Does pavement contribute to earth global warming?

Question

Consider all the parking lots, streets and highways. They used to be areas of vegetation.
When the sun shines pavements turn really hot and they stay hot well into the night. If it were a patch of grass I wouldn't burn my feet on it.
So could pavement be a significant contributor to our climate problem?

Answer 1

Yes they do. Per unit area they contribute significantly because as you correctly point out, they absorb a lot of heat energy from the sun. When the ambient (air) temperature falls this excess heat is radiated from the pavement as thermal radiation and it's this type of radiation that is trapped by greenhouse gases.

Heat from the sun is a different type of radiation (solar) and has a shorter wavelength than thermal radiation, this means it's not so easily trapped within our atmosphere. The more reflective surfaces such as snow, ice and water reflect much more solar radiation straight back into space. Problems arise when this heat from the sun is absorbed by surfaces and subsequently released as thermal radiation.

When we look at the world as a whole only a very small part of it is paved over so the total contribution that pavements make to global warming is a small one. As more land is paved over the effect is becoming greater and there's something of a feedback cycle at work.

Warmer temperatures melt snow and ice exposing the ground beneath, this absorbs more heat cuasing more snow and ice to melt and so on. The same thing happens following crop failure and drought, the barren soils absorb more heat than the crops that would otherwise be growing on them, this is especially true in some parts of Africa and Asia which have very poor soils to begin with and are much more susceptible to the effects of climate change.

It's not just pavement that absorbs heat, all surfaces do and the darker, denser, thicker and more conductive they are the more heat they absorb. In our major cities there's so much glass, steel, concrete and the like that temperatures are generally higher than in the rural surroundings (there are other factors at work as well). This is sometimes referred to as the Urban Heat Island Effect and is well understood by meteorologists and climatologists.

Answer 2

1. Almost true - greenhouse gases slow the transfer of heat. They are not like a lid on a boiling pot that release no heat. There is a logarithmic effect. Each new CO2 molecule causes less warming than the last CO2 molecule. 2. True - but these gases also accumulate from natural causes. 3. True. 4. ? 5. True, but scientists do not yet understand solar amplication at the poles. 6. Depends on what you use as your reference period. According to the CRU, 1998 is still the warmest year on record. Yes, it was an El Nino year but so was 2006. 7. Not yet. There is strong evidence that galactic cosmic rays are involved in the formation of low level clouds that cool the Earth. There is still some debate about how this fact plays out in the climate. Hendrik Svensmark at the Danish National Space Center still has high hopes that his theory will gain the ascendancy. 8. False. 9. False. But past climate changes prove that the recent warming is not necessarily outside natural climate variability, which was the claim by alarmists. 10. Absolutely true. Some people confuse this with the Urban Heat Island effect, but poorly sited stations occur in rural locations as well as urban. Some of these weather stations are located on top of parking lots! The fact this causes artificial warming is self-evident to anyone who understands heat transfer. More importantly, McIntyre did a reconstruction using only good quality stations rated CRN1-2 and found a significant change in the US temp record.

Answer 3

UHIE

Global Warming crowd doesn't like to hear about it.

Urban Heat Island Effect

Does it add to the global climate problem? That's hard to say, but there is no doubt that it adds to urban warming. Where it enters the global warming equation is that most warming data is still dependent on ground-based stations, despite the capabilities of satellites to accurately measure global temps. Many weather/temperature stations are located at airports because they were originally built from a practical need. The boom in the air industry led to urbanization around airports - just like sea ports through the ages.
http://globalwarming.org/article.php?uid=766

Ask someone who flies sailplanes - you get INCREDIBLE thermals over pavement. A hang-gliding friend of mine claims to have had his life saved by a thermal from a patch of pavement once up in the Rockies (He said he was going down like being "pushed by the thumb of God" until he caught it.) You've likely seen the "mirage" effect over hot pavement. It's a lot of heat. Probably not enough to effect global climate, but possibly enough to skew temperature recording.


Really, Bob? The "definitive" paper is "Peterson, T.C., Assessment of urban versus rural in situ surface temperatures in the contiguous United States: No difference found. J. Climate, 16, 2941–2959."? If it is so "definitive", then why did T.C. Peterson decide to revisit the topic a few years later and come to the conclusion that "The implications of
this work on U.S. climate change analyses is that, if the highest population stations are avoided (populations above 30,000 within 6 km), the analysis should not be expected to be contaminated by UHIs."

http://lwf.ncdc.noaa.gov/oa/climate/research/population/article3abstract.pdf

You are priceless, Bob - you make it so easy. Thanks.

If you check out the paper, he's suggesting that they drop ~30% of these stations affected by UHIE. That ain't chicken scratch...

Answer 4

Significant? No.

Just not enough pavement.

It's easy in global warming to get distracted by small things. We need to focus on the big ones; cars, electric power plants, factories, homes.

3DM below is either ignorant or fudging the truth when he says:

"Global Warming crowd doesn't like to hear about it."

That's silly. This statement, like many other denier statements (note that the link is to a denier's propaganda website, not to any real science), assumes scientists are dumb and don't look at obvious things. Of course, climate scientists have thoroughly investigated the possibility that the Urban Heat Island Effect is affecting the global warming data. It's definitely not. The definitive paper is:

Peterson, T.C., Assessment of urban versus rural in situ surface temperatures in the contiguous United States: No difference found. J. Climate, 16, 2941–2959.

EDIT2 - 3DMs still fudging the truth. He stopped quoting Petersen's 2004 paper when continuing would demolish his argument. Let's finish. While Petersen found that, using advanced statistical techniques, he could find a tiny effect (signal) from the high population sites, it was too small to change the global warming trend data:

"However,comparison between U.S. Historical Climatology Network (HCN) time series from the full dataset and a subset excluding the high population sites indicated that the UHI contamination from the high population stations accounted for very little of the recent warming."

So, according to the very paper 3DM cited, the UHIE doesn't change the facts about global warming. Presumably he'll now stop posting skeptical stuff. About this issue, anyway.

Answer 5

No, pavement is made with chemicals and stuff yes, but in return, it cracks so it can adapt to heat, it also absorbs the suns heat, yes it burns feet, but gravel pokes at them, and I've adapted to that, so I'm sure you can adapt to pavement, haven't you heard of these things called sandals, be sure not to get black colored ones, because they won't help you much though.

Answer 6

No more than deserts and rocky landscapes. Think of how hot sand and shale get. Also it wouldn't add to warming because it is only absorbing more of the sun's heat, not producing its own heat.

Answer 7

Anthropogenic heeating of urban areas, which is caused by physical changes of that environment and the release of energy (heat), is estimated to be 0.03 W/m2 world-wide.

The combined anthropogenic RF is +1.6 [ -1.0, +0.8] W/m2.
The combined natural RF ( solar irridiance, volcanic aerosols) is + 0.12 [-0.06, +0.18].

* RF is defined as the change in net irridiance at the Tropopause (boundary between Troposphere and Stratosphere).

Now, this is only regarding urban areas, not counting the roads in other places.

Answer 8

If pavements are replaced by our natural defenses such as rain forests, then Yes.

Answer 9

F you and global warming. I hope the ice does melt and we all drown alive