Originally posted by Ghost of a Duke
A great list (slightly scary).
My only query would be in regards to 'man made Global warming changing the climate.'
I seem out of step with a lot of great minds on this, but remain unconvinced about the extent to which man is changing the climate. (In any significant way). Destroying the planet sure; using up its resources and cutting down all ...[text shortened]... in this regards and perhaps man, in an almost mass hysteria, is over egging his true influence.
This isn't really the right forum for that discussion...
But then again as it stands any discussion on that topic at the moment is being completely
derailed by metal brain in the science forum, so I'll briefly respond here.
http://skepticalscience.com/
and
http://theconsensusproject.com/
and
http://www.theguardian.com/environment/climate-consensus-97-per-cent
are good places to get info on this... Phil Plait with his "Bad Astronomy" blog on slate is also
a good source of information
http://www.slate.com/blogs/bad_astronomy.html
But that's not a dedicated climate blog/site.
But the basics are really pretty simple:
The sun outputs the vast majority of its energy as visible light.
Our atmosphere is mostly transparent to visible light [clouds reflect/disperse that light, and dust absorbs it].
A portion of the incoming visible light reflects back passing back through the transparent air and into space.
The rest gets absorbed, and one way or another, gets turned into heat.
Warm objects emit infra-red radiation, and so the warm surface of the planet [and the warm air around it]
emits infra-red radiation [thus cooling down]. The warmer an object is, the more heat it radiates.
The emitted infra-red light then heads out through the atmosphere into space. [or some of it does...]
The planet is thermally stable IF the thermal radiation outwards is equal [on average] in energy content to
the visible radiation inwards from The Sun. If the energy in is greater than energy out the planet will warm up,
and if the energy in is less than the energy out the planet will cool down.
The interesting for this discussion element is this...
The atmosphere is nowhere near as transparent to thermal radiation as it is to visible radiation.
Many gases in the atmosphere absorb infra-red wavelengths, which means that they block the emission of
heat energy and thus act as an insulator.
And we can clearly observe this from space.
Satellites can look at the incoming spectra of light from the sun, the reflected light from the sun, and the
Earth's thermal emissions after passing through the atmosphere. [We can obviously see the Earth's thermal
emissions pre-atmosphere from the ground.] By comparing the spectra of the light emissions from the Earth
on the ground and after passing through the atmosphere we can see all the heat energy that got blocked and
by matching the spectra to known chemical absorption lines we can see what chemicals in the air were responsible
and by how much.
CO2 is one of those gasses. Another is water vapour.
We have changed the concentration of this gas from about 260~270 ppm to ~400ppm, or a roughly 50% increase.
And we have done so absurdly rapidly, in geological or historical climate change terms.
Reveal Hidden Content[CO2 levels during the depths of ice ages estimated at about ~180 ppm, so we have already increased CO2 levels up, more than they drop during a major ice age]
This increases the amount of outbound thermal radiation that gets absorbed by the atmosphere, increasing the
insulating effect it has and raising the temperatures and heat content of the land and oceans.
This increase in air temperature increases the ability of the air to hold water and increases evaporation rates
thus increasing water vapour content in the air... And water vapour is not only a green house gas, it's ~twice
as powerful as CO2. Thus increasing the insulation factor still further.
The increasing heat melts snow and ice, exposing darker water and land, which absorb more of The Sun's visible
radiation and generating more heat.
These effects are not evenly spaced around the globe and thus not only are the average temperatures and
humidity levels changed, there are large regional differences.
This causes fairly substantial changes in the climate as there is now more energy and moisture in the climate system
and the locations and scale of the temperature differentials that drive the climate have changed.
This causes changes in the biosphere as habitats change faster than species can adapt [along with other things
like cutting down trees and agriculture ect ect] which in turn has knock-on effects on the climate.
Different vegetation reflects different amounts of light, and transports differing amounts of water into the air.
This causes rising sea levels, as the water heats and expands, and as land ice sheets and glaciers melt.
All of the above is actually observable, and has been observed. It's basic physics.
There is much more, way more than enough to be convincing.
But I don't have the time or space to post it all here, and as I said, this is the wrong forum for this debate.
So I recommend checking out the links above.
The final point being, this is a consensus view among the experts in the field with ~97% of them agreeing on this.
There is no serious debate any more about whether this is an issue within the scientific community.
And that is really hard to achieve, because you advance in science, and get yourself noticed, by overturning
other peoples established ideas.
If everyone
Reveal Hidden Content[in science]
agrees on something, when under huge pressure to have the truth be something else, over many
decades of time and multiple generations... It's very likely true, and it would be foolish to operate on the
assumption that they are wrong.
You buy house insurance and flame proof materials because of the small possibility your house might burn down.
Not acting to help prevent further global warming would be like refusing to buy house insurance when there was
only a tiny chance of it not burning down on the hope that it wont happen.
You might just luck out, win the lottery, but it's a bad and stupid strategy to take.