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Stern's wheat graph redux

An anonymous commenter has posted an interesting observation about Lord Stern's graph of wheat yields, which was the subject of a posting a couple of days ago. For convenience, here's the graph as it appeared in the Stern report once again.

And here's how it appeared in the original paper by Wheeler et al.

There's a great deal of interest. For example, the dog-leg interpretation of the data is not part of the original paper, but instead appears to be a bit of spin added by the noble lord. Notice also that an inconvenient data point (indicated by my red arrow) has been deleted in the Stern graph. After Climategate, readers will of course be familiar with the idea that deleting inconvenient data is a technique that is widely accepted, and indeed one that has been endorsed by many at the top of the scientific establishment, including the president of the Royal Society.

Perhaps the most important difference between the two graphs is the inclusion of a second set of data points in the Wheeler graph. These show the effects of raised temperatures on wheat maintained at elevated CO2 levels. As is plain to see, the effect of temperature seems to be more than compensated for by the enriched atmosphere. In other words the conditions we are alleged to be subject to in future are actually beneficial for wheat.

It seems surprising to me that Lord Stern should have failed to notice this good news.

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Reader Comments (74)

What is surprising is that it has taken so long for the data manipulation to be found out. It is unfortunate that there seems to be nothing that isn't manipulated or cleansed for mass consumption.

It indicates that every pronouncement and report needs to be checked word for work, graph for graph against the originals. As it isn't picked up by peer review, maybe it should be done by say Climate Auditors ;-)

Apr 23, 2012 at 9:34 AM | Unregistered CommenterChrisM

But Stern was appointed by Blair for this spin.

Apr 23, 2012 at 9:42 AM | Unregistered Commentermydogsgotnonose

At the time of writing, Stern was no "noble lord". I demand a retraction.

Apr 23, 2012 at 10:11 AM | Unregistered CommenterRichard Tol

Stern was made a lord for producing what Blair needed, regardless of the truth. Political patronage is still a powerful tool.

Apr 23, 2012 at 10:15 AM | Unregistered CommenterPhillip Bratby

Your eminence, as you know full well data just doesn't go missing and people don't ignore the obvious benefits of enhanced CO2 (or for that matter than e.g. in the UK 23,000 die of winter cold each year).

These are intentional changes and omissions intended to show a falsehood.

What we do not know is whether Stern himself participated in this or whether he simply gave his name to work done by some underling. But either way he is responsible.

Apr 23, 2012 at 10:21 AM | Unregistered CommenterMike Haseler

Just to clarify, ChrisM isn't Chris M (me). Luckily he seems to be a reasonable person, like me! =)

Apr 23, 2012 at 10:34 AM | Unregistered CommenterChris M

I was just about to post this on the earlier thread about CO2 fertilisation, but have seen this new related thread so will put it here now.

Over the last 20 years, the effects of elevated CO2 have been studied with Free Air Co2 Enrichment (FACE) experiments. These use plots of crops or other vegetation up to about 100m2 outside in the open air, and expose some to elevated CO2 by releasing it around the plot, while keeping others as controls. This is regarded as more realistic than laboratory or chamber experiments which do not expose the plants to the open air - in FACE, plants get real weather, etc.

There are about 15 such experiments around the world covering different crop regions and ecosystems types. One key one which is missing is tropical forests. However, a recent review paper (freely available!) is by Leakey et al (2009). The abstract says:

Plant responses to the projected future levels of CO2 were first characterized in short-term experiments lasting days to weeks. However, longer term acclimation responses to elevated CO2 were subsequently discovered to be very important in determining plant and ecosystem function. Free-Air CO2 Enrichment (FACE) experiments are the culmination of efforts to assess the impact of elevated CO2 on plants over multiple seasons and, in the case of crops, over their entire lifetime. FACE has been used to expose vegetation to elevated concentrations of atmospheric CO2 under completely open-air conditions for nearly two decades. This review describes some of the lessons learned from the long-term investment in these experiments.

First, elevated CO2 stimulates photosynthetic carbon gain and net primary production over the long term despite down-regulation of Rubisco activity.

Second, elevated CO2 improves nitrogen use efficiency and,

third, decreases water use at both the leaf and canopy scale.

Fourth, elevated CO2 stimulates dark respiration via a transcriptional reprogramming of metabolism.

Fifth, elevated CO2 does not directly stimulate C4 photosynthesis, but can indirectly stimulate carbon gain in times and places of drought.

Finally, the stimulation of yield by elevated CO2 in crop species is much smaller than expected.

While many of these lessons have been most clearly demonstrated in crop systems, all of the lessons have important implications for natural systems.

As it happens, I'm writing about CO2 effects on vegetation for AR5 right now! My focus is natural ecosystems as that's the scope of my chapter - someone else is covering the same issue in the food chapter, but we are keeping in touch. Hence I'd be genuinely interested if any readers can suggest other relevant papers on experimental work on this topic.

(PS I do have many other papers already, I'm not just relying on Leakey et al (2009), I only quote it above as it does seem to capture the general outcomes of the FACE experiments.)

(PPS Due to my writing I won't have time to answer questions here, but will check back later to see if anyone has posted any useful papers - or you can email them. Any important questions for me, please do add them to the "Questions for the UKMO discussion thread, which I will try to look at as soon as this particular deadline is past…!)

Thanks folks!


Apr 23, 2012 at 10:35 AM | Registered CommenterRichard Betts

ChrisM: "It indicates that every pronouncement and report needs to be checked word for work,".

And who do you think is going to do this?

Sceptics simply do not have the money to fund people to do the professional job that you require. Even if we volunteered to do the work you suggest. At best it would just be another post on WUWT which will be totally ignored by the & RS groupies and government advisers.

What should happen is that the science establishment itself should be its own biggest critique. That is probably the single most important aspect of real science ... that nothing gets by without someone wanting to critique it.

Science itself ... the whole scientific establishment is now a corrupt bunch of contemptible groupies whose only motive appears to be to "not rock the gravy boat of global warming", which has been so good at keeping the "global warming proving" funds rolling in.

I have science books from my grandfather, from my father, my own and I have read those which my son would use (if he weren't keen to do law).

From my grandfather's time to my father's science progressed so much that it was almost impossible to use the same textbooks. I similarly found little of relevance in the previous generation's science textbooks, because the subject had moved on. I now look at science text books and see that almost nothing has changed. I have no doubt that some areas like genetics may have seen vast breakthroughs, but I am increasingly getting the feeling that much of "science" has stagnated for the last 30 years.

Perhaps this is because we now lack the industry to use any hard science, perhaps it is a lack of funding outwith a few selected areas (like genetics) and I am being too harsh. But I suspect the real reason is because science has become a group-think grant-grabbing hire-an-scientist-to-make-any-old-view-sound-scientific enterprise in which far from critiquing the establishment like Stern, the whole ethos is to bow and scrape and produce the results that pander to the establishment's politics and generally brown-nose to get the next grant ... leading eventually to that ultimate accolade of the brown-nosing: Royal-society membership.

Apr 23, 2012 at 10:41 AM | Unregistered CommenterMike Haseler

Richard Betts; your analysis appears to leave out the fact that the ~ three times increase in growth rate seen in some NE US forests is because [CO2] below the canopy is raised above the dormancy level thus allowing much greater density of growth.

The same argument applies to any temperate area with significant variation of plant height and where growth is not constrained by water availability.

There is also the indirect effect of reduced stomata area allowing growth in areas where water is depleted, e.g. wheat in Western Australia.

Apr 23, 2012 at 10:46 AM | Unregistered Commentermydogsgotnonose

In defense and industry projects it is common to uses a Red Team to check and challenge the approach being adopted by the Blue team.

A Red team is a funded group of independent experts who undertaken assessments of projects and report to the customer.

In climate science they is clearly a need for an interdependently funded Red team to assess and criticize AR5 as part of the reports generation.

Apr 23, 2012 at 11:01 AM | Unregistered CommenterPaulus

Just as the IPCC was created to spread alarm about CO2, so Stern was called in to paint the bleakest picture he could (or the brightest for early, massive interventions). That many aspects of each initiative have not survived informed criticism is merely an intellectual victory. The political victories, on a spectacular scale - see the Climate Act in the UK for example, or the aggrandisement of several NGOs and state agencies (may their circles one day not overlap quite so much on the Venn diagram of vested interests!!) went to those spreading alarm. A huge amount of damage has been done to society in just about every way I can imagine through the degradation of moral and intellectual standards, the corruption of institutions, the targeting of even the very young for nefarious ends, and the hindering of sensible economic development by the promotion of expensive and inefficient energy sources.

At the very least, we can document and capture the excesses, the 'tricks', the machinations, and at least some of the harm being done.

At the very best, we can still hope for a turn of the political tide that will see rapid corrections. There are encouraging signs of this in Canada and in Australia, and perhaps in Poland too. A very shameful period in our history may be coming to an end soon. That's toward the best end of the possibilities. The really best would also include some effective pastoral care and rehabilitation of those who were profoundly disturbed by the scaremongering - the young, and other vulnerable groups, and some dramatic assistance to those communities most severely affected by the rise in food prices associated with the diversion of agricultural land and effort into producing bio-fuels.

Dum spiro spero</I>

Apr 23, 2012 at 11:12 AM | Registered CommenterJohn Shade

Are the "filled" points the response of the wheat to elevated CO2? It looks like a 20-30% increase in grain numbers which, provided 1000 grain weight and tiller numbers are maintained, is a corresponding increase in yield. To put that in perspecative Australian wheat breeders achieve ~1-2% increase in yield per annum. Wow, bring it on!

Apr 23, 2012 at 11:19 AM | Unregistered CommenterThe Quiet Farmer down under

Quiet Farmer -
I haven't access to the Wheeler et al. paper, but given the figure's caption, I suspect that the filled triangles (not inverted) relate to groundnuts, with the open inverted triangles refer to winter wheat.

Apr 23, 2012 at 11:34 AM | Registered CommenterHaroldW

Richard, I am a plant physiologist by training (are you? if not why are you writing the CO2 effects on vegetation for AR5?) and I am well aware of FACE experiments.

Bottom line is raised CO2 is beneficial to ALL plants, irrespective of whether they are C3, or C4.

Good overviews can be found at (which is written by plant physiologists).

Here is an example.

Vu, J.C.V., Allen Jr., L.H. and Gesch, R.W. 2006. Up-regulation of photosynthesis and sucrose metabolism enzymes in young expanding leaves of sugarcane under elevated growth CO2. Plant Science 171: 123-131.
The authors note that photosynthesis by C4 plants is thought to be nearly saturated at today's atmospheric CO2 concentration and that "a rise in atmospheric CO2 presumably may have little impact on C4 photosynthesis and growth." However, they report that numerous experiments have revealed there is "a positive growth response of many C4 plants to elevated CO2, although to a smaller extent than C3 plants."

What was done
In a study designed to see how the C4 crop sugarcane (Saccharum officinarum L.) responds in this regard, Vu et al. grew well watered and fertilized plants from stalk cuttings under field-like conditions in temperature-gradient greenhouses maintained at atmospheric CO2 concentrations of either 360 or 720 ppm, while measuring a number of plant parameters and processes.

What was learned
Relative to plants growing in ambient-CO2 air, the three researchers found that in plants growing in twice-ambient-CO2 air, a number of positive developments occurred: (1) leaf sucrose phosphate synthase was increased by 13% and 37% at 7 and 14 Days After Leaf Emergence (DALE), respectively, (2) leaf sucrose concentration was 31% and 19% higher at 7 and 14 DALE, respectively, (3,4) total chlorophyll and soluble protein were 31% and 15% greater, respectively, at 14 DALE, (5,6,7) Rubisco, pyruvate Pi dikinase and NADP-malate dehydrogenase were up-regulated by 21%, 117% and 174%, respectively, at 14 DALE, (8) leaf carbon exchange rate was 20%, 7% and 10% greater at 7, 14 and 32 DALE, respectively, and (9,10,11) stomatal conductance was 51% lower while there was 39% less transpiration and 26-52% greater water-use efficiency during growth and development. Then, at the end of the study, they determined that elevated CO2 did five other positive things: it (12) augmented leaf area by 31%, (13) enhanced leaf fresh weight by 13.5%, (14) increased stem fresh weight by 55.5%, (15) boosted total above-ground plant fresh weight by 44%, and (16) pumped up stem juice volume by an amazing 83%.

What it means
Vu et al. state that "the up-regulation of the key photosynthesis and sucrose metabolism enzymes at early stages of leaf development," together with "a reduction in leaf stomatal conductance and transpiration and an improvement in leaf water use efficiency and plant water status, could lead to an enhancement in leaf area, plant biomass accumulation and sucrose production for the CO2-enriched sugarcane plants," which was, in fact, what they observed in their experiment. Hence, since sugarcane is one of the four most important C4 crops in the world (Brown, 1999), and since about 20% of global gross primary productivity is provided by C4 plants (Lloyd and Farquhar, 1994; Cerling et al., 1997; Ehleringer et al., 1997), these findings bode well indeed for humanity and nature alike in a CO2-enriched world of the future.

Brown, R.H. 1999. Agronomic implications of C4 photosynthesis. In: Sage, R.F. and Monson, R.K. (Eds.), C4 Plant Biology. Academic Press, San Diego, CA, pp. 473-507.

Cerling, T.E., Harris, J.M., MacFadden, B.J., Leakey, M.G., Quade, J., Eisenmann, V. and Ehleringer, J.R. 1997. Global vegetation change through the Miocene/Pliocene boundary. Nature 389: 153-158.

Ehleringer, J.R., Cerling, T.E. and Helliker, B.R. 1997. C4 photosynthesis, atmospheric CO2 and climate. Oecologia 112: 285-299.

Lloyd, J. and Farquhar, G.D. 1994. 13C discrimination during CO2 assimilation by the terrestrial biosphere. Oecologia 99: 201-215.

Apr 23, 2012 at 11:41 AM | Unregistered CommenterKon Dealer

If CO2 were deleterious to growth, there would have been already systems in greenhouses to remove it from the internal atmosphere?

Apr 23, 2012 at 11:43 AM | Registered Commenteromnologos

Open triangles are at normal atmospheric conditions, filled triangles are at elevated CO2.

Apr 23, 2012 at 11:51 AM | Registered CommenterBishop Hill

With all due respect to the expertise of Dr Betts, should not a botanist or plant physiologist be writing about the effect of CO2 on plants for AR5?

Apr 23, 2012 at 11:57 AM | Unregistered CommenterDavid Chappell

Your Grace - thanks for following up my suggestion. I can access these papers for free, but it must be a hassle and/or an expense for those without subscriptions to get hold of them. I hope you feel vindicated for pursuing your original hunch.

Harold W, if you care to look at my comments on the earlier thread, you will see that Stern's misrepresentation of the data is blatant. The empty triangles are for elevated temperatures at conventional CO2 levels, while the filled triangles are for elevated temperatures at high (roughly double) CO2 levels. High temperature without high CO2 is irrelevant to the AGW debate, yet this is the data used by Stern, while the relevant data (high temp and high CO2) is deleted.

Once again I stress that the total picture from the data presented in Wheeler is patchy: it would be wrong to assert a simple 'CO2 = good' message from this paper. What is undeniable is that Stern has utterly subverted the data to support his political narrative.

Yet Another Travesty.

Apr 23, 2012 at 11:59 AM | Unregistered CommenterAnonymous

David, They should ask David Bellamy.

Apr 23, 2012 at 11:59 AM | Unregistered CommenterJace

Aha, yet another TRICK.

They wan't their heat-death without the beneficial CO2, but they can't have it.

Apr 23, 2012 at 12:05 PM | Unregistered CommenterTheBigYinJames

As CO2 levels were much higher at the time of the dinosaurs, if those levels were bad for plants how did all those large vegetarians grow at the time?

Apr 23, 2012 at 12:12 PM | Registered Commenteromnologos

but but but ... the yield is increasing with higher temp and CO2 ??

what do the marxists at University of Reading say about their graphs been adulterated and cherrypicked, sure there cannot be no scientific justification for removing an inconvenient triangle

cheeky monkeys

Apr 23, 2012 at 12:15 PM | Unregistered Commenterptw

It's not just one triangle they removed - they removed the WHOLE series of Temp+CO2, and left the series with the downturn which was just Temp increasing. It was obviously inconvenient to them that their doom scenario (Temp+CO2) actually produced a lovely upturn in yields.

So they just deleted it, and implied that the catastropic downturn was the one which applied to their doomsday scenario. Which it patently isn't.

Apr 23, 2012 at 12:22 PM | Unregistered CommenterTheBigYinJames

So, according to the origional graph, enhanced co2 with enhanced temps =greater yields!!

Apr 23, 2012 at 12:27 PM | Unregistered CommenterSunderlandSteve

yes you can remove a graph/series as it is inconvenient to your narratives, bad enough, but to just adulterate a graph you find inconvenient and remove samples until it all fits your narrative is plain cheeky.

one wonders why they bother planting the seeds at all, why not just produce us graphs that are alarming, it's cheaper that way (and nobody believes what they are telling anyway)

make a seed yields simulator ffs, with 25 parameters (5 accessible to pachauri and his minions only)
a GCM for seeds, then we're all fixed.

Apr 23, 2012 at 12:30 PM | Unregistered Commenterptw

me who thought there were serious scientists at UoR

bah !

Apr 23, 2012 at 12:31 PM | Unregistered Commenterptw

ptw - you've got the wrong end of the stick. The original authors from Reading showed all the data in their paper. They behaved like serious scientists. It was Stern and his crew who obliterated the inconvenient data.

Apr 23, 2012 at 12:36 PM | Unregistered CommenterAnonymous


Apr 23, 2012 at 12:36 PM | Unregistered CommenterBilly Liar

"Sceptics simply do not have the money to fund people to do the professional job that you require."

But Mike, climate sceptics are part of a well organised group, provided with vast funds by BigOil. We know this from Prof Mann's latest blockbuster of a book, so it must be true...

Apr 23, 2012 at 12:39 PM | Unregistered CommenterDaveS

anonymous yes true, sorry , but the UoR should complain for their data been adulterated.
at least they can say if the triangle was relevant

Apr 23, 2012 at 12:45 PM | Unregistered Commenterptw

I'ld give UoR now a pot of Stern's money to produce a new bunch of triangles in that area

Apr 23, 2012 at 12:47 PM | Unregistered Commenterptw

These gates are getting dull. How about Shredded Wheat?

Apr 23, 2012 at 12:58 PM | Unregistered CommenterAnonymous

Stern's lies by omission - there are no other words to describe them must be challenged in the correct forum.

Can I suggest that Lord Lawson is contacted and asked to raise this issue in the House of Lords- to which Lord Stern would have to answer?

Apr 23, 2012 at 12:59 PM | Unregistered CommenterKon Dealer

@Richard Betts

Suggest you talk to Donald Keiller, Ph.D. - Plant Biochemistry, Cambridge University - Deputy Head of Life Sciences at Anglia Ruskin University

He seems to know what he's talking about, if my instinct is correct ;)

Apr 23, 2012 at 1:08 PM | Registered Commentermangochutney

yes the "message" of this graph is pure Goebbels: it conveys that wheat will go the way of a tropic harvest which has lower yield.

Whereas the unadulterated graphs tell exactly the opposite.

this is demagogery of the worst kind.

Ask Paul , from the royal chossiety, to comment ?
what does he think about disappearing triangles

Apr 23, 2012 at 1:09 PM | Unregistered Commenterptw


Too long?

Apr 23, 2012 at 1:10 PM | Registered Commentermangochutney

Richard Betts's comment:

"Finally, the stimulation of yield by elevated CO2 in crop species is much smaller than expected."

seems at odds with the preceding ones. Am I missing something?

Apr 23, 2012 at 1:13 PM | Unregistered CommenterJames P

The basic problem is: "Absence or loss or integrity."

Apr 23, 2012 at 1:14 PM | Unregistered Commenterdrcrinum

I guess we will be told that it is normal scientific practice to exclude outliers.

Apr 23, 2012 at 1:15 PM | Unregistered Commenterpax

For reasons not clear to me, I have so far not been able to post the following here:

For constant updates of the outcomes of FACE experiments on nearly a thousand plant species go to For wheat it reports 60 studies as of 2009 that showed an average increase of yield of over 60% for a 300 ppm increase in atmospheric CO2, 4 times larger than claimed by Ainsworth 2006.
BTW, while the IPCC’s AR4 WGs 1 and 2 largely ignore this whole issue apart from a couple of dismissive and perfunctory paragraphs, the NIPCC’s Climate Change Reconsidered (2009) devotes over 200 pages to reporting plant by plant studies of the “Biological effects of Carbon Dioxide Enrichment”. For example, at p.381, the NIPCC reports the APSIM (heard of them?) study of three WA wheat trials, which found a linear 10-16% increase in yield for each extra 100 ppm of CO2, depending on the extent to which nitrogenous fertilisers were also applied.
Finally, check the CSIRO study (Crimp et al 2008) commissioned by Garnaut (2008), which e.g. reports (Garnaut, Table 6.5) for Katanning WA a wheat yield increase of 15.6% by 2030 in the absence of the carbon tax and any other mitigation, i.e. BAU plus rising temperature. Yields there will have increased by 18.9% by 2100 with CO2 stabilised by then at 550 ppm, and only by 14.6% with CO2 at only 450 ppm by 2100. Geraldton WA does even better in the BAU to 2030 case, but less well if still positive under 550 and 450 ppm.

In Moree NSW the "cumulative yield change" by 2100 will be 14.1% at 550 ppm and only 10.8% at 450 ppm. In fact at each of 10 wheat growing centres across Australia yields in 2100 are higher at 550 than with only 450, despite the claimed higher temperatures at 550 ppm. Garnaut rather downplayed these statistics, but at least unlike Stern he did report them.

Apr 23, 2012 at 1:20 PM | Unregistered CommenterTim Curtin


Apologies for the posting difficulties. Maybe try registering? (Link in nav bar on right)

Apr 23, 2012 at 1:22 PM | Registered CommenterBishop Hill

btw 'one wonders why they bother planting the seeds at all' - I'm still laughing at that.

The Stern Report was dated 30 Oct 2006 so Wheeler et al. really do need to say if they agree with Stern's use of their graph.

Apr 23, 2012 at 1:30 PM | Unregistered CommenterAlan Reed

I've been having a look at the b) graph in figure 3.4 and I think that the idea for the dog-leg came from the source for that graph.

Prasad's website is here and papers are available under publications:

The title of the graph is "Groundnut in India" but at least some of the groundnut studies were grown in Reading UK.

Apr 23, 2012 at 1:35 PM | Unregistered Commenterredc

I don't normally stand up for Blair, but the treasury commissioned the Stern Review. Brown.

Apr 23, 2012 at 1:37 PM | Unregistered CommenterPeter Dunford

Luv ya', KD, ::grin::

Apr 23, 2012 at 1:41 PM | Unregistered Commenterkim

The world is gradually catching on that a warmer world with higher CO2 would be a better one, sustaining more life and more diversity of life. The world is gradually catching on that catastrophes are unlikely.

This is devastating to the plans, the cause, the whatever. We see efforts to combat this. Over and over now, consensus climate science seems in a reactive phase, creating perverted research papers in order to battle skeptical critique.

Richard Betts, I love you too, but you must publicly damn this Stern stuff. Are you too busy to shore up your own credibility?

Apr 23, 2012 at 1:48 PM | Unregistered Commenterkim

I should have added that I think the source for Figure 3.4 b) is the bottom left panel of Figure 1 in this paper:

I suppose the dog-leg was then needed in 3.4 a) so the conclusion in the caption could be used:
"In both cases, crops show sharp declines in yield at a threshold maximum temperature."

Apr 23, 2012 at 1:50 PM | Unregistered Commenterredc

More CO2 = more wheat = more people ≠ Club of Rome goals

Isn't Stern a member of CoR or am I connecting the wrong dots?

Apr 23, 2012 at 2:22 PM | Registered Commentermangochutney

Stern's 'curve' looks more like a boomerang than a hockey stick. I hope His Lordship realises that boomerangs have an unfortunate habit of returning and smacking you in the back of the head, if you don't keep a careful eye on them.

Apr 23, 2012 at 2:33 PM | Registered CommenterSalopian

Kon Dealer, Tim Curtin,

Thanks for those papers, much appreciated!

David Chappell asks:

With all due respect to the expertise of Dr Betts, should not a botanist or plant physiologist be writing about the effect of CO2 on plants for AR5?

Answer: because

a) it's not just me writing it. Several authors are working on this, so it's not just the opinion or knowledge of one person

b) I do have a publication record in this field anyway - a few examples:

Betts, R.A. P. M. Cox, S. E. Lee, and F. I. Woodward, 1997: Contrasting physiological and structural vegetation feedbacks in climate change simulations. Nature, 387:796-799

Betts, R.A., O. Boucher, M. Collins, P.M. Cox, P.D. Falloon, N. Gedney, D.L. Hemming, C. Huntingford, C.D. Jones, D.M.H. Sexton and M.J. Webb, 2007: Projected increase in future river runoff through plant responses to carbon dioxide rise. Nature, 448: 1037-1042

Botkin, D.B., Saxe, H., Araújo, M.B., Betts, R., Bradshaw, R.H.W., Cedhagen, T., Chesson, P., Dawson, T.P., Etterson, J.R., Faith, D.P., Ferrier, S., Guisan, A., Hansen, A.S., Hilbert, D.W., Loehle, C., Murgules, C., New, M., Sobel, M.J., Stockwell, D.R.B., 2007: Forecasting the effects of global warming on biodiversity. Bioscience 57(3) 227-236

Ben B B Booth, Chris D Jones, Mat Collins, Ian J Totterdell, Peter M Cox, Stephen Sitch, Chris Huntingford, Richard A Betts, Glen R Harris and Jon Lloyd, 2012: High sensitivity of future global warming to land carbon cycle processes. Environ. Res. Lett. 7 024002 doi:10.1088/1748-9326/7/2/024002

Kim, I do indeed disapprove of the CO2 effects being missed out of that Stern figure.

MDGNN, the abstract and paper I mentioned did include the indirect effect of reduced stomatal opening.

BTW please note that I quoted the abstract of the Leakey paper - it was not my own work. For further questions on that, please read the paper (I provided a link, and its open access).



Apr 23, 2012 at 2:33 PM | Registered CommenterRichard Betts

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