New skeptic publication in Nature Climate Change rebuts Åström et al. claims of increased deaths due to heat waves

Stockholm_observatory_weather_station1

Stockholm observatory weather station, source of the temperature record

Rebuttal to Åström et al. Attributing mortality from extreme temperatures to climate change in Stockholm, Sweden., published in Nature Climate Change by Paul C. “Chip” Knappenberger, Patrick J. Michaels, and Anthony Watts

Last fall, the press pounced on the results of a new study that found that global climate change was leading to an increasing frequency of heat waves and resulting in greater heat-related mortality. Finally a scientific study showing that global warming is killing us after all! See all you climate change optimists have been wrong all along, human-caused global warming is a threat to our health and welfare.

Not so fast.

Upon closer inspection, it turns out that the authors of that study—which examined heat-related mortality in Stockholm, Sweden—failed to include the impacts of adaptation in their analysis as well as the possibility that some of the temperature rise which has taken place in Stockholm is not from “global” climate change but rather local and regional processes not related to human greenhouse gas emissions.

What the researchers Daniel Oustin Åström and colleagues left out of their original analysis, we (Chip Knappenberger, Pat Michaels, and Anthony Watts) factored in. And when we did so, we arrived at the distinct possibility that global warming led to a reduction in the rate of heat-related mortality in Stockholm.

Our findings have just been published (paywalled) in the scientific journal Nature Climate Change as a Comment on the original Oustin Åström paper (which was published in the same journal).

We were immediately skeptical because the original Oustin Åström results run contrary to a solid body of scientific evidence (including our own) that shows that heat-related mortality and the population’s sensitivity to heat waves was been declining in major cities across America and Europe as people take adaptive measures to protect themselves from the rising heat.

Contrarily, Oudin Åström reported that as a result of an increase in the number of heat waves occurring in Stockholm, more people died from extreme heat during the latter portion of the 20th century than would have had the climate of Stockholm been similar to what it was in the early part of the 20th century—a time during which fewer heat waves were recorded. The implication was that global warming from increasing human greenhouse gas emissions was killing people from increased heat.

But the variability in the climate of Stockholm is a product of much more than human greenhouse gas emissions. Variations in the natural patterns of regional-scale atmospheric circulation, such as the Atlantic Multidecadal Oscillation (AMO), as well as local impacts associated with urbanization and environmental changes in the direct vicinity of the thermometer are reflected in the city’s temperature history, and the original Oudin Åström et al. publication did not take this into account. This effect is potentially significant as Stockholm is one of Europe’s fastest growing cities.

But regardless of the cause, rising temperatures spur adaptation. Expanded use of air conditioning, biophysical changes, behavior modification, and community awareness programs are all examples of actions which take place to make us better protected from the dangers associated with heat waves. Additionally, better medical practices, building practices, etc. have further reduced heat-related stress and mortality over the years.

The net result is that as result of the combination of all the adaptive measures that have taken place over the course of the 20th century in Stockholm, on average people currently die in heat waves at a rate four times less than they did during the beginning of the 20th century. The effect of adaptation overwhelms the effect of an increase in the number of heat waves.

In fact, it is not a stretch to say that much of the adaptation has likely occurred because of an increased frequency of heat waves. As heat waves become more common, the better adapted to them the population becomes.

Our analysis highlights one of the often overlooked intricacies of the human response to climate change—the fact that the response to a changing climate can actually improve public health and welfare.

Which, by the way, is a completely different view than the one taken by the current Administration.

References:

Knappenberger, P., Michaels, P., and A. Watts, 2014. Adaptation to extreme heat in Stockholm County, Sweden. Nature Climate Change, 4, 302-303.

Oudin Åström, D., Forsberg, B., Ebi, K. L. & Rocklöv, J., 2013. Attributing mortality from extreme temperatures to climate change in Stockholm, Sweden. Nature Climate Change, 3, 1050–1054.

The paper:

Adaptation to extreme heat in Stockholm County, Sweden

Online at: http://www.nature.com/nclimate/journal/v4/n5/full/nclimate2201.html

============================================================

Further detail by Anthony:

It should be noted that Nature Climate Change, which tends to be a fast track journal, took months to publish our correspondence, going through a longer than normal review process for such a short correspondence, and only did so along with a reply from Åström et al. Despite this uphill slog, we persevered.

Personally, I think the response from Åström et al. is ludicrous, especially this part:

“Our data indicate that there is no adaptation to heat extremes on a decadal basis or to the number of heat extremes occurring each year. “

Basically what they are saying is the people of Stockholm are too stupid to use an air conditioner or electric fan when it gets hot, and are incapable of any adaptation.

The other part of their response:

Our method of comparing the climate during two 30-year periods is valid for any two periods.

Well no, not really, and it is this flaw in their method that was a central point of our paper.

Variations in the natural patterns of regional-scale atmospheric circulation, such as the Atlantic multidecadal oscillation (AMO) as well as local impacts associated with urbanization and environmental changes in the direct vicinity of the thermometer are reflected in the city of Stockholm temperature history, and the original Åström et al. publication did not take this into account. By not looking at these factors, and by just taking the Stockholm temperature data at face value, assuming all of the heat extremes in it were “climate change” induced instead of being partially influenced by other effects, including the AMO and the city itself, allowed Åström et al. to become victims of their own confirmation bias.

For example, look at the GISTEMP record from Stockholm (which ends before 2000, not my fault). Note the 1900-1929 period.

Stockholm_data_GISTEMP

Åström et al. compared two periods of Stockholm temperature data: 1900–1929 and 1980–2009, and used them as the basis for their entire paper. Here is their method from the abstract posted on the NIH website:

Methods: We collected daily temperature data for the period 1900-2009 and daily mortality data for the period 1980–2009 in Stockholm, Sweden. The relationship between extreme temperatures and all-cause mortality was investigated through time series modelling, adjusting for time trends. Attribution of mortality to climate change was calculated using the relative risks and baseline mortality during 1980-2009 and the number of excess extreme temperature events occurring in the last 30 years as compared to our baseline period 1900-1929. Results: Mortality from heat extremes doubled due to warming associated with climate change. The number of deaths attributable to climate change over the last 30 years due to excess heat extremes in Stockholm was estimated to be 323 (95% CI: 184, 465) compared with a reduction of 82 (95% CI: 43, 122) lives saved due to fewer cold extremes.

Only one problem, a big one, note that right after 1929 there was a big shift in the AMO data – what happens to the AMO in 1930 is essentially a “sea change”.

Åström_et al._AMO

After 1930, the AMO was positive (warm phase) for over 30 years, went negative (cold phase) again around 1963-64, and stayed negative until a big uptick around 1998.

The AMO was primarily in its cold phase during the 1900–1929 period, and primarily in its warm phase during the 1980–2009 period — a difference likely to be responsible for some portion of the increase in extreme-heat events identified by Åström et al. and inappropriately attributed to global climate change. See Sutton and Dong 2012 for an explanation as to why the AMO affects the temperature record of Europe.

Then there were the changes/growth in the city itself, some movements and encroachments on the Stockholm observatory station, plus the fact that the mortality numbers they cited didn’t make sense when compared to other studies of trends in heat-related mortality across the United States and Europe which have reported declines in both total mortality and the sensitivity of urban populations to extreme heat,despite an increasing frequency of extreme-heat events.

Despite the long review, to the credit of Nature Climate Change, they recognized that we had a valid argument that mostly nullified the Åström et al. paper. Otherwise we’d never have gotten this published. Unfortunately, we can’t counter all the media hype from the original publication, but I hope readers will cite our rebuttal when appropriate.

Knappenberger_Michaels_Watts_Correspondence_original (PDF)

– Anthony

 

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does anybody know how can a global phenomenon be pinpointed to “Stockholm”, an area that is 0.0000376% of the world?

Anthony, why don’t you post the entire review correspondence. An example of such a correspondence is here http://www.leif.org/research/Review-History-1850.pdf and can be very illuminating.

Perseverance paid off! Congratulations. And book marked!

omnologos says:
April 30, 2014 at 7:06 am
does anybody know how can a global phenomenon be pinpointed to “Stockholm”, an area that is 0.0000376% of the world
Well, during the last global ice age [some 25,000 years ago] Stockholm’s pinpointed 0.0000376% of the world was under ~2 km of ice…

that doesn’t answer my question…what is the validity of the original paper, looking for climate change at the most local of levels?
during the last ice age ice wasn’t just in Stockholm…

Anthony Watts says:
April 30, 2014 at 7:11 am
@leif that decision is up to the corresponding author, Knappenberger
Then pass it by him…

Evan Jones

Note that surface station in the picture is a Class 4 for heat sink proximity (Leroy (2010). That would likely cause an spurious exaggeration in trend.

Leif,
The papers are paywalled at Nature Climate Change. I don’t have the option of posting them.
-Chip

Chip Knappenberger says:
April 30, 2014 at 7:24 am
The papers are paywalled at Nature Climate Change. I don’t have the option of posting them.
The papers, yes, but the referee’s reports and your response are not paywalled. And even if they were, people with access to the papers could read the correspondence as well and assess to what degree the objections reports were valid. Looking forward to your next excuse 🙂

omnologos says:
April 30, 2014 at 7:17 am
during the last ice age ice wasn’t just in Stockholm…
That is my point: Stockholm was fairly representative of the icy conditions over a large part of the globe, in spite of covering only 0.0003…%.

Jimbo

We have to send out an urgent government warming for the people of Stockholm to STOP getting onto planes and visiting countries on the equator. They also need to stop taking saunas.
If I lived in Stockholm and the weather got really hot I would open my triple glazed windows.

SWEDISH CHARTER BEGINS WEEKLY FLIGHTS TO MOMBASA
Kenya’s tourism sector is poised for a major boost as Novair begins weekly flights from Stockholm, Sweden to Mombasa starting 1st Dec 2011.
http://www.magicalkenya.com/index.php?option=com_content&task=view&id=1067&Itemid=290

——

Who, What, Why: How hot can a sauna safely get?
…….The society recommends that people with health complaints such as heart disease, high blood pressure, asthma or skin disease stick to “moderate” temperatures of below 90C, while pregnant women should keep the heat below 70C.
http://www.bbc.co.uk/news/magazine-10912578

Leif,
The reviews are confidential, according to an agreement I signed.
-Chip

Chip Knappenberger says:
April 30, 2014 at 7:40 am
The reviews are confidential, according to an agreement I signed.
I have submitted scores of papers and never had to sign anything….
so why you?

Congratulations Anthony.
I had a look at the authors’ reply (before reading what you have written here), and the claim that “there is no adaptation to heat extremes” jumped out at me as being a rather absurd statement.

Sleepalot

“For example, look at the GISTEMP record from Stockholm …”
I’d like to, but you didn’t provide a link. Is it this?
http://data.giss.nasa.gov/tmp/gistemp/STATIONS/tmp_645024640000_14_0/station.txt

Jimbo

Let’s not forget our old friend UHI in all this.

Abstract
Near surface climate in an urban vegetated park and its surroundings
‘Near surface climate was observed through temperature profiling from the surface to 2.47 m height in an urban vegetated park and its surroundings in central Stockholm, Sweden. Measurements were conducted during three summer days by mobile traverses. Air temperature differences between the built-up area and the park were in the range of 0.5–0.8 °C during the day and reached a maximum of 2 °C at sunset. The thermal stratification of the air was mainly stable in the park and unstable in the built-up area. Inverse air temperature profiles in the park were less stable in open than in shady areas, and close to neutral at midday. The most unstable air was found in the north–south orientated canyons in the early afternoon. Possible heat advection from the surroundings, and thus uncoupling between the surface and the air, was identified through temperature gradients pointing at different directions within the 2.47 m profile. Examples at midday indicated that warm air advected as far as 150 m into the park.
http://link.springer.com/article/10.1007/s00704-006-0259-z
————–
Abstract
Road Climate in Cities:A Study of the Stockholm Area, South-East Sweden
…..The results of this study show that it is important to consider the climatological effect that is generated by large city areas when dealing with road climatology. The urban heat island has a marked impact on the air and road surface temperatures. This effect can be calculated essentially as a function of the distance from the city centre. This is especially true for air temperature but less so for road surface temperature.
…..
http://onlinelibrary.wiley.com/doi/10.1017/S1350482701004091/pdf

HomeBrewer

Would be great if someone could extend the “GISTEMP record from Stockholm” graph to current date, living in Sweden I got a feeling that there’s a small decline hiding.

Dave Yaussy

Leif, am I missing something? What are you suggesting that Chip is hiding?

John McClure

I wonder when they added the driveway next to the Stevenson screen.
This can’t be right, max temperature appears to be 24C (75.2F) during these heat waves? What was the max temp during the heat waves?
250 Years of Weather Observations at the Stockholm Observatory
http://www.smhi.se/polopoly_fs/1.17736!webbNr27_eng_ver.pdf

Jimbo

In 1977 strict new standards came into force in Sweden and almost all new homes have triple glazing. If you are elderly or infirm please don’t forget to open your windows during a heatwave.
http://www.homebuilding.co.uk/advice/key-choices/green/triple-glazing

Dave Yaussy says:
April 30, 2014 at 7:51 am
Leif, am I missing something? What are you suggesting that Chip is hiding
I’m not suggesting he is hiding anything. It would be of great interest to see the objections that the reviewers had and how the authors countered them. If reviews were published along side with the paper we might get better reviews and attempts of the ‘establishment’ to block or delay worthy papers that do not follow the party line would be severely hampered. What is not to like about this?

Dave Yaussy

OK, now I understand. Thanks.

Jeff Alberts

that shows that heat-related mortality and the population’s sensitivity to heat waves was been declining in major cities across America and Europe as people take adaptive measures to protect themselves from the rising heat.

What rising heat??

John McClure

Unless I’m missing something, you don’t even need AC at these “heat wave” highs. Its in the 70s F.
The elderly in the danger zone
“The researchers defined a heat wave in Stockholm as a period of over two days with an average 24-hour temperature exceeding 19.6° C.”

Old England

It hadn’t particularly struck me before that UHI becomes ‘self sustaining’ and results in its own growth, But of course the more people fit air conditioning then the more hot air is expelled from buildings raising temperatures locally within the city …. and so climate scientists blame global warming and more people fit air conditioning raising local temperatures within the city …. etc etc etc

John McClure

Sorry, here’s the source for the quote in my last comment:
http://sciencenordic.com/heat-waves-take-toll-stockholm

Chuck Nolan

lsvalgaard says:
April 30, 2014 at 7:14 am
omnologos says:
April 30, 2014 at 7:06 am
does anybody know how can a global phenomenon be pinpointed to “Stockholm”, an area that is 0.0000376% of the world
Well, during the last global ice age [some 25,000 years ago] Stockholm’s pinpointed 0.0000376% of the world was under ~2 km of ice…
———————————
People are there…the ice is gone…
Ah ha…proof of cagw.
cn

Leif,
I appreciate that the reviews and reviewer comments are potentially important/interesting pieces of information (see here for example, http://www.worldclimatereport.com/index.php/2011/05/02/attempts-to-box-us-out/)
How do you interpret the “confidentiality” portion of Nature’s publication policies:
http://www.nature.com/authors/policies/confidentiality.html
-Chip

Chip Knappenberger says:
April 30, 2014 at 8:13 am
How do you interpret the “confidentiality” portion of Nature’s publication policies
As I read it, they apply to all material during the review period. After the paper is published I don’t see any continued confidentially is stipulated.

Walt The Physicist

@ lsvalgaard says:
April 30, 2014 at 8:01 am
Totally agree with Leif Svalgaard. Making the reviews accessible to public is a first step that is badly needed to counter recent hijacking of sciences by incompetent or politically motivated people. Not limited to climate sciences… State of physics is similar… Never encounter restrictions on publishing the reviewer’s comments either.

Greg

What stands out in the temperature graph is the drop in annual mean temperature during the war years. Twelve degrees colder _on average_.

Marlo Lewis

Congrats Chip, Pat, and Anthony. I’m hoping you will clarify a few points for me.
(1) If no adaptation had occurred between the 1900-1929 and 1980-2009 periods, then there would have been 2,993 heat-related deaths in the latter period instead of 689. Correct?
(2) What was the aggregate heat-related death toll during the 1900-1929 period? According to Åström et al., the aggregate death toll in 1980-2009 was 689, of which they attribute 288 to global warming. So my simple arithmetic suggests the death toll in the “baseline” period was 401. Is that correct?
(3) How much bigger is Stockholm’s population in 1980-2009 than in 1900-1929? Presumably if we adjust for population, 401 heat-related deaths in 1900-1929 is a much higher mortality rate than 689 heat-related deaths in 1980-2009. Is that the basis for your statement that the current heat-related mortality rate is four times lower than the rate at the start of the 20th century?

Leif – it appears obvious that Stockholm represented a fairly bigger areas when it and the surroundings were covered by ice.
the same is not obvious now and ought have been demonstrated in the original paper – just like too short a time tells weather from climate, too small an area does the same.
with regional models useless for the foreseeable future, city studies sound risible wrt global warming

John Boles

Killer heat waves in Sweden? Hard to imagine…

omnologos says:
April 30, 2014 at 8:25 am
the same is not obvious now and ought have been demonstrated in the original paper –
Then the rebuttal is also not valid generally and may only be relevant for the 0.000376% that is Stockholm. This is the obvious implication of your [perhaps] flippant comment. I would, as is clear, disagree with that harsh conclusion and suggest that the rebuttal has wider implications and is valid not just for Stockholm.

Eliza

“as people take adaptive measures to protect themselves from the rising heat” debunked already there is no rising heat….
http://images.remss.com/msu/msu_time_series.html
Dismiss the trend line its not valid. Its a curve and it ain’t going up LOL..

UAN

Curious what qualifies as a heat wave in Stockholm/Sweden? How hot does it get? Are we talking about 80 degrees F, 90F, 100+F? For a week or more at a time?

Mike Maguire

lsvalgaard says:
“Well, during the last global ice age [some 25,000 years ago] Stockholm’s pinpointed 0.0000376% of the world was under ~2 km of ice…”
“That is my point: Stockholm was fairly representative of the icy conditions over a large part of the globe, in spite of covering only 0.0003…%.”
What 2 km of ice that accumulated over a period of what could be thousands of years tells us is something totally different than what comparing temperatures during 2 different 30 year periods at one location in the same century.

HomeBrewer

Jimbo
“In 1977 strict new standards came into force in Sweden and almost all new homes have triple glazing. If you are elderly or infirm please don’t forget to open your windows during a heatwave.”
It’s often better to keep the windows closed since our houses are well insulated.

UAN

To answer my own question, from the paper it says:
Heat extremes were defined as days warmer than
the 98th percentile of the 2-day moving average of daily mean
temperatures (lag0-1). The second percentile for cold corresponds
to temperatures below – 6:3 C and the 98th percentile for
heat corresponds to temperatures above 19.6 C.
So anything about 67 F is a heat wave?? Really?

Thank you!
It looks like a typo here with 64:
“After 1930, the AMO was positive (warm phase) for over 30 years, went negative (cold phase) again around 1964-64, and stayed negative until a big uptick around 1998.”

Mike Maguire says:
April 30, 2014 at 8:41 am
something totally different than what comparing temperatures during 2 different 30 year periods at one location in the same century.
See my reply to omnologos at 8:32

Alf

John–are you kidding? Many old people are cold at 19.6 C

RickA

lsvalgaard:
I would like to see the review process correspondence also. However, I have to agree with Chip that there is a requirement of confidentiality. Look at this portion of the page Chip linked to:
“After a manuscript is submitted, correspondence with the Nature journal, referees’ reports and other confidential material, whether or not the submission is eventually published, must not be posted on any website or otherwise publicised without prior permission from the editors.”
You need permission from the editors for anytime after the manuscript is submitted. I read “after” to cover even after publication.
Perhaps the Authors will request permission?

PMHinSC

Chip Knappenberger says:
April 30, 2014 at 8:13 am
“How do you interpret the ‘confidentiality’ portion of Nature’s publication policies…”
Shouldn’t the question be: how does Nature interpret Nature’s publication policies?

Alan Watt, Climate Denialist Level 7

I thought Swedes adapted to cold weather by taking off their clothes, working up a really good sweat in a sauna, and then running outside and rolling in the snow? If this works for them, then in hot summers they should put on warm coats, play a couple of rounds of curling in an especially frigid ice rink, then lay outside in the sun.
Has anyone studied excessive mortality in Stockholm from the wintertime sauna practice?
Actually I think Swedes take saunas in the summer as well. I don’t know whether this is because they like to be clean, like to sweat, or like to be naked. But if people are sweating [ha!] about the mortality effects of 0.8° C of global warming, then I would think EU would quickly move to ban saunas, assuming the national health ministry of Sweden doesn’t do it first.

Anthony
Coincidentally one of the first articles I wrote on Historic temperatures back in 2009 was a study of Stockholm.
Even more intriguing was that nearby Uppsala had a longer temperature record than Stockholm which showed the warmth of the 1730’s and put the modern period into its proper context
http://chiefio.wordpress.com/2009/10/09/how-long-is-a-long-temperature-history/
Included in the article is a study on the considerable effects of UHI in both cities. Not all the links now work but most do.
Phil Jones also noted the warmth in both the Swedish record and CET . Here is my comment quoting Phil jones that the 1730′s was the warmest decade until the 1990′s and that natural variability might be underestimated.
http://wattsupwiththat.com/2014/01/17/phil-jones-2012-video-talks-about-adjusting-sst-data-up-3-5c-after-wwii/#comment-1539164
‘UNUSUAL CLIMATE IN NORTHWEST EUROPE DURING THE PERIOD 1730 TO 1745 BASED ON INSTRUMENTAL AND DOCUMENTARY DATA’. Jones and Biffa. Revised version published 2006.
http://rd.springer.com/article/10.1007%2Fs10584-006-9078-6
tonyb

Michael Jankowski

19.6 is below “standard” temperature…some heat wave.

Jimbo

Stockholm at 0.0000376% of the world. Never again will a Warmist tell me that the USA is only a small part of the world – I will point them to this thread.

mpainter

Knappenburger: Publish the correspondence. Leif is right.

John McClure

Alf says:
April 30, 2014 at 8:47 am
John–are you kidding? Many old people are cold at 19.6 C
Exactly Alf,
I just found this on Found this on myweather2.com:
Home > Holiday Destinations > Sweden > Stockholm > Climate Profile
June and July are the 2 months for high temps.
excerpts:
June Temperature
Throughout the month of June daytime temperatures will generally reach highs of around 19°C that’s about 67°F. At night the average minimum temperature drops down to around 10°C, that’s 50°F.
In recent times the highest recorded temperature in June has been 30°C that’s 87°F, with the lowest recorded temperature 0°C, about 32°F.
July Temperature
Throughout the month of July daytime temperatures will generally reach highs of around 23°C that’s about 73°F. At night the average minimum temperature drops down to around 13°C, that’s 56°F.
In recent times the highest recorded temperature in July has been 41°C that’s 106°F, with the lowest recorded temperature 6°C, about 43°F.
Relative Humidity
The average daily relative humidity for June is around 63% and July 66%.
I guess the key question is the frequency. High 80s – 100+ F with over 60% humidity is a heat wave.

RickA says:
April 30, 2014 at 8:51 am
“After a manuscript is submitted, correspondence with the Nature journal, referees’ reports and other confidential material, whether or not the submission is eventually published, must not be posted on any website or otherwise publicized without prior permission from the editors.”
The paper itself is confidential until published and thus belongs in the same category as all the other material. After publication, the paper is clearly not confidential and thus also not all the other material in the same category.
You need permission from the editors for anytime after the manuscript is submitted. I read “after” to cover even after publication.
Having dealt with such matters for over 40 years it is clear to me that the editors are concerned with the confidentially of the material during the review process in order not to damage the process or to ‘scoop’ the authors’ findings. On the other hand, lawyers are clever in writing ambiguous conditions hoping to deter otherwise reasonable behavior. I will doubt that Chip had to actually ‘sign’ any agreement in longhand.