Monday, October 22, 2007

There goes the neighborhood (UPDATED)

UPDATE: 10/25/2007 - the paper has appeared http://www.pnas.org/cgi/reprint/0702737104v1

ABSTRACT: The growth rate of atmospheric carbon dioxide (CO2), the largest human contributor to human-induced climate change, is increasing rapidly. Three processes contribute to this rapid increase. Two of these processes concern emissions. Recent growth of the world economy combined with an increase in its carbon intensity have led to rapid growth in fossil fuel CO2 emissions since 2000: comparing the 1990s with 2000–2006, the emissions growth rate increased from 1.3% to 3.3% y–1.The third process is indicated by increasing evidence (P =0.89) for a long-term (50-year) increase in the airborne fraction (AF) of CO2 emissions, implying a decline in the efficiency of CO2 sinks on land and oceans in absorbing anthropogenic emissions. Since 2000, the contributions of these three factors to the increase in the atmospheric CO2 growth rate have been {approx}65±16% from increasing global economic activity, 17±6% from the increasing carbon intensity of the global economy, and 18±15% from the increase in AF. An increasing AF is consistent with results of climate–carbon cycle models, but the magnitude of the observed signal appears larger than that estimated by models.All of these changes characterize a carbon cycle that is generating stronger-than-expected and sooner-than-expected climate forcing.
Thanks to Hank Roberts for the pointer. He's right it is bad news in many ways (see comments).
--------------------------------------------------------------

Via Stoat who stole it from In It for the Gold, a recent article claims that the North Atlantic is not absorbing as much CO2 as it warms, a reasonable proposition. Still there are doubters and one of our furry friends remarks :
But airbourne fraction is still about 55%, so this can't be happening globally.
Sadly yes, Virginia, it is happening globally
Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks

Proceedings of the National Academy of Sciences , October 2007.
Josep G. Canadell, Corinne Le Quere, Michael R. Raupach, Christopher B. Field, Erik T. Buitenhuis, Philippe Ciais, Thomas J. Conway, Nathan P. Gillett, R. A. Houghton, and Gregg Marland

Carbon sink slowdown contributing to rapid growth in atmospheric CO2

This study finds that the recent swift increase in atmospheric CO2 is due to faster economic growth coupled with a halt in carbon intensity reductions, in addition to natural sinks removing a smaller proportion of emissions from the air. Efficiency of natural sinks to remove emissions from human activities has been declining for 50 years.

While rising anthropogenic emissions due to increased economic growth have been established as the driver of accelerated atmospheric CO2 this study shows that both the slow down of natural sinks and the halt to improvements in carbon intensity are contributing more than one third of the increase.

More tomorrow when the actual paper is available.

UPDATE: 10/23 - Well the Joesep Canadell's paper still moulders in the grave of not for attribution, and has not been released on the PNAS web site, which is curious, but it is all over the news. Some more meat from Scientific American
Specifically, oceans and plant growth absorbed only around 540 kilograms per metric ton (1,190 pounds per short ton) of the CO2 produced in 2006, compared with 600 kilograms per metric ton (1,322 pounds per short ton) in 2000. Coupled with an emissions growth rate of 3.3 percent—triple the growth rate of the 1990s—the atmospheric burden is now rising by nearly two parts per million of CO2 a year, the fastest growth rate since 1850, the international team of researchers reports in Proceedings of the National Academy of Sciences USA.
but as they say there is a lot of noise in a lot of data but google is your friend (although Eli gratefully acknowledges another friend who has provided a preprint), so our paws did the keyboarding and found a recent presentation by Canadell that has a lot of the information in the paper. The key point is that the amount of CO2 emitted each year is going through the roof. The fraction of the carbon emitted each year going into the atmosphere has increased over the last half century
and the amount going into the oceans has decreased about the same amount while the land fraction stays about the same.The sharp eyed bunnies should look at what happened to the fraction of emitted CO2 that went into the land during the huge 1998 el Nino year. It plunged faster than the Arctic sea ice coverage this September. The take home is that theCO2 fertilization effect combined with higher temperatures will not save the day.

but, perhaps Mighty Mouse can. Eli is going for one of those beers you guys hid in the bathtub with the ice.

17 comments:

Belette said...

Its interesting to see these AF numbers. WMO claims 55%; they say ~45%, and claim to detect a trend since 1958... but if the trend is there, its rather small in the noise, and much less than the 55-45 difference. See what you think of the paper itself.

Steve Bloom said...

The North Atlantic CO2 papers (actually two of them, the first and fourth, the latter of which is the publicized one) can be found here.

SCM said...

I posted this on Stoat already but what the hell :-) There was similar news from the Southern Ocean not long ago...

http://news.bbc.co.uk/2/hi/science/nature/6665147.stm

http://www.sciencemag.org/cgi/content/abstract/316/5832/1735

Cynthia said...

So NIMBY strikes again!?!

Hank Roberts said...

This seems to be working toward the idea of including biological processes --- plankton species and behavior -- in the climate models.

Hans Erren said...

But the sink is growing more than proportional to emissions.

http://home.casema.nl/errenwijlens/co2/sinkratio2003.gif

Steve Bloom said...

SciAm made an arithmetics error: Those pounds per short ton figures are actually per metric ton. Per short ton would be 1080 and 1200 pounds respectively.

Magnus said...

What sink would that be, and what scale is that in?

http://www.globalcarbonproject.org/global/ppt/GCP_CarbonCycleUpdate.ppt#770,25,Slide 25

TimC said...

According to Hadley MET, within the next decade 1998 will become the norm for the global average temperature. As such it does not look good for the land sink - if one is looking simply at 1998. However I also noticed that there wasn't as severe a drop in co2 absorption by land in 2005 where that year was more or less tied 1998 for the global average temperature.

Do we know what the reason for the difference in absorption was for those two years since it would appear not to have been temperature?

Dano said...

Hans, the sink has never caught up to emissions in your real purty graph. That is: the biosphere isn't absorbing our emissions. You can stumble around and try to distract away from that fact if you wish, but it won't work here.

Best,

D

Anonymous said...

The yearly growth rate in emissions may have increased significantly (from 1% to 3%) since 2001 -- a 2% change --, but that's clearly a drop in the bucket compared to the recent increase in the yearly increment of CO2 added to the atmospheric concentration.

The latter went from an average of about 1.5ppm in the 80's and 90's to an average of 2ppm over the last 5 years -- an increase of 30% (ie, over 10x the change due to yearly emissions increase).


If the absorption by sinks dropped from 600 kg/MT to 540 kg/MT from 2000 to 2006, that means the remainder (what was added to the atmosphere) increased from 400 kg/MT to 460kg/MT, a 15% increase.

Why the relatively large drop in absorption by sinks over such a short period?

And what caused the OTHER half of the 30% increase from an average of 1.5ppm per year to an average of 2ppm per year? (assuming, again, that this increase in the average is "real")

Increased fire with the warmer (dryer) conditions on land is one possibility.

Hank Roberts said...

Probably mostly ocean changes. The productivity of the polar oceans is tied to the thin layer under the floating ice, as I recall. Most of it is very small organisms, lots of them.

One example from Antarctic but there's plenty published on the Arctic as well. This is just a Google Grab-Bag example to encourage others to search.

Google still hasn't enabled their "I'm Feeling Brilliant" ("Wisdom") search option.

http://icb.oxfordjournals.org/cgi/content/full/41/1/57



"... sea ice microalgal production is exceeded by phytoplankton production on an annual basis in most offshore regions of the Southern Ocean, blooms of sea ice algae differ considerably from the phytoplankton in terms of timing and distribution. Thus sea ice algae provide food resources for higher trophic level organisms in seasons and regions where water column biological production is low or negligible. A flux of biogenic material from sea ice to the water column and benthos follows ice melt, and some of the algal species are known to occur in ensuing phytoplankton blooms....."

S2 said...

TimC said:
"Do we know what the reason for the difference in absorption was for those two years since it would appear not to have been temperature?"

Global annual temperature is probably to broad a brush - I would guess that regional and temporal variations during the year probably play a big part.
For example, in 1998 the really hot months were May to August inclusive - the peak of the NH growing season (though February was hot as well). In 2005 the summer was cooler, butJanuary, March & April were warm, as were September and October.

Hank Roberts said...

Today:

http://www.pnas.org/cgi/reprint/0702737104v1

Hank Roberts said...

Any chance someone can explain where the error bars would be on these charts?

Michael Tobis said...

There's more on the Canadell work here with links to some press release stuff and a very interesting powerpoint. It appears that the ocean saturation issue is something of a sideshow.

The main story is that recent emissions trajectories lie substantially outside the boundaries of the standard emissions scenarios, and not on the happy side.

nonymously, Michael Tobis

EliRabett said...

Michael, I agree that is a sideshow wrt what is actually happening and that is clear from the paper. OTOH one is constantly confronted by the "it will all be absorbed by the biosphere/oceans so be happy, don't worry". Policy wise it is not a sideshow, which scientists have to recognize.