3 ms·
I'm still trying to understand: I know, CO2 is a greenhouse gas: So, light from the sun warms the surface of earth which, then, from Planck black body radia
by graycat 11y ago
I'm still trying to understand:
I know, CO2 is a greenhouse gas: So,
light from the sun warms the surface
of earth which, then, from Planck
black body radiation, radiates more
infrared light. As we can see from
our exhaled breath, CO2 is invisible,
that is, does not absorb visible light.
But CO2 does absorb light in three
narrow bands in the infrared, one band
for each of bending, twisting, and
stretching of the molecule. So, thus
absorbing infrared, CO2 gets warmer
and warms the atmosphere and is a greenhouse
gas.
I've looked a little on the Internet
for details of the absorption spectra
of CO2 and how to calculate the
rates as a function of concentration,
temperature, distance, pressure, etc.
Anyone know how to get such background
info?
That is, something like in
a greenhouse, CO2 lets the visible
light from the sun through to the
ground but traps some of the
infrared light from the ground
that otherwise would escape to space.
Maybe since the Little Ice Age,
the oceans are still warming up?
Maybe the sea level rise is due to
the water expanding due to being warmer?
Maybe the recent increases in CO2
concentration in the atmosphere
are from CO2 from the warmer oceans and
the point that cooler water absorbs more
CO2 and warmer water absorbs less and, thus,
releases CO2?
During the Little Ice Age, as civilization
grew and developed, likely the
rate of CO2 from human activity was
increasing, but, then, maybe the significantly
lower temperatures of the Little Ice Age
were due not
to less CO2 from human activity
but from less solar activity, e.g.,
in terms of sun spots,
the Maunder Minimum?
Maybe going back to the Medieval Warming Period,
the higher temperatures, IIRC, higher than now,
e.g., growing grapes in England, have
agriculture boom
and wealth and cathedral construction increase,
were due not to more CO2 from human
activity or more CO2 at all but from
more solar activity, i.e., sun spots?
Maybe the higher temperatures since the
end of the Little Ice Age have been
due to more solar activity? E.g., from
about 1940 to 1970, the CO2 from
human activity was increasing but the
level of solar activity was decreasing and,
also, the temperature was decreasing.
So, more CO2 from human activity but
lower temperatures?
Maybe the last 15 years or so of increasing
CO2 from human activity but relatively stable
temperatures have been from less solar activity?
Maybe the temperature changes are driven more
by changes in the level of solar activity than
by the changes in the levels of CO2
from human activity or the levels of CO2
in the atmosphere from CO2 released from
warmer oceans, from volcanoes, from rotting
plants, etc.?
Trying to make sense out of all of this:
Effect of solar activity? More solar
activity means more sun spots and, thus,
more solar wind blowing past earth. But,
there are claims that one of the main
sources of cloud formation on earth is
cosmic rays hitting water molecules
and, thus, stimulating the formation
of water droplets and, thus, clouds. But
supposedly more clouds have a net cooling effect,
maybe from clouds reflecting more sunlight?
So, more cosmic rays hitting the atmosphere
would have a net cooling effect.
But there are claims that more solar
wind blocks some of the cosmic rays,
thus, reduces cloud formation, and
has a net warming effect.
So, if believe this chain of causes, then
more solar activity means more sun spots,
more solar wind, fewer cosmic rays
hitting water molecules, less formation
of water droplets, less cloud formation,
and net warming. Any good sources of evidence
for such a causal chain? Anyone debunk
such stuff? Anyone believe such stuff?
- clock_tower 11y agoHuman emissions levels were very low in the Little Ice Age, compared to today. The only proto-industrialized part of the world was Europe, and Braudel estimated that Europe had access to 1.5-2.5 million horsepower total from all machinery (including wind- and water-power). That's roughly 2 gigawatts of power; we might guess that burning fuel for heat produced about the same order of magnitude. (Fuel was very expensive as late as the 1930s; Orwell has some interesting statistics in _The Road to Wiglan Pier_.) Double that is probably enough to account for the rest of the world: not more than 10 gigawatts of human-generated power and heat, some fraction of it from wind and water. 10 gigawatts is probably too large. Today, the United States apparently consumes about 2,000 gigawatts (2 terawatts) of power from power plants, and another 2 from all other sources; Europe, China, and the rest of the world probably consume another 2-4 terawatts apiece, for close to a petawatt total -- about 100,000 times the power output of the world in the Little Ice Age. I don't rule out the possibility that human emissions are having no effect or a limited effect -- or that their effect is positive, by keeping the Little Ice Age from developing into the real thing -- but I'm also not ruling out that the prophets of doom might be on to something. (Jeremiah was simply correct, after all.) I'm hoping that emissions-cap negotiations get somewhere, and that we see more use of alternative energy (especially nuclear and geothermal), more artificial and biological carbon sequestration, more hybrid and electric cars (and is it too much to wish for, to hope that we see more commuter rail?), and general efforts to keep things from getting out of hand. We don't know what happens next, after all, and we only have to get it wrong once. Besides, if these sorts of things start producing hazardous levels of global cooling in 50 years, we can just scale them back, or even remove some filters from remaining coal-fired plants. This sort of effort will be expensive, but I'd rather risk doing more than we need to than not doing enough...
- graycat 11y agoHere's a related question: Supposedly now the CO2 concentration is about 400 parts per million (maybe by weight) and up from ballpark 200. Okay, how much CO2 is 200 parts per million in the atmosphere? Then, how does that much CO2 compare with what comes from human activity? Or, over a time interval while CO2 concentration increases by, say, 1 part per million, how much CO2 was generated during that time interval? Why? (1) The atmosphere is a biggie thing, and maybe CO2 from human activity is tiny in comparison, too small to represent increasing CO2 concentration by 200 parts per million. Need some numbers to know. (2)There are claims that CO2 emitted into the atmosphere by human activity is tiny compared with that from volcanoes and rotting vegetation. If so, then we have to ask where the CO2 for the increased concentration is coming from? From the oceans as they slowly warm from the cooling of the Little Ice Age? My point about the cooling of the Little Ice Age was that it was likely not caused by reductions in CO2 from human activity. Indeed, as the climate cooled, humans had one heck of an incentive to burn all the firewood they could find. So, the Little Ice Age seems to be a case where there was drop in temperature without a drop in CO2 from human activity. If so, then there have to be some causes of temperature change other than changes in the rate of CO2 emissions from human activity. That is, apparently there would be climate change even without humans.