That last part about 1940-1975 is telling, given that we now have a cleaner atmosphere, and less aerosols to reflect sunlight, it goes without saying that more sunlight now reaches the surface.

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They are home to the strangest ecosystems known, in which organisms get by without sunlight, using as an alternative source of energy the sulphurous gases spewed from deep inside the earth.

ECONOMIST: 20,000 leagues under the sea

That is necessary because the balloon concentrates sunlight up to 400 times, and without this cooling the cell would quickly burn out.

ECONOMIST: Monitor

By cooling such devices with liquids, IBM reckons it can increase the amount of sunlight that can be focused on them without destroying them, thus increasing the amount of electrical energy they produce.

ECONOMIST: Monitor

Unlike other technologies, Sequesco says it can convert carbon into liquid fuel without sunlight, which would avoid the Achilles heel of similar technologies.

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Without photosynthesis, the process by which plants use sunlight to convert carbon dioxide into energy, the trees effectively starve.

BBC: NEWS | Science/Nature | Climate threat has plants quivering

Perhaps the most interesting part of this design is its dual-mode power system, which consists of the standard solar cell array as well as a nuclear power source, allowing the rover to operate continuously and in areas that go long periods without sunlight.

ENGADGET: Chinese engineers reveal nuclear-powered lunar rover