The Age of Stupid

[Uzor]

Well, that clears that up. And illustrates the general lack of utility of the iPad.

It's possible, but unlikely, particularly in the case of Venus. Mars at least had a respectable magnetic field at one point, we believe; there's no evidence that Venus ever did. We do at least have a chance of making the discovery on Mars, though again, Venus is unlikely we'll ever know for sure, given the inherent hostility of the environment.

Actually; scientists believe Venus to be more likely to house organisms than Mars. The main purpose of a magnetic field is to keep unwanted cosmic radiation (and solarflares) away from the planet. There are organisms, however, that are seemingly unaffected by these. Tardigrade is one such animal; which can actually thrive in an environment where the radiation is 10000 times higher than the lethal dose for humans. There's also organisms which thrive is seemingly impossible situations, such as near-zero temperatures, temperatures of several hundred degrees, vacuum, with no sunlight etc. Scientists actually believe there may be organisms living inside of the clouds on Venus, as studies suggest that some compounds in the atmosphere of Venus can't be created naturally unless an organism create them.

That being said;

Untrue. Most evidence suggests that, for the vast majority of the planet's lifespan even after the rise of photosynthetic organisms, CO2 levels were significantly higher than they are today. Now, we can't be as accurate with those theories as we can with more recent periods, say, the past million years or so, because we don't have ice cores for them. Nor will we.

Ever.

Because for tens of millions of years at at time there have been no ice caps. At all.

It depends on the study you read, though. There's an undisputed period between 300-500 mil years ago when it was significantly higher, though. Carbon dioxide isn't the only dangers though; The methane(GWP: 25) concentration is more than twice that of what it was 250 years ago. There's also gases that normally don't even exist in the atmosphere, such as trichlorofluoromethane(GWP: 4750), CCl2F2(GWP: 10900), CCl2FFClF2(GWP: 6130), CHClF2(GWP: 1810), CH3CCl2F (GWP: 725), CH3CClF2(GWP: 2310), CBrCIF2(GWP: 1890), CBrCIF3(GWP: 7140), CH2FCF3(GWP: 1430), Carbon tetrachloride (GWP: 1400), Sulfur hexafluoride (GWP: 22800) and other Halocarbons.

Carbon tetrachloride in particular is extremely dangerous as a global warming house, as it is 22800 times more potent as a greenhouse gas than carbondioxide. Latest reports show that the atmosphere has over 7.4 ppt of Carbon tetrachloride, which has an atmospheric halftime of 800-3200 years.

That being said, the last gas's contribution to global warming is estimated to be less than 0.2% compared to the total effect of Carbon Dioxide, but all the other sources of Global Warming can't be ignored, as the other greenhosue gasses (excluding methane) has a radiative forcing of 0.5 (methane has 0.5 and carbon dioxide has 1.7). Methane in particular is interesting, as an increased temperature runs the risk of an arctic methane release from the smelting permafrost and release from the glacier. Historically, large methane excursions have been linked to dramatic climate shifts - the Paleocene-Eocene thermal maximum and the Permian-Triassic extinction event being the most notable; the last being the worst mass extinction in history.

As a matter of fact, the atmospheric methane concentration has increased by 150% since 1750, and accounts for 20% of the radiative forcing from all the other greenhouse gasses (excluding carbon dioxide). Additionally, none of these gases even hold a candle to the water vapor - which is by far the largest component of the greenhouse effect.

 

[Raesvelg]

Preface your comments on Venus with "some scientists", and you'd be closer to the truth there. It's conceivably possible, but not likely. The conditions on Venus are enormously hostile, and there's little to no evidence of life barring some atmospheric compounds which can occur by means other than biological.

The P-T extinction has a theoretical link with methane clathrates, aye, but mostly because they can't really figure out what may or may not have caused the event. It's far enough back that even the geologic record is questionable; about the only thing we know about it is that the Siberian flood basalt event coincides nicely with the start of it. It's also noteworthy that the event was so catastrophic that having a ridiculous amount of the continent of Asia in a state of continuous volcanic eruption for what was like hundreds of thousands of years is considered insufficient to create the sort of climatic disturbance and extinction that we see during the event.

And you're not really reading what I'm writing, are you? Given that I've brought up the P-T extinction event multiple times so far in this thread...

Either way, methane is most certainly a potent greenhouse gas, and the rising levels of it indicate that we're in a warming trend. Which we already knew. Part of my problem with the more hysterical elements of the global warming fringe are that they regularly violate the "mediocrity principle", i.e. they seem to believe that there is something enormously special and singular about this particular warming event, simply because it coincides with, and may be at least partially driven by, human industrial activity.

And yes, CO2's only real significance as a greenhouse gas is its prevalence; though it's important to note that even with that caveat, the exact amount of the effect attributable to CO2 is a matter of some debate. Estimates range from around 8-10% to around 25%, which is, to say the least, a significant variability.

 

[Uzor]

Reason I brought the P-T extinction up again was for the exact reason that you had brought it up several times.

And yes; the mediocrity principle annoys me too. I'm actually not a greenhouse-craze that believe the apocalypse should arrive within a decade if this warming keeps up. In my opinion this warming trend is one of the earth's natural warming stages. I do, however, believe that mankind is speeding the process up. The reason I've taken the pro-global warming stance in this thread is because you're clearly anti-global warming. As such, I chose to take the opposite side to represent the opposing side so that people can form their own opinion based on the fact both sides represent.

That; and my father is one of the pro-global warming crazies that believe the world will end "within your (as in, my) lifetime". As such, I could always use some new arguments as I constantly bicker with him, lol.

 

[Morcheeba]

And I thank you, both, for your roles ;p

Although I don't have nearly the comprehension on the matter needed to contribute, for the most part I understand both sides. I think I'll just participate and do my part to take care of our home, that I can be happy with.

 

[Uzor]

There's still other reasons to be wary of the nature other than global warming, though; such as not throwing batteries in the garbage (as the chemical substances in the battery will leak out in to the environment if you do), not throw electronics in the garbage, not throw broken glass with the normal garbage etc. It all have benefit that you may or may not think of, and it all have consequences you may or may not think of that's completely unrelated to global warming.