Soren,

You didn't grasp the point I was making, now did you? The one about seasons, and the fact that the link you provided to illustrate your argument about a long term global warming on Mars, was in fact talking about normal seasonal variation. On Earth, Southern Winter marks an increase in size of Antarctica. On Mars, the Southern winter also corresponds with perihelion (the closest point to the Sun), so Southern winters are much colder than Northern Winters on Mars.


Anyway - Please tell me what normal summer/winter temperature variations have to do with Global Warming on Earth - or Mars for that matter? 

Soren's AAS (Answer Avoidance Strategy)

Ok - You've changed your point again - haven't you? You're dodging the inevital embarassment by making a different point and just pretending that it was the point you were making all along. You might see it as a way of saving face, but people who have been following this thread are perfectly aware of your dodging tactics.

Well, if you persist with dodgy arguments, you need to use dodging tactics.

Answer

Mars and Earth are just not very alike. I have been following the exploration of Mars very closely through another forum:

http://www.unmannedspaceflight.com/

The Martian atmosphere is extremely thin. On the surface, the atmospheric pressure varies from 0.03kPa to about 1kPa, compared to a mean atmospheric pressur eof 101.325kPa on Earth.

The Martian atmosphere is not exactly a vacuum compared to the surface of the moon, but you would describe it as a medium to high vacuum, comparable to the best vacuum obtainable using a common single stage vacuum pump here on Earth..

So even though the CO2 concentration is around 95%, it's still at an extremely low pressure.  You can't compare apples and pears.

The factor that is important in terms of surface temperature on Mars is the dust content of the atmosphere. Again, totally the opposite applies compared to the Earth. The higher the dust content on Mars, the higher the temperature.
This particular urban legend started because of a sequence of images taken over 6 years in the 1990's that showed a slow decline in the Southern Polar Cap of Mars. Of course, the processes are totally different to that on Earth and there is no evidence of any long term trend, but the urban myth persists.

Didn't you watch the video? It explains it better than I could.

- because you don't understand high school physics.

Which part of vacuum don't you understand?

Ok, what else? Have you heard of the inverse square law?

What distance is Mars from the Sun?  
What do you think Solar irradiance would be at that distance compared to 1366kW/m2 at the distance of the Earth? *
What is the height of the Martian atmosphere?

Don't you think that CO2 causes a greenhouse effect on Mars?

Of course it does, but there are other considerations that I think you can work out for yourself. (if you wanted to)

*(OK - I'll tell you - it's 590 kW/m2)

muso wrote on Nov 6^th, 2009 at 2:54pm:


And of course none of this matters on Earth. Everywhere else it is a complex issue  - here the only thing that matters is the change of CO2 from 0.028 % of the atmosphere to 0.0387 % and even 0.050 %. ANd that only because we can pin it on the pasty faced hite guys with fat wallets.

Science is amazing, isn't it (for an invention of said pasty faced white guys.)


Sign the petition:

http://www.corybernardi.com/

Here it is slowly:

The irrelevance of saturation CO2 in the atmosphre to seasonal melting and freezing on Mars is explained by refernce to complex science. Other factors are more important, don't you know, and all that.

The centrality of a miniscule change in the miniscule CO2 levels in the atmosphere here are explained by refernce to complex science. Other factors are less important, don't you know, and all that.

In Copenhagen there is going to be a push  for a massive shake-down of pasty faced white guys (us in the developed countries) who also happened to invent science. The science which is used to explain the relevance/irrelevance of complex factors, depending on what promotes the success of the shake-down.

Soren wrote on Nov 7^th, 2009 at 7:06am:


THe climate on Mars is extremely complex. We're only just starting to get a handle on it now. If you read this fact sheet, you'll see that there are a number of factors that drive it, and it has little in common with that of the Earth:

http://www.howard.k12.md.us/white/FastFactsMarsClimate.html

Mars doesn't have life, let alone a finely balanced set of ecosystems and over 6 billion people.

As far as the Earth is concerned, there are certainly a lot of complex factors that define the Earth's climate. However, the increase in greenhouse gases in the atmosphere is the parameter that will upset the fine balance on Earth, and we are already starting to see some very early signs of that happening.

It's a bit like the human brain. If you drink alcohol, you change the way it operates. It may be a very complicated system, but the factor that determines the change in behaviour is down to one input variable - the alcohol consumed.

Substitute atmospheric circulation for brain, and greenhouse gases for alcohol in the above example and you get the general idea.

pjb05 wrote on Nov 7^th, 2009 at 10:00am:


If you can't understand the science, I am compelled to provide analogies, weak or otherwise.

Of course there is a difference between not being able to understand and not wanting to understand.

The "Gaia hypothesis" actually works quite well. The Earth tends to compensate for changes quite well. Microbial life is a very important buffer to maintaining viable atmospheric conditions- but there are limits.  James Lovelock and other supporters of the idea now call it "Gaia theory", regarding it as a scientific theory and not mere hypothesis, since they believe it has passed predictive tests.

It's certainly undeniable that life has altered the composition of the Earth's atmosphere, starting with blue-green algae (Cyanobacteria) and that the Earth's combined ecology tends to provide some degree of homeostasis. Of course, the concept of a conscious Gaia is not mainstream. That's the domain of some very drug-altered individuals who usually grow their hair long.

mozzaok wrote on Nov 7^th, 2009 at 10:45am:


That's others - Not you, Soren.

Actually you'd be surprised how many people out there think that AGW is a hoax.  A friend of mine who owns a small business is convinced that it's a conspiracy. His business association puts out a magazine with a great many denialist articles.  The majority are just ordinary people who understand neither the science nor the magnitude of the problem.