taxes cause economic growth….
Lovejoy’s nifty understanding of statistics would make him a star at the Bureau of Labor and Statistics…
Embrace the stupid…
Love Hockey
Joy Stick
Mann square
Statistical analysis where they used proxies for temperature, and guessed at emissions, and guessed at feedbacks…and have a 99% certainty? I am about 99% certain his analysis is flawed.
A list of some of Lovejoy’s ~500 publications since 1981:
http://www.physics.mcgill.ca/~gang/reference.list.htm
It includes a preprint of the Climate Dynamics paper, in case one or two people here might bother to look at it before giving their opinions of it.
Gary Pearse says: April 11, 2014 at 5:39 pm
——————————
One of those 135 Rhodes Scholars was my uncle. Also his brother (a.k.a my dad) graduated from McGill circa 1933. My wife was flown there when she was a kid after shattering her jaw back in the 70’s. I have nothing but praise for that institution.
Prof Lovejoy will likely get to endure a couple of more gdecades of global warmings winters like this past one. Unless he retires to FL to escape global warming disguised as global cooling.
if you go 180 for what the say you will find the truth .Carbon is plant food it will increase yield s of food growps and help all peoples they don’t want this because they a cult of death
They need to have a close look at previous interglacial peaks eg:
http://en.wikipedia.org/wiki/File:Ice_Age_Temperature.png
The current warming appears quite mild compared to previous interglacial peaks!
More than “one or two” people have clearly read the paper and none of them seem too impressed.