Weaver wrote:
And yes, current levels are higher than have ever been seen before.

CO2 concentrations have been far higher during the geologic past.

Ice core samples date back over 150,000 years - many, many cycles of normal systems. The highest natural concentration of atmospheric CO2 in the historical record was 290 parts per million (ppm). Current atmospheric levels are at 390ppm and rising - I would be surprised if it tops out at 500ppm, possibly much higher.

Multiple cores date back to about 400k. At least one reaches to about 800k. Other proxy data extend our record much, much farther. The current CO2 concentrations surpass those known from orbital-driven cycles of the last ~ million years.

nimbus wrote:
Thanks for pointing out the errors. I had heard about the large consensus amount climate researchers which is why I was shocked when I was being taught the opposite in an earth science class!

Although, my lecturer mentioned in class that he was listed as one of approximately 3000 “scientists” who agreed that there was a discernable human influence on climate in an IPCC report but he was never asked if he supported this view by any survey, but his name was added to the list. See link... http://climaterealists.com/index.php?id=3477

I really have no idea about such a claim. I suppose there's always room for error, or self delusion, or malicious intent.

The 97% consensus, however, only concerns active climatologists. Your instructor is an oceanographer. Whether he was or was not accidentally counted as supporting IPCC consensus has no influence on the results of three studies that have now demonstrated a 97% consensus among active climatologists.

97% consensus doesn't mean that anthropogenic climate change is occurring. Nature doesn't care about consensus. It's not defined by our ideas. 97% consensus means that almost every single researcher that actively studies the Earth's climate seems convinced that anthropogenic climate change is occurring. These are the folk who study this system for a living, day in and day out. These are the folk best acquainted with theory and data. While their consensus may not prove anything conclusively, it should help you to at least appreciate just how compelling the data are, and how much research you should require of yourself to reach a differing conclusion. In my view, if you want to diverge from expert consensus (when there is significant consensus), you better become an expert.

Really? I mean I know that CO2 has been increasing over over the last 100 years but (correct me if I'm wrong) I had heard that CO2 levels have at times in the earth's history been alot higher due to natural causes than they are today. But the earth didn't burn to a frazzle back then only because solar output from the sun was not as great as it is today, but if we had those really high CO2 levels today - in combination with what solar irradiance is today - then we would boil.

That is essentially correct. We have evidence of CO2 levels above 1,000 ppm in the geologic past, for example, but solar calculations-- in which we have very high confidence-- indicate solar irradiance was lower.

Darwinsbulldog wrote:
A lot of this [so-called] 'reasonable skepticism" is driven by the Christian right, who [even if they believe in global warming, and many don't] reckon the Jeebus zombie raptor will come down and sort it out for them. The other big misinformers are the fossil fuels industries, who have a vested interest. George Bush came from Big Texas Oil and the religious right...I rest my case.

You are probably right.. but I don't like you're arguing style. Yes, many skeptics of global warming are biased but not all are. And even if someone is biased due to a religious or political belief it does not necessarily mean that they are wrong about climate change. In this case, however, my skeptical lecturer is neither a christian nor employed by an oil company.

Also it works both ways. For instance, on the other side they say things like "global warming is being exaggerated by the greenies and the liberals because the greens want more money for their causes and the liberals want more taxes on the rich, green taxes etc..."

Both sides can claim that the other is biased and has vested interests. And this makes it harder for the public to know what is actually going on.

The truth is that, at this point, there are very, very few climate "skeptics" who are not biased by politics or industry. Like I suggested, just take a few hours to skim through the articles and abstracts publish by the Journals of Science and Nature. When you get a feel for just how deep census really is, how great the level of concern among researchers, and how interesting the published data and research are, you'll start to find it very difficult to empathize with climate "skeptics." At this point, the position can only be held through willful ignorance or nefarious intent. The data clearly overwhelmingly support consensus.

OMGturt1es wrote:The truth is that, at this point, there are very, very few climate "skeptics" who are not biased by politics or industry.

The big irony is that many of the 'skeptics' see a conspiracy by the left in the whole AGW theory. They assert that the left has constructed (or at least hijacked) AGW purely for political and financial gain. This is like claiming that scientists only purpose in developing evolutionary theory is to get rid of religion, when it's just an unintended side-effect. In the case of AGW the scientists tell it like they see it, the politicians and economists try to figure out how to deal with the situation, and it just so happens that a few mega-rich corporations will have to change their ways.

And the actual conspiracy was the anti-AGW campaign funded by Exxon and others that the Royal Society condemned..

http://www.guardian.co.uk/environment/2 ... l.business

There was even a boardroom revolt by the Rockefeller family over the same issue.

http://scienceblogs.com/deltoid/2008/05 ... rese_1.php

Yet the denidiots rant conspiracy! without getting the irony

Areopagitican wrote:Of course, that's how small a percentage of the atmosphere? Isn't debating 290 v. 390 quibbling over tenths of a percent of the atmosphere? Hmm... Just wondering.

It's more than tenths of a per cent, do the math.

But, in any event, it's a significant increase in terms of the warming it can cause, and as the concentration continues to increase the earth's temp will continue to rise, until come the year 2100 it will have risen a good 4 to 5 degrees C over today, and that's not going to be good for you or your children. Ninety years!

Areopagitican wrote:Of course, that's how small a percentage of the atmosphere? Isn't debating 290 v. 390 quibbling over tenths of a percent of the atmosphere? Hmm... Just wondering.

I'm no climate scientist but recognise a fallacy when I see one.

An analogy would be injecting 0.1g of botulism into your arm and saying "well this is less than 0.1%" of my body weight.. I'll be fine!"

The fact that CO2 is a small % of gas in the atmosphere is irrelevant. It will have a certain effect depending on how much is there which will not be altered by the presence of other gases (well maybe it will in complex ways, but not in the way your post implies).

Imagine there was only CO2 in the atmosphere, exactly how much there is now. So atmosphere % of CO2 is 100%. It has a certain warming effect. Now add 1billion times that volume of some other gas into the atmosphere that has no warming effect. Now atmosphere % of CO2 is <0.1%. Will that now make any different to warming? Of course not.

Panderos wrote:

Areopagitican wrote:Of course, that's how small a percentage of the atmosphere? Isn't debating 290 v. 390 quibbling over tenths of a percent of the atmosphere? Hmm... Just wondering.

I'm no climate scientist but recognise a fallacy when I see one.

An analogy would be injecting 0.1g of botulism into your arm and saying "well this is less than 0.1%" of my body weight.. I'll be fine!"

The fact that CO2 is a small % of gas in the atmosphere is irrelevant. It will have a certain effect depending on how much is there which will not be altered by the presence of other gases (well maybe it will in complex ways, but not in the way your post implies).

Imagine there was only CO2 in the atmosphere, exactly how much there is now. So atmosphere % of CO2 is 100%. It has a certain warming effect. Now add 1billion times that volume of some other gas into the atmosphere that has no warming effect. Now atmosphere % of CO2 is <0.1%. Will that now make any different to warming? Of course not.

Indeed, but it would sure as hell send the earth's temp plummeting!

It's difficult tor many to envision why relatively small changes in the atmosphere's C02 content can have such large effects, going from the preindustrial norm of 280ppm to today's 390ppm is a 39 per cent increase in C02's concentration, sufficient to have pushed earth's temp up by .6 degrees C. Increase it to 450ppm, where it's fast headed, and you have a sixty per cent increase, enough to push earth's mean annual temp up by some 4 degrees C in time (about 90 years from today).

The bigger the system you're dealing with the smaller the changes to it need to be to cause big changes in it, and while a 4 degrees C increase doesn't seem like much it's almost as big an increase as what brought the last Ice Age to an end 10,000 years ago, talk about big effects!