Friday, March 21, 2014

Open Thread

An open thread for comments, most for this Twitter dude who thinks the rise in CO2 since the Industrial Revolution is 95% natural. (I can't justify polluting my Twitter feed any more correcting somone's basic errors, so the conversation can continue here instead.) Science shouldn't be investigated in 140 characters anyway.


steve said...

Skeptic, lukewarmer, and Pielke favorite cartoonist Josh also believes this.

David Appell said...

Yes, there is a lot of confusion (and denial) about this subject.

In answer to @ClimateRealists, no, I did not say 95% of CO2 was from man.

I said that almost all of the extra CO2 in today's atmosphere and ocean is from human sources -- burning fossil fuels and from land use changes.

In fact, humans have emitted roughly twice as much CO2 as has built-up in the atmosphere.

David Appell said...

Here was the tweet from ClimateRealists:

David Appell said...

Here is the (unpublished, un-peer reviewed) paper this guy on Twitter thinks has disproven all of the IPCC consensus science:

"Carbon cycle modelling and the residence time of natural and
anthropogenic atmospheric CO:
on the construction of the
'Greenhouse Effect Global Warming" dogma.'"
Tom V. Segalstad

Did I say it wasn't peer reviewed? At least it wasn't written in crayon.

Most of the references in this paper are from before 1990, and many from before 1970.

Needless to say, the science has advanced considerably since then.

Its main thesis is:

"Both radioactive and stable carbon isotopes show that the real atmospheric residence time (lifetime) is only about 5 years, and that the amount of fossil-fuel
in the atmosphere is maximum 4%. Any CO2 level rise beyond this can only come from a much larger, but natural, carbon reservoir with much higher 13-C/12-C isotope ratio than that of the fossil fuel pool, namely from the ocean, and/or the lithosphere, and/or
the Earth's interior."

It's a mistake to say that any CO2 beyond the 5-year residence time of CO2 is natural. That's about the residence time for a *given* CO2 molecule, which then is either taken up by land or by the ocean. But these sinks are also sources, which is why CO2 is building up in the atmosphere.

David Archer wrote a great little book called "The Long Thaw" that goes into the carbon implications in detail. And he has some good papers on his Web site:

As he puts it in his book “The lifetime of fossil fuel CO2 in the atmosphere is a few centuries, plus 25% that lasts essentially

By "essentially forever" he means hundreds of thousands of years.

That doesn't mean it's the *same* CO2 molecule in the atmosphere all that time. That molecule goes into the land or ocean, but in doing so it changes the carbon cycle enough so that another CO2 molecule almost always, in effect, appears in the atmosphere.

The result is that human emissions change carbon content of the atmosphere (and the ocean, too) for a long time.

I think that's one big thing Segalstad misses in his paper.

David Appell said...

There was an article published on a Norwegian news site about Segalstad's claims:

From the deck (Google translation):

"The ongoing rise of atmospheric CO2 content is not natural. Tom V. Segalstad misinterpret laws and geochemical data, writes Gisle Nondal, Richard Bellerby and Are Olsen in this post."

David Appell said...

The real question is, if almost all the extra CO2 in today's atmosphere is natural, where's it coming from, and why did the increase start concurrently with the Industrial Revolution.

In a longer Twitter forum, this guy admits he doesn't know:

Until someone can answer those, the hypothesis is junk.

Richard Lawson said...

Your Twitter dude, @MDSebach, is a devotee of Ayn Rand. I tossed in the one about Ayn Rand Collected Social Security,_but_grabbed_social_security_and_medicare_when_she_needed_them
and he and a few other Randians fell n it like sharks on a leg of lamb.