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Author Topic: Another consequence of global warming  (Read 4837 times)
Ivan
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« on: July 06, 2015, 01:16:08 AM »

Another consequence of global warming - from   http://www.space.com/29831-water-escapes-a-warm-planet-will-earth-become-like-mars.html




This article was originally published on The Conversation. The publication contributed this article to Space.com's Expert Voices: Op-Ed & Insights.

We already knew about Venus. We had our suspicions about Mars. Now we’re sure.

Our two closest solar system neighbors once had oceans – planet-encircling, globe-girdling, Earth-like oceans. But waterbearing planets are fragile. Venus didn’t have the right stuff and lost her oceans to space. We have the smoking gun. And now we know that Mars, also, poor Mars, couldn’t hold on. Mars has lost to space at least 80% of all the water it once had.


Et tu, Earth? What about you? More to the point, what about us? Despite water’s apparent abundance, what does the future hold for the most precious material on our planet? Will we find a way to mistreat our reserve of irreplaceable water and turn our planet into a planetary desert, like our neighbors Venus and Mars? Kick the temperature up a few more notches, thanks to a runaway greenhouse effect, and the ultimate consequence of global warming could be ejecting the water from our planet.

Water on the atomic level

Let’s try our hand at interplanetary forensics. First, let me introduce you to the atomic constituents of that substance chemists call H2O, which most of us more commonly know as water. The H represents the atom hydrogen. The O represents the atom oxygen. The number two after the letter H tells us that a single molecule of water is composed of two hydrogen atoms and one oxygen atom.

In order to enter the world of CSI: Solar System, we need to understand the structure of atoms in a bit more detail. Hydrogen is hydrogen because its nucleus has one positively charged proton, which is orbited by one negatively charged electron. The nucleus, however, can also include one neutron, which lacks a charge. Even with one neutron, the atom still has a positive charge in the nucleus of +1. It’s therefore still hydrogen, but with one critical difference: it is much heavier, about twice as heavy, in fact, thanks to the additional neutron.

Chemists call this kind of heavy hydrogen deuterium. Deuterium behaves identically in chemical reactions to regular hydrogen; it’s just heavier. Remember that H2O molecule? When made with a deuterium atom, it’s an HDO molecule. It would taste the same, and it would provide the same sustenance to your flowers and gerbils, but it would weigh more.

That extra weight makes all the difference, because Isaac Newton’s and Albert Einstein’s unavoidable law of gravity says that deuterium is pulled downward toward the surface of a planet much more strongly than is regular hydrogen. When deuterium and regular hydrogen are both free to bounce around in a planet’s atmosphere, the regular hydrogen will bounce much higher. And if the planet’s gravity is weak enough – which is the case for Earth, Venus and Mars – regular hydrogen can bounce so high that it can escape into space, whereas the deuterium remains forever bound by gravity to the planet.

Artist conception Galileo’s probe
Pin It Galileo’s probe lasted less than an hour before being destroyed by Jupiter’s atmosphere.
Credit: NASA, CC BYView full size image
A base-level ratio for the solar system

In 1995, NASA’s Galileo probe measured the ratio of hydrogen to deuterium in the atmosphere of the giant planet Jupiter and found that ratio to be about 40,000-to-1.

Jupiter is such a massive planet that neither hydrogen nor deuterium can escape. Consequently, planetary scientists are quite certain that all the materials involved in the mixture of gases and dust that formed the sun and all the planets in our solar system formed with the same ratio of hydrogen to deuterium as the Galileo probe found for Jupiter’s atmosphere. We take it as a given that all the water originally deposited on Venus, on Earth, and on Mars also had that same ratio of hydrogen to deuterium.

Now let’s do some chemistry. If I wanted to make 20,000 water molecules, I would need a total of 40,000 hydrogen (H) and deuterium (D) atoms (of which 39,999 would be H and 1 would be D), plus, of course, 20,000 oxygen (O) atoms. In my mixture of 20,000 water molecules, I would be able to make 19,999 H2O molecules and one HDO molecule, given my initial ratio of hydrogen to deuterium atoms.

The real H-to-D ratios

In a cup of water scooped from any part of any of Earth’s oceans, in any local freshwater pond from any continent, in any cup of tea in any city, in an Alpine glacier or a hot spring in Yellowstone, the hydrogen-to-deuterium ratio is 6,250-to-1, not 40,000-to-1.

Why so low? The evidence suggests that early in Earth’s history, our planet lost a great deal of hydrogen (but not deuterium). As the hydrogen atoms escaped to space, the H-to-D ratio would have dropped from 40,000-to-1 to only 6,250-to-1. In fact, the Earth may have lost as much as 80% of its original population of hydrogen atoms, and since, on Earth, most hydrogen atoms are bound into water molecules, the loss of hydrogen atoms is likely equivalent to the loss of water.

Artist conception atmospheric probe on VenusPin It An atmospheric probe descends through the Venusian cloud deck.
Credit: Ames Research Center and Hughes Aircraft Company, CC BYView full size image
NASA’s Pioneer Venus spacecraft, way back in 1978, dropped a probe that parachuted into and measured the properties of Venus’ atmosphere. One of its shocking discoveries was that the hydrogen-to-deuterium ratio on Venus is only 62-to-1, fully 100 times smaller than the ratio on Earth.

The clear implication of this discovery is that Venus was once wet but is now bone-dry. Venus, as we now know, has a surface temperature of 867 Fahrenheit (463 Celsius). Venus once had oceans, but Venus warmed up and the oceans boiled off the surface. Then ultraviolet light from the sun split the water molecules apart into their constituent atoms. As a result, the lighter hydrogen atoms bubbled up to the top of the atmosphere and escaped into space, while the heavier deuterium atoms were trapped by Venus’ gravitational pull. The hydrogen-to-deuterium ratio in Venus' atmosphere is the crucial clue that provides the evidence for what happened a billion or more years ago on Venus.

Mineral veins on Mars
Pin It Mars looks pretty dry now, but mineral veins were deposited by fluids moving through rock.
Credit: NASA, CC BYView full size image
Now, in research just published in Science this spring, a team of scientists led by G L Villanueva of NASA Goddard Space Flight Center has used powerful telescopes on Earth to map water (H2O) and its deuterated form (HDO) across the surface of Mars. They’ve confirmed the results obtained by NASA’s Curiosity/Mars Science Laboratory in 2013 that the hydrogen-to-deuterium ratio on Mars is smaller by a factor of about 7 compared to that on Earth. This measurement tells us that Mars, like Venus, has lost lots of hydrogen, which means Mars, like Venus, has lost lots of its water.

The total amount of water identified in all currently existing water reservoirs on Mars (the ice caps – which have some water but are mostly frozen carbon dioxide; atmospheric water; ice-rich regolith layer; near-surface deposits) would generate a global ocean about 21 meters (68 feet) deep. The deuterium measurements tell us that Mars once had about seven times more water, enough water to create an ocean that would have covered the entire planet to a depth of at least 137 meters (445 feet). The evidence is now clear: Mars has lost at least 85% of the water it once had. (And that estimate assumes the Earth has not lost any of its water; if the Earth also has lost 80% of its original water reservoir, then Mars has lost 97% of its original water reservoir.)

Venus, dry
Pin It Is Venus' present Earth’s future?
Credit: Magellan Project, JPL, NASA, CC BYView full size image
Whither goest Venus and Mars….

Venus and Mars. Mars and Venus. Planetary scientists know that both planets were wet and Earth-like in the beginning; they also know that neither Venus nor Mars could hold onto their water for long enough to nurture advanced life forms until they could flourish. The lessons from Venus and Mars are clear and simple: water worlds are delicate and fragile. Water worlds that can survive the ravages of aging, whether natural or inflicted by their inhabitants – and can nurture and sustain life over the long term – are rare and precious.

If we allow the temperature of our planet to rise a degree or two, we may survive it as a minor environmental catastrophe. But beyond a few degrees, do we know the point at which global warming sends our atmosphere into a runaway death spiral, turning Earth into Venus? We know what the endgame looks like.

David A Weintraub is Professor of Astronomy at Vanderbilt University.

This article was originally published on The Conversation. Read the original article. Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google +. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Space.com.
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biff
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« Reply #1 on: July 06, 2015, 08:25:40 AM »

Scary stuff,
           One wonders when we will all waken up and get it into our head that we have to change our attitudes,
        It is all such deadly serious stuff. There is plenty of talk from the powers that be but very little action .
    It seems to me,that the different countries are more interested in crippling each other,s respective currencies than trying to reverse climate change.
                                               Biff
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HyperUniverse
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« Reply #2 on: July 06, 2015, 08:48:27 AM »

As long as our global economy is based on accumulating wealth, we will continue to kill other humans, other animals, our Earth, and soon our Solar System when space travel will become more easily (keep it this way and in a million years we will destroy the Universe, too).

Let's be honest, we will never go back to living standards from a 1000 years ago, with no electricity (no electric power plants to pollute); no mechanical vehicles to pollute, no steam trains either, just clean natural living.

So it seems our fate is sealed......
« Last Edit: July 06, 2015, 08:53:12 AM by HyperUniverse » Logged
Ivan
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« Reply #3 on: July 06, 2015, 05:44:13 PM »

Well there are ways to live a comfortable lifestyle with nothing like the CO2 emissions that we currently produce. However, individuals, companies and governments would need to commit money to things like large PV arrays, battery storage etc, rather than costa-del-sol package holidays, jet skis and the latest four wheel drives. There's still plenty of opportunity for industry and employment, and as anyone who lives off-grid knows, there are some serious capital expenditures at the beginning, but running costs are much lower and life can still be comfortable.

I liked this article, because it's talking about some fairly complex stuff, but in a way that is very easy to understand.
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AndrewE
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« Reply #4 on: July 06, 2015, 07:50:07 PM »

I think there's a flaw in this.  If I remember my school science...
Hydrogen gas (H2) molecules are so small (Molecular Weight 2) and hence so fast that (because of fewer collisions) they diffuse faster than the escape velocity from our atmosphere, so they effectively rise through it and disappear into space. However there isn't a lot of hydrogen gas generated on earth...   Photosynthesis may split water - but it creates oxygen and sugars.  I can't think of any natural hydrogen generators, it's not even very significant in volcanic emissions (0.5 to 1.4% according to http://volcanoes.usgs.gov/hazards/gas/)
Deuterium gas (if any such molecules should happen to exist) might well hang around (MW around 4)... BUT water vapour in the atmosphere is H2O so the molecular weight is around 18, but still only 19 if one of the atoms is deuterium, HDO.  One hydrogen atom in 40,000 may be Deuterium, but only one MOLECULE in 160,000,000 will be D2 - if you can find a "hydrogen" molecule.

Are they saying that the difference in the diffusion rates between molecules of weight 18 and 19 is enough for the light water to disappear?  In that case why haven't the other planets got residual D2O lakes? or that this just illustrates the end point after the fractional distillation of an atmosphere?
If they are saying that runaway warming would eventually heat the atmosphere to the point where that difference in molecular weights (18 vs 19) would strip the H2O off and leave the HDO, I would imagine that we'd all be long gone by then anyway, so  it's not much of a concern to us or a very effective propoganda tool either...

We need to worry about the next degree or two of warming (which will probably finish us off), not the subsequent 10, 20, or even 50![/sub]
« Last Edit: July 06, 2015, 08:00:37 PM by AndrewE » Logged
RIT
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« Reply #5 on: July 06, 2015, 10:37:07 PM »

Throwing some facts down on a page and then asking a question is not an article - its a question.

Its also a question that is easy to research by just finding out what happen in the past, such as

     https://www.ncas.ac.uk/index.php/en/climate-blog/397-warm-past-climates-is-our-future-in-the-past

Which contains the following 

Quote
During the Eemian (125,000 years ago) the climate was warmer with summer temperatures in the Arctic region about 2-4°C higher than today.

Temperature rises are not an issue for the Earth's hydrogen, they are an issue for Mankind and its ability to support 7B+ people.

Also talking a lot about Venus means nothing if some details are not provided. Most people are told that Venus is about the same size as the Earth, fewer are aware that its mass is about 82% of Earth's. So its ability to retain hydrogen atoms is a lot less regardless of the fact that it is also a lot nearer the sun and so receives more heat radiation. It also has only a weak magnetic field (compared to the Earth) so solar winds can reach the outer atmosphere and so strip it of atoms all the way up to oxygen.
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« Reply #6 on: July 06, 2015, 11:12:56 PM »

I think there's a flaw in this.  If I remember my school science...
Hydrogen gas (H2) molecules are so small (Molecular Weight 2) and hence so fast that (because of fewer collisions) they diffuse faster than the escape velocity from our atmosphere, so they effectively rise through it and disappear into space. However there isn't a lot of hydrogen gas generated on earth...   Photosynthesis may split water - but it creates oxygen and sugars.  I can't think of any natural hydrogen generators, it's not even very significant in volcanic emissions (0.5 to 1.4% according to http://volcanoes.usgs.gov/hazards/gas/)
Deuterium gas (if any such molecules should happen to exist) might well hang around (MW around 4)... BUT water vapour in the atmosphere is H2O so the molecular weight is around 18, but still only 19 if one of the atoms is deuterium, HDO.  One hydrogen atom in 40,000 may be Deuterium, but only one MOLECULE in 160,000,000 will be D2 - if you can find a "hydrogen" molecule.

Are they saying that the difference in the diffusion rates between molecules of weight 18 and 19 is enough for the light water to disappear?  In that case why haven't the other planets got residual D2O lakes? or that this just illustrates the end point after the fractional distillation of an atmosphere?
If they are saying that runaway warming would eventually heat the atmosphere to the point where that difference in molecular weights (18 vs 19) would strip the H2O off and leave the HDO, I would imagine that we'd all be long gone by then anyway, so  it's not much of a concern to us or a very effective propoganda tool either...

We need to worry about the next degree or two of warming (which will probably finish us off), not the subsequent 10, 20, or even 50![/sub]

Ozone layer I think is the Key, lots of UV up there that splits water vapour into monatomic Hydrogen and Oxygen, and Hydrogen atoms are easily fast enough to escape gravity whereas oxygen is not. O3 is the result I think.

Desp
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RIT
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« Reply #7 on: July 07, 2015, 01:36:36 AM »


Ozone layer I think is the Key, lots of UV up there that splits water vapour into monatomic Hydrogen and Oxygen, and Hydrogen atoms are easily fast enough to escape gravity whereas oxygen is not. O3 is the result I think.

Desp

I think Ozone is formed from the spiting and recombine of just Oxygen which is normally found in a stable O2 configuration while Ozone is O3.   
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Ivan
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« Reply #8 on: July 07, 2015, 02:07:09 PM »

If there aren't any hydrogen generators on earth, then there are probably even fewer on Mars and Venus!

This loss is nothing to do with water, only to do with free hydrogen gas.

There are some bacteria that produce hydrogen, though I cannot remember which. Lightning produces hydrogen, as do electrolytic processes. Hydrogen is in the Earth's atmosphere at 1ppm.

What is interesting is that Mars and Venus lost most of their water despite meteoric / comet delivery. It's also interesting to consider that Earth has probably lost 80% of its water already (which is probably why we don't have a planet-wide ocean), presumed through this mechanism
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« Reply #9 on: July 07, 2015, 03:58:54 PM »

....Earth has probably lost 80% of its water already (which is probably why we don't have a planet-wide ocean), presumed through this mechanism

I wouldn't agree with that .

Earth was fully covered by water, when a celestial body has hit our planet.
Thus one single mass of land appeared over the sea level.

If you bring all the continents together, they fit quite perfect in a single land mass.
And ever since that impact, you can see the tectonic plates movement are spreading the continents apart.

So I don't agree with Earth's lost 80% of its water.


Regards
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Ivan
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« Reply #10 on: July 07, 2015, 04:06:43 PM »

Well in that case, you're basically disputing the deuterium/hydrogen ratio difference, for which there is unequivocal evidence.
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HyperUniverse
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« Reply #11 on: July 08, 2015, 09:18:28 AM »

I didn't comment anything about your precious deuterium/hydrogen ratio difference,
I was just not agreeing with you on why Earth is not fully covered by water,

But if you really want to tell us something about this deuterium/hydrogen, then can you explain it better - when Earth has lost this 80% of it?
As I understand from other clever people (called scientists) Earth is 4.54 billion years old.

And you say that Earth's lost 80% of its precious gases over what....the same 4.54 billion years, or in the last 1000 years?

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Ivan
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« Reply #12 on: July 10, 2015, 12:15:36 AM »

Have a read of the article. The 80% loss of water is a direct deduction from the D/H ratio.

What they're saying is that we all start off with the same Deuterium/hydrogen ratio - basically from the protoplantary disc. Jupiter is so massive that hydrogen can't diffuse away. So that sets the starting D/H ratio. Then we look at Mars and Venus that have pretty much lost all their water - and the more recent geological evidence from rovers on Mars have pretty much proved that there was once vast quantities of water on Mars. The D/H ratio on these planets is vastly different - demonstrating that a lot of hydrogen has disappeared over time. Then look at the earth - it also has a much higher ratio of D to H than Jupiter, though not as much as Mars or Venus - showing that we too have lost a large amount of water and from the difference in ratios we can work out more or less how much.

The loss is over 4.5billion years, not 1000.

The question is, with global warming, will the extra kinetic energy within the atmosphere accelerate the rate of hydrogen loss?
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HyperUniverse
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« Reply #13 on: July 10, 2015, 08:57:03 AM »

Well from my understanding, the other planets have lost their gases because they didn't have enough planetary mass, to hold onto these gasses,
So in my mind no matter how hot Earth's atmosphere will get (global warming) our planet will hold onto these gases (or loose just a tiny amount of them), because Earth's mass is bigger than the others'.

So as long as we don't "export" too much mass out of our planet, I think we are pretty safe for the next 4.5 billion years.........

Or am I not thinking straight?


And another reason that keeps me calm over the matter, is that we humans will soon make space travel easier, at least for unmanned spacecrafts.
Just send few of these to the nearest planet or moon covered by water or ice, and extract and bring here on Earth large amounts of it.

It doesn't matter the time to travel there and back will be 100 years.
Sending 10 such crafts, means we get a boost in water supply every 10 years,
Add more crafts later, and it means a boost every 5 years, or even every year,
....and so on.....

Now the question is....should we stop developing new technologies to allow us to do that in the future, just because the research and development of such technologies is a pollutant itself too?
Would be better to save some CO2 now, or shall we exploit this planet as much as we can with the knowledge that in the future we will replenish our supplies from other planets?

Another reason why I am not afraid of this global warming.....
in the past all living things on Earth were relying on Earth & Sun to supply them with the necessary materials & energy to stay alive.
I think we've past that stage, now we have the knowledge and power to keep ourselves alive without the nature's help.
Is that today we are just more concerned with who should rule over the others, rather than applying such technologies.
Imagine instead of building arsenals to kill other people, we would build giant filters to clean up the CO2 in the atmosphere.....

So to be clear in everybody's mind.....
if we don't develop such technologies (mass space travel), all living things on Earth will DIE, not because of humans polluting the planet, but because of our Sun will one day die.
And then no matter how "green and unpolluted" Earth will be, it will still die.
And the intelligence that will live at that point on this planet, has the duty to move the seeds of life on another celestial body, and make a home for them there.
But if that intelligence will be indoctrinated by their ancestors, not to develop any technologies because they will dump CO2 and other harmful gasses in the atmosphere, then they will be singing and dancing happy in Earth's green pastures while the planet will be engulfed by the dieing Sun.

There is no hope for LIFE to carry on, on this planet.
We need the technology and power to move to another.
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A.L.
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« Reply #14 on: July 10, 2015, 10:33:08 AM »

or shall we exploit this planet as much as we can with the knowledge that in the future we will replenish our supplies from other planets?

- no comment required
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