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Earth Science

Cities' Heat Can Affect Temperatures 1000+ Miles Away 263

Posted by timothy
from the let's-terraform-earth dept.
Living in dense cities makes for certain efficiencies: being able to walk or take mass transit to work, living in buildings with (at least potentially) efficient HVAC systems, and more. That's why cities have been lauded in recent years for their (relatively) low environmental impact. But it seems at least one aspect of city life has an environmental effect felt at extreme distances from the cities themselves: waste heat. All those tightly packed sources of heat, from cars to banks of AC units, result in temperature changes not just directly (and locally) but by affecting weather systems surrounding the source city. From the article: "The released heat is changing temperatures in areas more than 1,000 miles away (1609 kilometers). It is warming parts of North America by about 1 degree Fahrenheit (0.6 degrees Celsius) and northern Asia by as much as 1.8 degrees Fahrenheit (1 degree Celsius), while cooling areas of Europe by a similar amount, scientists report in the journal Nature Climate Change. The released heat (dubbed waste heat), it seems, is changing atmospheric circulation, including jet streams — powerful narrow currents of wind that blow from west to east and north to south in the upper atmosphere. This impact on regional temperatures may explain a climate puzzle of sorts: why some areas are having warmer winters than predicted by climate models, the researchers said. In turn, the results suggest this phenomenon should be accounted for in models forecasting global warming."
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Cities' Heat Can Affect Temperatures 1000+ Miles Away

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  • by Anonymous Coward on Monday January 28, 2013 @03:34AM (#42713449)

    more than 1,000 miles away (1609 kilometers)

    Seriously, if you have one rough rounded number you can't do an exact convert and add false precision to the statement...

    • Re: (Score:3, Interesting)

      by AliasMarlowe (1042386)

      more than 1,000 miles away (1609 kilometers)

      Seriously, if you have one rough rounded number you can't do an exact convert and add false precision to the statement...

      At least they didn't quibble about the difference between the UK Statute mile and the US Survey mile (the US mile is longer by 3.2mm [unc.edu]), or even the rounding error of over a third of a km in their conversion.

    • by Genda (560240) <mariet&got,net> on Monday January 28, 2013 @04:06AM (#42713561) Journal

      I took chemistry a long time ago. The teacher said if you turn in dissociation constants with more than two decimal places, he'd mark them wrong (for those students who did their calculations on digital devices and copied all 10 digits of result.) He explained that these were chaotic events and everything past the second digit was noise.

      I think the point of the very specific number above is simply it being a single data point. In fact heat effects may travel tremendously further than even that. More important, if heat is shifting the jet stream, secondary and tertiary effects may be happening downstream many thousands of miles and include drought, flood, or unseasonable weather. As well, the city heat drives low altitude moisture and chemical particulates (soot and industrial dust) into the higher atmosphere (potentially punching a hole in the common inversion layers) and that moisture/nucleation may have significant down wind impacts as well. I'm looking forward to seeing what the models say. If we're lucky, the effect will be more cloud cover, increasing earth's albido, and be a thermal cooling factor over-all. If not, it may be adding to a climate that is growing ever more unstable and that's bad news for everyone.

      My question is, why isn't anyone talking about the air pollution problems happening this month in China? Air that's being called lethal by some, over 40x more polluted that world health limits recommend. Here's a story [freerepublic.com] about a factory that burned for 3 hours because nobody could tell the difference between the smoke and the pall of smog. My greatest concern is that over the last ten years there have been several events of smog from China reaching the western U.S., this being the worst smog event in remembrance, there is a real chance it could make it to America. Thankfully, it winter and most likely will be washed into the sea by storm systems. Had this been summer we would certainly be facing serious environmental threat. So why isn't this a HUGE conversation right now, virtually nobody is even talking about it.

      • by dbIII (701233) on Monday January 28, 2013 @04:32AM (#42713651)

        My question is, why isn't anyone talking about the air pollution problems happening this month in China?

        I thought we'd been talking about that for years (especially around the time of the Olympics) and haven't stopped.

      • by Sockatume (732728)

        Augh! Talk about teaching a good idea for the wrong reasons. If you can measure your original data to n significant figures, and your conversion factors and constants and so on go to the same number of significant figures, then there's no reason why you can't quote the final value with the same precision. (I'm glossing things over here; addition and subtraction work differently to multiplication and division.)

        There's nothing magical about "two decimal places", especially given that the number of decimal pla

        • by Genda (560240)

          Since the dissociation constant is a ratio of dissociated ion vs associated whole dissolved molecules in solution (at equilibrium between between ionization and recombining) the value is completely independent of quantities or units of measure (the ratio between the two at let's say STP would remain constant, ergo Dissociation Constant.). Also because this process is incredibly sensitive to temperature and mechanical motion (including brownian motion), fine scale measurements are very noisy in nature. Which

          • by Sockatume (732728)

            Actually strictly speaking your dissociation constants have units that depend upon the reaction, given that they're a special case of the equilibrium constant. (It seems it's typical to eliminate units by some means or another.) While I understand that the measurements are tricky and noisy (I was never much good at labs) there is no intrinsic physical limit on their precision, and it would be more informative to point out that you can have no greater precision in your final results than you have in your inp

      • My question is, why isn't anyone talking about the air pollution problems happening this month in China?

        Yeah, because what would /. be without dupes? [slashdot.org]

      • Hey, You, a student of Dr Swaminathan too? He too would give a D for any lab sheet turned in without calculating the estimate of experimental error, or if the reported result had too many significant digits. But he was doing freshman Physics at IIT-M, not chemistry.
    • you can't do an exact convert and add false precision to the statement...

      Evidently you can.

    • by BlackPignouf (1017012) on Monday January 28, 2013 @06:12AM (#42713983)

      It reminds me of a joke.

      A tour guide in front of the pyramid of Gizah : This pyramid is 4507.5 years old.
      A tourist : Wow! Which dating methodology did you use to achieve such a precision?
      Tour guide : It's quite simple actually. I got this job in summer 2005, and it was 4500 years old at that time.

  • ... But this directly contradicts those greenhouse-gas warming models that assume that the "heat island" effect is of little or no significance. To the best of my knowledge, that is the majority of them.
    • Re: (Score:3, Insightful)

      by Anonymous Coward

      Not really. The overall temperature difference is the same. This is just affecting how the change is distributed. It's notable, and explains a known issue with the models, but it doesn't in any way invalidate the overall predictions, i.e., things are getting warmer.

      Seriously, the entire waste heat production of humanity is nothing compared to solar heating. Solar heating is ~170 petawatts. The total energy production of humanity isn't even a tenth of a percent of that. Closer to a hundredth of a perce

      • Re: (Score:3, Interesting)

        by viperidaenz (2515578)

        Also the vast majority of CO2 production is not man-made. The carbon cycle is massive. We just tipped the balance it was in by chopping down some carbon sinks and burning up some reserves.

        • by Viol8 (599362) on Monday January 28, 2013 @05:30AM (#42713841)

          Unfortunately tipping the balance is all that is required to mess it up.

          • Here's the thing that should clear on the order of crystal to those most sentient amongst us: if there is the slightest chance that our wanton use of the earth's resources is not without global consequences and repercussions, we are fools if we don't do everything we reasonably can to mitigate the damage our presence creates. We may or may not be the only self-aware species on the planet, but there's a decent probability we are the most self-aware, and one would imagine that incredible privilege comes wit
    • by SuricouRaven (1897204) on Monday January 28, 2013 @04:12AM (#42713593)

      The heat island effect has always been taken into account for purposes of observation - when some of your data points are located in cities, you need to either discard them or compensate in some manner. This study shows that the effect covers a far wider area than previously thought. A few minor revisions to the models are needed. That doesn't mean previous predictions are suddenly all wrong - just that they are not as accurate as they will be once these revisions are implimented.

    • by ssam (2723487)

      The part of the earth that has warmed the most or the north pole. i am not sure how you could account for that by an urban heat island effect.
      http://www.giss.nasa.gov/research/news/20130115/ [nasa.gov]

      • by Gabrill (556503)

        Heat disburses in air. All the heat is still there, mixed in with the rest of the earth (and it's atmosphere).

    • Many a times issues like this get brought up, and all of them have turned out to be nothing. Lets wait and see what comes of this.
    • by Sockatume (732728)

      You're talking about local weather versus global climate. It's perfectly natural that an effect might appear at one scale and not the other.

  • by CRCulver (715279) <crculver@christopherculver.com> on Monday January 28, 2013 @03:43AM (#42713493) Homepage

    One of the concepts that interested me in Larry Niven's classic science-fiction work Ringworld [amazon.com] is a civilization having to move its planet out from its sun in order to avoid perishing in their waste heat. I haven't seen that possibility explored so much in the years since. With studies like this, along with Kurzweil-ish woo-woo of extrapolating growth, can we talk an amusing guess at how long until heat waste renders the Earth, or at least certain parts of it uninhabitable?

    • by Sockatume (732728)

      The excellent "Do The Math" blog estimates that we have 400 years [ucsd.edu] until we're consuming as much energy as the planet is receiving from the sun. That's a good rule of thumb I think. Anything beyond that and by definition we can't have our current combination of albedo and surface temperature.

      Interestingly that estimate also states we have about 1500 years until we're using as much power as the sun produces in total, and we'll need to use the entire galaxy's power output in about 2500 years.

      • Re: (Score:2, Funny)

        by Anonymous Coward

        Ah, the joys of exponential extrapolation. Are you enjoying your 20 GHz processor, your 10 million wikipedia articles or the km-deep carpet of bunnies covering the surface of the Earth? :-)

        • by Sockatume (732728)

          Right, the whole point is that it's a riductio ad absurdum: the conclusions of the model on a long time scale make it obvious that the model can't be sustained.

        • by peragrin (659227)

          ah but if we figure out FTL in 1500 years we will be using that kind of power outputs.

          • by Sockatume (732728)

            Assuming we can create a Dyson sphere, which would require us to consume most of the solar system for building materials.

          • by DarkOx (621550)

            Even if we develop near light travel and start to explore deep space with multi-generational bio-sphere ships we could easily use energy on such a scale.

            Lets assume we can accelerate a space craft to .9C, that puts some near by galaxies in reach, within a few generations. I don't think you anything beyond that is practical because I don't think for social reasons it will be possible to stay on mission when none of the oldest living crew people can remember any of the folks who started out.

            So to get anywher

        • by JWSmythe (446288)

          Why would I mess with something so slow? I have 32Ghz (4Ghz * 8 cores).

          As for the bunnies, we don't have quite that many here. We've been burning them to keep the steam engines running.

          • by gl4ss (559668)

            Why would I mess with something so slow? I have 32Ghz (4Ghz * 8 cores).

            As for the bunnies, we don't have quite that many here. We've been burning them to keep the steam engines running.

            twenty vw beetles from 1960 don't go as fast as a single ferrari from 2013, no matter how much arm, intel and amd are trying to convince you.
            besides, we're already making energy that doesn't originate from the sun..

    • by Genda (560240)

      One would think there would be a way to convert the waste heat to let's say microwaves and shoot them at the moon. With a proper array on the moon you could immediately power a lunar civilization and remove earth's waste heat, two birds with one stone. If we created a small device that converted waste heat locally to hydrogen by splitting water, we could reclaim that energy or a reasonable amount of it. Heat concentrators could be used to remove heat from our cities where it would be converted to a frequen

      • by Sockatume (732728)

        Currently we use tens of terawatts. The power output of the best continuous-fire lasers or maser (and I use that term loosely) is on the hundreds of kilowatts. Pulsed lasers peak in the mega- to terawatt range but average power output is a lot less.

        • by Genda (560240)

          But what percentage of our industrial process ends up being waste heat, and what is the largest feasible array of transmitter one could reasonable build in, let's say the middle of the desert? Clearly the idea of building arrays of thousands or tens of thousands of high powered emitters would be daunting, however for any society looking to move their planet to accommodate increasing waste heat, it would seem to me should have the where with all to create huge, high efficiency quantum emitters to convert was

          • by Sockatume (732728)

            Yes, and eating a car is easier than eating the moon, but it's still quite daunting even assuming currently energy consumption remains constant.

            It's not an issue of waste heat, by the way: thermodynamics demands that every joule of energy we generate and subsequently use winds up as heat eventually.

          • by Rockoon (1252108)
            "Waste heat" is an interesting beast. At low levels of waste its not something to worry about, while at high levels of waste its an opportunity to generate electricity from it.
      • by ibwolf (126465)

        If we could actually capture and convert the waste heat into some form of usable energy, I believe we have plenty of use for it right here on Earth.

        • by Sockatume (732728)

          ...where it would be dissipated into heat again when used. You can't consume energy without (ultimately) releasing that much energy as heat.

    • With studies like this, along with Kurzweil-ish woo-woo of extrapolating growth, can we talk an amusing guess at how long until heat waste renders the Earth, or at least certain parts of it uninhabitable?

      Probably not. You've got to remember, that all this carbon we're currently emitting used to be a part of the carbon cycle. The Cretaceous period had half again as much atmospheric carbon as we do currently. A warming world might inconvenience humanity, and probably a bunch of other species, but it will advantage a whole bunch more. For the world as a whole, it's pretty much unimportant - it's been through such changes before.

      This is part of the problem with the semi-religious zeal of the lunatic fringe of t

  • by sciencewatcher (1699186) on Monday January 28, 2013 @03:59AM (#42713545)
    Serious, first thing to look for a thermal is the local town, absent mountains or hills. A large parking lot already does do fine. I know of a military airport which has a cemetary nearby, the dense black marble is sufficient.
    • by gl4ss (559668)

      umm which doesn't have much to do with this modelling of if that heat affects temperatures 1000 miles away from said cemetery.

    • The glider pilots in the DFW area refer to the plowed black-earth fields east of Dallas as "Texas brick lifters" in what I have been told is only mild exaggeration. So apparently heat island effects are not relegated to urban areas.

  • by CaptainOfSpray (1229754) on Monday January 28, 2013 @04:08AM (#42713577)
    I've seen a map of thunderstorm frequency for UK which shows that a majority occur directly downwind (in prevailing wind direction) from cities, and size and frequency of storms is related to size of the city. Thunderstorm frequency and severity also relate to frequency and severity of lightning damage and hailstorms. If I can find that again, I'll post a link (unless someone else gets there first).
  • Great (Score:4, Funny)

    by viperidaenz (2515578) on Monday January 28, 2013 @04:31AM (#42713647)

    Yet another significant factor not accounted for in climate change models.

    Also: News flash - Concentrated heat sources effect weather, back to you Tom Tucker.

    • by Sockatume (732728)

      Didn't the Berkley study explicitly evaluate the urban heat island effect and find it had no bearing on the models?

      That's a rhetorical quesiton.

      • by Rockoon (1252108)
        I don't know about its bearing on models, but there have been studies that umade claims about data selection that could not have been accomplished due to a distinct and complete lack of the information necessary to make that selection, that have ruled that the heat island effect has no meaningful impact on the temperature record (I'm looking at you Wei-Chyung Wang, bullshit science fraudster.)
        • by Sockatume (732728)

          I was referring to last year's study. I recall the accusations against Wang but as far as I can tell they were never actually substantiated.

          Imagine that! Independent confirmation of results on one hand, and unsubstantiated innuendo on the other.

        • by Sockatume (732728)

          You mean this [nature.com], wherein independent confirmation (from a third source this time) found the same conclusions from trustworthy data?

  • Time to destroy the cities before we are all swimming, or over heated, or something.

  • I love it when when, when converting US customary units to SI units, the precision of numbers suddenly increases by orders of magnitude. 1000 miles is obviously an approximation. Let's be charitable and say it means 10x10^2. If you convert it to kilometers the precision should stay the same. 10x10^2 miles is about 16x10^2 or 1600 km.
    • I knew I had to put another when in there, but this is ridiculous...
    • by Sockatume (732728)

      You've still got too many significant figures in your output. There's only one in the input, so 2000km.

      • by rasmusbr (2186518)

        You've still got too many significant figures in your output. There's only one in the input, so 2000km.

        That's correct, but practically speaking, when you translate some statement about reality you may want to avoid making the statement more surprising than the original statement. In this case you'd be spicing up the story quite a bit if you rounded it up to 2000 km.

      • Strictly speaking you're right, but as it is not a scientific article I think you're allowed a little leeway in deciding what the actual precision probably was. After all there is no way to tell whether 1000 really means 1x10^3, 10x10^2, 100x10^1 or precisely 1000.
  • I always thought that anything you plugged into something that was measured in thousands of Megawatts ought to get pretty hot.
  • by argStyopa (232550) on Monday January 28, 2013 @07:06AM (#42714121) Journal

    Think of the impact this would have, if many of the data-recording points for temperature were slowly surrounded by urbanization or in the 'heat shadow' of urban areas?

    http://www.john-daly.com/ges/surftmp/surftemp.htm [john-daly.com]

    He makes a compelling case, the refutation of which has been on the order of "of course they considered this, they're experts"...when there's no trace of such analysis or correction applied to East Anglia conclusions or IPCC reports through at least 2005 (after which I stopped bothering to read them).

    • Re:Hm, really? (Score:4, Informative)

      by Sockatume (732728) on Monday January 28, 2013 @08:45AM (#42714497)

      It was covered extensively in the BEST study and the correction was found to be negligible. (They applied the correction anyway.)

    • Think of the impact this would have, if many of the data-recording points for temperature were slowly surrounded by urbanization or in the 'heat shadow' of urban areas?

      In that case, it would be a good thing we have a backup with the satellite record.

  • How do those Europeans do it - managing to lower Europe's temperatures with their waste heat? Why can't we do that?

    On a more serious note, we all know that man-made stuff affects weather patters, but every large natural thing affects weather patterns as well. The weather is easy to affect, but what we should care about is not whether we affect the weather, but whether we do harm. Too many people run these together.

  • by pubwvj (1045960) on Monday January 28, 2013 @12:30PM (#42716825)

    "Living in dense cities makes for certain efficiencies: being able to walk or take mass transit to work, living in buildings with (at least potentially) efficient HVAC systems, and more."

    None of these are valid justifications for cities.

    Transportation: I can and do walk, rarely needing a vehicle. No need for mass transport either. I live on a farm and work there as well as in the forest. No need to drive. I often go months without getting in a car or truck.

    Efficient HVAC: Our high thermal mass, well insulated home is far more efficient requiring far less energy for heating than city buildings and it requires no cooling. It also doesn't affect the local or distant environments.

    Cities stink, are filthy dirty, centers of disease and filled with vermin of both the four legged, six legged and two legged sort. Cities can't produce their own food or fuel and they can't get rid of their own wastes. Studies show that they are black holes, blemishes on the environment, soaking up the resources and polluting thousands of square miles around them.

    The only question is where else do we put all those people?

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