Posted on 04/30/2007 7:57:26 AM PDT by Maelstorm
Science Daily — Earth sits between two worlds that have been devastated by climate catastrophes. In the effort to combat global warming, our neighbours can provide valuable insights into the way climate catastrophes affect planets.
Modelling Earth’s climate to predict its future has assumed tremendous importance in the light of mankind’s influence on the atmosphere. The climate of our two neighbours is in stark contrast to that of our home planet, making data from ESA’s Venus Express and Mars Express invaluable to climate scientists.
Venus is a cloudy inferno whilst Mars is a frigid desert. As current concerns about global warming have now achieved widespread acceptance, pressure has increased on scientists to propose solutions.
The key weapon in a climate scientist’s arsenal is the climate model, a computer programme that uses the equations of physics to investigate the way in which Earth’s atmosphere works. The programme helps predict how the atmosphere might change in the future. “To members of the public it must seem like climate models are crystal balls, but they are actually just complex equations” says David Grinspoon, Denver Museum of Nature and Science, and one of Venus Express’s interdisciplinary scientists.
The more scientists look at those equations, the more they realise just how complicated Earth’s climate system is. Grinspoon puts the predicament like this: “In fifty or a hundred years, we will know whether today’s climate models were right but if they are wrong, by then it will be too late.”
To help increase confidence in the computer models, Grinspoon believes that scientists should look at our neighbouring planets. “It seems that both Mars and Venus started out much more like Earth and then changed. They both hold priceless climate information for Earth,” says Grinspoon.
The atmosphere of Venus is much thicker than Earth’s. Nevertheless, current climate models can reproduce its present temperature structure well. Now planetary scientists want to turn the clock back to understand why and how Venus changed from its former Earth-like conditions into the inferno of today.
They believe that the planet experienced a runaway greenhouse effect as the Sun gradually heated up. Astronomers believe that the young Sun was dimmer than the present-day Sun by 30 percent. Over the last 4 thousand million years, it has gradually brightened. During this increase, Venus’s surface water evaporated and entered the atmosphere. “Water vapour is a powerful greenhouse gas and it caused the planet to heat-up even more. This is turn caused more water to evaporate and led to a powerful positive feedback response known as the runaway greenhouse effect,” says Grinspoon.
As Earth warms in response to manmade pollution, it risks the same fate. Reconstructing the climate of the past on Venus can give scientists a better understanding of how close our planet is to such a catastrophe. However, determining when Venus passed the point of no return is not easy. That’s where ESA’s Venus Express comes in.
The spacecraft is in orbit around Venus collecting data that will help unlock the planet’s past. Venus is losing gas from its atmosphere, so Venus Express is measuring the rate of this loss and the composition of the gas being lost. It also watches the movement of clouds in the planet’s atmosphere. This reveals the way Venus responds to the absorption of sunlight, because the energy from the Sun provides the power that allows the atmosphere to move.
In addition, Venus Express is charting the amount and location of sulphur dioxide in the planet’s atmosphere. Sulphur dioxide is a greenhouse gas and is released by volcanoes on Venus.
“Understanding all of this will help us pin down when Venus lost its water,” says Grinspoon. That knowledge can feed into the interpretation of climate models on the Earth because although both planets seem very different now, the same laws of physics govern both worlds.
Understanding Mars’ past is equally important. ESA’s Mars Express is currently investigating the fate of the Red Planet. Smaller than the Earth, Mars is thought to have lost its atmosphere to space. When Martian volcanoes became extinct, so did the planet’s means of replenishing its atmosphere turning it into an almost-airless desert.
“What happened on these two worlds is very different but either would be equally disastrous for Earth. We are banking on our ability to accurately predict Earth’s future climate,” says Grinspoon. Anything that can shed light on our own future is valuable. That is why the study of our neighbouring worlds is vital.
So, when planetary scientists talk of exploring other worlds, they are also increasing their ability to understand our own planet.
Note: This story has been adapted from a news release issued by European Space Agency.
Mars on the other hand is much smaller than Earth and has a much thiner atmosphere. More sunlight gets through but it is farther away from the sun so receives less than half the sunlight that Earth does at the surface and it has less clouds to trap the energy which makes it very cold.
Mars currently is going through a Global Warming of its own and it would be interesting to see if Venus has also had an increase in temperature. If all the planets are showing an up tick there may be a reason to believe that an outside factor namely the sun is responsible for much of the warming. (It was hard to keep a straight face writing that) No, the sun responsible for warming? Now get the hell out of here! lol
The one thing that we do know is that the Earth has been significantly warmer in the past. So much so that no ice caps existed at the poles and we did not face a run away green house effect. Earth has also underwent extreme levels of volcanism and that didn't do it either. Earth has been hit by extinction level impacts from space and that didn't trigger a run away green house effect. If those things didn't do it we certainly aren't going to. We may wipe ourselves out and even most of the life on the planet (though I doubt that) but Earth will recover and survive as if we never existed at all.
All that manufacturing on Venus and Mars sure f***ed them up!
I guess those Martian and Venusian SUVs were very active 5 billion years ago...
It is still President Bush’s fault!
Premise #2: Climate of Mars suffered catastrophe millions of years ago, and the planet lost it's atmosphere. Using advanced computer models, scientists are discovering that climates are much more complicated than they had thought.
Premise #3: The Earth has seen temperatures go up a degree or two over the last hundred years or so.
Conclusion: Mankind is destroying our planet through industrialization and we need to dismantle our economy and live in harmony with nature.
Simply a lie. We do not know how either Venus or Mars started. Just another GW pantload.
Were there SUVs on Mars and Venus?
Just more hyping of the BIG SCAM...create the chaos then the Dems are here to fix it...of course at taxpayer expense....(do we know these clown carpetbaggers, or what?)
People who don’t believe in “martian-made” and “venetian-made” global warming are no different than Holocrust deniers.
Then they say:
"As Earth warms in response to manmade pollution, it risks the same fate."
If the warming before was caused by the sun - why is it such a stretch to think that it may be this time also?
Note the weasel word “possible”.
Where I’m sitting was under hundreds of feet of ice about 10,000 years ago (the Columbian Glacier)and in looking out the window I see no glacier. Obviously there was very significant global warming 10,000 years ago that melted all these glaciers. There was also significant global cooling to have caused them in the first place. All of this global warming and cooling without any possible human intervention. Apparently there is some other climate change mechanism other than that espoused by St. Algore.
This isn’t so complicated.
Venus is too close to the sun.
Mars is too far from the sun.
“Water vapour is a powerful greenhouse gas and it caused the planet to heat-up even more. This is turn caused more water to evaporate and led to a powerful positive feedback response known as the runaway greenhouse effect”
OK. So how in the world did the Earth recover from the balmy days of the dinosaurs, when there were no icecaps and the oceans were apparently well over 100 deg. F in places? There was absolutely a LOT more H20 in the atmosphere then...
(Possible hint: There is no such thing as 101% humidity.)
Conservative Capitalist Christian Republicans are responsible for Galactic and Universal Warming?
This is almost right. Since Mars is so much smaller than the Earth, its iron core has cooled and hardened. That killed the volcanoes but more importantly, it killed the magnetic field, which is what protected Mars from most of the solar wind streaming constantly from the Sun. That solar wind slowly blew away the Mars atmosphere into space.
The Sun's heat varies by less than .5 degrees over the last million years. But the Sun's magnetic field, which stretches to all the inner planets, is quite variable. When the Sun is more active, during the height of the sunspot cycle, it's magnetic field shields the Earth from slightly more cosmic rays.
On the quiet side of the Sun's magnetic cycle--no sunspots = less magnetic field--more cosmic rays get to the Earth's atmosphere, which are powerful seeds for cloud formation. More average cloudcover acts to cool the Earth, even to the point of a mini ice age like we had 200-300 years ago when sunspot activity virtually ceased.
As we've said, this climatology stuff is quite complex; much deeper than the simplistic "global warming" hypothesis that beguiled me and everyone else thirty years ago.
Not only that, but there much geologic evidence that the glaciers melted quite rapidly. We have many high hills in Utah that have large, rounded boulders scattered on hilltops, rocks that were deposited there when glaciers on nearby mountains quickly melted and caused great floods that carried the boulders along for miles and left them stranded atop the hills. So what caused the fast temperature rise and glacier meltdown? The sun did it all by itself. I’m convinced that the Anasazi indians did not drive SUVs at the time.
Arguably all three planets are equally subject to the effects of a single cause, solar heating. So why, in the case of Earth, do we insist that human activity is the principle cause of climate change? Jeepers, it appears that Jupiter and even Pluto have heated up in fairly recent times -- that is, at a time when solar activity has been off the scales....
Of course, there's not much science can do about solar activity: We just have to grin and bear it.
Of course, to acknowledge that fact doesn't provide much of a rationale for applying for a research grant geared to "fixing" global warming!
It seems we need to be doing more research on the sun....
Thanks for posting this, Maelstrom!
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