The World Set Free -- Watch it here.
Cosmos: Season: 1 Episode: 12
'Cosmos: A Spacetime Odyssey' -- "Ancient Greenhouse Worlds" (Background for Sunday's Episode)
from dailygalaxy.com -- May 31, 2014
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Is Venus the Ultimate Poster Child for Global Warming?
Venus was created at about the same time as Earth, in about the same place, and it's roughly the same size - it would therefore have started with the same materials as us, drawn together from the same region of the planet forming dust left over from the sun. But Venus now has only 0.001% of our water content, and a couple of flybys by the dynamically named Venus Express may have revealed the reason.
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Climate scientists believe that the planet experienced a runaway greenhouse effect as the Sun gradually heated up. Astronomers believe that the young Sun was dimmer than the present-day Sun by 30 percent. Over the last 4 thousand million years, it has gradually brightened. During this increase, Venus’s surface water evaporated and entered the atmosphere.
“Water vapor is a powerful greenhouse gas and it caused the planet to heat-up even more. This is turn caused more water to evaporate and led to a powerful positive feedback response known as the runaway greenhouse effect,” says Grinspoon.
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Cosmos: A Spacetime Odyssey Recap 6/1/14:
Season 1 Episode 12 “The World Set Free”
by Jackalz, celebdirtylaundry.com -- June 1, 2014
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The Earth keeps a detailed diary in the snow, the ice layers have ancient air trapped inside of them. The 20th century was the beginning of the carbon dioxide increase in our oxygen; CO2 is building up in the atmosphere warming up the planet. Neil shows us the Earth in the Infrared; we see its own body heat. The incoming light from the sun hits the surface; the Earth absorbs the heat making the infrared light. With no CO2 on our planet, Earth would be a big snowball. A small greenhouse effect is a good thing, though a big one won’t have a good outcome. [...]
Once there was a world that wasn’t too hot or cold, it was just right. Then there came time where the life it sustained began to see that our planet was change, it’s not like we didn’t see it coming. As far back as 1896, Savante a Swedish scientist new that with more CO2 the ice in the Arctic would melt; the Guy Calendar was the one who proved that it was happening. In 1960 Carl Sagan had the first calculation of the runaway greenhouse event in Venus, he warned about the people increasing the greenhouse’s effect by releasing far too much CO2. Since Carl spoke those words, we’ve burdened the world with tons of carbon dioxide; if we don’t change the way our planet is headed, what’s going to happen for our kid’s future? We inherited a bountiful world, but now our carelessness and greed put everything at risk. [...]
The perma-frost that is now thawing is producing CO2 also, this is going to be doubling the CO2 rate in the world; the air, the water and the land are all getting warmer. This may not be our fault, it could just be nature; could it be the sun? No the sun is not responsible, the energy output from the sun hasn’t changed for years. It’s now clear that we are changing the climate, the sun isn’t the problem; but it is the solution. [...]
It was a stunning documentary of what's happening to the planet, even as we tweet.
Watch it, when you find the time.
The World Set Free -- Watch it here.