Eli5 Is it possible that global warming is literally the result of humans are making the earth darker?


I’m sure this is just a really stupid question based on multiple misunderstandings, but what if global warming was literally just the result of more dark-colored buildings and structures such as blacktop roads? Are we making the earth absorb more sunrays, and therefore increasing the heat energy within the atmosphere?

In: 0

Not really because most of the energy doesn’t hit the land, it hits the ocean, and most of what we’ve built covers a tiny area. The majority of North America is extraordinarily rural with huge swaths of fields and forests and deserts, Siberia is still Siberia

Open ocean is very dark, it only reflects about 6% of the light that hits it. [You can see the effect on a globe showing overall albedo(percent reflected light)](https://upload.wikimedia.org/wikipedia/commons/4/40/Ceres_2003_2004_clear_sky_total_sky_albedo.png), notice how dark the oceans are relative to the land masses and how much more area they cover

The system also balances where visible light is absorbed by dark objects (the ocean) making them hotter causing them to emit more IR radiation into the sky and off into space. More dark means more light absorbed but also more IR emitted which should raise everything up a tiny bit to a new happy temperature.

More CO2 in the atmosphere keeps the IR from being emitted because the CO2 catches it and bounces a fraction of it back downwards towards the surface just like a blanket trapping warm air near you. The more CO2 or equivalent in the atmosphere the more likely it is that an IR photon will get caught and eventually bounced back towards the surface, this means that instead of just retaining some percentage more energy from being hotter, you slow the rate at which the heat can leave the massive dark and exposed area of the ocean. Since that’s the vast majority of the area, slowing its outflow has a wayyyyyy bigger impact than capturing a tiny bit more heat in the cities

Kind of? A small fraction of it is attributable, but what you’re thinking of is the albedo of a certain surface. High albedo = more light reflected (whiter in color) and low albedo = less light reflected (blacker in color). Building materials such as asphalt have lower albedo values, which can lead to the formation of “heat islands,” which are relatively concentrated areas of darker colored materials that absorb a disproportionate amount of heat. Unfortunately, oftentimes you will find such “heat islands” concentrated around redlined communities, especially in the US or Canada. As bacon12345 has said though, the majority of energy from the sun doesn’t hit land – the sea is dark enough and large enough to be much more of a contributer to global warming.

It is part of it. More to do with shrinking polar ice caps which reflect light that are displaced by water which absorbs much more of the light. Massive deforestation and horrible water management also contribute drastically to the problem. Landfills that have food waste which gives off methane which is many times more effective in trapping in heat aka the greenhouse effect.

You’re not completely wrong in that the dark asphalt of wide suburban roads and parking lots contributes to heat island effects, but those are extremely local and aren’t driving global climate change in the way that atmospheric and polar albedo are. That said, you’ve pointed out a good example of how auto-oriented development hurts communities beyond tailpipe emissions, which seems to be left out of the discussion about electrifying cars.