#### Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Options

# Blog - stabilization wedges (part 5)

I'm finally starting a blog entry on Pacala's critique of his own plan:

Blog - stabilization wedges (part 5)

I feel tremendously guilty at how long this has taken, but I guess my excuse is that I've been busy reorienting my professional activities, moving away from theoretical physics to something new while trying to use a bit of the same math. That's the idea of those network theory posts, which will become a paper or two someday.

Anyway, I want to get back to some things more closely related to 'Plan C'. I would love help.

• Options
1.
edited April 2011

in October 2007 appeared this

http://ngm.nationalgeographic.com/2007/10/carbon-crisis/img/stabilization_wedges.pdf

which has 8 wedges, compared to the 7 of 2004. I don't know why these three years' emissions seem to have only added one wedge, while the one year between this NG article and the talk added a lot more.

Comment Source:About your question, I've googled a little bit: in October 2007 appeared this [http://ngm.nationalgeographic.com/2007/10/carbon-crisis/img/stabilization_wedges.pdf](http://ngm.nationalgeographic.com/2007/10/carbon-crisis/img/stabilization_wedges.pdf) which has 8 wedges, compared to the 7 of 2004. I don't know why these three years' emissions seem to have only added one wedge, while the one year between this NG article and the talk added a lot more.
• Options
2.

Perhaps one could leave it as a puzzle for the readers...

Comment Source:Perhaps one could leave it as a puzzle for the readers...
• Options
3.

I suppose if we can find the sourcedata for the plot of emissions between 1957 and 2007 we could check.

Comment Source:I suppose if we can find the sourcedata for the plot of emissions between 1957 and 2007 we could check.
• Options
4.

There is Mauna Loa data and between 2004-2007 there was an increase of 6 ppm.

Comment Source:There is [Mauna Loa data](http://www.esrl.noaa.gov/gmd/ccgg/trends/mlo.html) and between 2004-2007 there was an increase of 6 ppm.
• Options
5.

Hmm, I don't immediately see how this increase, taking into account the growth rates for each year, leads to another wedge, especially because your section The New Stuff of 2008 adds many more wedges.

Or perhaps the New Stuff refers to 2007, because there was a growth rate of 2,3 (not really 3) in 2007 instead of 1,5 for 2004, see

Annual growth rates

In 2008 and 2009 growth rates were smaller again (economic crisis?)

Comment Source:Hmm, I don't immediately see how this increase, taking into account the growth rates for each year, leads to another wedge, especially because your section The New Stuff of 2008 adds many more wedges. Or perhaps the New Stuff refers to 2007, because there was a growth rate of 2,3 (not really 3) in 2007 instead of 1,5 for 2004, see [Annual growth rates](http://www.esrl.noaa.gov/gmd/ccgg/trends/mlo.html#mlo_growth) In 2008 and 2009 growth rates were smaller again (economic crisis?)
• Options
6.
edited April 2011

Okay, now I've actually written the blog entry! Everyone take a look!

Blog - stabilization wedges (part 5)

The actual blog article should have the video of Pacala's talk embedded in it, to make it very easy and tempting to watch. Right now only 1649 people have viewed this video on Youtube. We can see what happens after I blog about it.

I'm not delighted by this blog entry: Pacala's talk was a mish-mash of many ideas, and my summary lacks his charm. But oh well...

Frederik: I decided not to mention the change in the number of wedges in my blog entry, though I added a tiny bit to Stabilization wedges, and I'll add more later. It seems 7 wedges became 8 because instead of trying to keep carbon emissions constant at 7 gigatonnes/year instead of growing to 14 in 50 years, he switched to trying to keep carbon emissions constant at 8 gigatonnes/year instead of growing to 16 in 50 years.

A more important problem: I do not understand why he says that if the land sink (of carbon) fails, we'll need 26 additional wedges! I can't see where he's getting this number from.

Comment Source:Okay, now I've actually written the blog entry! Everyone take a look! [[Blog - stabilization wedges (part 5)]] The actual blog article should have the video of Pacala's talk embedded in it, to make it very easy and tempting to watch. Right now only 1649 people have viewed this video on Youtube. We can see what happens after I blog about it. I'm not delighted by this blog entry: Pacala's talk was a mish-mash of many ideas, and my summary lacks his charm. But oh well... Frederik: I decided not to mention the change in the number of wedges in my blog entry, though I added a tiny bit to [[Stabilization wedges]], and I'll add more later. It seems 7 wedges became 8 because instead of trying to keep carbon emissions constant at 7 gigatonnes/year instead of growing to 14 in 50 years, he switched to trying to keep carbon emissions constant at 8 gigatonnes/year instead of growing to 16 in 50 years. A more important problem: I _do not_ understand why he says that if the land sink (of carbon) fails, we'll need 26 additional wedges! I can't see where he's getting this number from.
• Options
7.
edited April 2011

Could it be something like this extremely handwaving argument?

There is about 3 kg/m² carbon in soils and sediments and 1.2 in tree trunks and roots. In the atmosphere there's about 1.6 kg/m² carbon (in the form of carbon dioxide), so if 1.6 corresponds to 8 wedges (to avoid doubling) then the 4.2 corresponds to 21 wedges, assuming all of it would be released.

But so many wedges could only be provided by carbon capture, so the partitioning in wedges stops to make sense. E.g. if methane is released from permafrost it doesn't matter how many wind farms you would build.

Comment Source:Could it be something like this extremely handwaving argument? There is about 3 kg/m² carbon in soils and sediments and 1.2 in tree trunks and roots. In the atmosphere there's about 1.6 kg/m² carbon (in the form of carbon dioxide), so if 1.6 corresponds to 8 wedges (to avoid doubling) then the 4.2 corresponds to 21 wedges, assuming all of it would be released. But so many wedges could only be provided by carbon capture, so the partitioning in wedges stops to make sense. E.g. if methane is released from permafrost it doesn't matter how many wind farms you would build.
• Options
8.
edited April 2011

Thanks, Frederik. I will ask about the meaning of "26 wedges" near the end of my blog post, and include your guess, citing you of course. I'll do it in a way where I take all the blame for mistakes or confusion...

Comment Source:Thanks, Frederik. I will ask about the meaning of "26 wedges" near the end of my blog post, and include your guess, citing you of course. I'll do it in a way where I take all the blame for mistakes or confusion...
• Options
9.

Actually I got tired and did not ask about the meaning of the "26 wedges". This figure comes from some analysis of a simulation in which, because of insufficient CO2 fertilization, the Amazon rainforest dies and the permafrost melts and releases lots of methane. I think the exact figure is less important than the point Pacala is really trying to make: we need to understand the effects of CO2 fertilization, and if they're not big enough we could be in serious trouble.

Comment Source:Actually I got tired and did not ask about the meaning of the "26 wedges". This figure comes from some analysis of a simulation in which, because of insufficient CO<sub>2</sub> fertilization, the Amazon rainforest dies and the permafrost melts and releases lots of methane. I think the exact figure is less important than the point Pacala is really trying to make: we need to understand the effects of CO<sub>2</sub> fertilization, and if they're not big enough we could be in serious trouble.
• Options
10.

Actually I got tired and did not ask about the meaning of the "26 wedges".

Yes, I also have the impression that the 26 wedges is just a preliminary estimate, which could be way off, so the specific number isn't so relevant.

I agree it's much better to emphasize Pacala's point:

we need to understand the effects of CO2 fertilization, and if they're not big enough we could be in serious trouble.

Comment Source:> Actually I got tired and did not ask about the meaning of the "26 wedges". Yes, I also have the impression that the 26 wedges is just a preliminary estimate, which could be way off, so the specific number isn't so relevant. I agree it's much better to emphasize Pacala's point: > we need to understand the effects of CO2 fertilization, and if they're not big enough we could be in serious trouble.
• Options
11.

About vegetation, today I became aware of C3 and C4 plants:

Today, C4 plants represent about 5% of Earth's plant biomass and 1% of its known plant species.[11] Despite this scarcity, they account for about 30% of terrestrial carbon fixation.[8] Increasing the proportion of C4 plants on earth could assist biosequestration of CO2 and represent an important climate change avoidance strategy.

Comment Source:About vegetation, today I became aware of [C3](http://en.wikipedia.org/wiki/C3_carbon_fixation) and [C4 plants](http://en.wikipedia.org/wiki/C4_carbon_fixation): From the Wikipedia page: > Today, C4 plants represent about 5% of Earth's plant biomass and 1% of its known plant species.[11] Despite this scarcity, they account for about 30% of terrestrial carbon fixation.[8] Increasing the proportion of C4 plants on earth could assist biosequestration of CO2 and represent an important climate change avoidance strategy.
• Options
12.
Aaaargh... Florifulgurator is at the edge of running berserk! After tears an swears and many trials he didn't manage to post the following part of a comment at the blog. Why ever.

Shilong Piao, Xuhui Wang, Philitppe Ciais, Biao Zhuz, Tao Wang, and Jiu Liu, Changes in satellite-derived vegetation growth trend in temperate and boreal Eurasia from 1982 to 2006, Global Change Biology preview 31 March 2011:

Abstract (...) although a statistically significant positive trend of average growing season NDVI is observed (0.5 × 10−3 year−1, P= 0.03) during the entire study period, there are two distinct periods with opposite trends in growing season NDVI. Growing season NDVI has first significantly increased from 1982 to 1997 (1.8 × 10−3 year−1, P < 0.001), and then decreased from 1997 to 2006 (−1.3 × 10−3 year−1, P= 0.055). (...)
Comment Source:Aaaargh... Florifulgurator is at the edge of running berserk! After tears an swears and many trials he didn't manage to post the following part of a comment at the blog. Why ever. ------------------ Shilong Piao, Xuhui Wang, Philitppe Ciais, Biao Zhuz, Tao Wang, and Jiu Liu, <i>Changes in satellite-derived vegetation growth trend in temperate and boreal Eurasia from 1982 to 2006</i>, Global Change Biology <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2011.02419.x/abstract">preview 31 March 2011</a>: <blockquote><b>Abstract</b> (...) although a statistically significant positive trend of average growing season NDVI is observed (0.5 × 10−3 year−1, P= 0.03) during the entire study period, there are two distinct periods with opposite trends in growing season NDVI. Growing season NDVI has first significantly increased from 1982 to 1997 (1.8 × 10−3 year−1, P &lt; 0.001), and then decreased from 1997 to 2006 (−1.3 × 10−3 year−1, P= 0.055). (...)</blockquote>
• Options
13.

No need to go berserk - you can always just post the comment and email me to make sure I fix things.

Comment Source:No need to go berserk - you can always just post the comment and email me to make sure I fix things.