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Rideau Canal Skateway

Filed under: — gavin @ 22 February 2018

I’ve been interested in indirect climate-related datasets for a while (for instance, the Nenana Ice Classic). One that I was reminded of yesterday is the 48-year series of openings and closings of the Rideau Canal Skateway in Ottawa.

Rideau Canal Skateway. Lauren Bath

Since 1971, the National Capital Commission (NCC) in Ottawa has (once the ice is thick enough for safe skating) methodically tried to keep the frozen canal available for ice skaters (by clearing snow, smoothing surfaces, filling cracks etc.). This is possible only if the weather permits – first by being cold enough to sufficiently freeze the ice, and second by not being warm enough to melt the ice surface as the season progresses. Apart from the first season, which was not planned ahead of time, each year since has been anticipated to start in the second half of December (or early January) and ideally extends to March.

However, DJF temperatures in Ottawa [Updated link to correct Ottawa] have been rising, and so one might anticipate some trends in opening/closing dates and the length of the skating season. This year’s season (Jan 5th to Feb 21st) was shorter than the average season, but is that part of a trend?

The weather factors underlying the year-to-year variability in the season length were explored in Brammer et al (2015), and they used that to predict a slow decline in viability over time. For instance, the correlation of season length to the (negative) mean DJF temperature anomaly is over 0.4 0.6 (and over 0.8 for the skating days).

Oddly enough the full data set of season dates, length (since 1971) and skating days (collected since 1995) does not appear to be publically available from NCC. However, some of it is around (here and here), and so one can put together a full dataset of season lengths, skating days (since 1995), and opening/closing dates (since 2002).

Updating the Brammer et al graph to 2018 (including the record shortest season in 2016) is straightforward:

Rideau Canal Skateway. Brammer et al (updated)

As expected, there are clear trends in season length (a reduction of ~23±11 days (95% CI) since 1972), and while there are decreases in skating days, they aren’t significant due to the too short period (similarly with the available opening/closing dates). There is of course the possibility on non-climatic artifacts. Increasing skill/experience of the Skateway managers might prolong the season, while decreasing tolerances for risk(?) might shorten it. These are issues that are hard to quantify without much greater amounts of the meta-data associated with the opening and closing.

Nevertheless, we have another independent dataset which conforms to our expectations that outdoor ice in North America is suffering.


  1. J.R. Brammer, J. Samson, and M.M. Humphries, "Declining availability of outdoor skating in Canada", Nature Climate Change, vol. 5, pp. 2-4, 2014.

43 Responses to “Rideau Canal Skateway”

  1. 1
    Titus says:

    What would be helpful is to put this into context with historical records before 1970 which was the peak of the global cooling scare. I have old encyclopedia entries that talk about the gradual increase in ice from the early 20th century. Observations from the gradual earlier closing of the Russian northern coast for shipping from late 1940’s because of the increasing ice. Is their any actual data that goes back that far.
    Not much info on internet probably due to Russia cold war days. Here’s a history piece quite interesting:

  2. 2
    Danny Bloom says:

    A ‘cli-fi’ stage play ‘Extreme Whether’ written and directed by veteran playwright Karen Malpede is set for March 1-18 run in Manhattan.

    If you live anywhere near New York City, like in New Jersey or Connecticut or Pennsylvania — or Boston or Washing or Chicago for that matter — make a beeline for the La MaMa theater to see this timely show.

    Heralded as “brilliant” and “important” in performances in French and English in Paris several years ago, ”Extreme Whether” has been performed at live reading and theater workshops as well, and it’s new show in Manhattan is sure to attract a new generation of theater-goers.

    In addition, since the subject matter is so timely, in this Age of Trump, expect drama critics from the New York Times, the New York Post, The Village Voice, the Nation, The Washington Post, the Associated Press and Reuters, not to mention U.S.-based reporters for the BBC and the UK Guardian to catch this topical show.

    It’s cli-fi, and as you know by now, cli-fi comes in an assorted of colors: novels, movies, stage plays, poems, paintings, performance art and song lyrics. With “Extreme Whether,” Karen Malpede has put her stamp on the rising genre of cli-fi, and this will be a show you won’t want to miss.

    Sp in this new genre of cli-fi (climate fiction), “Exteme Whether” — not ”weather” but ”whether” please note — is a fierce expose of politically motivated censorship and a look at the courage it takes to keep up the fight for truth against immensely powerful forces.

    It is, also, equally, a love story: of people for nature, a girl for a deformed frog, two embattled climate scientists for truth and one another, and an old man,”Uncle,” for the world he is about to leave. Inspired by crusading climate scientist, James Hansen, and Arctic ice scientist Jennifer Francis, and praised by both.

    ”Extreme Whether” asks how can we act to save ourselves from catastrophic climate change, and what are the nefarious forces acting against our survival?

    Starring Rocco Sisto, Clea Straus Rivera, Khris Lewin, Dee Pelletier, Emma Rose Kraus and George Bartenieff.

    Theater Three Collaborative is a social justice internationally touring theater company.

  3. 3
    David Appell says:

    Gavin, you might be interested in New Hampshire’s Lake Winnipesaukee’s ice-out date:

  4. 4
    Ed Davies says:

    Gavin, you’ve been living in the US too long: “National Capitol Commission” → “Capital”.

    “Capitol” is a odd US word which specifically means the buildings where the Federal or State legislatures meet. It doesn’t mean the whole cities containing those buildings and it’s not used much anywhere outside the US, not even in Canada as far as I know.

    [Response: Ooops. Fixed. – gavin]

  5. 5
    Yvan Dutil says:

    The relationship is weak because the ice thickness is only proportionnal to the square root of degree freezing days.

    I am working on a similar project by on the ice bridge formation in front of Quebec city since 1610.

  6. 6
    CCHolley says:

    Not sure if this fits the criteria, but the Minnesota Department of Natural Resources has tracked ice out dates of Minnesota lakes since 1843.

  7. 7
    Michael Porter says:

    That DJF link for “Ottawa” is for Ottawa, Kansas, not Ottawa, Ontario, Canada…

    [Response: Ha! I will fix it right away. Unsurprisingly if I use the right Ottawa, the DJF correlation to the skating season increases to about 0.6. – gavin]

  8. 8
    MarkB says:

    One has to wonder if the Dutch have such records given their long tradition of skating on canals. If so they may go back much further.

  9. 9
    Nick Rouse says:

    There is an over 1000 year record of the first cherry blossom of the year in Kyoto, Japan clearly showing recent global warming.

  10. 10
    Serrara says:

    How ironic of a post considering the Arctic is going through yet another warming spell. Sigh.

  11. 11
    dhogaza says:

    Markb: “One has to wonder if the Dutch have such records given their long tradition of skating on canals. If so they may go back much further.”

    Google for some general information “Elfstedentocht” … the race hasn’t been held for about 20 years.

  12. 12
    Saryan Sha says:

    It’s a miracle, people can walk on water again! Well, by skating.

    Making a skateway is often, also possible by not having heavy people skate-walk on the frozen skateways.

    Puns apart, it’s truly remarkable that such a phenomenon has been flourishing for almost half a century.

    It certainly shows climate changes are reliable, as opposed to what the media has been conveying, and peace reigns in such areas.

    A wonderful monent to skate-walk on frozen water.

  13. 13
    Marco says:

    MarkB + dhogaza,

    The “Elfstedentocht” is a bad example. The first was in 1909, with only 15 being held since then. Not very reliable statistics and not very far back.

    Also, the regulations have been tightened quite a bit. Several of the earlier tours would never ever have been held today, because the ice would not be able to withstand the thousands and thousands of participants. The ice in 2012 was likely much, much better than the ice for the first two tours in 1909 and 1912, but not with 16,000 people vs fewer than 100.

    With the constant work on the waterways in the Netherlands, I doubt there actually are *any* reasonable statistics of first/last ice, skating days or similar for any Dutch waterways. The weather station of De Bilt, however, has been in use since the early 18th century, and so is likely more reliable, warts and all.

  14. 14
    Titus says:

    @9 Nick Rouse says: “There is an over 1000 year record of the first cherry blossom of the year in Kyoto, Japan clearly showing recent global warming”

    Thanks for posting. Looked at the record and the decline started in late 1800’s and has continued at the same pace till now. The question that raises in my mind is what changed back then to start the long gradual decline and by inference the long gradual rise in temperature?

  15. 15

    T 14: Looked at the record and the decline started in late 1800’s and has continued at the same pace till now. The question that raises in my mind is what changed back then to start the long gradual decline and by inference the long gradual rise in temperature?

    BPL: I’m just guessing here, but maybe the industrial revolution?

  16. 16
    Digby Scorgie says:

    Titus @14

    Are you joking? The decline started in the late 1800s, accompanied by the long gradual rise in temperature. Nothing to do with the Industrial Revolution perhaps?

  17. 17
    Mr. Know It All says:

    5 – Yvan Dutil

    Yes, ice thickness proportional to square root of freezing degree days – but only if all other things are equal – snow, rain, cloud cover, heat island changes, water sources flowing into the canal, etc. So, the real reason for varying thickness can’t really be determined without a lot more data. The chart above is essentially meaningless.

    On another note, NOAA has been caught again. Here’s a quote from a comment: “Sooner or later the chickens are going to come home to roost for the liars at NOAA.” Real Climate scientists best get over there and do some educating:

    Don’t shoot me – I’m just the messenger.

  18. 18
    Titus says:

    @15 & 16 say: “Decline caused by industrial revolution”.

    Interested now to understand how the industrial revolution started this sharp decline in the 1800’s? What was the mechanism and what science is there to support this?

  19. 19
    Catherine McMullen says:

    Gavin, you might be interested in the RinkWatch project:

  20. 20
    dhogaza says:

    mr. kia said:

    ‘On another note, NOAA has been caught again. Here’s a quote from a comment: “Sooner or later the chickens are going to come home to roost for the liars at NOAA.” ‘

    On reading his link, I come across this comment attached to a chart that shows a clear long-term declining trend in arctic sea ice:

    “As we know from DMI, sea ice extent has stabilised in summer, and has slightly increased since 2007.”

    It’s the classic technique of cherry picking a start-point that’s below the end point then claiming “increase!”

    While ignoring the long-term trend …

    mr. kia, people here see through that kind of stuff immediately.

  21. 21
    nigelj says:

    Mr Know it all @17

    The Paul Homeward article critical of the NOAA report on the arctic region makes some amazingly basic mistakes.

    For example Paul claims summer arctic ice is “stable”. This is nonsensical as its based on just a couple of years. This is natural variation. You would need ten years of stable sea ice to be able to claim things have truly stabilised. The longer term 50 years downwards trend is pretty relentless and constant with no sign in the graph posted of any fundamental change in the trend.

    Paul claims the arctic ice sheet has become thicker in the last decade, but the graph he posts shows the direct opposite. The basic trend over the decade is declining thickness.One year is a slight anomaly to the trend, probably because of natural variation for that year, but the overall trend is indisputably less thickness.

    NOAA claimed the arctic is warming twice as fast as the rest of the planet. Paul responds by saying there’s been very little change in arctic temperatures. This is nonsensical, because the graph he posts shows approximately 1 degree of change over approximately 17 years which (assuming the graph is reliable) is twice the rate of the planet as a whole as NOAA stated.

    Paul claims arctic temperatures were higher in the 1930s, however he is reading the error bars. This early data is none too reliable, and the dark trend line shows recent temperatures are higher.

    Sorry Pauls article is complete nonsense.

  22. 22
    Phil Scadden says:

    Mr Know-next-nothing. If you read blogs with that degree of cluelessness, no wonder you are misinformed. Learnt anything at all about critical thinking? If so, try using it on that blog post.If you cant spot the problems, I sure someone will help but I doubt that would help learn how not to be fooled.

  23. 23
    Keith Woollard says:

    Titus @ 14 – UHI

  24. 24
    Digby Scorgie says:

    Titus @18

    I smell a rat. Anyone who has visited this website will have seen discussions of the mechanisms behind our changing climate. So I suspect you’re just trying to provoke people for the fun of it.

  25. 25
    Titus says:

    @23 & 24: I’m genuinely serious. Take a look at Nick Rouse link again:

    According to data, green house emissions didn’t really take off until 1950’s. Therefore what caused the rapid decline before and a relatively stable after through to current time. Just seems odd. Is something else at play?

  26. 26

    T 25: According to data, green house emissions didn’t really take off until 1950’s.

    BPL: According to WHAT data? Specify.

  27. 27

    Titus, #25–

    I’m not sure of the ultimate provenance of this image, so don’t take it as the last word in accuracy. But I think it at least illustrates the point, which is that, while emissions have indeed been on an accelerating curve, the increase in atmospheric concentration did indeed start back around the beginning of the 19th century–not in the 1950s.

    Recall, too, that since the relationship between CO2 (or any other GHG) and warming is logarithmic, the earlier increases have a greater effect than you would think.

  28. 28

    NOAA has been caught again. Here’s a quote from a comment: “Sooner or later the chickens are going to come home to roost for the liars at NOAA.”

    The allegations are garbage. It’s become fashionable for sources like Breitbart and their ilk to smear NOAA or NASA or both for “lying” about climate change, but when you read the pieces critically, it invariably turns out that the charges are completely unsupported.

    In the case of the link you give, compare the NOAA data slammed with these graphs from multiple sources independent of them:

    You’ll find that the NOAA claims are correct, and the criticisms–well, not. (For instance, it is completely ludicrous to claim that ice extent has stabilized since 2007.)

    It’s all the more risible given the fact–per JAXA–that 2018 has so far had the lowest daily extent ever for the time of year:

  29. 29

    Taking a second look, that idiot Homewood apparently misread 2012 extent as belonging to 2007.

    Had he written ‘extent has stabilized since 2012’, it still would have been a misleading cherry-pick, but it would at least have made sense.

    Boy, when somebody bungles the yearly date on their own cherry-pick–and when the two dates in question are the two record-low years in the relevant annals–you know they are a careful and credible analyst…

  30. 30
    Keith Woollard says:

    Titus at #25 – so was I

  31. 31
    Keith Woollard says:

    Also Titus, the data in the spreadsheet doesn’t match the exaggerated graph

  32. 32

    Titus, Keith, and anybody interested–

    Just for fun, I downloaded the cherry blossom data and the Law Dome CO2 data and imported them into an Excel sheet.

    CO2 data:
    Cherry Blossom data:

    The CO2 data start with a value of ~281 ppm and rise to ~374 (IIRC), while the cherry blossom data–given in DOY, Day Of Year–vary pretty wildly, with a high value of 120 and a low value of (I think) 88. So to get them to display on one graph you must scale them.

    CO2 data scaling formula: ([value]-281)/10
    Cherry blossom scaling formula: (120-[value])/2

    Additionally, I thought it would be nice to show a smooth of the cherry blossom data, since it’s highly variable. So I did basically what I call a 10-year retrospective average, with a couple of kludges where there are multiple years with missing data. (As I said, this was just for fun.)

    The result, I think, gives a reasonable indication that the curves are not incompatible. It’s pretty naive scientifically–I haven’t tried, for instance, to correct for the logarithmic nature of GHG forcing. And we know for sure that a lot more is going to affect temperature and thus the blossoms than just CO2–atmospheric and oceanic circulation patterns will clearly have a big effect from year to year. But, allowing for random fluctuation, the overall patterns do seem to follow.

  33. 33
    Ian Forrester says:

    I have been following the number of days the Tibbitt to Contwoyto winter road has been open over the past 17 years. This has been decreasing at a rate of slightly less than 1 day per year (you can get the data by Googling Tibbitt to Contwoyto winter road). This road was important for a number of companies to start mining operations. They were persuaded by well known AGW denier Tim Patterson that there will be cooling for several decades. These mines will become non-functional if the decrease in operating days continues to decrease at the same rate.

    Tim Patterson’s comments at a Canadian Senate meeting can be found here:

  34. 34
    jb says:

    31,25,26, etc.

    The plot is wrong. It uses full bloom data for the years 800-1950 and first bloom data thereafter. First bloom is about 1-2 weeks earlier. If you plot full bloom data only, you still get a steadily descending trend after 1800, just not as severe at the end.

  35. 35
    Thomas says:

    I don’t think I am going to far out on a limb to equate Tim Patterson’s (Professor of Geology, Department of Earth Sciences, Carleton University) credibility on AGW/CC science with that of your average Caribou found in the region.

  36. 36
    Mr. Know It All says:

    33 – Ian

    Used to live in interior Alaska in the late 70s, early 80s. Back then temps of -30s F to -50s F were common, and -60 was not unheard of. I watch the temps in the newspaper and rarely do they get into the -30s today. So, it is warming for sure, and it seems like winter temps are MUCH warmer than they used to be. Definitely not a scientific study, but just my observation.

    Here in the Pacific NW, summers are considerably hotter the last few years than they were during say 15 years starting in 1990. 90s used to be uncommon, but now they’re fairly frequent. Time to move north!

  37. 37
    Ray Ladbury says:

    I wasn’t able to find statistics with a cursory search, but it occurs to me that the stats on Trail Ridge Road in Rocky Mountain National Park might be interesting. It is the highest continuously paved road in the CONUS.

    There could, of course be confounding factors–e.g. snow plows may have gotten better and money for plowing might have varied from year to year. However, Trail Ridge ought to be fairly sensitive–it sometimes gets closed even in July due to blizzards.

  38. 38

    #33–Wow, what a denialpalooza that hearing was! Not even a pretense at hearing from mainstream science, and with no recognition of the essential relevant physics–well, maybe in one case, with *selective* recognition of same.

    I didn’t find a complete set of season dates for the road, unfortunately; the earliest I came up with were for 2000, whereas the road itself dates back to the 80s. There is an interesting Masters thesis, by then-University of Waterloo geography student Erika Zell, which used ERA-interim reanalysis data and regional modeling to analyze trends over the entire span:

  39. 39

    Re my #28-9 and its antecedents: I stumbled onto the perfect graph to illustrate. It’s from “zebraphile”s blog:

    He uses 12- and 1323-month means to illustrate both extent and area trends over the satellite era. The decline in sea ice is very clearly ongoing, and pretty clearly accelerating over time.

  40. 40

    Reflecting on that graph a bit, I used woodfortrees to do a rough-and-ready trend analysis, using successive 5-year linear trends:

    Yep, that suggests acceleration, too, though not monotonically over the whole span.

  41. 41
    Paul D says:

    Re #11 – and this is entirely anecdotal, but my memories in the 1960s-70’s were of relatively short but reliable spells of ice skating conditions on the C&O Canal in Washington DC. It used to be a regular part of winter in Washington DC. Now it is so rare that everyone is afraid to try it even when it stays cold enough. It’s considered a daredevil activity by younger generations – as this reddit comment shows:

    Then there used to be the longer skating season afforded by the shallow water of the DC Lincoln Memorial Reflecting Pool. That’s been banned by the National Park Service altogether.

  42. 42
    Mal Adapted says:

    Mr. Ironically Anosognosic Typist (my emphasis):

    On another note, NOAA has been caught again…
    Don’t shoot me – I’m just the messenger.

    Well, your message is that you suspect wrongdoing by NOAA, when no evidence of wrongdoing actually exists. Can we shoot you now? (Figuratively speaking, of course! I couldn’t shoot you, even if I knew where you lived.)

  43. 43
    Dave says:

    In Re: Titus, (#1, 2/22; @ 11:42P) — A very astute commenter who knows the minutia of British temperature records all the way back to Fahrenheit’s 1720 instrument, has for years been blasting us, ‘worry-ers,’ with his acumen. He, as you, talked a Good Line about all of the Fables of “The Warm Arctic.” I had gone toe-to-toe with the bloke, and more than once, @ Judith’s, and greatly respected his acumen. We promised each other, further e-mails, which never developed, but a chance selection of my local (CO Springs) librarians, for a book of Month, grabbed my attention about two years ago. It was a measured [non ‘partisan’] history of the Jeannette Saga/tragedy:

    As this Wiki mentions, there have lingered, going back to the days of whalers in the N. Pacific, Tall Tales about sailing the Arctic and the Northern Coast of Russia. Much of it, as was established by Lt. Cmdr. George Washington DeLong, purest Hooey. Much like your mention of the “earlier closing of the N. Russian coast from the late 1940’s due to increasing ice.” Same point my long lost sparring partner made.

    But … Hooey.

    Ditto, your tid bit on ‘the peak of the global cooling scare.’

    Properly understood, the concerns expressed about the potential for a ‘pronounced cooling,’ voiced by some modelers and folks who were in nascent phases of comprehending some aspects of a wildly complex set of interacting, climatic feedbacks, were attempting to express in words, the Great Planetary Non-linearity. The FACT is, Earth (during the last ~Three million years) can take tiny bits of what was termed “Chaos’ for a while, and make of that: Ice Ages! (I trust you are ‘On Board,’ W/planetary glaciation, during the Pleistocene. Right?)

    So, it’s the SAME mechanism, now far more thoroughly understood, than in the late seventies, which Swings wildly one Way, towards building a mile or two of Ice upon Manhattan’s Central Park, and then the other, giving us the Holocene’s Grand, ten thousand years of Thaw—so that the Egyptians might construct the world’s most immense buildings, to date. The “Scary” point was, that by 1972 there existed zero further Doubt, that the metronomic, regular, Ice – to – Thaw, Thaw – back – to – Ice, cyclicity was known to be timed by Saturn and Jupiter, two-stepping their way towards elongation of the Earth’s orbital eccentricity, and then relaxing that effect. The PROBLEM was, how could such a tiny alteration of out planetary solar budget evoke such a huge transformation of Physical State and temperatures, upon the surface?

    Both Ways!

    So, the answer, quite like Professor Lindzen up MIT has long argued, is that mainly, Earth’s atmosphere either has an increased or decreased Water Content, governed by the Clausius – Clapeyron equation (hike the surface temperature by 1%, and you intensify the ‘airborne water-vapor’ by ~ 7%; viz.: The “Green House Effect.” And the key is, we have learned that the tiny tail that wags that Dog, is the atmospheric tug of war twixt Two sets of manmade and natural ‘trace actors’; A) those such as sulfur aerosols, which Chill the water out of the Air, and B) those such as CO2 & CH4, which do the opposite. That is why, forty years after the initial Assessment was rendered as to the severity of the Greenhouse Situation, for President Carter by the Academy of Sciences, as computers have evolved from the Stone Age to the i-phone, and despite @ least a thousand-fold more time on task with both field and heuristic climatic studies, the original uncertainties between the Two sides to the Tug of War, that is, PLUS 50% OR MINUS 50%, have not wavered much. Hope this helps.