Naked Science Forum
Life Sciences => The Environment => Topic started by: Ron Maxwell on 12/01/2010 09:30:02
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Ron Maxwell asked the Naked Scientists:
A little of the atmosphere is lost to space at its highest levels. If you heat a gas, it expands, which could be the case with the atmosphere during global warming.Â
Does this mean that more of it would be lost, and if so, would it be enough to have an effect on global temperature?
What do you think?
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That's a nice question. Don't know if there have been any research on that yet though, I guess that as we also are transferring 'new molecules' due to our use of earths deposits of oil methane etc, you have that process to consider too.
What I understand as happening is that all the layers will expand and that there, as a whole, will become a 'larger' atmospheric surface area encompassing Earth. That should give it a possibly larger heat regulation too I think? But there are a lot of unknowns in this process, even though it seems plausible. The last layer of our atmosphere, the exosphere, is the sole 'heat regulator' for Earth. But what one have to remember is that it's only as the air-layers under it have become 'saturated' that the heat will raise to the next layer. All processes and layers will 'raise further up' as the the heat builds up due to kinetic energy, and that include water vapor.
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"There is a layer in the atmosphere called the tropopause. It is a the thin boundary between the troposphere - the atmosphere’s lowest layer where our daily weather occurs - and the stratosphere where high altitude weather balloons fly.On average the tropopause lies about 6 to 8 miles above the Earth’s surface, though its exact height can range between 5 and 11 miles depending upon latitude, temperature and season. The importance of the tropopause, however, is not its elevation, but what happens there.
For it is in the tropopause that gaseous water reaches its maximal height before phase changing back into either its liquid or solid forms. Because of this, the stratosphere and all other atmospheric layers above it are virtually absent of water and, therefore, not part of our planet’s water cycle. But the tropopause is a critical part of that cycle. It is the final safety net where water vapors are re-constituted into denser forms that gravity can pull back down to Earth’s surface as rain, sleet, snow or hail
Like an enlarging sponge, the atmosphere will draw up more water vapor as it expands, complimenting the aforementioned heat radiation by further cooling both the land and the liquid heat sink system. While this will also increase the total cloud canopy available to deflect solar energy away from the planet, it is unlikely to decrease overall global warming since the larger canopy will now be distributed over a proportionately larger area as the atmosphere expands outward (consider the increasing surface area of a balloon as it expands)..
The exosphere is the uppermost layer and limit of our atmosphere. It is the space where manmade satellites orbit the Earth. It begins at approximately 620 miles above the planet’s surface, though its actual height can vary with latitude, temperature and season, just like the tropopause. It is from here that atmospheric atoms and molecules escape into free space. Though there is still enough gravity to recapture particles in this layer - even satellites fall back to Earth if they don’t maintain sufficient orbit velocity to overcome gravitational pull - minute particles can fall prey to other dominating forces in the exosphere.
Most prominent of these counter-gravity factors is solar wind. The solar wind is a stream of charged particles ejected from the upper atmosphere of our Sun on a regular basis. It consists mostly of electrons and protons which travel at high rates through space. Amongst other things, when they enter the ionosphere (a layer found below the exosphere) these particles create a visible aurora called Northern Lights. Higher up, however, they can randomly collide with atoms and molecules in the exosphere, knocking them in all directions including into free space.
The energy transferred during such impacts can provide sufficient escape velocity required to overcome the remaining gravitational force in our uppermost atmospheric layer. Unfortunately, if this escape velocity is combined with an outward trajectory, there is little hope that particular atom or molecule will ever return to Earth."
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From Bursting the Atmosphere: what happens when rain falls up? (http://trafn.com/burstatmosphere.pdf)
And one worry this paper address is that we will find that water vapor raise above this last layer, maybe even reach a height where it can disappear from gravity. If that happens there will be a very dry planet for us to survive on. But all of this are guesses. It's a new situation for us, maybe not for Earth though :) It seems as we already have had two instances where methane have gone wild f.ex without us losing the water vapor to space.
So I hope that scenario only will be that, a scenario that is. Still, we do know that methane seems to have gotten loose before, and, if it would do so again? from the frozen deposits under under our oceans, well, then we will be all to late for us, and that's why the tundras releases worries me so much. A lot of people studying geology and Earth’s history says the same. At the Permian-Triassic extinction event . (Around 280 to 230 million years ago) and at the Paleocene-Eocene Thermal Maximum (63-40 millions years ago), the beginning of what life we know today, this scenario seems to have happened twice already.
And at the Permian-Triassic extinction around 96 percent of all sea life and 70 percent of Earth’s land animals died, To be gone , never, ever, coming back, and furthermore, it is also the only known mass extinction of insects. 57% of all families and around 83% of all related gene groups/materials were killed. We’re still paying our dues for that one in reduced genetic materials etc, although it happened a quarter of a billion years ago.
But I think we can see a beginning of a change in the rain and cloud formations/canopies developing over a lot of Europe recently falling out as rain and snow. Those cloud formations won't stop the input from the sun though, neither will they stop the releases of new man made CO2, binding even more heat in the atmosphere and accelerating the methane releases from the tundra etc, but it will make the weather locally cooler in a lot of places, over a extended period of time.
Unfortunately enough they seem to occur over just the same areas that would have the greatest financial and scientific abilities to do something about it, and as people locally will see the heat not accelerating due to cloud covers my guess is that a lot of people will presume that there is little ground for the warnings from the scientific community.
But most of this are my own assumptions, even if I personally think they are correct and supported by the data I've seen so far. Earth is a very big (to us that is:) non-linear system and we will be one step behind whatever processes happening, remember that we only have started to investigate the atmosphere on a world-wide basis quite recently, and I'm expecting new surprises as time ticks on.
That Earth is described by me as being 'non linear' means that I believe that when the change reaches a certain state, the 'system' (Earth) can tip over to another state of climate fairly quick, and by then we will just have to hold on to our hats :) Hope I answered some of your thoughts here. And yeah, wish I could paint a brighter picture.