Ross McKitrick and John Christy have published a new paper in the Journal of Hydrology.

McKitrick, Ross R. and John Christy (2019) Assessing Changes in US Regional Precipitation on Multiple Time Scales Journal of Hydrology vol. 578 Nov 2019, https://doi.org/10.1016/j.jhydrol.2019.124074

From rossmckitrick.com

The published version is temporarily available at this link. If that does not work a pre-print is available here. The Supplement is here. We look at the claim (made by the recent US National Climate Assessment) that US precipitation increased over the 20th century, that precipitation extremes did likewise and that confidence is high that this is due to greenhouse gases. We discuss 2,000 year drought proxies that reveal Hurst behaviour (long term persistence) which means spurious trend detection is a risk.

Here is the abstract


We estimate trends in US regional precipitation on multiple time spans and scales relevant to the detection of changes in climatic regimes. A large literature has shown that trend estimation in hydrological series may be affected by long-term persistence (LTP) and selection of sample length. We show that 2000-year proxy-based reconstructions of the Palmer Modified Drought Index for the US Southeast (SE) and Pacific Coast (PC) regions exhibit LTP and reveal post- 1900 changes to be within the range of longer-term natural fluctuations. We also use a new data base of daily precipitation records for 20 locations (10 PC and 10 SE) extending back in many cases to the 1870s. Over the 1901–2017 interval upward trends in some measures of average and extreme precipitation appear, but they are not consistently significant and in the full records back to 1872 they largely disappear. They also disappear or reverse in the post-1978 portion of the data set, which is inconsistent with them being responses to enhanced greenhouse gas forcing. We conclude that natural variability is likely the dominant driver of historical changes in precipitation and hence drought dynamics in the US SE and PC.

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John Garrett
September 14, 2019 6:30 am

Last year, my region had rainfall that exceeded the previous two highest record years ( 2003 and 1889, respectively).

This resulted in a deafening media chorus loudly pronouncing that record-breaking rainfall was, “THE NEW NORMAL.”

What has the new year brought forth?

The region’s year-to-date rainfall is well below average; we’re in a drought.

The media silence is deafening.

Reply to  John Garrett
September 14, 2019 7:34 am

Give it another six months, then it’ll be global warming again.

Reply to  cirby
September 14, 2019 10:20 pm

In six months drought will be the “new normal” as they switch from one hysterical claim to another in order to sell papers.

The Guardian used to be one of the top UK broadsheets, it was recently ( fittingly ) reduced to tabloid format and is nothing more than a leftwing campaign platform for SJW issues now.

Reply to  John Garrett
September 14, 2019 7:59 am

The media silence is deafening.

If the papers print an untruth, they can be forced to correct it, not just buried away on the back page, but the correction has to be printed with as much prominence as the original untruth. example

Reply to  commieBob
September 14, 2019 11:54 am

Commiebob, but what if they just ignore something? No penalty?

Johann Wundersamer
Reply to  commieBob
September 17, 2019 9:53 am

BoyfromTottenham September 14, 2019 at 11:54 am

“but what if they just ignore something? No penalty?”

NO penalty, if they just ignore something then the RULE # 1 comes into effect:


Reply to  John Garrett
September 14, 2019 9:38 am

This silence will continue, without a doubt.

The slow death of news dissemination organizations continues with financial pressures claiming one outlet after another, whether print or electronic. In their interest to remain solvent, news media have gone all in for “headline journalism” as a cost cutting, hopefully readership increasing technique.

This strategy, unfortunately, throws veracity out the window simply because accuracy or truth is not at all important with regard to the headline. The “scare” or shock is all that matters: The newspaper was purchased, the channel was watched, or the click was generated.

Mission accomplished.

But in the process, a society trained perpetually less in critical thought, compounded by short attention spans, accepts the headline as true – then spreads the word as “being in-the-know” requires. Millennial SJWs masquerading as reporters makes the situation even worse.

Now add to the equation interest groups with massive financial stakes in, as an example, global warming, as well as governments or individuals with insatiable desires for power. The alliance between these parties and deliberately misleading news media (too short of cash to actually report and analyze thoroughly) is very easy to create, and understand. Both stand to gain greatly.

Of course catastrophe is coming, it’s worse than we thought, and records will be continuously broken as the “new (very uncomfortable) normal” takes hold: The power brokers need a crisis, and news media need headlines and clickbait.

After all….how many news outlets have survived reporting that 115,682 commercial aircraft carrying 17 million passengers landed safely today? A “Made As Instructed” poll showing the alleged, and shocking opinions of a statistically invalid, biased sampling of a completely uninformed group of respondents — sells much better. So does “The End Is Nigh !”

Reply to  TomBR
September 14, 2019 10:24 pm

“The End Is Nigh !”

It’s worse than that, we are now at the End of the Nigh .

Personally, I’m waiting for the end of Nye.

Reply to  John Garrett
September 15, 2019 2:26 am

Some ten years or simo ago when the UK had a few dry years that was the new normal. Then we had a few years of heavy floods. The new new normal. Now total rainfall is pretty much the old normal so the problem is that we get it all more quickly.

The same happened with cold – when we had a cold winter that was the Gukf Stream slowing. Haven’t had a cold winter for a few years so now that’s not happening. I suspect if we get a decent cooling trend that will be the fault of CO2 as well.

Orson Olson
September 14, 2019 6:50 am

John- ever since the Hockey Stick fiasco from twenty years ago, I have closely followed the science news about climate. Mr admittedly selective retrospective is that us amounts to the hunt for New (and BETTER!) Hockey Stick’s to promote and…”justify” alarm. As we so often see, the above paper is geared to correct one of at least three New (Improved@) Hockey Sticks currently circulating in the media.

Is anyone else here similarly unsurprised? (WARNING: the generation of skeptics and qualified senior scientists doing this important corrective labor is aging. Who will replace them?)

It burns
Reply to  Orson Olson
September 14, 2019 7:38 am

Take a look at Ben Davidson and his work over at Suspicious Observers.

Steven Mosher
Reply to  Orson Olson
September 14, 2019 8:31 am

Nobody will replace them.

1. They publish very little for others to BUILD UPON
2. They don’t teach.
3. With RARE exceptions they only do “negative” work.. see the above for an example. While
hundreds of papers get published showing the effects of climate change, the best they can do is
find a few weak papers to attack. Like the HS.. side show material.

Joel O’Bryan
Reply to  Steven Mosher
September 14, 2019 9:22 am

Every scam, hustle, and con job runs its course. Every. One.

The Gen Z’ers are learning not to trust anything on the internet or news.
They see “Fake News” everywhere in their social circles, social news.

They are growing up knowing that not just is Climate Change is a scam, but the socialism efforts around it. It’ll drive the Climate Scammers crazy(-er) pushing them to ever more ridiculous claims till they all collapse under the weight of their own dishonesty.

Steve Rowland
Reply to  Joel O’Bryan
September 14, 2019 10:12 am

I hope you are correct

Michael Jankowski
Reply to  Steven Mosher
September 14, 2019 9:30 am

It’s tough to “BUILD UPON” publications which show there’s nothing to be alarmed about or no link to GHGs. Do you think the USGS, NOAA, etc, are going to fund more studies to find the same thing?

Gary Pearse
Reply to  Steven Mosher
September 14, 2019 9:34 am

Moshe1&2- yes gatekeeping and dismissal/ threats of it, career stagnation , starving for grants,… has been a very effective way to keep the otherside marginalized. And #3? Phil Jones had the best commentary on why he didnt surrender data to sceptics! Funny how you can be absolutely correct but so wrong. Let them eat cake!

Kevin kilty
Reply to  Steven Mosher
September 14, 2019 9:35 am

I am not sure how to characterize this comment as other than a narrow view with a sweeping conclusion.

Your first point seems subjective to me. Do you have a point of reference? Do you have an objective measure?

Is teaching important to objective testing either side of the GCC (global climate change) debate. Or is teaching more like a way to gather disciples? Is gathering disciples a positive or negative thing? Might it be propaganda?

And is there anything wrong with negative work? Doesn’t negative work clean up error, just as engineering disasters and accidents are a means of learning? Success sometimes comes without any understanding of why something worked.

Let me summarize a brief story that serves as an argument against just about every statement you made. In the early 1970s there was a mania called “Palmdale Bulge”. R.O. Castle had gathered first-order leveling data and concluded that southern California was bulging upward ominously. What followed was research growth, papers published, research monies flowing here and there, hand wringing in the media–lots of work to build upon, and all of it “positive”.

At some point in the early 1980s someone did a careful analysis of the stack-up error in the first order leveling and determined that all of the unexplained, but non-credible features of the bulge could be attributed to a systematic bias from the way surveyors worked at the time. The whole Palmdale Bulge mania now began to deflate with nary a mention of it at all in the geological literature after 1987 (a book was published recently that included the topic by someone who failed to even mention that I had provided her with all of my notes on the topic).

Positive work to build upon in this instance just perpetuated the mania inflation, there was no “teaching” component involved at all, and negative work put an end to the mania and its associated waste of resources.

Ron Long
Reply to  Steven Mosher
September 14, 2019 10:02 am

Steven Mosher, I am personally very offended by your derogatory remarks re ageing scientists. I am 73 and still very active in mineral exploration and am a regular contributor to local geological causes, for instance, interpreting the paleo-environment of dinosaur foot prints in Malargüe. I consider myself a mentor to younger geologists and have given several classes to them (in exchange for great barbecues), which classes include diatremes, structure interpretation, use of supervised classified imagery, etc. So, you have my sincerest invitation to… SNIP! There I snipped myself to spare ctm the trauma of it, so fill in the missing words as you see fit.

Gary Pearse
Reply to  Ron Long
September 14, 2019 1:30 pm

Ron, good on you. I’m still an active geologist and mining engineering consultant at 81 with recent hydrometallurgical processing patents for rare metals. I’ve come to know quite a few old geologists and engineers still at it. Why would someone in good health want to retire from this wonderful career?

Reply to  Steven Mosher
September 14, 2019 12:04 pm

So what are you doing about it Mosher? Other than p*ssing on the people who do?

Incidentally, do you think publishing and teaching a counter narrative is easy? Just go and do it? What’s happened to the careers of Tim Ball, Judith Curry, and Peter Ridd? Did they not do the exact things that you insist need to be done? And where are they now?

Reply to  davidmhoffer
September 14, 2019 12:13 pm

Forgot Roger Pielke in that list. There’s many others of course. Remember Robert G Brown who was a regular here and then inexplicably stopped writing and commenting?

There’s a price to be paid for publishing and teaching and doing positive work. Not many ever get into a position to be able to do it, and when they do….

So lend a hand instead of p*ssing on the few people who are at least doing something.

Reply to  davidmhoffer
September 14, 2019 8:01 pm

Willie Soon as well?

J Mac
Reply to  Steven Mosher
September 14, 2019 12:06 pm

Mosher’s response is metaphorical ‘distress quacking’ as another Climate Canard takes an analytical bullet through the gizzard. RIP Climate Canards!

Reply to  Steven Mosher
September 14, 2019 1:04 pm

I’m with Steven on this.

If it isn’t “showing the effects of climate change” it can’t be “climate science”.

Reply to  Steven Mosher
September 14, 2019 5:42 pm

“hundreds of papers get published showing the effects of climate change”

No they don’t. First off, the entire premise is bogus, because the term “climate change” itself, used in this context is bogus, and is a leftist/phony scientist (i.e. you) parrot meme.

Second, show a paper where the effects of “climate change” (your bogus “climate change” that is -global effects of atmospheric CO2 going from 280ppm to 400ppm) are verified by true scientific methods. The number is zero, not hundreds.

Crispin in Waterloo
Reply to  Steven Mosher
September 15, 2019 3:35 am

Steve M

It only do I do original work and publish it, I also am a follower, an implementer, of the admonition to “refute what is false and vain”.

I feel we have an obligation to do both. This year I have three publications on progress and none on refutation of BS. However, works are in progress.

A WHO committee came up with a model of PM exposure that is supposedly giving useful information on the number of premature deaths related to indoor air quality. It has more BS calculation and estimation in it than a Chinese biogas digester.

I was talking to a UC faculty member (UC is behind this foolishness) about it this week and he commented negatively on the Category 5 BS that finds its way into public health policy documents. Sometimes, with our pens, we have to “stay the hand of the oppressor”. Sometimes knowledge, volition and action leads to refutation alone.

The paper referenced in the article above is an example of refuting what is false and vain, plus a correct analysis of what is demonstrably true and trustworthy. It is representative of the academic ideal.

I hope this work by my neighbour McKitrick and friends is the new normal.

Reply to  Steven Mosher
September 15, 2019 1:04 pm

Steven Mosher:
A lot responses. People feel strongly about you. US regional precipitation. I guess if there are records for another region that are sufficient, then their paper can be followed and applied to that.

Now let’s you and I place a value on those hundreds of papers you mentioned. It could be negative. Let’s say 80% of the hundreds of papers are right. What do we get for that? It’s a contender for the most worthless large body of scientific work done. The solar panel and wind turbine response doesn’t provide net value. Can you name one thing that hasn’t been done that we need to know and are going to know in the next ten years from these people that will have any value? They’ve fired their gun, they have no more rounds left. So climate scientists that are not these two authors are the king. The king of what?

Keep up the good work. We don’t WUWT to go out of business.

Earl Jantzi
September 14, 2019 7:07 am

What are you doing using FACTS in this debate? Don’t you know that “feelings” are more important than facts?

IPCC official, Ottmar Edenhofer, speaking in November 2010: “But one must say clearly that we redistribute, de facto, the world’s wealth by climate policy. … one has to free oneself from the illusion that international climate policy is environmental policy. Instead, climate change policy is about how we redistribute, de facto, the world’s wealth…” “This has almost nothing to do with environmental policy, anymore.”
From Der Spiegel

Reply to  Earl Jantzi
September 14, 2019 7:43 am

Subject: “Using The False Climate Change Scare To Redistribute The World’s Wealth”

Earl J wrote:

“IPCC official, Ottmar Edenhofer, speaking in November 2010: “But one must say clearly that we redistribute, de facto, the world’s wealth by climate policy. … one has to free oneself from the illusion that international climate policy is environmental policy. Instead, climate change policy is about how we redistribute, de facto, the world’s wealth…” “This has almost nothing to do with environmental policy, anymore.”
From Der Spiegel”

There are many other such quotations from the current “brain trust” of scoundrels and imbeciles, some of which are located at http://green-agenda.com – for example:

”No matter if the science of global warming is all phony… climate change provides the greatest opportunity to bring about justice and equality in the world.”
Christine Stewart, former Canadian Minister of the Environment

Here is the problem:

1. These statements are just virtue-signalling – the scoundrels who say these statements have much darker and more selfish objectives.

2. The poverty-stricken societies that we are supposed to bail out by sharing our wealth are thousands of years older than our North American societies, and they should be much richer that we are. Why are they so poor? Because they are extremely dysfunctional and corrupt. We could give them ALL our wealth and they would squander it in a few decades and be poor again.

3. The covert objective of many of these scoundrels is to form a totalitarian society with themselves as de-facto kings – absolute rulers looking down on all their peasants. What they really lust after is power and control – and they are so imbecilic that they actually think they are much more intelligent than the rest of us.


”My three goals would be to reduce human population to about 100 million worldwide, destroy the industrial infrastructure and see wilderness, with its full complement of species, returning throughout the world.”
David Foreman, co-founder of Earth First!

”A total population of 250-300 million people, a 95% decline from present levels, would be ideal.”
Ted Turner, Founder of CNN and major UN donor

”The prospect of cheap fusion energy is the worst thing that could happen to the planet.”
Jeremy Rifkin, Greenhouse Crisis Foundation

”Giving society cheap, abundant energy would be the equivalent of giving an idiot child a machine gun.”
Paul Ehrlich, Professor of Population Studies, Author: “Population Bomb”, “Ecoscience”

”The big threat to the planet is people: there are too many, doing too well economically and burning too much oil.”
Sir James Lovelock, BBC Interview

”We need to get some broad based support, to capture the public’s imagination… So we have to offer up scary scenarios, make simplified, dramatic statements and make little mention of any doubts… Each of us has to decide what the right balance is between being effective and being honest.”
Stephen Schneider, Stanford Professor of Climatology, Lead author of many IPCC reports

”Unless we announce disasters no one will listen.”
Sir John Houghton, First chairman of the IPCC

”It doesn’t matter what is true, it only matters what people believe is true.”
Paul Watson, Co-founder of Greenpeace

”Childbearing should be a punishable crime against society, unless the parents hold a government license. All potential parents should be required to use contraceptive chemicals, the government issuing antidotes to citizens chosen for childbearing.”
David Brower, First Executive Director of the Sierra Club

”We’ve got to ride this global warming issue. Even if the theory of global warming is wrong, we will be doing the right thing in terms of economic and environmental policy.”
Timothy Wirth, President of the UN Foundation

”No matter if the science of global warming is all phony… climate change provides the greatest opportunity to bring about justice and equality in the world.”
Christine Stewart, former Canadian Minister of the Environment

”The only way to get our society to truly change is to frighten people with the possibility of a catastrophe.”
Emeritus Professor Daniel Botkin

”Isn’t the only hope for the planet that the industrialized civilizations collapse? Isn’t it our responsibility to bring that about?”
Maurice Strong, Founder of the UN Environmental Program

”A massive campaign must be launched to de-develop the United States. De-Development means bringing our economic system into line with the realities of ecology and the world resource situation.”
Paul Ehrlich, Professor of Population Studies, Author: “Population Bomb”, “Ecoscience”

”If I were reincarnated I would wish to return to earth as a killer virus to lower human population levels.”
Prince Phillip, Duke of Edinburgh, husband of Queen Elizabeth II, Patron of the Patron of the World Wildlife Foundation

”The only hope for the world is to make sure there is not another United States. We can’t let other countries have the same number of cars, the amount of industrialization we have in the US. We have to stop these third World countries right where they are.”
Michael Oppenheimer, Environmental Defense Fund

”Global Sustainability requires the deliberate quest of poverty, reduced resource consumption and set levels of mortality control.”
Professor Maurice King.

”Current lifestyles and consumption patterns of the affluent middle class – involving high meat intake, use of fossil fuels, appliances, air-conditioning, and suburban housing – are not sustainable.”
Maurice Strong, Rio Earth Summit

”Complex technology of any sort is an assault on the human dignity. It would be little short of disastrous for us to discover a source of clean, cheap, abundant energy, because of what we might do with it.”
Amory Lovins, Rocky Mountain Institute

”I suspect that eradicating small pox was wrong. it played an important part in balancing ecosystems.”
John Davis, Editor of Earth First! Journal


September 14, 2019 7:09 am


So much evidence… …so little time.

Rivers in Western Canada (the Athabasca, the North Saskatchewan, etc.) exhibit a cyclical flow – as I recall, warmer is dryer (lower river flow).

Pacific salmon runs are (again from memory) much stronger in cooler weather, and decline sharply in warm periods. We recently had a near-record salmon run, after decades of decline.

Evidence from many sources seems to be building, to indicate we are entering a global cooling period – we’ll see.

I just don’t have the time to chase this data any more. Regrettably, those that are funded to do so seem to be programmed to fabricate evidence of global warming, even though there has been no global warming for 10-15 years!

If these warmist scoundrels and imbeciles would just look at the evidence all around them and get rid of their programmed CAGW (Church of Al Gore, Warmist) religious dogma, they might even write some worthwhile scientific papers…

Mind you, they’d have to leave the Church of Gore and the House of Hansen, and all the financial and social benefits of being on the cutting edge of BS.

September 14, 2019 7:17 am

The above post from 2012 is located at this address – the previous address is now obsolete.


September 14, 2019 8:04 am

Allan, Re: your observations on certain actors fabricating evidence with religious fervour, it seems Petteri Taalas concurs. See: https://m.theepochtimes.com/in-unprecedented-move-head-of-key-meteorological-organization-slams-climate-extremists_3076409.html

September 14, 2019 7:28 am

Couple of years ago I made LA & SF precipitations graphs
Can’t trace the SF graph since I’m away from home.

Reply to  vukcevic
September 14, 2019 1:09 pm
September 14, 2019 7:57 am

A large literature has shown that trend estimation in hydrological series may be affected by long-term persistence (LTP) and selection of sample length. – emphasis mine.

Now that’s the typical issue with the statistical “science” of everything CAGW now isn’t it? The carefully curated selection of ‘time length’ considered to be a mythical baseline of “normal”. The (self anointed) Drought Monitor is the worst offender, what with their bright RED “drought” maps.

Ron Long
September 14, 2019 8:03 am

Good report, Ross and John. Your comment “within the range of long-term natural fluctuations.” is the comment also commonly made by geologists, with respect to sea-level markers through geologic time. I was living in Reno, Nevada when there was a significant drought and, imagine the horror, docks at Lake Tahoe were left stranded on land. This prompted a submersible examination of the depths of Lake Tahoe and produced photos of Indian stone rings (used to support curved branches forming a shelter) about 90 feet below current lake level. One of the Long Term Droughts around a thousand years ago? Sobering realization!

September 14, 2019 8:08 am

Funny how things cycle back and forth.. like there are some feedback processes in play. Imagine that.

Right now the Southern Hemisphere is cooling and since it is mostly water, that’s no doubt a pretty big deal. Cooler water means less water vapor (vapour) which typically means less rain and fewer clouds. After this winter, it will be very interesting how the Northern Hemisphere looks next April as the tropical Pacific doesn’t have all that warm water available to send to the mid and upper latitudes in the Pacific.

With a solar minimum the photons from the Sun hitting us have a different energy profile than during a more active Sun and if we get a volcano or two going off big time, we could be in a big hurt temperature wise. Might have to start eating all that corn we use to power our cars.

Bruce Cobb
September 14, 2019 9:14 am

Claims made by the NCA4 and previous versions are all Alarmist claptrap, produced by bureaucrats. This is a part of the swamp that may never get drained, even during a 2nd Trump term. Deeply-entrenched, they are.

Harry Lins
September 14, 2019 9:18 am

Imagine how different the entire discourse on hydro-climatic trends would have been over the past three decades had only researchers understood and acknowledged that natural systems exhibit long-term persistence. Had they recognized this fact, they would have used techniques wherein the null hypothesis assumed ‘change’ rather than ‘no change.’ Unfortunately, most investigators continue to use white noise models in estimating trend significance, so it is especially encouraging to see that Ross and John have taken a more precise approach.

Gary Pearse
September 14, 2019 9:22 am

As a geologist, extracting meaningful trends from data on earth systems requires 1) suitably long time horizons and 2) a magnitude of change that sticks up out of the noise.

For example, evidence that the earth had its highest temperatures of the Holocene during the suitably named Climate Optimum (CO) is strengthened by the fact that the proxy data is necessarily a multi-hundred year smoothing and multi-decadal, notably warmer periods undoubtedly are lost in this smoothing. It can also be reliably stated that the earlier Eemian interglacial was even warmer than the Holocene. The modern instrumental period is therefore barely a single data point.Rainfall/flood/drought data is of the same kind.

Recorded history and geological data supports much of suitable proxy data. For example we understand the significance of large tree stumps in the Russian and North American barrenlands or the same above the present treeline in mountain ranges or appearing from beneath receding mountain glaciers. We understand the significance of the historical record of George Washington’s troops spiriting cannons away from British held Manhattan by rolling them over ice to New Jersey, or New Yorkers walking across the ice to Staten Island in the early 19th Century or Vikings growing grain and raising sheep in Greenland, or having a wine industry in Scotland in Medieval times.

September 14, 2019 9:50 am

Coming droughts at the higher latitudes are addressed in my latest updated report.
Click on my name to read it.

Bob Weber
September 14, 2019 10:58 am

I very much enjoyed reading the pre-print discussion of the general long-term persistence conundrum, and their views on trends.

The paper is timely for me as less than 3 weeks ago I put together an overview of solar-forced climate change using US precipitation and wet/dry extremes data from 1901. When the US precip anomaly is detrended, as it was for that image, the real positive trend re-emerges that corresponds to the wet/dry and PDSI data extremes.

If their paper had included a third section on the entire US data, they might’ve had a stronger conclusion on the overall trend since 1901.

The long-term persistence they mention I think is due to the duration and magnitude of either of two states of solar activity, a long term low activity regime or a long-term high activity epoch with solar cycle dependence. The worst drought peaked the early 1930s in the solar minimum after five lowish activity cycles, whereas the highest precipitation wet years peaked after strong solar cycle 21-23, decades after the anomaly average had turned positive after the dust bowl years, after the 1935 start of the solar modern maximum, a period of higher solar energy that drove higher Nino 3 & 4 temps, higher SST, and higher CO2.

AGW is impossible as Mauna Loa CO2 is mostly all from CO2 outgassed from the sun-powered tropical regions Nino 3 and 4. Nino4 outgasses year-round. If those areas ever fall by 4C, all ocean CO2 outgassing will cease.

September 14, 2019 12:16 pm

By chance I’ve been looking at the Palmer Drought Severity Index (PDSI) and the Palmer Modified Drought Severity Index (PMDI) lately. I’ve used data from the NOAA CLIMDIV

Mssrs. Christy and McKitrick are correct that Palmer drought have high Hurst exponents. I have found the same in the CLIMDIV data. The CLIMDIV data for the PMDI is monthly from 1895, with 1495 monthly records (often expressed as N = 1495). The Hurst exponent of that CLIMDIV PMDI data is 0.86.

However, when adjusted for autocorrelation the effective N for that dataset is not 1495. Instead, the effective N is equal to 8. And with only 8 independent data points, statistical significance is … well … elusive.

The problem is that as an article in Nature magazine was headlined, “Nature Is Naturally Trendy”. Any dataset with a high Hurst exponent will naturally have many more trends than we’d expect from independent random data. And many climate datasets, including temperature and sea level datasets, have high Hurst exponents.

I’ve been beating this drum for a while. In 2015 I wrote a post called “A Way To Calculate Effective N” in which I discussed and experimentally verified the effect of high Hurst exponents on the statistics of things like the Nilometer data. Let me shamelessly recommend that post as an overview of the subject and the size of the effect of high Hurst exponents on statistical significance.

My thanks to the authors for highlighting what I see as a very important and frequently overlooked issue in the statistics of climate. It’s a hard nettle to grasp because it shows that many claimed trends, when adjusted for autocorrelation, are not even approaching statistical significance.


Bob Weber
Reply to  Willis Eschenbach
September 15, 2019 6:58 am

Any dataset with a high Hurst exponent will naturally have many more trends than we’d expect from independent random data.

It seems a high Hurst exponent is a significant indication of many short-term trends and changes. The short-term state changes often to a different state with a new short-term trend and offset. The US precipitation data has those features. The precipitation data looks to me to be responding to both short-term and accumulated influence from somewhat auto-correlated solar forcing.

Reducing N because of auto-correlation ignores important information for understanding the short-term trend changes and drivers. Perhaps there are limitations to the application of auto-correlation and Hurst exponents.

A high Hurst exponent seems to say ‘the droughts/rains persisted because they persisted’, ie self-dependent. What sense is that? In other words, ‘it’s raining because it’s been raining’. What can be learned from this? What makes it start or stop raining should be the question. How does Hurst answer that?

There’s gotta be a better way.

Ulric Lyons
September 14, 2019 1:10 pm

“Over the 1901–2017 interval upward trends in some measures of average and extreme precipitation appear, but they are not consistently significant and in the full records back to 1872 they largely disappear. They also disappear or reverse in the post-1978 portion of the data set, which is inconsistent with them being responses to enhanced greenhouse gas forcing.”

In other words there is no long term trend in rainfall despite the globe apparently warming, whatever caused the said warming. The same for the UK.

Jim Sternhell
September 14, 2019 5:21 pm

http://sydney.edu.au/environment-institute/publications/recording-adapting-climate-science-business/ Go to 1 hour and 11 minutes for Professor Andy Pitman’s response to a question. I almost fell off my chair on the night scrambling for my note pad. Very revealing.
For those who want the transcript-
I’ll answer the first bit and this may not be what you expect to hear, but as far as the climate scientists know, there is no link between climate change and drought. Now that may not be what you read in the newspapers and sometimes hear commented, but there is no reason a priori why climate change should make the landscape more arid and if you look at the bureau of meteorology data over the whole of the last 100 years there’s no trend in the data, there’s no trend. There’s been a drying trend in the last 20 years but there’s been no drying trend in the last 100 years and that’s just an expression of how variable the Australian rainfall climate is. There are in some regions and there are not in other regions. So the fundamental problem we have is we don’t know what causes droughts and much more interesting we don’t know what stops the drought. Well, we know its rain but we don’t know what lines up to create drought breaking rains and that’s an area of very active research.

Feel free to send my transcript around and share the podcast link. The transcript was done for Lord Monckton, so the work might as well be spread far and wide. Lucky for me that Andy Pitman has a very pleasant voice. Did you note how the key points of interest to us climate realists were repeated. On the night, it was a relaxed response- no accidental slip of the tongue. I was tossing up whether to ask the question- if the media are misrepresenting the science, isn’t it your duty to the purity of science to do what ever you can to expose these misconceptions and unnecessary angst created in society? or to not compromise the podcast landing on the internet and remain silent. I decided to remain silent and leave it to my political contacts to expose climate scientists and ridicule the left of centre politicians in the Australian Parliament .

Reply to  Jim Sternhell
September 14, 2019 6:02 pm

” but as far as the climate scientists know, there is no link between climate change and drought”

In statements such as this, at least on here, it would be wise to differentiate between bogus “climate change” and real climate change. I doubt that there is no demonstrable link between real climate change and drought.

Why do we keep using the media, and fraudulent F-grade scientist parrot meme “climate change” as if it isn’t bogus? Actual climate change is a real phenomenon.

September 14, 2019 6:11 pm

“For the vast majority of mankind accept approaches as though they were reality, and are more influenced by those things that seem, than by those things that are.” ~ Machiavelli , The Prince

As McKitrick & Christy (2019) clearly shows, there is no empirical evidence supporting CAGW’s hypothesis that rising CO2 levels have had any significant affect on precipitation trends in the US.

Moreover, even IPCC’s AR5 Report admits, there is no empirical evidence supporting the hypothesis that rising CO2 levels have had any statistically significant affects on global trends for: hurricanes, typhoons, cyclones, tornadoes, droughts, floods, precipitation, thunderstorms, tropical storms, sub-tropical storms and hail…

The empirical evidence also show we’ve enjoyed about 0.85C of total beneficial global warming (of which CO2 has only contributed about 0.3C~0.4C of the total) since the end of the Little Ice Age in 1850, and that higher CO2 levels have increased crop yields and made plants more drought resistant, which have also been a huge boon for humanity: longer growing seasons, less frost loss, less severe winters, earlier springs, lower food prices, less land area required for agriculture, increased arable land area in Northern latitudes, and a vast increase in global greening (equivalent to twice the land area of the lower US 48 states).

The CAGW hypothesis is dead.

Historians will be flabbergasted the CAGW hypothesis lasted as long as it did, and will blame Leftists’ massive CAGW propaganda campaign for deluding their citizens into believing this hoax as a means to steal $trillions, destroy capitalism and gain power and control over the economy and their citizens…

Reply to  SAMURAI
September 14, 2019 9:01 pm

Mod: On the quote, I meant to write “accept appearances as though…”

September 14, 2019 10:40 pm

Eastern Australia is at present experiencing a severe drought that is promoted in the media (once again) as being “the worst ever”. I have made a comparison of historical drought rainfalls at Wellington, NSW where rainfall data are available since 1881. The analysis shows that droughts of similar severity to the present drought have occurred every 10-15 years for various durations from 6 months to 5 years. Furthermore there is no trend towards more frequent or more severe droughts in recent years. A better description of the present drought is perhaps “the worst in memory” on the basis that most of us often have relatively poor memory of severe events in our past; especially if we are only indirectly affected by the events. https://briangunterblog.wordpress.com/2019/09/13/wellington-nsw-drought-rainfall/

September 14, 2019 10:57 pm

Another site that may be of interest. I have plotted up annual rainfalls at 200 long-term stations, worldwide, and found very few examples of long-term increases or decreases in rainfall. https://briangunterblog.wordpress.com/2018/10/22/worldwide-200-rainfall-trends/

September 15, 2019 7:04 am

For those of you who like to puzzle, here is an interesting graph:


It shows that the global trend of warming (hadcrut4gl) is almost entirely due to the warming in the NH.
Someone who also frequents WUWT, Jim Ross, has looked at the individual months, and it seems the cause of this strange trend is due entirely to more sunshine hours in the summer months.

Obviously, in its turn, that means that less clouds and rain is travelling to the higher NH latitudes.

Now why would that be?

(You can click on my name to read my report on the coming droughts on the higher latitudes)

September 15, 2019 7:25 am

Hi Brian

Indeed. Your findings (= no change) make sense but it also has to do with the time period that you chose.
By accident you chose the correct period. Like I did here:

However, from Hale cycle to Hale cycle there is a slight difference, as you can see from my results.
In 2014, the clock was at a maximum – and indeed we had a couple of very dry years here since then- while it seemed to be hanging up in the air. However, there are signs that the pendulum has started swinging downward again meaning that the drought time here is almost over.
Unfortunately I am afraid for you guys in the NH the problems are just beginning.

But, hey, that is just my opinion!

Reply to  HenryP
September 16, 2019 2:43 pm

Oh, wonderful. Henry is back. You may know Henry, the guy who fits a quadratic curve to four and only four points and seems to consider the result as being a profound, insightful, and meaningful way to predict the future.

Pass …


Reply to  Willis Eschenbach
September 17, 2019 7:56 am

Hi Willis

You are always so clever and I admire you greatly but here I donot understand your argument. You only need 4 points to define a function and if the correlation is very high you can use that function, at least in between the points that are relevant.
As an example: when we do spectro-photometry we first measure the extinction / absorbance of a component X dissolved in Y over a range of wavelengths. We chose the wavelength that has the highest extinction and feed 4 solutions of a component X with 4 different concentrations to measure the absorbance. If we find a linear or logarithmic or quadratic with high correlation we will say: Bingo. And then we can analyse a solution with an unknown amount of component X dissolved in it….But the accuracy all depends on how high the correlation coefficient is and obviously we must stay within the boundaries of our chosen 4 concentrations of X in Y?

Anyway, going over my files, I found this interesting file:


If I do a hindcast here to the Hale cycle before the first reported Hale cycle (point 0 = ca. 1906-1926), I would have said: 1060 mm /year. The actual result was apparently 1100. I am out a little bit, – e.g. the error could be due to inaccuracy of measurement in the past –
but what you can clearly see is that the result of 1100 is not at all on the curve (going up) , which is exactly as I predicted. Namely, the water goes up and comes down, predictably, as if on the curve of the pendulum of a clock. The range of change per Hale episode is indeed very small.

But Willis, is not that what you have always said: that the difference in global T and rainfall are surprisingly small if we look at it over longer periods of time?

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