I've been reflecting on climate change and pondering how much of it is truly man-made. Anyone who's shoveled a walkway know that the snow melts faster beside the walkway than it does in the middle of your yard. This is because you've exposed the ground which can absorb the sun's heat. Whereas the snow in the yard reflects it.

The same is true of glaciers: They melt away from rock faces (ie, terminal morrains, bergschrunds, etc.), and as more of the Earth's surface is exposed, the more heat the surface of the Earth can absorb, and the faster the rest of the Earth's ice can melt.

Consider the combined surface area of all the roads and parking lots that are cleared of snow each winter (as well as the increased number of roads and parking lots which capture a lot of heat each year). Snow clearing to the scale as is seen in recent decades far exceeds what has been accomplished in the past. Even as recently as the early 20th century people still made their way around on top of the snow in sleighs.

How much of a contributor to climate change can be attributed simply to roads and the relatively modern practice of snow removal?

  • $\begingroup$ If you think about it though, urban areas make up a very small part of the world. Snow in most places in the world pretty much stays where it is until it melts. $\endgroup$ – Barry Carter Oct 9 '19 at 17:52
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    $\begingroup$ tandfonline.com/doi/abs/10.1080/02723646.2016.1242351 $\endgroup$ – farrenthorpe Oct 10 '19 at 4:25
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    $\begingroup$ @farrenthorpe Are you able to summarize the conclusion of that study? $\endgroup$ – ShemSeger Oct 10 '19 at 17:42
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    $\begingroup$ It mentions that clearing snow does contribute a small measurable amount to the urban heat island effect. However, the contribution of the urban heat island effect to global climate change is quite small. $\endgroup$ – farrenthorpe Oct 11 '19 at 3:24
  • $\begingroup$ Cool. Finally a scientific excuse not to clean the pavement :-) $\endgroup$ – ebv 2 days ago

Urban areas, where most snow clearing is done, are heat islands already, so it would be tough to disentangle the effect of clearing snow off roads. Whitewashing black asphalt is one of the strategies being tried to reduce the heat effect in the summer, though, and black asphalt is seen as a big factor in heat islands, so it seems reasonable that exposing black pavement in winter would also have some impact, but detailed studies so far have mostly focussed on deadly summer heat, not winter effects.

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Although snow clearance makes a theoretical difference to climate change by reducing the amount of solar radiation reflected, the difference to average temperatures is negligible, so small as to be unmeasurable. In most cases the snow would melt within a few weeks anyway, so clearance makes no practical difference to global warming.

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    $\begingroup$ Can you please add some evidence or references to back up your statements? After all you expect for your own questions "an accurate estimate, not just a wild guess which anybody could make." (earthscience.stackexchange.com/questions/17733/…) so it should be fair that you provide the same $\endgroup$ – samcarter Oct 9 '19 at 21:51
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    $\begingroup$ Quora. What percentage of land area in the world is covered with pavement? 0.15% $\endgroup$ – Keith McClary Oct 10 '19 at 2:27
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    $\begingroup$ Areas between 35 south latitude and 30 north latitude hardly ever get snow. Snow is so infrequent in those locales that many of those places do not have any snow removal equipment whatsoever. $\endgroup$ – David Hammen Oct 12 '19 at 5:11
  • $\begingroup$ In UK snow near sea level seldom lasts more than 10 days and some years we get none at all. $\endgroup$ – Michael Walsby Oct 12 '19 at 8:11

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