the facts about global warming

[jason_85]

(02-22-2010 08:25 AM)HarpoSpoke Wrote:  1: It's important to remember what the claims are here and what is being proposed. Extraordinary claims require extraordinary evidence. We are being asked to believe that humans have suddenly taken control of the earth's climate with only circumstantial evidence to back that up. (and compelling evidence against it) And we are being asked to make major lifestyle changes with very weak arguments to back that up.

Hi Harposmoke, and thanks for the welcome
I think this point underlines another issue on its own. Personally, I don't think it's the onus is only on the believers of global warming, but lies quite evenly on both sides, maybe even more on the table of deniers. One could argue that to state that global warming is not going to happen with the significant addition of a gas known to increase radiative forcing is in itself a strong allegation. I personally do not view the belief of global warming as an idea that must be proven for it to be taken seriously, simply because it makes the most sense given the data. It's by no means the only explanation, nor do I think we should stop asking questions, but to dismiss it based on the lack of absolute proof (whatever that might look like) would, in my view, be quite arrogant given then substantially higher "pile of evidence" compared to other theories. That said, I think this is itself a complex discussion which could warrant another blog article...

(02-22-2010 08:25 AM)HarpoSpoke Wrote:  2: While past behavior is no guarantee, it is certainly a large strike against AGW theory. No one can argue that isn't a very noteworthy point. There is a reason why your side never mentions it.

Yes it's a shame we don't have an example from the past, and that's simply because current events are unprecedented in earth history. Therefore in this case, past history is quite a poor tool in terms predicting the greenhouse effect. It does however tell us that solar activity was far more important in the past than it has been since the onset of the industrial revolution, which tells us we should look for "something else" which might be forcing global temperature.

(02-22-2010 08:25 AM)HarpoSpoke Wrote:  And let's also note that much of this is based on predictions which assume a continued path (i.e. humans won't adapt in any way to potential climate changes). So this exact argument can be used against many of the claims of AGW supporters.

can you elaborate on this? I don't quite understand what you mean.

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(02-22-2010 08:48 AM)HarpoSpoke Wrote:  1-Did you note the lack of correlation between CO2 and temps in the 600 million year chart? That's not a problem for the theory? You appear to require correlation with other forcings (i.e. sunspots).

Here's the image again:



In answer to the question: not really, as far as I can tell CO2 has not been a significant driver for temperature in the past (it could be the case that increases in temperature have, in the past, causes releases of CO2 which have perpetuated further temperature increases, but that's another issue). CO2 increases radiative forcing, but can quickly become saturated (ie. it can only turn up the heat so much), this is reflected in the CO2 history quite well (you never have low temp without low CO2 in the past, other than at 450 million years ago, dunno what happened there, will look into that. any ideas? Ozone maybe?)

(02-22-2010 08:48 AM)HarpoSpoke Wrote:  2-As mentioned, you seem very willing to dismiss sunspots as a driver due to the divergence after the 1970s. That's fair (though there is more to the sun than that). But the very next graph contains similar divergences between temps and CO2 (i.e. 1945-1975) Isn't it also fair to dismiss CO2 as the driver? You'll note a similar temperature climb to 1975-2000 prior to 1950...predating our CO2 emission jump. Temperatures again rose prior to CO2 rises....just as we have mentioned from earlier climate periods.

ok so here's the graph on sunspots and temp:



and here is the one on CO2 and temp:



What I find interesting about the events between 1950-1970 is that, to me (and this is ofcourse pretty loose considering the lack of past evidence), it seems like we are seeing a global shift between sunspot forcing and CO2 forcing. I'm no climate expert so this may or may not be a valid theory, but it seems like it to me. Before 1970 we can see a strong correlation between sunspots and temperature. It seems like temperature is "following" sunspot exposure by about a decade. CO2 is doing more or less nothing to affect the climate. Global temperature then responds to a downward shift in sunspot forcing during the 1950s, during which time CO2 is increasing strongly. Then it seems like, as CO2 forcing increases and sunspot forcing remains steady, global temperature seems to shift from a dependance on sunspots to CO2 in the 1970s.

This is why I don't consider the lack of correlation between CO2 and temperature before the 1970s to be an issue, because I believe that the correlation didn't exist.

(02-22-2010 08:48 AM)HarpoSpoke Wrote:  Given the claims and demands for lifestyle changes, we need more than that. The theory appears to be based on what you said there. "We can't explain it, so CO2 must be the answer". That's not compelling proof.

Now combine the correlation I just proposed with the fact that we already know CO2 to be a greenhouse gas, and the fact that we are emitting levels of CO2 never seen in human history (or during the history of many other species on this planet), at speeds likely never to have been experienced in the history of our planet, and the question is: How can you imply or suggest that it would NOT increase CO2? Just a thought. Thanks for the questions I'll try to make my article more concise

(02-22-2010 08:48 AM)HarpoSpoke Wrote:  What we have here is fodder for an interesting theory...not a major lifestyle change for the human race.

That's another can of worms. Even if what I am saying is true, the impact is whole other complex issue.

It is not unreasonable to suggest that it is very possible that both levels could rise to a level closer to what might be termed the "average" or "normal" level for the planet, although that might not be true. In any case, if either or both rise significantly, it will not be anything out of the historical norm.

(02-22-2010 05:00 PM)JohnWho Wrote:  I agree that this graphic should not be used in an attempt to disprove the AGW by CO2 concept, however it certainly should be used to show exactly what it shows - that we are currently in a time of very low levels of both atmospheric CO2 and atmospheric temperature.

What you're saying is ofcourse true, we can see it just from the graph. But what you're implying, and correct me if I'm wrong, is that going back to the historic "norm" would not be a bad thing. The earth has no "norms", and taking CO2 levels and temperatures back to a time when life, the continents and the atmosphere were completely different would be nothing less than a global disaster.

In regards to the attempts of some scientists to create these hockeystick graphs, I think that's a big mistake. There is little evidence for warming that is out of the ordinary, and one would be bending figures if they would ever claim that. What is out of the ordinary, is CO2 levels. It is expected that temperature responses to CO2 levels should lag the emissions by some time, so what is it that makes you think the temperature won't increase? Neither side here has any historical evidence to back up their argument, that's the problem really, and given that CO2 is a known greenhouse gas, wouldn't it make sense to argue that the increase of this gas way beyond historic levels would not influence the atmosphere?

(02-22-2010 05:00 PM)JohnWho Wrote:  "Why do the AGW supporters continuously use misleading arguments, false information, sometimes direct lies, and other poor science concepts to support their concept?" Heck, if it is real and based on solid "settled" science, why do they need to do any of this? Why, for example, isn't Al Gore's "An Inconvenient Truth" straightforward and truthful? If it is really happening, the science should be unassailable, and it is not. Worse, in some cases, it would be laughable if the main stream media (especially here in the US) wasn't so complacent.

Yeah it's a shame. I suppose the fact is that the real figures just aren't that exciting, it was the same thing in "The great global warming swindle". There seems to be a shocking-graphs arms race between the two sides... The media knows very well that "a rumour gets half way around the world before then truth can get its pants on".