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2013 SkS News Bulletin #17: Cowtan and Way (2013)

Posted on 22 November 2013 by John Hartz

  • Exposed: The myth of the global warming 'pause'
  • Global warming hasn’t stopped, new data finds
  • Global warming proponents and sceptics agree on one point: study into myth of 'pause' merits more research
  • Global warming since 1997 more than twice as fast as previously estimated
  • Media ignore study finding globe is warming twice as fast as thought
  • Missing data from Arctic one cause of pause in temperature rise
  • Our work is unlikely to be last word on slowdown, say authors of new paper
  • Planet warming much faster than previously thought
  • Recent surface warming has probably been underestimated
  • Recent warming may have been dramatically underestimated
  • Revised global warming models needed as data gap filled
  • Typhoon Haiyan must spur us on to slow climate change

Exposed: The myth of the global warming 'pause'

Scientists can now explain the “pause” in global warming that sceptics have used to bolster their arguments. Sceptics had claimed we have nothing to fear from climate change because it has stopped being a problem.

A new study has found that global temperatures have not flat-lined over the past 15 years, as weather station records have been suggesting, but have in fact continued to rise as fast as previous decades, during which we have seen an unprecedented acceleration in global warming.

The findings will undermine the arguments of leading sceptics, such as the former Chancellor Lord Lawson, who have criticised scientists from the Met Office and other climate organisations for not accepting that global warming has stopped since about 1998.

Exposed: The myth of the global warming 'pause' by Steve Connor, The Independent, Nov 18, 2013


Global warming hasn’t stopped, new data finds

New research by scientists at the University of Ottawa and the University of York in the United Kingdom believe they have found the missing heat in global climate models.

Many climate-change skeptics look to data that suggest that there has been a pause in global warming since 1997. Temperatures from 1997 to 2010 have barely increased according to current datasets.

However, due to the limits of global weather stations, there are important gaps in data that make the models incomplete. The Arctic and Antarctic are two such places.

Dr. Kevin Cowtan of the University of York, along with PhD student and cyrosphere specialist – someone who studies ice – Robert Way of the University of Ottawa, used satellite data to fill in the missing gaps.

Global warming hasn’t stopped, new data finds by  Global News, Nov 14, 2013


Global warming proponents and sceptics agree on one point: study into myth of 'pause' merits more research

A study suggesting that the "pause" in global warming is not real has managed to unify climate scientists and their arch-sceptics over the need for further research to clarify whether global average temperatures really have flat-lined over the past 15 years.

Global warming proponents and sceptics agree on one point: study into myth of 'pause' merits more researchby Steve Connor, The Independent, Nov 18, 2013


Global warming since 1997 more than twice as fast as previously estimated

A new paper published in The Quarterly Journal of the Royal Meteorological Society fills in the gaps in the UK Met Office HadCRUT4 surface temperature data set, and finds that the global surface warming since 1997 has happened more than twice as fast as the HadCRUT4 estimate. This short video abstract summarizes the study's approach and results.

The study, authored by Kevin Cowtan from the University of York and Robert Way from the University of Ottawa (who both also contribute to the climate science website Skeptical Science), notes that the Met Office data set only covers about 84 percent of the Earth's surface. There are large gaps in its coverage, mainly in the Arctic, Antarctica, and Africa, where temperature monitoring stations are relatively scarce. These are shown in white in the Met Office figure below. Note the rapid warming trend (red) in the Arctic in the Cowtan & Way version, missing from the Met Office data set.

Global warming since 1997 more than twice as fast as previously estimated, new study shows by Dana Nuccitelli, Climate Consensus-the 97%, The Guardian, Nov 13, 2013


Media ignore study finding globe is warming twice as fast as thought

After hyping an alleged "pause" in global warming, mainstream media have entirely ignored a groundbreaking study finding that warming over the last 16 years has actually proceeded at the same rate as it has since 1951 with no "pause" compared to that time period.

The study, published in the Quarterly Journal of the Royal Meteorological Society by Dr. Kevin Cowtan of the University of York and Robert Way of the University of Ottawa, found that the average global surface temperature has warmed 0.12 degrees Celsius between 1997 and 2012 (see the bold "Global" line in the graph above) -- two and a half times the UK Met Office's estimate of 0.05°C (see "Met Office" line). According to the new estimate, over the last 16 years the globe has warmed at the same rate as it has since 1951.

Writing about the study at the scientific blog Real Climate, climate scientist Stefan Rahmstorf concluded that the public debate about the "pause" has "become"completely baseless"and that any speed bump in warming is "not surprising" with natural variability:

Faux Pause: Media Ignore Study Finding Globe Is Warming Twice As Fast As Thought by Shauna Teel, Media Matters, Nov 18, 2013


Missing data from Arctic one cause of pause in temperature rise

Keeping track of our planet's temperature is no easy task.

The keepers of such long-term data sets, usually government institutions, know they have to account for numerous variations to keep a consistent measurement of temperatures through time. Without that, it is impossible to know how our world is changing.

Yet today's thermometers are not the same as those 100 years ago. The time of day that temperature measurements are taken has changed. Then there's the issue of coverage -- where, exactly, those thermometers are located. In more remote places, there are fewer measurements. 

Missing Data from Arctic One Cause of Pause in Temperature Rise by Stephanie Paige Ogburn and ClimateWire, Scientific American, Nov 18, 2013


Our work is unlikely to be last word on slowdown, say authors of new paper

Recent research suggesting the so-called slowdown in surface warming might be less than previously thought has been met with interest from both climate scientists and skeptics. We hear from the authors about some of the queries raised and why they think their research is not the final say on whether or not the "slowdown" is real.

Our work is unlikely to be last word on slowdown, say authors of new paper by Roz Pidcock, The Carbon Brief, Nov 20, 2013


Planet warming much faster than previously thought

The planet may be warming much more – and much faster – in recent years than many experts have believed, according to a new study released this week by the U.K.-based Royal Meteorological Society.

Prepared by British and Canadian researchers, the study reports that the rise in global temperaturesover the past 15 years has been significantly underestimated due to gaps in temperature data around the world, largely in Earth's polar regions.

“It turns out that we only have surface measurements over about 84 percent of the globe," said Weather Underground's Dr. Jeff Masters, noting that there are no direct measurements oftemperatures in places like the Arctic even today, especially across its vast stretches of sea ice.

No Global Warming 'Pause,' Planet Warming Much Faster Than Previously Thought: Report by Terrell Johnson, The Weather Channel, Nov 15, 2013


Recent surface warming has probably been underestimated

If you want to take someone’s temperature to see if they have a fever, you know where to put the thermometer. (Sorry, infants.) But where do you take the temperature of Earth’s climate? Inconveniently, the answer is “everywhere”—you need measurements covering the planet to properly calculate the global average surface temperature. That’s no big deal for Europe, where a local weather station is never far away, but it's much more of a problem for the North and South Poles where records are hard-won. A new analysis shows that how you deal with this problem makes a difference in what temperature you end up reading.

Building a global temperature dataset is a huge undertaking, because that’s only the half of it. Lots of careful corrections need to be made to the raw measurements to account for things like instrument changes, weather station placement, and even the time of day the station is checked.

One of the most commonly used datasets, dubbed “HadCRUT4” in its current incarnation, is maintained by the UK Met Office and researchers at the University of East Anglia. That dataset lacks temperature records over 16 percent of the globe, mostly parts of the Arctic, Antarctic, and Africa. Each group that manages one of these datasets faces this problem but deals with it a little differently. In HadCRUT4, the gaps are simply dropped out of the calculated average; in NASA’s GISTEMP dataset, these holes are filled in by interpolating from the nearest measurements.

The new study by Kevin Cowtan of the University of York and Robert Way of the University of Ottawa evaluates a few different methods for dealing with these gaps and shows that HadCRUT4 has probably been off by an important amount over the last few years.

Recent surface warming has probably been underestimated by Scott K Johnson, Ars Technica, Nov 15, 2013


Recent warming may have been dramatically underestimated

The so-called global warming "pause"—in essence, the contention that global warming has slowed down or even stopped over the past 15 years—drew dramatic media attention. Arguably, it derailed the entire rollout of the U.N. Intergovernmental Panel on Climate Change's Fifth Assessment Report back in late September.

All that....and yet a new study in the Quarterly Journal of the Royal Meteorological Society suggests there might not have even been a global warming "pause" at all. Rather, the notion of a "pause" may just be the result of incomplete data: In particular, a lack of weather stations in the remote Arctic region. That gap is problematic because we know that Arctic amplification is occurring and global warming is moving particularly fast there. The dramatic new low in Arctic sea ice extent in the year 2012 put an exclamation point on that finding.

Study: Recent Warming May Have Been Dramatically Underestimated by Chris Mooney, Mother Jones, Nov 15, 2013


Revised global warming models needed as data gap filled

A recent study using new techniques has filled in some of the information gaps in global temperatures and predictions of warming, and counters claims that warming has levelled off.

The interdisciplinary team of computational scientist Kevin Cowtan of the University of York in England, and cryosphere specialist and PhD candidate Robert Way of Canada, say that using satellites they have filled in large areas of the earth not covered by observational monitoring.

This previous “gap” in data has always resulted in skewed and underestimated reports and projections of what is really happening. 

Revised global warming models needed as data gap filled by Marc Montgomery, Radio Canada International, Nov 18, 2013


Typhoon Haiyan must spur us on to slow climate change

But what about the global warming pause much beloved by sceptics? There are always variations due to solar activity and other effects, but a new study by British and Canadian scientists Kevin Cowtan and Robert G Waycasts doubt on any pause. It suggests that the global temperature rise of the last 15 years has been greatly underestimated.

The reason is the data gaps in the weather station network, especially in the Arctic. If you fill these data gaps using satellite measurements, the warming trend is more than doubled, and the pause disappears. The trend of the last decade looks exactly the same as the trend since the 1950s.

Typhoon Haiyan must spur us on to slow climate change, Op-ed by Chris Huhne, Comment is Free, The Guardian, Nov 17, 2013

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Comments

Comments 1 to 8:

  1. Wow, lots on the C&W paper here. The main thing I would like to know (so I can clearly and accurately convey it to others) is: Exactly how much additional warming does the study suggest we have experienced.

    In the fifth paper cited, the quote: " 0.12 degrees Celsius between 1997 and 2012 (see the bold "Global" line in the graph above) -- two and a half times the UK Met Office's estimate of 0.05°C" suggests that there is an additional .07 degrees of warming we should add to the total. But that seems more like a rounding error than a major adjustment. Had we been at 8.5 Celsius above pre-industrial, or so before this reanalysis? So are we now acutally closer to 8.6? Or is there something more dramatic that I'm missing?

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    Moderator Response:

    [JH] The articles contained in this bulletin are only the tip of the iceberg so to speak. Similar articles have been written and published in many languages other than English throughout the world. 

  2. wili @1, you have it exactly right.  This is, at most, a minor adjustment on the long term surface temperature trend.  It only appears consequential when you look at very short term trends, such as that from 1998.  Looking at such short trends is largely meaningless in science because the trends do not statistically differ from the long term trend, and any adjustment that makes a noticable difference only to those short term trends will be largely inconsequential to the overall science.

    The problem is, in order to avoid the implications of the science, AGW deniers have been focusing heavily just such short term trends.  That focus of theirs is shown by C&W to be misguided in that the phenoman they purportedly draw attention to largely disappears with just a minor correction.  Indeed, they are in a cleft stick if looked at logically.  If they draw attention to the minor nature of the correction, they at the same time draw attention to the unscientific nature of their focus on short term trends.  Alternatively, if they draw attention to the short term trend, C&W shows their argument to be based on using only restricted data.

    Of course, AGW deniers are not logical.  So, whether C&W punctures their rhetorical bubble remains to be seen.  

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  3. The total change in temperature is very small - the Cowtan and Way data remains within the 95% uncertainty range of HadCRUT4. Changes in yearly variations, though, do affect extremely short term trends. 

    All of the 'skeptic' noise about the "hiatus", discussions of "16 years", and in fact any trends derived from start points in the 1998 El Nino, deliberate selections of periods just short of statistical significance - are simply noise about noise. Trends over that time, as the authors of this paper point out, are just not statistically significant and don't have enough data to separate between short term variations and any change in climate trends.

    That said, the Cowtan and Way paper makes the various skeptic/denier claims about slowdowns even less sensible. Which is why the 'skeptics' are up in arms (WUWT has something like 8-9 posts on the subject) - the paper removes one of their favorite misleading rhetorical points. 

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  4. This 'better understanding' has prompted new attempts to discredit the science and anyone who tries to more fully present it. These attempts to discredit also help 'better understand' who is genuinely interested in 'better understanding this issue' and who would prefer to have people 'maintain certain popular beliefs so that gambles on damaging and unsustainable pursuits can get maximum payout'.

    The popularity of benefiting from burning fossil fuels, something that clearly can't be continued by future generations for the few billion years humanity could enjoy life on this planet, makes this a significant public perception battle ground issue. There are many other pursuits that are similarly damaging or not sustainable. If this incredibly popular unsustainable and damaging pursuit, burning fossil fuels, actually loses the public opinion war among those who benefit most from it, then the rest of the unsustianable and damaging pursuits that many among the most fortunate have gambled on getting away with would likely fall as well.

    The result would be a massive change of the global socioeconomic system. It would be a change for the better, except for those who only care about getting the most benefit they can for themselves. There would be massive 'disappearances of unjustified wealth related to unsustainable and damaging pursuits'. That is the clear motivation of the attacks on the science's implications that the burning of fossil fuel must be dramatically reduced.

    Keep up the good work that helps everyone better understand this issue. It makes it harder for the uncaring to excuse their attitudes and actions. However, the will to fight against the required change is clearly very strong. Some people will never accept a 'better understanding if it means they can't benefit as much as they wish to'.

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  5. re: "Media ignore study...", Media Matters, Nov 18, 2013

    I don't think this is true. In a way it is "faux news" as in "Faux pause: Media ignore study..." (as the complete title of that article tells). John Hartz wrote in a comment: "The [cited] articles contained in this bulletin are only the tip of the iceberg..." and he is more than just right on that one. In Germany, mainstream media (including Radio/TV features) did report about the findings of the study - e.g. Süddeutsche Zeitung Nov 15, Der Spiegel Nov 15, Berliner Morgenpost Nov 14, T-Online News Nov 16, Telepolis Nov 20 and many, many more (not even mentioned are Blogs). As it needs just one (big) News Agency (Reuters, AFP or the like) and one short news snippet there to get a news item into the worldwide news flow, it is highly unlikely that US media did not cover this.

    One part of the general problem regarding AGW is that it is just so easy today to get a message into the media and this is a well known and heavily (mis)used fact from the Denialistas. Media outlets are quite happy to push any news in "controversial" areas (that is, content generating furious reactions from readers) and they will not let down on that.

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    Moderator Response:

    [JH] The Media Matters analysis focused on the MSM coverage of Cowtan and Way (203) within the U.S.   

  6. @will  If we were at 8.5C above pre-industrial half the planet would be dead.  We are about 0.8C above pre-industrial so 0.07C is a pretty significant (additional) increase over a 15 year period.

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  7. Ha! Thanks for the correction. I of course meant .85C.

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  8. As the Arctic ocean warms, it heats the air above it.  This leads to rising air more often than was previously the case or if you like, a reversal, or at least a weakening of the Polar Hadley cell.  This has been shown by the weakening and wobbling of the Arctic jet stream as the Arctic Hadley cell slows down. The speed of the Jet stream is dependent on the speed of rotation of the Hadley cells on either side of it. A strong conventional Polar Hadley cell keeps weather patterns, where most thermometers are located, pushed southward, keeping the heat of souther regions in the south.  As the cell weakens and reverses, more heat from the tropics shifts northward.  The corollary of more heat shifting north is heat being removed from the south and thus, perhaps, the apparent stalling of the rise in temperature since most thermometers are located below the Arctic circle.

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