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Comment by jjtheblunt | Hacker News Reader

i wonder how much contribution to hotter and hotter summers corresponds to more and more concrete / asphalt.

In the Phoenix areas that abut open nature, one can feel the radiant heat for a long time from concrete/asphalt after the sun intensity has reduced, in contrast to walking off into desert land where the air temp immediately feels many degrees cooler.

How much does that matter? (And that proliferation of concrete/asphalt is an obviously man-made issue.)

Edit: thanks to responses for terms i hadn't thought to look up. Very useful sites.

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>How much does that matter? (And that proliferation of concrete/asphalt is an obviously man-made issue.)

My understanding is that globally this matters little, but locally, this can matter a lot.

You do need to account for this to some extent when comparing long term temperature measurements at the same location.

> My understanding is that globally this matters little, but locally, this can matter a lot.

My understanding is that they checked in places with and without concrete (like the ocean, remote areas, etc).

The urban heat island effect is well understood: https://en.wikipedia.org/wiki/Urban_heat_island

It is not the reason for global warming, but it can be the reason places like Chicago and Phoenix are hotter than their nearby surroundings.

I am confident that the heating effect of "heat islands" has been studied, as I'm pretty sure I've seen mention of such, but I'll leave the search for that as an exercise for the reader. Though the EPA has a whole bunch of information, and you might wish to start here:

https://www.epa.gov/heatislands/measuring-heat-islands

a graduate student at Berkeley gave a presentation on exactly this topic, a few years ago. From first-hand viewing, they used maths to determine range of effect of the heat entrapment in urban enclaves, at several scales. It was rigorous enough for the serious science in the room, and was well-received. The result is basically as someone else said -- local effects are very large, but regarding the whole climate, not a driver basically.

It's somewhat approached through the concept of Urban Heat Islands. I would also imagine that rocks and mountains store plenty of thermal energy similar to a urban heat island. I don't know enough to offer a substantial comment beyond that.

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