Watts Posts Paper Claiming "Spurious" Warming in U.S. Climate Record

[donsutherland1]

The paper can be found at:

http://wattsupwiththat.files.wordpress.com/2012/07/watts-et-al_2012_discussion_paper_webrelease.pdf

Some quick thoughts:

- The paper makes the claim that the lower tropospheric temperatures (which have been running cooler than surface temperatures) are an upper bound. Claims they trend faster than surface temperatures. Recent literature suggests otherwise. Instead, the lower troposphere has been warming more slowly than the surface.

- The Berkeley Earth Surfact Temperature (BEST) study reviewed more than 39,000 stations, both in the U.S. and globally. The Watts study is based on 779 U.S. stations.

- Assuming that the Watts study correctly applies the Leroy methodology, the question as to whether the "well-sited" stations are representative of the U.S. overall is not addressed. Concentration could lead to a tainting on account of regional variability.

- The paper attacks the NCDC's approach to data homogenization, but that quality control approach of adjustment/correction has not been disavowed in the literature. BEST used multiple statistical approaches and reached similar conclusions about the overall reliability of the data. Watts may be advocating an outlier approach to adjustment, especially as earlier last freezes, later first freezes, plant hardiness zones, bloom times, etc., are consistent with a warming, not stable, U.S. temperature regime.

- Watts notes that his study found that the airport stations are, on average, better-sited than others. Yet, he largely dismisses the data from those stations, which leads to an even cooler outcome than would otherwise be the case. In short, he is arriving at a conclusion that rests on a sample that is not necessarily random and not necessarily representative.

- Watts suggests that GISS and NOAA arrive at similar temperature trends due to incorrect data homogenization. As both pursue independent approaches to data homogenization, odds that both are incorrect, while Watts's approach is correct, may be low.

- In sum, Watts's paper constitutes a frontal attack on the U.S. climate record, as he suggests only a small number of stations are properly sited and rejects the broadly-accepted methodologies used for quality control. IMO, it is difficult to believe that the U.S. climate record, particularly with all the effort that is made to assure its quality, is unreliable. I suspect that the Watts paper likely will not have a large impact overall. It will be embraced by climate change contrarians on account of its claim that there is "spurious" warming in the U.S. climate record. It won't be embraced by the overall climate science field.

I'll be interested to see how the paper is received by the scientific community.

[The_Global_Warmer]

Watts has to worry about how many clicks his website gets, how much funding he gets from sponsors of the cause, and how much his books sell.

Given the current state of the climate and the United States heat waves helping push ghg warming into the consciousness of the Country, he is getting more desperate.

[ORH_wxman]

Watts has to worry about how many clicks his website gets, how much funding he gets from sponsors of the cause, and how much his books sell.

Given the current state of the climate and the United States heat waves helping push ghg warming into the consciousness of the Country, he is getting more desperate.

I agree with many of Don's points...however, I disagree with just about everything you posted here.

You attack motive of funding, when the funding for the pro-AGW view is much higher...then you point that the recent heat waves in the U.S. have made him more desperate when global temperature rise has essentially halted the past decade and considerably slowed since the turn of the century.

In short, you have injected politics into the debate.

[donsutherland1]

In the case of the Watts paper, I believe it will be subjected to peer review. How it fares through that process could be revealing. Should the paper be published, the text of the published paper vs. the released copy could provide insight into how the paper was received by the scientific community. IMO, this is the way issues such as those raised in the paper should be vetted. Waging verbal wars across blogs is not a good way to flesh out scientific understanding. Peer review remains the most effective approach.

[LakeEffectKing]

I agree with many of Don's points...however, I disagree with just about everything you posted here.

You attack motive of funding, when the funding for the pro-AGW view is much higher...then you point that the recent heat waves in the U.S. have made him more desperate when global temperature rise has essentially halted the past decade and considerably slowed since the turn of the century.

In short, you have injected politics into the debate.

Agree, Will.

I have differing opinions on many of Don's takes, wrt, AGW....however, his professionalism while sharing his POV's has ALWAYS earned my respect! That said, the statistical analysis (with the "outlier", but precedented and accepted methodologies) are of more robust significance, IMO, at first read. But Don's take on the reaction in the various "camps" will be dead on IMO. Hopefully, everyone will embrace this as a civil attempt at conducting science...and not just some super well orcherstrated disinformation campaign...which any thought of should be squashed with the release, (according to the many of the contributors) of all data, methodologies, etc. for complete scrutiny to be applied.

[Jonger]

This should be interesting.

[ORH_wxman]

Agree, Will.

I have differing opinions on many of Don's takes, wrt, AGW....however, his professionalism while sharing his POV's has ALWAYS earned my respect! That said, the statistical analysis (with the "outlier", but precedented and accepted methodologies) are of more robust significance, IMO, at first read. But Don's take on the reaction in the various "camps" will be dead on IMO. Hopefully, everyone will embrace this as a civil attempt at conducting science...and not just some super well orcherstrated disinformation campaign...which any thought of should be squashed with the release, (according to the many of the contributors) of all data, methodologies, etc. for complete scrutiny to be applied.

I agree with the selection of the data in Don's points, but 700+ sites is not small either. The one point I do not really agree with is the adjustments for classification of sites as urban/rural and their corresponding changes has always been the most controversial of the data adjustments for both NCDC and GISS. The time of obs (TOBS) adjustment is pretty solid overall and does create a warm bias in older temperatures, but the UHI and classification have been criticized in the past as being more subjective and not taking into effect upstream boundary layer effects as much as they should.

Regardless, people shouldn't get into an AGW vs anti-AGW war over this. The paper isn't disproving global warming, it is confirming it with its positive temperature trend, but it does at least bring some more scientific scrutiny to light on the siting adjustments and classification methods.

But throwing political slander certainly doesn't help with the actual science....but we already knew that.

[donsutherland1]

I would prefer that the discussion be civil and focused on the science. The way I see it, there are upsides to the paper:

1. If the paper is rejected for publication, arguments that the U.S. climate record is deeply flawed would be undermined.

2. If parts of the paper hold up--and I actually think a mixed outcome may be a more likely one--then efforts to improve the climate record can be pursued. A more accurate climate record would be beneficial in advancing scientific study.

3. Renewed focus on the temperature record from the BEST study and this paper may lead to questions concerning how to improve the data adjustment process. Clearly, data has to be adjusted. Attacks on data adjustment efforts carried out by NCDC, GISS, and others, as "manipulation" or worse, is not helpful.

Adjustment is not unique to trying to improve the climate record. For example, in economics, one adjusts for seasonality, among many other factors. The CPI is periodically revised with the basket of goods weighted to better reflect consumer purchasing patterns (i.e., food has had a shrinking weight, while the health-related components have had increasing weights). With few exceptions, most of the economic community accepts such adjustments.

[TerryM]

Could we here in Canada borrow Mr Watts for a season or two. The crops are burning up, MYI older than my cat has disappeared and my AC costs are staggering. Please do a study here Tony. I want my ice back.

Terry

[Entropy]

Here's my two cents on the matter.

- I think the paper, in its current form, is somewhat flawed, but there may be some validity to the new techniques for identifying & adjusting for site changes & urban heat island effects.

- The flaw I see is that Watts comes to his conclusion (i.e. that U.S. warming over the past 30 years is roughly half that reported by NCDC) largely by rejecting sound statistical-based adjustments to the climate record to correct for KNOWN inhomogeneities.

- Watts reports that, for the period 1979-2008, CRN 1 & 2 sites show a warming of +0.16C/decade, whereas CRN 3, 4, & 5 sites show a warming of +0.25C/decade. Watts further reports that 20.9% of sites qualify as CRN 1 or 2, and 79.1% are CRN 3,4, or 5. Although unreported, using this information, one obtains a trend for all sites of +0.23C/decade. According to Watts, the official trend reported by NCDC is +0.31C/decade. Watts adopts the trend for the raw, unadjusted CRN 1&2 data as the actual value, in drawing his conclusion that warming is roughly half that previously shown.

- Assuming Watts' values are correct, this implies NCDC adjustments during the period increased the trend by about .08C/decade. The adjustments used by NCDC on the USHCN dataset include the TOBS (time of observation), MMTS (switch from the cotton region shelter to the MMTS sensor), and a correction for urban heat island effects. The time of observation adjustment is due to the old practice among cooperative observers to re-set the min/max thermometer during the afternoon or early evening. This imparted a slight warm bias, because daily highs would sometimes occur at the time of re-set for the following day. The MMTS adjustment was based on data showing that MMTS-based daily mean temperature readings were somewhat lower than corresponding values obtained from thermometers housed in the cotton region shelter. The adjustments are all published by NCDC: http://www.ncdc.noaa.gov/oa/climate/research/ushcn/

- I, personally, do not believe the outright rejection of the NCDC adjustments will pass peer-review, especially since the adjustments themselves are based on peer-reviewed methodologies in some cases 20+ years old. It's kind of ironic that the premise of the paper is that the temperature record is insufficiently adjusted for siting problems & UHI, while rejecting other adjustments outright.

- Nevertheless, there may be some validity (on the order of 0.07C/decade) to Watts' contention that the UHI effect & other land use changes are affecting the record. This is the difference between the raw trend for all USHCN sites and those identified as CRN 1 & 2 by Watts. Still, I think there are some questions regarding the extent to which the difference in trend is due to siting problems & not other differences. For instance, since Watts uses only the raw values, if more of the CRN 1&2 sites have switched to MMTS or been subject to changes in the time of observation, that could also explain the cooler trend found. This may be a plausible explanation for the differences in light of Watts observation that the CRN 1&2 sites were affected more by the NCDC adjustments than the CRN 3,4,&5 sites.

- Finally, I suspect the timing of this was to distract from the BEST study. It's worth noting also that Watts only looked at the U.S. and only during the 1979-2008 period. The conclusions are not necessarily valid elsewhere or during different time periods (especially since most of the changes and corresponding adjustments to the USHCN occurred during this time frame). This is especially true for the global land & ocean temperature datasets, since nearly 70% of the globe is ocean.

[ORH_wxman]

Here's my two cents on the matter.

- I think the paper, in its current form, is somewhat flawed, but there may be some validity to the new techniques for identifying & adjusting for site changes & urban heat island effects.

- The flaw I see is that Watts comes to his conclusion (i.e. that U.S. warming over the past 30 years is roughly half that reported by NCDC) largely by rejecting sound statistical-based adjustments to the climate record to correct for KNOWN inhomogeneities.

- Watts reports that, for the period 1979-2008, CRN 1 & 2 sites show a warming of +0.16C/decade, whereas CRN 3, 4, & 5 sites show a warming of +0.25C/decade. Watts further reports that 20.9% of sites qualify as CRN 1 or 2, and 79.1% are CRN 3,4, or 5. Although unreported, using this information, one obtains a trend for all sites of +0.23C/decade. According to Watts, the official trend reported by NCDC is +0.31C/decade. Watts adopts the trend for the raw, unadjusted CRN 1&2 data as the actual value, in drawing his conclusion that warming is roughly half that previously shown.

- Assuming Watts' values are correct, this implies NCDC adjustments during the period increased the trend by about .08C/decade. The adjustments used by NCDC on the USHCN dataset include the TOBS (time of observation), MMTS (switch from the cotton region shelter to the MMTS sensor), and a correction for urban heat island effects. The time of observation adjustment is due to the old practice among cooperative observers to re-set the min/max thermometer during the afternoon or early evening. This imparted a slight warm bias, because daily highs would sometimes occur at the time of re-set for the following day. The MMTS adjustment was based on data showing that MMTS-based daily mean temperature readings were somewhat lower than corresponding values obtained from thermometers housed in the cotton region shelter. The adjustments are all published by NCDC: http://www.ncdc.noaa...research/ushcn/

- I, personally, do not believe the outright rejection of the NCDC adjustments will pass peer-review, especially since the adjustments themselves are based on peer-reviewed methodologies in some cases 20+ years old. It's kind of ironic that the premise of the paper is that the temperature record is insufficiently adjusted for siting problems & UHI, while rejecting other adjustments outright.

- Nevertheless, there may be some validity (on the order of 0.07C/decade) to Watts' contention that the UHI effect & other land use changes are affecting the record. This is the difference between the raw trend for all USHCN sites and those identified as CRN 1 & 2 by Watts. Still, I think there are some questions regarding the extent to which the difference in trend is due to siting problems & not other differences. For instance, since Watts uses only the raw values, if more of the CRN 1&2 sites have switched to MMTS or been subject to changes in the time of observation, that could also explain the cooler trend found. This may be a plausible explanation for the differences in light of Watts observation that the CRN 1&2 sites were affected more by the NCDC adjustments than the CRN 3,4,&5 sites.

- Finally, I suspect the timing of this was to distract from the BEST study. It's worth noting also that Watts only looked at the U.S. and only during the 1979-2008 period. The conclusions are not necessarily valid elsewhere or during different time periods (especially since most of the changes and corresponding adjustments to the USHCN occurred during this time frame). This is especially true for the global land & ocean temperature datasets, since nearly 70% of the globe is ocean.

The TOBS adjustment problem is largely negated by using the 1979-2008 baseline as most of the sites that used the old practice were well before this time...there are still a few that need to be adjusted for TOBS, but much less than you see in the older records. This makes the raw values for rural "CRN 1/2" sites closer to the actual trends than would be if they dated it back further.

[dabize]

I agree with many of Don's points...however, I disagree with just about everything you posted here.

You attack motive of funding, when the funding for the pro-AGW view is much higher...then you point that the recent heat waves in the U.S. have made him more desperate when global temperature rise has essentially halted the past decade and considerably slowed since the turn of the century.

Document this bolded statement please.

The "pro AGW view" is a pretty political way of putting it, BTW. Unless your position is that 1) the Earth isn't warming and/or 2) that humans have nothing to do with it are scientifically supportable statements.

[ORH_wxman]

Document this bolded statement please.

The "pro AGW view" is a pretty political way of putting it, BTW. Unless your position is that 1) the Earth isn't warming and/or 2) that humans have nothing to do with it are scientifically supportable statements.

My statement wasn't political at all...it was fact. Papers that support AGW are much better funded than the alternative, mostly because there's way more of them. For someone to say that the reason they issue a paper was because they need funding is ridiculous if you only accuse one side of it with no evidence.

Friv brought the political conjecture into the thread by speculating on Watts' motive and then speculating again that he is "desperate" because of the recent US heat waves. Both statements completely unscientific.

It shouldn't turn into that kind of debate like too many threads seem to.

[dabize]

My statement wasn't political at all...it was fact. Papers that support AGW are much better funded than the alternative, mostly because there's way more of them. For someone to say that the reason they issue a paper was because they need funding is ridiculous if you only accuse one side of it with no evidence.

Friv brought the political conjecture into the thread by speculating on Watts' motive and then speculating again that he is "desperate" because of the recent US heat waves. Both statements completely unscientific.

It shouldn't turn into that kind of debate like too many threads seem to.

But thats not what you said - you said that "funding for the AGW point of view" is greater, which carries the clear implication that more funding supports pro AGW opinion than anti-AGW opinion, presumably in the propaganda war that is now being funded largely by fossil fuel interests. This is manifestly untrue as a general statement. You said nothing about science. Watts does not exactly have a record as a reputable scientist - he is a political actor, with funding from Heartland. It is clear that this is what Friv was referring to when he said that that "Watts has to worry about how many clicks his website gets, how much funding he gets from sponsors of the cause, and how much his books sell"

You are of course correct that there are many fewer scientific papers supporting the anti-AGW position, but this is for the very good reason that there are very few scientific grounds for doing so. This point is trivial - there are no doubt also many more papers supporting the validity of the p-orbital than opposing it for the same reason.

[ORH_wxman]

But thats not what you said - you said that "funding for the AGW point of view" is greater, which carries the clear implication that more funding supports pro AGW opinion than anti-AGW opinion, presumably in the propaganda war that is now being funded largely by fossil fuel interests. This is manifestly untrue as a general statement. You said nothing about science. Watts does not exactly have a record as a reputable scientist - he is a political actor, with funding from Heartland. It is clear that this is what Friv was referring to when he said that that "Watts has to worry about how many clicks his website gets, how much funding he gets from sponsors of the cause, and how much his books sell"

You are of course correct that there are many fewer scientific papers supporting the anti-AGW position, but this is for the very good reason that there are very few scientific grounds for doing so. This point is trivial - there are no doubt also many more papers supporting the validity of the p-orbital than opposing it for the same reason.

I'm not sure what is so difficult about my statement, funding is greater for pro-AGW papers. If you support Friv's post then that is your business, but it had zero scientific grounds. I could easily say that Hansen is subjectively adjusting the GISS UHI/classification data so he keeps the government funds rolling in, but that is totally unscientifc and pure conjecture.

On top of it all, Watts' paper isn't debunking global warming, it is helping confirming it by producing positive trends in the temperature record. It is just questioning the magnitude.

The only real achievement arguments like that do is to divert everything away from the science. Don't people want to know the truth? I know Friv said that in the arctic thread. If they want to know the truth, then they wouldn't divert attention away from the actual scientific method, and instead embrace it.

[dabize]

I'm not sure what is so difficult about my statement, funding is greater for pro-AGW papers. If you support Friv's post then that is your business, but it had zero scientific grounds. I could easily say that Hansen is subjectively adjusting the GISS UHI/classification data so he keeps the government funds rolling in, but that is totally unscientifc and pure conjecture.

On top of it all, Watts' paper isn't debunking global warming, it is helping confirming it by producing positive trends in the temperature record. It is just questioning the magnitude.

The only real achievement arguments like that do is to divert everything away from the science. Don't people want to know the truth? I know Friv said that in the arctic thread. If they want to know the truth, then they wouldn't divert attention away from the actual scientific method, and instead embrace it.

You simply ignored the point I was making. Read what I said again. My objection was to the tendentious way you phrased your statement about relative funding of the "AGW point of view". I thought that this conflation of political and scientific was unhelpful, especially since you were essentially criticizing Friv for making this discussion political.

[phlwx]

You simply ignored the point I was making. Read what I said again. My objection was to the tendentious way you phrased your statement about relative funding of the "AGW point of view". I thought that this conflation of political and scientific was unhelpful, especially since you were essentially criticizing Friv for making this discussion political.

It seems like you're the only one making the discussion political at this point because you wish to pick nits over how someone words something.

(Of course, by the time I stick my head back in this thread it will likely be hijacked with the usual back-and-forth, so I'm pretty sure having a substantive discussion of the paper is about as likely as the Cubs winning a world series this year).

[Ellinwood]

Who the hell cares about the funding. This is about the science. Get over yourselves get get back on topic.

Watts does have some merit in his paper, but like others here I agree that there could/should be a decent amount of modification to the final paper (especially since people in the comments spotted several grammar/label errors ). It was a bold move to make those claims against the official adjustments, but there is probably a good middle ground to be had somewhere.

[bluewave]

Who the hell cares about the funding. This is about the science. Get over yourselves get get back on topic.

Watts does have some merit in his paper, but like others here I agree that there could/should be a decent amount of modification to the final paper (especially since people in the comments spotted several grammar/label errors ). It was a bold move to make those claims against the official adjustments, but there is probably a good middle ground to be had somewhere.

This recent effort is old news. The NCDC already discussed the issues that he raised in the earlier effort and found

no merit to them.

http://www.ncdc.noaa.gov/oa/about/response-v2.pdf

there is no indication from this analysis that poor station exposure has imparted a bias in the U.S. temperature trends.

[Srain]

A new day is dawning for the CC Forum where staff is going to become more heavily involved and politics will be removed to OT/PR. Let's keep this discussion civil and on topic. Thanks.

[Jonger]

Could we here in Canada borrow Mr Watts for a season or two. The crops are burning up, MYI older than my cat has disappeared and my AC costs are staggering. Please do a study here Tony. I want my ice back.

Terry

Last year was the wettest season on record in Detroit. There is no pattern... Just stop it with that.

[LakeEffectKing]

This recent effort is old news. The NCDC already discus)sed the issues that he raised in the earlier effort and found

no merit to them.

http://www.ncdc.noaa.gov/oa/about/response-v2.pdf

there is no indication from this analysis that poor station exposure has imparted a bias in the U.S. temperature trends.

Watts has revisited the issue and comes to a different conclusion...debate will enhance the general knowledge of the subject matter....hand waving won't...

[bluewave]

The paper can be found at:

http://wattsupwithth..._webrelease.pdf

Some quick thoughts:

- The paper makes the claim that the lower tropospheric temperatures (which have been running cooler than surface temperatures) are an upper bound. Claims they trend faster than surface temperatures. Recent literature suggests otherwise. Instead, the lower troposphere has been warming more slowly than the surface.

- The Berkeley Earth Surfact Temperature (BEST) study reviewed more than 39,000 stations, both in the U.S. and globally. The Watts study is based on 779 U.S. stations.

- Assuming that the Watts study correctly applies the Leroy methodology, the question as to whether the "well-sited" stations are representative of the U.S. overall is not addressed. Concentration could lead to a tainting on account of regional variability.

- The paper attacks the NCDC's approach to data homogenization, but that quality control approach of adjustment/correction has not been disavowed in the literature. BEST used multiple statistical approaches and reached similar conclusions about the overall reliability of the data. Watts may be advocating an outlier approach to adjustment, especially as earlier last freezes, later first freezes, plant hardiness zones, bloom times, etc., are consistent with a warming, not stable, U.S. temperature regime.

- Watts notes that his study found that the airport stations are, on average, better-sited than others. Yet, he largely dismisses the data from those stations, which leads to an even cooler outcome than would otherwise be the case. In short, he is arriving at a conclusion that rests on a sample that is not necessarily random and not necessarily representative.

- Watts suggests that GISS and NOAA arrive at similar temperature trends due to incorrect data homogenization. As both pursue independent approaches to data homogenization, odds that both are incorrect, while Watts's approach is correct, may be low.

- In sum, Watts's paper constitutes a frontal attack on the U.S. climate record, as he suggests only a small number of stations are properly sited and rejects the broadly-accepted methodologies used for quality control. IMO, it is difficult to believe that the U.S. climate record, particularly with all the effort that is made to assure its quality, is unreliable. I suspect that the Watts paper likely will not have a large impact overall. It will be embraced by climate change contrarians on account of its claim that there is "spurious" warming in the U.S. climate record. It won't be embraced by the overall climate science field.

I'll be interested to see how the paper is received by the scientific community.

Don, this is all a bit confusing in light of Watts praising the BEST project on his blog.

Some multiple quotes:

http://wattsupwithth...my-visit-there/

I think, based on what I’ve seen, that BEST has a superior method

And, I’m prepared to accept whatever result they produce, even if it proves my premise wrong

[donsutherland1]

I think, based on what I’ve seen, that BEST has a superior method

And, I’m prepared to accept whatever result they produce, even if it proves my premise wrong

I agree. The BEST study is exhaustive and its methodology is very strong. That it upheld the validity of the major temperature data sets suggests that prospects of undermining that validity overall is low.

[WeatherRusty]

A new day is dawning for the CC Forum where staff is going to become more heavily involved and politics will be removed to OT/PR. Let's keep this discussion civil and on topic. Thanks.

That's great. One problem I have however pertains to what is perceived as 'science' coming from the skeptical 'side' is nothing but a finely cloaked political, ideological attack on the mainstream science behind climate change. The science is not political, the debate is.

Good luck trying to discern the difference!

[WeatherRusty]

I'm not sure what is so difficult about my statement, funding is greater for pro-AGW papers. If you support Friv's post then that is your business, but it had zero scientific grounds. I could easily say that Hansen is subjectively adjusting the GISS UHI/classification data so he keeps the government funds rolling in, but that is totally unscientifc and pure conjecture.

On top of it all, Watts' paper isn't debunking global warming, it is helping confirming it by producing positive trends in the temperature record. It is just questioning the magnitude.

The only real achievement arguments like that do is to divert everything away from the science. Don't people want to know the truth? I know Friv said that in the arctic thread. If they want to know the truth, then they wouldn't divert attention away from the actual scientific method, and instead embrace it.

What are "pro-AGW papers"? I thought there were science papers. You introduce the aspect of debate and motive when implying there are sides to the issue.

When a study is done on ocean CO2 absorptivity for instance, do you feel the purpose of the study is to prove or disprove AGW? The aggregate of all studies tends to support AGW so of course more funding goes into those studies looked at in hindsight.

Tell me Watts' motive is not first to help dispel the concept of significant global warming by proving the U.S. temperature record to be questionably accurate. Let's hope his study, which just happens to coincide with the release of the BEST study, just like 'Climategate' just happened to coincide with 'Copenhagen' bears some scientific fruit.

[Ottawa Blizzard]

Could we here in Canada borrow Mr Watts for a season or two. The crops are burning up, MYI older than my cat has disappeared and my AC costs are staggering. Please do a study here Tony. I want my ice back.

Terry

Could the fact that average temperature records have risen over the past 50 years be at least in part due to the fact that airports which were once located in rural areas (Pearson in Toronto for example) are now in urban areas? When you drive your car out of the city in the wintertime, you can see the temperature drop substantially on your car thermometer, for example. If Ottawa's recording station were located in, say, Almonte, as opposed to the airport, would not the average temperature be lower?

[PSUBlizzicane2007]

Could the fact that average temperature records have risen over the past 50 years be at least in part due to the fact that airports which were once located in rural areas (Pearson in Toronto for example) are now in urban areas? When you drive your car out of the city in the wintertime, you can see the temperature drop substantially on your car thermometer, for example. If Ottawa's recording station were located in, say, Almonte, as opposed to the airport, would not the average temperature be lower?

You're ignoring the fact that all of those formerly rural now suburban/urban areas as a whole have a raised temperature which contributes to the warming of the climate.

[TerryM]

Could the fact that average temperature records have risen over the past 50 years be at least in part due to the fact that airports which were once located in rural areas (Pearson in Toronto for example) are now in urban areas? When you drive your car out of the city in the wintertime, you can see the temperature drop substantially on your car thermometer, for example. If Ottawa's recording station were located in, say, Almonte, as opposed to the airport, would not the average temperature be lower?

Would this explain temp differences in say Gore Bay, Moosonee or Blair? Too many places that haven't grown show the same pattern. If I drive out of Cambridge in winter temps depend on the direction I'm headed, leaving Kitchener things usually get warmer & I think the same it true of London unless you head north.

IThe urban heat island effect was pretty well covered by BEST.

Terry

[toronto blizzard]

You're ignoring the fact that all of those formerly rural now suburban/urban areas as a whole have a raised temperature which contributes to

the warming of the climate.

No I don't think he's ignoring that fact