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Green energy

I had an interesting conversation tonight that has left me a bit dumbfounded and very curious.....
Solar energy-possibly not a good thing large scale? The suns rays come to earth and provide us what we need, then bounce back into the atmosphere which is what keeps the earth warm. Summer months the rays are closer and shifted at a different angle which is why the temps are higher, it's easier to burn, etc etc. BUT solar panels absob the rays and don't bounce them back into the atmosphere. On a large scale could excessive use of solar energy (such as used to power entire cities) could problems with the "heating" of the earth?
Has anyone of heard about studies or anything like this?
We talked about the pros and cons of wind turbines too and I'm just blown away by the negatives to green energy I had never heard about before!

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Disclaimer: I have *not* studied the thermodynamics of green energy or even of conventional energy generation, for that matter.

However, I believe I have a pretty good understanding both of basic science and of our planet.

Earth's surface is roughly 70% water and 30% land. Not all of the land is habitable, even with 6 billion (!) people pushing into marginally habitable regions.

So let's say that roughly 25% of the Earth's surface is habitable (in other words, 5/6 of the land). (Keep in mind large, uninhabitable--or barely habitable-- landforms like the Sahara Desert, the Empty Quarter of Saudi Arabia, the Gobi Desert, Siberia, the Northwest Territories, northern Greenland, the Deccan, the Hindu Kush, most of the Himalayas, the Kalahari, the Outback, and Antarctica.) 25% is no doubt wildly off, but I'm pretty sure it's higher than what it should be, and it will therefore act conservatively in what follows.

Of this 25% of the planet that's habitable, how much *actual surface area* will be devoted to solar energy collectors in the future that your interlocutor was conjuring? By "solar energy collectors," I mean panels, solar ovens, passive water heaters, double-pane windows with seasonally appropriate reflectors/pass-through filters...anything which converts solar energy into a more useable form for the benefit of people or their animals. Plants don't need our help converting solar energy; they've been doing it for millions of years.

I'll wait while minds, calculators, and spreadsheets do their thing.

[tick tick tick :wink:]

OK. Got it?

75% of the Earth's surface will NOT be affected in any way by solar energy collectors, since this 70% ocean + 5% uninhabitable land is by definition unsuitable for development.

We already experience a large "bounce-back" of solar energy every day due to perfectly normal cloud formations. What will differentiate the bounce-back of solar collectors from that of cloud formations, which are orders of magnitude larger?

Just some questions to ask your conversation partner. Also ask him/her where the information s/he's coming up with came from. It sounds very alarmist as well as perhaps non-scientifically based. I myself would welcome sound science on this point.

Cynthia H.
Sunset Zone 17, USDA Zone 9

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Thank you Cyn for making it possible for me to sleep tonight! I was so dumbfounded by a legit sounding opposition to my stance on solar energy I never even REALLY thought it over :twisted: Can't wait to talk to my brother tomorrow and pop his big fat "I'm always right" balloon!
Hehe, I love my brother I do, but he gets the most hairbrained thoughts some days and drags my gullable butt right down with him.

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First with forests being cut down and cities sprouting up and paving over the land a little cooling may not hurt. Second with CO2 and Methane being dumped at a higher rate in to the air heating the Earth is not the problem.

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