How we know we’re warming the planet - The Washington Post
Broadly speaking, here are two reasons why the Earth could be warming up. Either more heat is reaching the Earth’s surface, or else less heat is escaping out into space. On the first, there’s no evidence of a significant increase in heat reaching the earth. True, solar activity can shift from year to year. But satellite data shows that total solar irradiance has declined slightly in the past 30 years, even as the planet continues to warm. Scratch that theory.
So something’s keeping the heat in. Physicists have long known from lab experiments that greenhouse gases like carbon-dioxide can absorb certain frequencies of infrared radiation and scatter them back toward the Earth. We also know these gases are increasing in the atmosphere, largely due to the burning of fossil fuels (checking this involves some fairly straightforward chemistry). And, indeed, satellite data has shown that less and less infrared in the specific frequencies in question is escaping out into space, while more is bouncing back to the Earth’s surface. There's your culprit.
Now, it’s not entirely that simple (see here for the IPCC’s graphic of other, smaller factors influencing the climate), but that’s the basic story.
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3 comments:
Yes, that's their story and they are sticking to it. Yet, a simple comparison of temperatures in the atmospheres of Earth (with 0.04% carbon dioxide) and Venus (with a whopping 96.5%) shows that the Venus temperature at any given pressure is just 17% higher than the corresponding Earth temperature, and that temperature difference is precisely explained by the two planets' distances from the Sun, nothing else. So there is no greenhouse effect at all, and their story simply doesn't jibe with that crucial evidence of two detailed planetary atmospheres.
I think many are tunnel-visioning on CO2 - my question is not just about 7 billion people exhaling so much CO2's effect on any greenhouse, but the added stress upon our planets ability to keep 7 billion people who generate an average 100 watts of body heat per person. Think about that one - all that extra heat just from a human population - on top of any other heat-generating sources (vehicles, construction, etc.). Any thoughts on that? 700 billion watts of extra heat has got to do something.. no?
JRQC
This is for JRQC. Averaged over the surface of the Earth, taking into account what is reflected (albedo effect) and what is scattered by atmosphere, the energy flux from the Sun amounts to 240 Watts/(square meter). 700 billion Watts averaged over the surface of the Earth amounts to .0014 Watts/(meter square) and so can be safely ignored as far as climate is concerned. Nonetheless this might be difficult to believe if you find yourself trapped in a crowded movie theater when the AC breaks down...
Dalcio
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