CARBON dioxide is not an air pollutant. It is plant food. All life on Earth depends on it. It is natural. It forms the bubbles in bread, champagne, and Coca-Cola. You breathe it out, and plants breathe it in.
The Earth contains a lot of CO2, but the atmosphere contains so little that the United Nations’ Intergovernmental Panel on Climate Change (IPCC) rightly calls CO2 a “trace gas”. A scientific mystery is why the air does not hold more CO2 than it does. Half a billion years ago, there was almost 20 times today’s CO2 concentration.
Most farmers would prefer to grow crops under much-higher concentrations of CO2 than today’s 385 parts per million—less than 1/25 of 1 percent of the atmosphere. To feed the world, low CO2 concentration is not such a great idea. High concentrations are better, and they cause no harm. Experiments have shown that even delicate plants such as orchids thrive at CO2 concentrations of 10,000 ppm.
That is why U.S. Supreme Court Justice Anthony Scalia has declared that if CO2 is to be labeled an “air pollutant”, then so must Frisbees and flatulence.
What about the danger of overheating the Earth by CO2? Al Gore is spending $300 million telling us “global warming” will be a catastrophe. Yet a survey of 539 scientific papers containing the words “global climate change” and published between January 2004 and February 2007 found not a single one that provided any evidence that “global warming” would be catastrophic. It does not matter how many scientists or politicians say that more CO2 will cause a catastrophe. To true scientists, what matters is whether any real-world data support the idea.
If CO2 is a powerful greenhouse gas, we would have seen a great warming trend in Indonesian temperature history. We haven’t. Recent temperatures, according to the Tyndall Centre for Climate Change Research, have been scarcely warmer than they were 70 to 100 years ago. Instead of a strong warming trend, the Indonesian data are dominated by year-to-year changes and natural oscillations every 50 to 100 years.
It is remarkable to find documents on the Internet, circulated by WWF-Indonesia, trying to scare the unsuspecting public by saying the temperature in Indonesia has “increased by 0.3º C” over the twentieth century and that one can expect additional warming of 0.1 to 0.3º C per decade for the next 20 to 100 years.
In a humid, equatorial nation such as Indonesia, with annual temperatures between 23º and 32º C, there is little chance of seeing those predicted warming trends, or any of the predicted changes in rainfall.
Professor Mezak Ratag of the Indonesia National Agency for Meteorology & Geophysics says,
“The output from different models is often different and sometimes contradictory. For example, [a UK climate model] predicts increases in temperature and decreases in precipitation for Indonesia, while [a German model] predicts an increase in both temperature and precipitation.”
When climate models say that both increased and decreased rainfall are possible, they are not actually making any predictions.Worse, climate scientists from Stanford University and the University of Washington in the United States recently admitted that the islands of Java and Bali are not even represented as land in many global-circulation models [used by the IPCC].
The 100-year mean temperatures over the period 1901-2000 for March-April-May, June-July-August, September-October-November, and December-January-February are 26.2, 25.6, 26.1, and 25.9º C, respectively. This confirms the clear dependence of the basic climatology of Indonesia on the arrival and relative intensity of the sun overhead. More sun means warmer weather, and vice versa. It is as simple as that.
More sun also means more rain, except that during the December-January-February season there is an additional large contribution from the northwest monsoon and the southward migration of the inter-tropical rainbelt.
Look to matahari (the sun in Bahasa Indonesia) rather than CO2 as the key player in Indonesia’s climate.
Cutting CO2 emissions by sharply curtailing the use of gasoline and other fossil fuels will make no difference to the weather. It will merely lead the foolish to feel good about “saving the planet”. Even if the planet needed saving, all proposed mitigation measures would be futile. It would be cheaper and less irresponsible to adapt to warmer weather as—or rather if—necessary.
We have already seen food prices double and triple worldwide because the “green” movement told us biofuels would “save the planet”. Science, however, demonstrates that biofuels have a bigger carbon footprint than does gasoline.
Foolish mitigation measures that owe everything to political fashion and nothing to scientific rigor are already harming the world’s poor. It is time to stop the hysteria about CO2 before anyone else gets hurt—or even killed.
Willie Soon is a geoscientist at the Solar, Stellar and Planetary Sciences division of the Harvard-Smithsonian Center for Astrophysics. He will address the International Symposium on Climate and Weather of the Sun-Earth System, hosted by Indonesia’s National Agency for Meteorology & Geophysics in Jakarta November 24-26.
Christopher Monckton is chief policy adviser to the Science and Public Policy Institute in the USA. (http://scienceandpublicpolicy.org).
This article has been republished from Indonesia Matters with permission from Dr Soon.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
“U.S. Supreme Court Justice Anthony Scalia has declared that if CO2 is to be labeled an “air pollutant”, then so must Frisbees and flatulence.”
I wonder if Justice Scalia made this comment before or after the election of Barack Obama. Mr Obama has stated that he will declare Carbon Dioxide a dangerous pollutant
http://www.bloomberg.com/apps/news?pid=20601087&sid=a2RHIj_6hvV0&refer=home
The lunatics are taking over the asylum
How do we know if Indonesia has warmed or not.
Remember you can’t measure the temperature. Louis has proved it. And so has Vince.
And the you can’t trust the thermometers’ locations anyway as they’re surrounded by the shady palm tree island effect.
But mostly there’s nothing better the Indonesians would love than a semi-permanent AGW El Nino.
I have proved you can’t measure the temperature? I wonder where I did that – news to me.
Luke,
Louis says you can’t measure a global temperature, but I would think he would agree you can measure temperature at places in Indonesia.
What is the longest temperature series for a place in Indonesia – not in a city and therefore likely to be affected by heat island effect?
Yes Jen – but yo’all have been telling us how difficult it is to measure regional temperature. Indonesia sure is a diverse mountainous place with even small islands like Lombok having different climatic influences on different sides. High mountain peaks unsampled – maybe the montane coenoclines might be changing big time from AGW?
Big cities full of heat islands? A difficult political system perhaps – not conducive to accurate measurements – and you have reminded us previously about Chinese and Russian data quality.
And so much cloud reflecting that radiation away – and so much Indonesian-ocean flow through currents bringing an ocean climate buffer.
Are you sure you’ve checked this out.
Which side of Lombok was your thermometer on? 🙂
Now to be fair – I think given you raked poor old David Jones over so hard on Melbourne data (only to find out it was as he said) – in the interests of impartiality – we should ask you too put up the Indonesian temperature data? Let’s have a look see.
Following Luke’s suggestion:
I’ve just sent the following note off to this adress:
E-mail:anmet@bmg.go.id
“Hi, I was wondering whether there is publically available temperature data for specific sites in Indonesia and which site has the longest historical record. Kind regards,”
There is an interesting paper here: http://www.gisdevelopment.net/aars/acrs/2000/ts5/env008.asp
What a load of sentimental rubbish. I can’t believe that someone who considers themselves a scientist would publish such rot.
A pollutant is something that can be good, but in excess is bad.
A pure oxygen atmosphere would be bad us, no oxygen would be bad for us.
A pure CO2 atmosphere would be bad for us, no CO2 would be bad for us.
It’s not an issue of if something is good or bad, it’s a matter of what we are adapted to. I can’t believe the number of times I have seen such blatant stupidity on this and other blogs.
A 12 year old could spot some of the flaws in this piece. The most ridiculous thing is the banal statement that CO2 is ‘plant food’ and therefore could not possibly do anyone any harm. Water is also a prerequisite for life; would Willie Soon like to try drinking several gallons in a very short space of time? Water is plant food, so surely it could not do them any harm. The Sun provides plants with the means of making food, so surely you could not possibly be harmed by the Sun?
This survey of 539 papers – who did it, and where was it published?
Indonesia lies near the equator. Models predict, and observations confirm, that equatorial regions, being very humid, experience a smaller forcing from increasing CO2 than polar regions do. The quoted mean temperatures tell us nothing at all about trends, data that is conspicuously absent from this piece.
What do the authors make of the rapid warming observed at temperate latitudes, and the even more rapid warming observed at high northern latitudes? Why do they think the stratosphere is cooling?
RW,
Perhaps a 12 year old could but clearly an older person can’t – quoting from the piece in question ““The output from different models is often different and sometimes contradictory. For example, [a UK climate model] predicts increases in temperature and decreases in precipitation for Indonesia, while [a German model] predicts an increase in both temperature and precipitation.”
So the models don’t.
And what rapid warming in the temperate zones – evidence please and not modelling results.
Incidentally the earth’s thermal state is not determined by the temperature of its atmosphere but by the temperature of the solid earth itself. From the point of heat content the whole AGW is a furphy but it is very well argued and only the gullible seem to have swallowed it hook, line and sinker.
For what it’s worth, the earth has a quiescent electric field (surface to ionosphere) of some 100 volts per vertical meter. This electric field will dissipate when the electric current powering it diminishes or collapses.
NASA has just realised that the Flux Tube Events are real, and that the Earth is continuously receiving billions of amperes of electric current from the Sun and space.
As most of us understand, electric currents passing through matter generate heat.
Have you considered the remote possibililty that these measured electric currents might be the driver of earth’s thermal state?
In addition the Sun’s heliopause has become 25% smaller and this is probably due to a reduction in galactic electric current powering the sun, hence the absence of sunspots, cooler temperatures and hence a cooling earth. Cold periods and lack of sunspots is a documented historical fact. Plasma universe theory provides a simple explanation based on physics we well understand, not on a emergent theory based on consensus.
And we explained all the above without a computer model – just plain simple physics and electrical engineering.
RW, What do you make of this:
“Abstract
Recently climatologists have indicated that the global warming is currently happening as a result of human activities. Such evidences were shown by the increasing trend of surface temperature that taking place at a number of big cities and industrial areas all over the world. This just brings impact on microclimate but it doesn’t have much influenced for the atmospheric mean temperature.
In fact, the analysis result of the atmospheric mean temperature based on radiosonde data observed in several big cities in Indonesia show the cooling between -2.730 and -5.510 from its normal. This indicates that nuclei condensation (aerosol) particles on the atmosphere over Indonesia were quite abundant. It can be related with the fact that Indonesia is an archipelago consists of thousand of islands – 70 % of Indonesian region is ocean.
On the other hand we can assume that the global warming that is usually connected with surface temperature cause the increasing of evaporation from ocean. And these aerosols will be trapped at mixing layer and cannot go higher. So that the propagation of sun radiation will prevent from going through and this cause the cooling temperature of atmosphere in this layer. The problem is how far from the surface that the global warming can affect the atmospheric layer.”
from http://www.gisdevelopment.net/aars/acrs/2000/ts5/env008.asp
As some who has lived and worked in Indonesia for a period of 15 years and visits there regularly I can tell you that there are individual area’s in Indonesia were the weather pattern has changed.
I can also tell you that I have spoken to a provincial governor who was so worried about the changed local rainfall/moonsonal patterns that he commissioned a US government agency to investigate the reasons.
The conclusion – land use and tropical rainforest clearing.
I was even part of the governors re forestation project.
Millions and Millions of hectares of tropical Rainforests have been cleared in Sumatera, Kalimantan and Suliwesi.
Tropical rainforests grow in beds of peat. Tropical rain forests create their own weather. When you fly low over tropical rainforests you can actually see their own little eco climate.
Tropical rainforests are neutral. Once you enter deep into a tropical rainforest there is no active life at the base. No animals, no feed for animals, no flowers. Bird life can live in the canopy.
As regards UHI. In one major city I know well, the population has tripled in 30years. Temps in 2006 reached unprecedented 40+ degrees. In the 1970’s This city had a large rainforest on it’s outskirts. This forest kept the city under a semi permanent cloud cover. The cloud cover is now more intermittent since the rainforest has been obliterated. In the 1970’s ,this same city had a huge population of polluting motorised rickshaws. When flying into the city you could see a huge brown murky cloud from these polluting machines trapped between the ground and the cloud base. The cloud base has disappeared and the polloution has been cleaned up. The sun now beats down on the city and this in turn has raised the ambient temperature.
The Sasmito et al paper linked to by Jennifer shows there is no THS over Indonesia; this is consistent with what Santer’s lauded study found! David’s other AGW fallacies include increased land temperature, which is barely above statistical error at best, and Stratospheric cooling; such cooling is extremely debatable and ignores the long-term effect of eruptions and destruction of ozone.
“This survey of 539 papers – who did it, and where was it published?”
Scientific Consensus on Climate Change
Klaus-Martin-Schulte
Energy and Environment Volume 19 No 2 2008
http://scienceandpublicpolicy.org/images/stories/papers/reprint/schulte_two_colmun_fomat.pdf
Poor Louis – so confused as to what’s modelled and what’s not.
Try http://www.ssmi.com/msu/msu_data_description.html – satellite data says it’s warmed over Indonesia too.
But within the Asian haze and fire pollution over Indonesia – is this the best place to look for evidence of AGW.
And EOS (which I’m sure Louis gets) says on 21 Oct 2008 – “Not to Worry: Solar Magnetic Activity of Cycle 24 is increasing”
David Hathaway says ” the ongoing lull in sunspot numbers is well within historic norms for the solar cycle”
The data show the cycle minimum was reached in 2007 and the average IMF has now begun to increase, as expected for the next solar cycle….
So much for Sun worshipers?
E&E – say no more ! say NO more …
Luke
“But mostly there’s nothing better the Indonesians would love than a semi-permanent AGW El Nino.”
That doesn’t make any sense are you trying to say AGW causes the SOI. Also why would the Indonesians want a semi-permanent El Nino? Perhaps you can enlighten us what effects it has on the monsoons and ocean temperature. I doubt you will because it contradicts your belief system.
SJT
I note your constant usage of the words consensus and bad. One is used to discover religous truth and the other a moral judgement on something you do not agree with. It is not science it is religion albeit a pagan one but still religion. Do you have a green prayer mat?
Lamprey
Sun worshippers?
How about CO2 worshippers.
By the way ever published anything youself in the peer reviewed journals or do they keep sending you rejection slips.
Indonesia is the least likely place to have experienced global warming, according to Patrick Michaels. Again, I urge both skeptics and alarmists to read his recent books, ‘The Satanic Gases (2000)’ and ‘Meltdown (2004)’. I found them both in my local library.
Michaels does a good job of explaining climate and weather in a humourous, unbiased manner. He pays respect to both sides of the equation. He explained that locations near the equator and on the ocean have highly regulated temperatures due to the high moisture content in the air (warm, moist air rises, taking the heat with it). Rio, for example, which is near the equator, has an average high in the low 90 F (32 C) range whereas that high would be much higer in a non-ocean area. Note the high end of the range for Indonesia is 32 C. We get highs like that in some parts of Canada in the summer.
He was making those comments in reply to a Canadian GCM which was predicting warming of up to 300% in places. It had predicted warming up to 49 C in the US Gulf states. The only way that could happen, according to Michaels, would be to drain the Gulf of Mexico and blacktop it.
Most of the warming is taking place in the coldest parts of the world ‘in the winter’. That includes Siberia and Northwest Canada, but not Antarctica. The Russian leader was pleased to hear that Siberia was warming.
On a humourous note, a wag in a Canadian blog made a comment on the Tar Sands in northern Alberta. He claimed it was naturally polluted with oil in the sand and that Alberta was doing its best to clean it up by extracting it. I don’t think Greenpeace and other activist/alarmists will see the humour in that somehow. Many religious zealots seem to have that dour quality.
Luke: ‘E&E – say no more ! say NO more …’
So you would be standing by the Oreskes paper then? Woohoo!
DHMO
http://news.mongabay.com/2006/0503-ucar.html
http://www.nature.com/nature/journal/v441/n7089/pdf/nature04744.pdf
http://www.gfdl.noaa.gov/~gav/REPRINTS/VS_07_GWnCIRC.final.pdf
http://www.agu.org/pubs/crossref/2007/2007GL030854.shtml
Monsoon – perhaps http://www.nature.com/news/2008/081106/full/news.2008.1213.html
Luke so you have no personal knowledge in order to explain you proclaim the word. Come EL Nino more rain or less rain in Indonesia? Whichever it is why is it so? Or do you just have links to regurgitate?
Well that was a waste of time on DHMO.
Ummmm let’ see …. gee dats a hard ‘un mate. Looks like we’re back to clubbing rocks.
I think El Nino might bring less rain to Indonesia. Gee I wonder why…. might it be the due to the interplay of atmospheric circulation (such as the Walker circulation) and Pacific SSTs that the convective systems move away from the Archipelago. Try googling the very many explanations of ENSO mate.
(are these people serious?)
Luke that wasn’t so was it so you reckon less rain so why would the Indonesians want less rain? “Pacific SSTs that the convective systems move away from the Archipelago” Is that your way of saying the oceans get colder around Indonesia when El Nino is in force. If so by how much?
Yes I’m sure the Indonesians enjoyed the massive droughts and forest fires from El Nino events.
On SSTs being cooler – maybe not – Archipelago is a complex place for currents and SST patterns.
My use of the word “bad” was in reference to first paragraph of the topic itself, don’t blame me for setting up the moral judgements.
You might also like to point out my constant use of the word “consensus”, because I can’t remember the last time I used it here.
Luke you go again “Yes I’m sure the Indonesians enjoyed the massive droughts and forest fires from El Nino events.” I am sure they are not crazy even if you say they are.
The first signs of an El Niño are:
1. Rise in air pressure over the Indian Ocean, Indonesia, and Australia
2. Fall in air pressure over Tahiti and the rest of the central and eastern Pacific Ocean
3. Trade winds in the south Pacific weaken or head east
4. Warm air rises near Peru, causing rain in the northern Peruvian deserts
5. Warm water spreads from the west Pacific and the Indian Ocean to the east Pacific. It takes the rain with it, causing extensive drought in the western Pacific and rainfall in the normally dry eastern Pacific.
So the principle factor is less rain for Indonesia (and Australias north) because evaporation decreases with colder sea surface temperature.
SJT
“CARBON dioxide is not an air pollutant. It is plant food. All life on Earth depends on it. It is natural. It forms the bubbles in bread, champagne, and Coca-Cola. You breathe it out, and plants breathe it in.”
Yup it was you and now you have lied. Now about the color of that prayer mat
DHMO you’re sooo knowledgeable – swoon ….
But sigh – DHMO – but did you check out the SST anomalies round Indonesia in 1982/93 and 1997/98 …. hmmmm … a tad warmish? darn …
I think you’ll find the relevant Hadley cell also moves. location …
But back to the chase – the story of El Nino and AGW isn’t clear. Some have suggested more events. Some not.
Some have hypothesised about the Pacific adopting a warmer “mean state”
But disturbingly for me – two different papers documenting the century long decline in the Walker circulation with modelling confirmation.
Now I’m not saying there’s going to be a a drought every year but some very long scale predicted changes are starting to occur.
Whether El Nino continues to operate on a different base needs to be determined.
You could do well to read my links and regard them as some random google.
SJT: so what is your opinion on what would be the optimal level of [CO2]? Do you agree with Hansen (350 ppm)? or those who consider zero emissions best, leading to long term decreasing [CO2] for so long as uptakes continue at the present nearly 6 GtC p.a. which would reduce us to the 1750 level perhaps as early as 2070 if not before? If uptakes drop in line with reducing emissions, what then for CO2 fertilisation? Will wheat etc yields remain as they are, or fall? Was 1750’s 280 ppm ideal? Would it feed 6.5+ billion? You rely on reductio ad absurdem. Can your rise above that for once? Willie Soon is very forbearing to tolerate your insults. If you are so smart, what is your own affiliation, or was his Harvard not good enough for you?
luke; the Vecchi paper states; “As temperatures rise and more water evaporates from the ocean, water vapor in the lower atmosphere increases rapidly. But physical processes prevent precipitation from increasing as quickly as water vapor. Since the amount of water vapor brought to the upper atmosphere must remain in balance with precipitation, the rate at which moist air is brought from the lower to the upper atmosphere slows down to compensate. This leads to aslowing of the atmospheric circulation.”
This is strange; Miskolczi explains how optical density is regulated by water vapor with verified increases in lower atmosphere and declines elsewhere in SH and RH; AGW depends on constant RH and overall increases in SH, neither of which is happening. Vecchi seems to be having a quid both ways. And what exactly are those physical processes which prevent precipitation from increasing as quickly as water vapor; and even if this were true why doesn’t the lower atmosphere water vapor form clouds and produce Spencer and Braswell’s negative feedback through increases in albedo?
As to Power and Smith; they assert that the 30 year average of the June-December SOI just occurred from 1977-2006; this was the PDO +ve phase, El-Nino dominated and featuring a -ve SOI. But have they looked at the commensurate period during the 20thC’s first +ve PDO; the SOI average is just marginally different.
Cohers – SOI been trending down for 30 years and way different to anything in 100 years. Why do you think climatologists are picking up on it. Why do you think they’re wondering what such a change means for ENSO indices and seasonal forecasting.
PDO and SOI aren’t well correlated in first half of the 20th century. So I’m suggesting you’re just grabbing at one cycle.
And Scott and Power have teased us – see their title – Walker circulation has changed but is El Nino still the same. Very interesting.
Now add on the STR change over the century.
The observed changes in SAM backed up by modelling by a number of groups.
If by now you’re not getting any gnawing doubts there’s something wrong…. well ….
Anyway where’s your 400 years of global temperature versus 400 years of PDO. Boing – ping – was that a spring gasket blowing …?
And Cohers – just when you think more evidence couldn’t wash in – our old friend the IOD – latest Nature Geoscience – IOD has also changed over the 20th century … bit of a pattern developing …
http://www.nature.com/ngeo/journal/vaop/ncurrent/abs/ngeo357.html
Add that to http://www.nature.com/news/2008/081106/full/news.2008.1213.html
Poing !
Dare one says there seems to be major changes across the whole southern hemisphere as extra “energy” redistributes.
It’s almost ironic that Jen would have posted on Indonesia just when this IOD paper has come out. And speaking of Indonesian SSTs it says:
“Strengthened upwelling in the eastern IOD sector implies
that there has been an intensification of the southeasterly trade
winds along the coast of Sumatra, and/or shoaling of the
thermocline in the eastern IOD sector2,16. Historical ship-based
measurements support a twentieth-century intensification of the
southeasterly trade winds offshore of Sumatra (Fig. 3c). This is
consistent with theories that preferential greenhouse warming of
landmasses will strengthen alongshore winds26. This process has
been linked to intensified coastal upwelling in other locations27,
and may account for the enhanced upwelling in the eastern IOD
region. The influence of twentieth-century warming on long-term
changes in the Walker circulation over the tropical Pacific11 may
have also enhanced eastern IOD upwelling. Twentieth-century
weakening of the Walker overturning cell has been accompanied
by an eastward displacement of convection over Indonesia and
shoaling of the thermocline in the Indo-Pacific Warm Pool11,25.
Both processes are consistent with an intensification of the IOD
via the eastern Indian Ocean upwelling region, with reduced
convection favouring the development of anomalous surface
easterly winds and shoaling of the thermocline assisting upwelling
of cooler waters.”
Wow !
Miskolczi doesn’t explain it at al. He claims it, but he offers no explanation.
To our resident expert on Miskolczi, SJT, who is evidently unable to answer the following questions I put to him nearly 2 days ago: “what is your opinion on what would be the optimal level of [CO2]? Do you agree with Hansen (350 ppm)? or those who consider zero emissions best, leading to long term decreasing [CO2] for so long as uptakes continue at the present nearly 6 GtC p.a. which would reduce us to the 1750 level perhaps as early as 2070 if not before? If uptakes drop in line with reducing emissions, what then for CO2 fertilisation? Will wheat etc yields remain as they are, or fall? Was 1750’s 280 ppm ideal? Would it feed 6.5+ billion?
Come on Tim – your CO2 fertilisation stuff is so trite. You’d be flat out detecting current levels in field trials. Look at the FACE experiments – incredibly variable results. And you have to have the rainfall to go with the CO2. In woodlands – seems that the acacias take over. Seems to affect the C/N ratios. And woody plants in general overrun grasses – and yes I await you obvious retort but CO2 increases frost sensitivity. One unusual cold snap and zappo !
How about some full disclosure here and not the usual sceptic simplistic nonsense.
Luke: Try Norby & Luo New Phytologist 2004, 162: 281-293; Long et al., in Plant , Cell, and Environment 2006.
luke; pdo and temp over 400 years; why 400? Anyhow, FIG 10 from this source is interesting;
http://www.ac.wwu.edu/~dbunny/research/global/glacialfluc.pdf
Which explains the modern era;
http://climate-skeptic.typepad.com/photos/uncategorized/2008/09/18/pdo.gif
400? coz that’s what data Franks has … expediency
no it doesn’t explain the modern era at all – – just the interdecadal variations.
Looks to me like a global warming signal coming over the top of an interdecadal oscillation
Your job still awaits you
Tim Tim Tim – fancy quoting Long
Science 30 June 2006:
Vol. 312. no. 5782, pp. 1918 – 1921
DOI: 10.1126/science.1114722
Food for Thought: Lower-Than-Expected Crop Yield Stimulation with Rising CO2 Concentrations
Stephen P. Long,1,2,3* Elizabeth A. Ainsworth,4,1,3 Andrew D. B. Leakey,3,1 Josef Nösberger,5 Donald R. Ort4,1,2,3
Model projections suggest that although increased temperature and decreased soil moisture will act to reduce global crop yields by 2050, the direct fertilization effect of rising carbon dioxide concentration ([CO2]) will offset these losses. The CO2 fertilization factors used in models to project future yields were derived from enclosure studies conducted approximately 20 years ago. Free-air concentration enrichment (FACE) technology has now facilitated large-scale trials of the major grain crops at elevated [CO2] under fully open-air field conditions.
In those trials, elevated [CO2] enhanced yield by ~50% less than in enclosure studies. This casts serious doubt on projections that rising [CO2] will fully offset losses due to climate change.
Luke: you need to read more of Long, eg 1991, and here, in Plant, Cell, and Environment (2006): Can improvement in photosynthesis increase crop yields?
STEPHEN P. LONG , XIN-GUANG ZHU , SHAWNA L. NAIDU & DONALD R. ORT
ABSTRACT
The yield potential (Yp) of a grain crop is the seed mass per
unit ground area obtained under optimum growing conditions
without weeds, pests and diseases. It is determined by
the product of the available light energy and by the genetically
determined properties: efficiency of light capture (ei), the efficiency of conversion of the intercepted light into biomass (ec) and the proportion of biomass partitioned into
grain (h). Plant breeding brings (greek n) and ei
close to their theoretical maxima, leaving ec, primarily determined by
photosynthesis, as the only remaining major prospect for
improving Yp. Leaf photosynthetic rate, however, is poorly
correlated with yield when different genotypes of a crop
species are compared. This led to the viewpoint that
improvement of leaf photosynthesis has little value for
improving Yp. By contrast, the many recent experiments
that compare the growth of a genotype in current and
future projected elevated [CO2] environments show that
increase in leaf photosynthesis is closely associated with
similar increases in yield. Are there opportunities to
achieve similar increases by genetic manipulation? Six
potential routes of increasing ec by improving photosynthetic
efficiency were explored, ranging from altered canopy
architecture to improved regeneration of the acceptor
molecule for CO2. Collectively, these changes could
improve ec and, therefore, Yp, by c. 50%. Because some
changes could be achieved by transgenic technology, the
time of the development of commercial cultivars could be
considerably less than by conventional breeding and potentially,
within 10–15 years.