Plant Food Fight – McIntyre and Betts over CO2 fertilization and IPCC report

It seems Dr. Richard Betts has penned a guest post for the tabloid climatology website known as “Carbon Brief” titled Understanding CO2 fertilisation and climate change. This looks to be a response to the recent NASA study that we covered here on WUWT titled: Inconvenient Study: CO2 fertilization greening the earth. I suspect the alarmists camp is taking some hits over the NASA study from people who are essentially saying “why wasn’t this widely reported along with all the gloom and doom you have been purveying”?

It seems Betts saw the need to embellish what we already know:

The speeding-up of photosynthesis – known as CO2 fertilisation – is well-known to be an important consequence of higher CO2 concentrations, along with increased water use efficiency. Under higher CO2, plants do not lose so much water through their leaves, so can be less impacted by drier conditions.But while the general principles of CO2 fertilisation are known, there is still much to learn about how these processes will operate under future conditions that have not yet been experienced.

Ah, there’s the rub, it’s the old “models and the future” argument that Betts is framing there, but that’s another argument.

On Twitter, Steve McIntyre noted this part of Betts essay:

Despite claims to the contrary, the conclusions of the IPCC take CO2 fertilisation properly into account in the assessment of climate change feedbacks involving the carbon cycle, and in the assessment of the impacts of climate change on ecosystems. They are also starting to account for this in the knock-on consequences for water resources, but that is more cutting-edge science and less advanced.

He’s having none of that, and called out Betts (citing the IPCC WG2 passage above with a screen cap) on Twitter and Betts replied:

McIntyre retorted:

And then, work or not like the famous XKCD comic “Duty Calls” he comes back, But Steve has already left the building thinking Betts really did have work to do and ended the conversation:

Correction and Note: in the way Twitter displayed these to me, it looked as if they were AFTER Betts has signed off, and the timestamps get reduced to 3h (3 hours ago) rather than the exact time of each Tweet. In the screencap below, it appears just as Twitter presented it to me, but it’s wrong. The Tweets after he says “”but I have work to do” actually came before that Tweet.

So, while Twitter presented it incorrectly, my interpretation followed that presentation and was wrong. The only way to be sure is to click through each tweet and get each timestamp.

I regret the interpretation error, and thanks to Richard Betts for pointing it out.

This just goes to show that Twitter really isn’t a very good medium for discussion and this sort of problem with Twitter timestamps has caused lots of trouble before. Now that I know about it, I’ll be more careful in referencing Twitter timelines in the future, as I’m sure readers will as well. – Anthony




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on gets paid to do this and one loses pay if they do this , you decide which one is able and willing to put the effort in.

Which is which?


‘there is still much to learn about how these processes will operate under future conditions that have not yet been experienced.’
Accept increasing CO2 levels is an approach already used with agriculture under controlled condition , so should very much allow for exactly this . But we know that climate ‘scientists’ have real problems with asking experts outside of their own area about any issues , such has statistics , perhaps becasue they find they get answer they don’t like or because it is reminder of how little they know.
So it is quite possible to find this out , or they could resort to ‘staying in their own house ‘ and added yet another area in which its claimed ‘only ‘ climate ‘scientists’ can be experts .

Follow the money

Betts: “there is still much to learn about how these”
IPCC is not ready to throw out the dendros yet.
Betts is fighting a civil war in the climate moolah camp, cautiously for now.
If CO2 “fertilization” is true, all the increasing tree bark follows temps increases studies fall apart. Basically Mann et al., et al., et al…
Betts main problem: if one branch of United Nations Climate Science falls apart under the analysis within the climate moolah camp themselves, all loses credibility. Hence his hanging on to little CYA tidbits supposedly about CO2 fertiliztion in the ARs.
C’mon climate guys! Dump the Dendros!


One sign of cult obsession is that in the minds of True Believers everything, even contrary evidence, somehow gets twisted to support their cause.

we don’t know natural flows well enough to measure the effect of fossil fuel emissions on atmospheric CO2, on surface temperature, on the climate system, or on photosynthesis.
this is why the talk is endless
and inconclusive
there are a whole lot of things that we just don’t know.

You should talk to Ferdinand Engelbeen….

Hello Hans,
Already replied to him several times to no avail… I suppose that he refers to his own work, not sure about that. Anyway what he wrote is many times refuted, the latest one above: that we don’t know the effect of increased CO2 on photosynthesis, even when every greenhouse owner knows that, they don’t supply CO2 to 1000 ppmv in their greenhouses just because they like it…

Mike the Morlock

Ferdinand Engelbeen May 3, 2016 at 11:11 am
His heart is in the right place and he is trying. His approach is on one facet it makes some sense, lets let him keep working he may in the end have something.
I have been reading his comments, and confess I don’t understand. But the enemy of my enemy is my friend. I will continue to read chaamjamal views, he is after all in the scheme of things a friend.

His mind’s in the right place. There will come a day when people will wonder why anyone swallowed this nonsense that our paltry contributions have driven global CO2 levels. It’s so ridiculous, and the evidence against it is so obvious.


Nobody in ‘climate science’ gets juicy grants by proclaiming ‘there’s no problem here, it’s better than previously thought’, which is why the Guardian won’t be running an article claiming ‘the planet is greening faster than predicted due to CO2 – we’re saved!’ anytime soon. Fear sells, good news doesn’t.

Bob Ryan

Given the nature of our planet, the one crucial question is what is the ideal level of CO2 (ppm) and the implied equilibrium temperature that will optimise living conditions for 7bn people and rising? It is undeniable that increased CO2 encourages plant growth and increases resilience. It is also undeniable that a warmer climate is net beneficial to human beings and with the possible exception of polar bears and penguins most other creatures as well. So, if we were able to fine tune our climate and the composition of the atmosphere would we be happy with the way it is now, the way it was 200 years ago or would an extra 2 degrees and a doubling of CO2 make life a lot easier for the occupants of planet earth?

In order to get a chance at +2C (Holocene Optimum), you’d almost certainly need a quadrupling of CO2. That would get us back to the recent Phanerozoic norm, ~1,500ppm. But the Holocene has been on a cooling trend since the early Optimum and we’d probably just be compensating for that.


The first doubling of CO2 in a no feedback world would produce a 1C warming. The second doubling would only produce a 0.5C warming. The next doubling would only produce a 0.25C warming.
You would need a lot more than a quadrupling of CO2 to get a 2C warming.
PS: The science indicates that the world is dominated by negative feedbacks, so each doubling of CO2 will produce less warming than indicated above.


@Mark W – Sorry to say, Mark, but each doubling does indeed produce about 1C. According to lab data, if pre-industrial was 280ppm CO2, 560ppm should yield 1C, 1120ppm CO2 should yield 2C, 2240ppm CO2 should yield 3C, etc. I think we’d agree, though, there probably isn’t enough fossil fuel to get us to even 560ppm.

Bob Ryan

Agreed on all of that Tab but the question I still feel needs answering is under what conditions is the capacity of the planet to sustain life optimised? People can argue about ECS, feedbacks and so on until doomsday what matters is that from a public policy perspective we know the direction in which we should be travelling. History tells us that a cold climate is associated with famine and pestilence and that a warm climate brings prosperity and growth. It seems to me that the whole debate is asking the wrong question: not how do we cut CO2 but what level should we aspire to?


Adam, don’t know where you get your data, but it contradicts everything I have ever read on the subject.
The affect of CO2 is (almost) logarithmic, not linear.


I think you got a little ahead of yourself there, Mark. If dT ~ log(C/C0) and C = 2*C0 implies dT = 1, then C = 4*C0 implies dT = 2, C = 8*C0 implies dT = 3, and so on.


I often wonder though:
how much CO2, beginning at 0 ppm, gives the first 1 degree C, and, at the other end, when does the level of CO2 reach a “saturation point” where no more warming occurs regardless of the amount of CO2 added?
I believe the first answer is “20 ppm”, but not sure of the second.

Gerald Machnee

The question is: what are you doubling from? 20ppm, 40ppm, 100ppm. What is your starting point?
Check this post from a little while ago by David Archibald:
7. David Archibald shows how the effect of increasing CO2 decreases logarithmically as CO2 increases in the following:
There is also another article on the Logarithmic heating effect of CO2:
An important item to note is that the first 20 ppm accounts for over half of the heating effect to the pre-industrial level of 280 ppm, by which time carbon dioxide is tuckered out as a greenhouse gas.


Less ice means penguins don’t have to walk as far to go from the feeding grounds to the nesting grounds. Less cold means less calories burned trying to stay warm while incubating first eggs, then chicks.
Warmer is better for penguins.
Less ice means that the polar bears will hunt nursing seals on land instead of on the ice pack. Seals will still be giving birth, they just change where they do it.
Less cold is not bad for polar bears.

Johann Wundersamer

MarkW on May 3, 2016 at 6:53 am
Less ice means penguins don’t have to walk as far to go from the feeding grounds to the nesting grounds.
agreed, Mark – and the food chains are :
CO2 fertilized sea plants -> fish -> seals -> polar bears
CO2 fertilized sea plants -> fish -> penguins
Ahoi – Hans


Adam, please cite your claims.
As far as I knew, most reported estimates erroneously assume the atmosphere as a black body, which it is not of course.


Is that ftard Betts trying to say the IPCC promoted the benefit of rising CO2?!

Sure sounds that way! Post comments on media sites saying the IPCC predicted CO2’s greening of the planet would be good!


“predicted” lol, highschool chemistry students would predict that without massive funding and flying all over the world.
Betts is very disingenuous and so are the rest of these cretins.
The IPCC predicts nothing, they hedge their bets by “projecting” opposed outcomes

David A

Also what the IPCC emphasizes in the summaries for policy makers reveals their bias most clearly.
Even so within the body of the main report, their bias is clear. They greatly underestimate the benefits, and assign no economic value to increased crop growth, improved crop heat and cold tolerance, large water savings, etc… They fail to account for their policy of using the way to warm model mean as a basis for predicting future harms, fail to adjust those future harms to accommodate that the warming is expected to be mostly at night, and in Polar areas of light population and low productivity, fail to use many peer reviewed publications detailing the known and manifesting benefits, fail to adjust their predicted harms as they are not manifesting.

Those things we know with certainty (CO2 enrichment and plant growth) are described as “there is still much to learn about how these processes will operate under future conditions” by Betts.
Yet, Betts has 100% confidence in CO2 warming where the correlation is extremely spurious with high uncertainty.
Ignoring data and embracing conjecture is the epitome of anti-science.


Farmers have been raising CO2 levels in greenhouses for many, many years. So the claim that we don’t know what will happen to plants in an elevated CO2 world are spurious at best.


Take a look here:
Plenty of others are doing the same thing.
In fact the first huge experiment was published in Scientific American in 1922


Sorry, it was Scientific American 1920. Here is the link:


It’s more “if-then science”. Based on ifs, hardly scientific


Can’t you people see the warning signs? It is obvious that we must reduce carbon emissions now, before the earth becomes so green and fruitful that it causes unprecedented population growth. A green, productive planet is surely unsustainable. Meager is the new prosperity.

I hope Steve might do a blog post on this to expand his point in more detail.

Well, twitter isn’t really a medium for being ‘measured’!

Crispin in Waterloo but really in Beijing

You don’t need much Twitter commentary to identify stupidity.

How long are skeptics supposed to be wasting away, being measured?


But, you see, consensus scientists are profoundly concerned that although release some proportion of the trapped carbon as CO2 will have the beneficial effect of turning the planet into a lush paradise filled with an abundance of life – on the flip side, there will possibly be a reduction in the area of sea ice.
How would we explain to our grandchildren that we had selfishly traded frozen wastelands for verdant forests and productive farmland.
And the children’s children’s children.
How will they judge us, when they realize that we abandoned them to several centimeters of additional sea level rise? Thus devastating the odd sand-castle.
Oh, the huge manatee!!!


Shhh dont say Manatee or you’ll have Alec Baldwin all ovet this chit


Well, that’s the sort of thing that environmentalist were supposed to be concerned about.
Remember when environmentalist were actually focused on protecting the environment and all the animals and plants that are in it.
Before the whole thing got hijacked by the CO2 monomaniacs.
Obviously, I only mentioned Manatees as a pun. But this is a good point. Let them protect Manatees, like a real environmentalist should.


During the winter months, manatee are known to congregate in streams near power plants. The water is warmer there.

Dennis Bird

I was recently banned from Disqus Science channel for saying C02 fertilization was good news. The moderator is a real global warming zealot. Sigh. So much for open discussion of science.


I would like to hear from someone in the seed industry. It seems many plants are optimized for higher CO2 levels, but this would not be less the case for so many of the big crop seeds we are using now which have been designed to compensate for the lower CO2 levels of the recent past and present. I bet Monsanto could really shed some light on this subject.

David A

I think if you go to CO2 science web site you will find many experiments on seed varieties currently used in the bulk of global production.

“And then, work or not like the famous XKCD comic “Duty Calls” he comes back, But Steve has already left the building thinking Betts really did have work to do and ended the conversation:”
You’ve been caught out by twitters confusing timeline. All the posts at the bottom were posted before he said “I could go on, but I have work to do!”.


His work is to lie for his country, or something.

Thanks for pointing that out so soon. Below, Anthony says he’ll make the correction.


A little off topic but very interesting…
“Three newly discovered Earth-sized planets may be prime spot to hunt alien life ”


Hunt alien life, or hunt *for* alien life? 😃


…Shhhh……I’m hunting alien wabbits !!

David A

oh, a safari. (-;


..Hopefully the hunter does not become the hunted !


I just posted this is Tips and Notes, but I love this part:
“There was only one problem: Before TRAPPIST launched, the preponderance of astronomical opinion held that such planets couldn’t exist. “The prediction was that the protoplanetary disk around such small stars would be too thin to make planets,” says TRAPPIST team-member Julien de Wit, now completing a post-doc at MIT. Gillon was unbothered by such claims. “The theories for exoplanets are based on very few observations,” he says. “I didn’t believe the theorists. I decided to follow my intuition.””
Love the part about “theories based on very few observations”. Kinka makes one nostalgic for Yamal.

Philip Mulholland

So as the level of carbon dioxide in the air increases, land plants grow better (by some estimates a 15% increase overall) and the land becomes greener.
With more land plants growing there is more food for all land based animal life, in effect the carrying capacity of this planet has increased for all land animals in the food chain.
So of the current 7.4 billion living today, 965 million people, who would otherwise be starving, have food as a direct result of this increase in the planet’s carrying capacity.
[ estimates the plant growth varies between 22% and 27% better than in the old 280 ppm days, depending on species. .mod]

David A

Yes, I have often used the 15% figure, although that is a conservative estimate. I do this partially to avoid over stating a case, and partially to account for the fact that their is a small decrease in some (not the nutrients we commonly look for in vegetables) nutrient density relative to the increase in bio-growth.

Retired Engineer Jim

Somewhat OT: I have been told, repeatedly, on another blog, that the carrying capacity of the Earth is 5.3B people. When I ask for a reference, I get no response. The same set of correspondents propose an “ideal” poulation for the Earth of 1B, with some stating that 550M is the right number. So, where is the reference(s) for a carrying capacity of 5.3B And hasn’t the world yet again proven that analysis wrong?

We’ve had a similar discussion here, a few years ago. The entire population of the earth could fit into a 1 km-diameter sphere, with room to spare. There were many other comparisons like that posted by readers (everyone could fit into Rhode Island, etc.)
The problem is that everyone wants to live in the choice spots; by the sea shore, on the river, near good paying jobs, etc. Since most people live where most people want to live, they assume the planet is getting crowded.
It’s not. It’s still mostly empty space, as far as the human population goes.

REJ, in my ebook Gaia’s Limits I did rather long and laborious caclulations concerning food, Complicated because you have to look at diet and calory composition (beef calories require 4x poultry calories, compared to 1x if humans ate the calories as corn meal), arable land changes, yield changes by crop given best practices (GMO), future spead of best practices, and no energence/reemergence of crop pathogens (ignoring UG99, 10 glyphosate immune weeds that have evolved just in 30 years, Bt resistant corn root borer,…), no limit on irrigation (parts of the Ogallala will be depleted by 2050), and no increase in cotton… Bottom line is about 9.1-9.3 billion. UN and Census Bureau have that population level reached by 2050. This carrying capacity assumes no constraints on virtual water (Egypt imports 60% of its wheat) or on liquid transportation fuels for farm machinery and food transport. How hard a limit this CC this is depends greatly on economic development and population in places like India, Africa and southeast Asia over the next 30 years. Frankly, the demographics do not look in favor of a soft landing. Too youthful, and too impoverished.

DBS, where people live is not the correct metric. Its where you can grow food. Most arable land is already in cultivation. What remains is increasingly marginal. And the green revolution in rice (dwarfing) and wheat (dwarfing, rust resistance) are in the past. Did you know that the largest producer of potatoes in the world is China? And that Chinese potato yields stopped increasing about 2000 because best practices had spread thruout the country? Or that European corn yields stopped rising about 1995 because of their rejection of GMO? Or that there has been no increase in Indian pulses yield (main Hindu source of protein) since the country was founded? All the pulses tonnage increase came from expanding arable land in northern India using irrigation from aquifers that are depleting and may be gone by 2030 unless monsoon patterns change (longer, slower, so less runoff and more recharge) –how likely is that?

I think it used to be that people lived where you could grow food. But recently that’s morphed into where the most/best jobs are.
There’s almost no food grown in Silicon Valley, or NYC. But more people come in all the time — for jobs, not for food.

Bubba Cow

ristvan has done much more discovery on this than I, but I have found these references and their links useful. It is difficult, for me anyway, to evaluate bias but I hope to think that some science reporting and the UN are not total throwaways – a caution though, propaganda is only a click or two away.
I’m pretty sure that growing food for fuel at least in terms of what is good for life and the planet is dumb.


ristvan, you haven’t covered converting back to farmland, land that has been idled due to govt actions.
There are also other technologies such as hydroponics that can drastically increase the amount of food per acre, even on land that is otherwise unsuitable for food production.
Regardless, the earth’s population will peak in the next 5 to 10 years, if it hasn’t already.


The example that I’ve seen quoted is that you could give every person currently alive one-quarter acre in Australia and still have Tasmania left over. As dbstealey says everyone wants to live in the best bits and near other people — which is why London is full and Wyoming is empty, I’m told!
But when you look at it like that you realise just how much unused space there is on the planet.

I once read a book “the green earth” that said that the earth could feed 132 billion people, on only one condition: an extensive land use planning: use the most fertile grounds for growing crops only, all people in towns on non-usable grounds (deserts, bare rock) and you can let the rest of nature wild as it is…
That book was based on the high population density of the two Holland provinces in The Netherlands, still exporting lots of food and flowers all over the world.
The problem is that the most fertile grounds are/were where most towns, factories and harbor installations are now: the delta’s and riversides, where the first farmers settled, just because the grounds were fertile…
Anyway, the (probable) peak of 9.5 billion in 2050 seems not a problem to feed and most population growth indeed is in towns.

Best exploration of this is Joel Cohen’s How many people can the Earth support Short answer is depends on assumptions which is why the book is so frustrating.
In short it depends on the assumed diet (#kcal/day amount of water). If you look at diet in industrialized countries 5 billion is pretty close to the limit so what you may have seen is the claim of 5 billion (5.3 is too exact) at today’s level of industrialized countries


That’s a rather sneaky way to make sure you get the last word.

Bruce Cobb

Warmunists like Betts prefer their Grimms fairy- tailed, climastrophic nintendo-modeled hobgoblins of the future to reality.


The positive effects are discussed and cited so often that the fr4uds had to hijack it and claim they were not willfully ignoring it. They were. Betts, what has he said about global greening in the past 15 years?
I bet very little to nothing.
It looks like a communist and it smells like a communist, acts like a communist. Must be a communist

Richard Betts

@Mark May 3, 2016 at 7:18 am
I’d be very happy to take that bet with you, cos you’d be wrong!
My very first paper looked at the effect of an expected future increase in vegetation cover (i.e.: global greening) on climate
In another paper I pointed out that the effects of rising CO2 on vegetation could reduce the effects of drought
There’s plenty of others if you care to look.

Filbert Cobb

Carbon dioxide enrichment of glasshouse atmospheres was already in use by the mid-1960s and was touted as a means of benefiting from the flue gases from power stations, as was using exchanged heat from the cooling tower waters to warm the glasshouses. The computers necessary to control the systems were the size of a small house

Steve Fraser

At the greenhouses on the former family farm in Ontario, they truck in the liquid CO2, warm it to gaseous state, and bubble it out with the water and fertilizer to the pepper plants. Sunlight, temps, nutrients, co2 and productivity are monitored and optimized.
To get an understanding of the depth of studies in this area, start with
Which describes an experiment into pepper productivity as the variable are varied.
Most beneficially, are references to other studies.


The mild warming, the great greening, the tremendous social progress, it’s yuge. And they wanna make us afraid and feel guilty over it? What fools.



David A

It is hard to imagine all the higher latitude nations worrying about getting a degree or two warmer.


And the lower latitude nations won’t warm; it’s a win-win. The alarmists have almost everything backwards or exaggerated. A madness of the crowd.


Heh, the cat’s out of the bag; Betts is just Streisanding it.
It’s a billion extra people that the greening is now feeding. The BRICs have understood this since before Copenhagen.

Dave in Canmore

I hunted up the “references” Richard Betts cites for his claim. Total baffle-gab and a complete fib that the IPCC talks about greening. These people are so dogmatic they are caught making mistakes every time their mouths open.


With the explicit task of exposing man’s role, the IPCC failed here. The bias to find that man is a bad actor is perverting and egregious; it cannot stand.

Pop Piasa

Perhaps it’s more accurate to state; “Mann is a bad actor (and Gore is no Thespian)”?

Dave in Canmore

I should say the fib was in his SPM reference

If Steve doesn’t do a post, I will do a point by point analysis of every one of Betts tweets and submit it to AW. Just spot checked a couple. Out of context, misrepresented….But I bet Steve will find them an irresistable target and he properly should have first dibs.


Yep. Betts should know that he shouldn’t poke the bear!


complete fib that the IPCC talks about greening
Chapter 5 IPCC 5th Assessment report, WG1
“Box 6.3: The Carbon Dioxide Fertilisation Effect” (23MB)
Betts points out WG2 references in the tweets, Chapters, 4, 18, 24.
The word ‘greening’ is mentioned explicitly in at least one of those, cf satellite imagery (Chapter 24, section, satellites being the major source for this phenomenon as mentioned in the MSM.

In Germany there is a quick growing new party founded only three years earlier, called “AFD” ( Alternative for Germany). This party has a good chance to get 20 per cent or even more in the next election for the german “Bundestag” in 2017. There ist only a 5 per cent electoral threshold in Germany.
They adopted on the 1st of May a new policy program, which reads in relation to climate change as follow:
“Das Klima wandelt sich, solange die Erde existiert. Die Klimaschutzpolitik beruht auf untaugli‐
chen Computer‐Modellen des IPCC („Weltklimarat“). Kohlendioxid (CO2) ist kein Schadstoff,
sondern ein unverzichtbarer Bestandteil allen Lebens.”
” The climate is changing since the Earth exists. The climate chance policy based on
ineffectively computer-models of the IPCC (climate Council of the world). Carbon dioxide (CO2) ist not a pollutant but an indispensable component of all life”
There are some more Details, but it would need too much space to list them all here.
Link, to whom is interested and proficient in German:
If there are spelling errors, you can buy it.


Another nice little bit; the greening is evidence that the carbon sink is not saturating, upon which so much of the doom is predicated.
I’ve mentioned it before, but should probably keep silent lest they catch on; I’m infiltrating the inner policy councils of the coccolithophores. They are plotting revolution.


I don’t have the chops to calculate it, but am curious how much of the energy which is supposed to be heating us is instead being sunk in calcified skeletons of sea critters.
CO2 doesn’t condense from the atmosphere, but it does sediment out of the oceans as these skeletons.

David A

I am curious how much of the energy which is supposed to be heating us, is instead used up in a very slight acceleration of the hydrological cycle. It is estimated that all the evaporation from the surface, returns within 10 days. How much energy does it take to shorten this by ten minutes, and would we notice? How much does this shorten the residence time of energy in the system?
Regarding Bio-growth and CO2 sequestering within it, I suspect there is a lag, and even if CO2 concentration remained fixed at 400 PPM, the greening would continue for some time in both individual plant and tree growth, and in increased or expanding green zones. As far as ocean sequestering of CO2, I suspect any increase in ocean life, and therefore ocean snow, (the sentiments falling to the ocean floor through the 3 D oceans) is increased long term binding of CO2 from the atmosphere.

DA, the miles thick limestone rock beds so common everywhere are all marine sequestered CO2. In fact, without those rocks being recycled in tectonic subduction zones as volcanic CO2 emissions, it is estimated that life would cease from lack of CO2 for photosynthesis in about 2.5-3 million years.

Nah. The poor little blighters can’t secrete no steenking calcium carbonate because they are bathed in concentrated carbonic acid. Haven’t you heard?


I’m actually pretty safe from exposure. They can’t read yet, but they vote with their bones.

kim may,
Most of the extra CO2 is going into land vegetation, as the need there is highest. Most land plants are C3 plants, which do thrive in much higher CO2 levels than today. Oceans have relative much higher CO2 levels and that level is not the most limiting factor. Other necessities are more important like the lack of iron, nitrogen, phosphate,…
Moreover, many water based plants like coccolithophores with a carbonate skeleton use a mechanism between C3 and C4 for their photosynthesis, which is less dependent of CO2 levels. The skeleton is built from bicarbonates which are abundant in seawater…
The overall uptake by (land + sea) plants nowadays is around 1 GtC/year due to the 110 ppmv extra CO2 pressure in the atmosphere. See:
The carbonate deposits in the past were enormous, but one shouldn’t underestimate the time frame. It did take many millions of years to build up all these layers. If I remember well, about 0.04 mm/year for the white cliffs of Dover (UK)…


Thanks, as ever.

Evan Jones

FWIW, I have read that ~2 BMTC calcifies on the ocean floors. Atmospheric CO2 increases at a little under 4 BMTC/yr. (to a ~780 BMTC sink).

David A

Ristvan, thanks, yes, eventually I guess it all recycles. Do you have any wags on how much energy it would take to accelerate the hydrological cycle, as I asked in my comment?


johnsut1 on May 3, 2016 at 6:27 am is right. The major premise of this post is wrong.


I told Betts a long time ago just to stop with the catastrophism. You know, we could all get along, as ultimately we will, when catastrophes never happen.
The climate propagandists are already trying to call catastrophism a construct of the skeptics. They are bargaining for their livelihoods and their reputations, and very weakly.

The problem is that their past catastrophic predictions are indelible, and public. And coming back to bite them hard.


“bite them hard”
tastes like chicken


I’ve also long been amused that Bill Clinton once called CO2 “plant food”, but only once. Since then, he’s shaddaped. I think he couldn’t resist the dig at Al Gore.


Oh, boy, thanks; I’d heard about this but not seen it.


But still no mention of C3 and C4 plant differences. You cannot talk about plant water requirements, if you do not specify which plant type. Increasing CO2 will have much less of an effect on C4 types.

David A

“C4 plants are those which photosynthesize following the mechanism called C4 Photosynthesis. They are found only in the angiosperms with about 8,000 members in 17 families (see list below), equivalent to about 3% of all land plants.”
Oh, and lots of weeds are C4 as well.

True, but not no effect. Maise is C4, and at 750ppm does about 12% better in greenhouse experiments. Less than half of typical for C3. Most food crops except maize, sugarcane, sorghum and millet are C3 including rice, wheat, soy, potatoes, pulses, all fruits and vegetables. Many interesting details in essay Carbon Pollution including experimental yield curves by ppm by crop for 10 major crops. All trees are C3. Phytoplankton are C3. C4 are about 15% of terrestrial plant species.

Steve Fraser

Especially in dry-land farming.


I’ve read that on wind free days, corn will often stop growing towards the middle of the day, as the CO2 levels in the fields have dropped to low for continued photosynthesis.

I posted yesterday on the effects of CO2 on a few Australian Trees, oh, and coffee.
Mainly because I am in tree planting mode to shame the Green Blob.

David A

ristvan, the link I gave showed a very different number, (3% vs 15%) ?


I recall Richard Betts working with Dr Tol on economic impacts of rising CO2. If I remember correctly Dr Tol did predict initial benefits of rising CO2. Maybe Increased Plant growth was one of those benefits


Tol will eventually find no upper limit to the benefits of warming and greening. It’s too bad we haven’t the resources to warm and green even more than we will.


Mebbe Nature existing outside of computer models?


Well, it took them two IPCC reports to discover that big ball of yellow gas in the sky.


The lead authors of the WG2 Chapters of course knew the drought porn of WG2 was intentionally misleading by omission. They of course knew about CO2 fertilization effects. But they probably didn’t didn’t figure they’d be so strong so soon (the fertilization effect and its reporting) so that they could get away with the misleading SPM statements. Betts is just in spin cycle.
Will there be an IPCC AR6 now?

Richard Betts says ” WG2 Ch4 section page 293 “high confidence that net terrestrial ecosystem productivity at global scale has increased” ”
This is, I think, the point Steve Mc is making. It’s in there, buried, underplayed, on page 293.
But take a look at the headlines in the WG2 SPM. It’s all about hazards, risks, floods, droughts
I started to count the number of times the word “risk” appears in the 34-page SPM. It’s over 200!


Who even read WG2? Shouldn’t there be a hat-tip to it in WG1?

Maybe clouds…

John Silver

Or maybe a brain….
They’re scarecrows, you know.


It is because of plants that fossil fuels even exist. Since fossil fuels are bad for the environment then all forms of plant life must be bad of the environment. In the name of fighting climate change, all forms of plant life must be eradicated. All carbon atoms on this planet need to be sequestered in the form of carbonate rocks and encased in concrete. That will get rid of CO2 but CO2 is really only a very minor player compared to the primary greenhouse gas in the Earth’s atmosphere. In the name of fighting climate change, all H2O on Earth must also be eradicated. The only question is how.


We could ship it to Mars

The twitter feed seems to reveal a tipping point.
Richard Betts seems to go off the deep end,endlessly self justifying himself.
Behaviour this unhinged will increase as the projections fall.
Behing the screen?
Pretty insubstantial figures.

Saul from Montreal

Anthony Watts posted: “And then, work or not like the famous XKCD comic “Duty Calls” he comes back, But Steve has already left the building thinking Betts really did have work to do and ended the conversation:”
@ johnsut1 May 3, 2016 at 6:27 am points out Mr Watts mistake:
“You’ve been caught out by twitters confusing timeline. All the posts at the bottom were posted before he said “I could go on, but I have work to do!”
Six hours and three blog posts later and Anthony Watts still has not corrected this erroneous jab at Dr Betts.

There’s no getting around it, Betts was spanked hard by McIntyre.
Betts asserts — against a mountain of evidence — that the effect of more CO2 is “negative”. Betts is flat wrong. No wonder he skedaddled from McIntyre.
And just for fun, here’s the XKCD cartoon:comment image

Question: What is the effect of the “greening of the planet” on the half-life of CO2 in the atmosphere? There was a paper here a couple of weeks ago that estimated the half-life was (down to) some 35 years. It seems to me that if higher CO2 levels both promote green plant growth AND reduce the water needed for green plants to grow, then there’s an acceleration effect, to wit: plants will thrive in dryer areas and grow more leaves which will absorb more CO2.
In short, won’t higher atmospheric CO2 levels result in higher rates of absorption by green plants? And isn’t this self-limiting? If the worry (by some) is that mankind is upsetting the balance of nature by burning stuff, won’t nature rebalance itself to recycle CO2 faster?

Michael Jankowski

The lunacy that Betts “directs”…
“…High-End cLimate Impacts and eXtremes (HELIX)
At HELIX we are assisting decision-makers and the research community in making adaptation to our changing climate more understandable and manageable by providing a set of credible, coherent, global and regional views of different worlds at 2, 4 and 6°C, with further focus on delivering the knowledge needs of Northern Sub-Saharan Africa, South Asia and Europe….”
Even Gavin will admit models can’t project sh!t about the future at the regional level. Betts professes that he can provide “credible” views at the regional level. So can I, and it doesn’t require computer models.

jolly farmer

Bettsy tweets all the headlines that didn’t make it into the Guardian.
Then goes back to his +6C computer games, whilst admiring his latest salary statement.


“there is still much to learn about how these processes will operate under future conditions that have not yet been experienced.”
ROFL – where is there a place on earth that has ever experienced anything but what has already been? Can he give an example of what he means by those conditions?

Johann Wundersamer

On Twitter, Steve McIntyre noted this part of Betts essay:
Despite claims to the contrary, the conclusions of the IPCC take CO2 fertilisation properly into account in the assessment of climate change feedbacks involving the carbon cycle, and in the assessment of the impacts of climate change on ecosystems. They are also starting to account for this in the knock-on consequences for water resources, but that is more cutting-edge science and less advanced.
He’s having none of that,
agreed, and you could proceed –
He’s having none of that – thus bringing the lie into the world.


Next, a paper by an alarmist (Bates), finding errors in “feedback” estimates, and that CO2 warmi9ng effect is small . . from what I hear via Mr. Monckton.


This is what Richard Betts was saying in 2005: “Stabilising climate to avoid dangerous climate change
— a summary of relevant research at the Hadley Centre” – January 2005
Prepared by Geoff Jenkins, Richard Betts, Mat Collins, Dave Griggs, Jason Lowe, Richard Wood
I can’t find a link any more, but I have a copy.
“As CO2 and temperatures increase due to man’s activities, several things happen. Firstly, extra CO2 acts as a fertiliser and increases the growth of vegetation — particularly in northern forests where warming also encourages growth — and this helps to offset man’s emissions (although new tree growth may darken the surface and act to warm the planet).
But in some parts of the world, where rainfall decreases and higher temperatures increase evaporation, vegetation will die back. Thus, instead of carbon being drawn from the atmosphere, it will actually return to the atmosphere to enhance already increasing concentrations.
The same thing happens in much greater quantities and on a global scale in soils, as microbial activity is accelerated in a warmer climate and more carbon dioxide is emitted. The combined effect of all these changes to the amount of carbon stored in ecosystems is shown below. The strength of the vegetation sink starts to diminish in the latter half of this century, and by the final decades it turns into a net source.”
The settled nature of “the Science” is shown in their summary, AR4 was in preparation:
“What constitutes ‘dangerous’ climate change, in the context of the UN Framework Convention on Climate Change, remains open to debate.
The physical (chemical and biological) climate system — or components of it — are capable of changing rapidly, and the trigger point for such abrupt changes could provide one of the ways of defining ‘dangerous’
We can also investigate the impacts of relatively gradual change — and their associated costs — to seek ways of defining a dangerous change.
The inertia of the climate system means that we could be committed to dangerous change, many decades before we reach the dangerous level.
Once we decide what degree of (for example) temperature rise the world can tolerate, we then have to estimate what greenhouse gas concentrations in the atmosphere should be limited to, and how quickly they should be allowed to change.
These are very uncertain because we do not know exactly how the climate system responds to greenhouse gases
The next stage is to calculate what emissions of greenhouse gases would be allowable, in order to keep below the limit of greenhouse gas concentrations.
This is even more uncertain, thanks to our imperfect understanding of the carbon cycle (and chemical cycles) and how this feeds back into the climate system”


What about reflection of sunlight? Green plants reflect the green part of sunlight, green is in the peak of the spectrum, where the sunlight have most of it´s energy. If there is a significant increase in green surface coverage measured by satellites, there is a significant amount of energy reflected. Right?
Seems to me like increased greening of the surface cuts off a bigger piece of the top part of the solar spectrum. It cuts off radiation right where it´s most effective if increased co2 would be a risk that potentially could lead to threatening rise of temperatures.
Here, have some negative feedback.
Although, I think it´s a very far-fetched idea that co2 leads to a rise in temperature, so I think the planet is just saying thank you for the help in burning hydrocarbons, which would be impossible without humans, by giving us more plants so we can feed more people, grow our population and burn more oil. So there is not much need for negative feedback. It´s all about making energy flow faster, bigger and stronger. Everywhere in the universe,

OK, you had your chance. McIntyres spag against the wall will make a useful post to discuss his tactics.

This gets even better:) Somebunny managed to cut off the time stamps from Richard Bett’s last set of tweets and shuffle them back to front to make is appear that Richard Betts came back after signing off. Curious because all the other tweets have time stamps.
Now some, not Eli to be sure, might think that there was a purpose to that.

Saul from Montreal

@Anthony Watts
Nobody is contesting the order the tweets appear in the screenshot. Your mistake was made regarding the interpretation of the order…on Twitter the newest tweets are at the top and earlier tweets appear below. What is offensive in my opinion is that this has been explained to you a week ago and no correction has been made.
In this card carrying skeptic’s (JREF) humble opinion you owe Dr Betts an apology or at the very least an acknowledgment that your accusation was a mistake.

I’ll have a look, and if a correction is needed, I’ll do it.

Yes please Anthony – thanks in advance. Eli’s post shows the correct order, with times. My tweet “I could go on, but I have work to do” was indeed my final tweet, after my tweets citing the specific sections of the WG2 chapters.