I started on this yesterday, had to put it aside for work, and I’m hugely busy today. Then I thought, you know, I have a whole army of people that can crowdsource an article, so why not ask them to help?
OK the premise starts with this press release:
Higher temperatures to slow Asian rice production
Production of rice will be thwarted as temperatures increase in rice-growing areas with continued climate change
Production of rice—the world’s most important crop for ensuring food security and addressing poverty—will be thwarted as temperatures increase in rice-growing areas with continued climate change, according to a new study by an international team of scientists.
The research team found evidence that the net impact of projected temperature increases will be to slow the growth of rice production in Asia. Rising temperatures during the past 25 years have already cut the yield growth rate by 10-20 percent in several locations.
Published in the online early edition the week of Aug. 9, 2010 in Proceedings of the National Academy of Sciences —a peer-reviewed, scientific journal from the United States—the report analyzed six years of data from 227 irrigated rice farms in six major rice-growing countries in Asia, which produces more than 90 percent of the world’s rice.
“We found that as the daily minimum temperature increases, or as nights get hotter, rice yields drop,” said Jarrod Welch, lead author of the report and graduate student of economics at the University of California, San Diego.
…
more here:
http://www.eurekalert.org/pub_releases/2010-08/uoc–htt080610.php
Problem is, I don’t quite believe this study, especially since the INTERNATIONAL RICE RESEARCH INSTITUTE shows this graph:
Average rice yield in the Philippines and a selection of
other rice-growing countries (tons per hectare) (Source: FAOstats)
Source: http://beta.irri.org/test/j15/index.php?option=com_content&view=article&id=393&Itemid=100104
I don’t know a thing about rice growing, but I figure some readers do. How can we have a temperature rise and CO2 rise in the past century and have 50 year increasing rice yields in the same Asian countries as the study?
Some other data:
http://asiapacific.anu.edu.au/newmandala/2009/09/10/more-on-thailands-low-agricultural-productivity/
http://beta.irri.org/test/j15/index.php?option=com_content&view=article&id=710&Itemid=100111
I can compile what readers find and post in comments and present it as a new article. Thanks for your consideration – Anthony
STOP PRESS
ROGER BLACK BBC CLIMATE GURU MISQUOTES RESEARCH FINDING IN USUAL ATTEMPT TO EXAGGERATE PURPORTED CLIMATE CHANGE!
Roger says “Yields have fallen by 10-20% over the last 25 years in some locations.”
http://www.bbc.co.uk/news/science-environment-10918591
The press release says”Rising temperatures during the past 25 years have already cut the yield growth rate by 10-20 percent in several locations.”
http://www.eurekalert.org/pub_releases/2010-08/uoc–htt080610.php
He just KNOWS what the findings are without even having to read the press release.
It’s not the yield that has supposedly fallen, but the rate of increase in the yield.
Rajan Alexander says:
August 10, 2010 at 9:41 am
Sounds a lot like the same problem with using tree rings as a temperature proxy.
It seems plants respond to water AND temperature when growing.
I’ve noticed when I don’t water the vegetables, we get poor yields, in spite of the warmer temperatures of summer.
Crop yields and tree rings are both a measure of plant happiness, not of temperature.
Jim Steele says:
August 10, 2010 at 3:55 pm
Figures don’t lie; but liars do figure.
A few respondents seem to have missed the point made in the abstract. Whether talking about total yield or growth in yield is immaterial to their argument. They’re saying that the yield is less than it otherwise might have been.
PhilJordan claims that Minnesota is the U.S. leader in rice production. Actually, Arkansas, California, and Louisiana are the leaders, in that order. Minnesota does do well with wild rice though, but that’s a different critter.
Economists have no knowledge of agriculture.
They are in no position to infer or claim in any way that global temperatures affect crop yield either positively or negatively. Temperatures can affect crops if they are outside the range that is optimum for the various crops in question. The factors are adequate moisture, adequate nutrition, and light and temperature. Additionally, for a given plant type on a given piece of land there is a finite maximum yield which is usually less than the theoretical. Without a detailed analysis by some crop science types these economists have no leg to stand on and credibility that is less than zero. The other thing is that even if the rate of increase of yield is lower than before perhaps the actual yields are as good as can be expected knowing that there is a potential maximum yield.
In my humble ass opinion, the study is just so much propaganda and made up balderdash.
A possible reason for yearly increases in rice production falling may have nothing to do with climate or technology. What if people who normally consume rice may be switching to consumption of other foods crops. Younger generations in Asia and the Indian subcontinent could be shifting to other non-traditional foods away from rice.
Therefore, farmers could just be adjusting to their customers preferences.
John
Quoting the results in the abstract:
“Higher minimum temperature reduced yield, whereas higher maximum temperature raised it;”
The minimum temperature correlation is simply false claim.
Patrick Kelly you are wrong.
Richard Black states “Global warming is CUTTING rice yields in many parts of Asia, according to research, with MORE DECLINES to come. Yields have FALLEN by 10-20% over the last 25 years in some locations.”
http://www.bbc.co.uk/news/science-environment-10918591
This totally untrue. There has been no reduction in yield. Yield is still rising as the IRRI graph shows. It is disingenuous to claim a slight reduction in the growth rate of production as a decline.
Pull the other one.
Wow! And what a title!
“It’s Worse Than We Thought – Negative Second Derivative Found!”
Weird, since all the rice grows in the tropicals, like Indonesia, seems pretty warm when I was there.
More warm = more rain.
More CO2 = more rice
it’s looking so bad I am now off to the shops to stock up my rice bubble stocks
I ran across a Japanese article last year that described a study of projected global warming vs rice production. It seems that increasing CO2 will fertilize and increase rice production as temperatures are projected to increase. There are temperatures above which the production of rice decreases.
This is probably a factual observation, but, other studies may use the IPCC forecasts for future temperatures (obviously incorrect) to forecast rice production. This is dishonest and a non-starter.
My great thanks to the two people who have sent me the rice article. I’m just in off the highway from a seven hour drive, I’ll get to it as soon as I can.
w.
If daily maxima/minima are so important, why do they not run the simulations this way instead of averaging?
EM Smith, ripper post! I was also going to mention SRI and its amazingly good results.
I also read that due to using the “green revolution” gm and non traditional rices, and growing continuously 3 harvests a year the soil gets no rest, and they now have a serious issue with Brown leaf Hopper bugs.
before when the soil was rested or other crops were rotated the bugs life cycle was disrupted, now they have a year round feed and breed, and once again Man has created a super pest in massive numbers due to idiocy and greed.
Smaller Organic and Mixed farms produce more and keep the land healthier.
The idea that higher temperature thwarts the production of rice is pure hogwash.
Guongdong Province is the southernmost province in China. It regularly gets two crops of rice a year, rather than the one a year in most of China. Some fortunate counties in the south of Guongdong Province even get three crops of rice a year.
Why? The higher temperature facilitates the growth of the rice, so that it ripens and yields crops in half or a third of the time as the provinces to the north.
More evidence that “scientists” start with why global warming is bad, and try to find answers. Every hothouse operator knows that higher temperature and higher CO2 concentration yield better growth.
As so often appears to be the case this seems to be deliberate propaganda. A press release which can be easily misinterpreted, like the BBC did (maliciously?), as a decline in rice yields rather than a decline in the rate of increase in rice yields! [i.e. They are saying rice yields are increasing, but not as fast as they did in the past (year-on-year)]
The question is : Why are the rice yields increasing at all?
Obviously most of this will be down to better varieties, farming practices, use of the water supply, and use of fertilisers. In their research they will have taken all these factors in to account to isolate the effect of warming, yet they still report an increase in yield.
The only conclusion is that the warming is responsible for the increased yields.
Since the “correlation is not causation” and “El Nino year” themes have already been discussed thoroughly, I’ll try to bring up some other points. By the way, for those without access to the article, the Wikipedia entry on rice, which already references this article, states that a causal mechanism, though suggested, is not yet established — and sorry in advance for all the statistical terminology.
The weaknesses that I can see just from the abstract and SI that haven’t really been discussed are:
1) The authors took short-term (year to year) temperature anomalies as a factor in the correlation, and then (presumably) equated them to long-term (gradual over decades) temperature changes. For a system as complex as a rice plant, I’m not sure you can assume those two types of temperature changes produce the same response.
2) The authors expected temperature changes many decades hence represent an equivalent variation in the predictors equal to several standard deviations. I bet if they computed the standard error of the prediction in yield at those conditions, it turns out to be quite large. In other words, they have lots of data about what happened when temperatures were 0.5 C above average for a given location, but using such data to predict what will happen when temperatures are 3 C above average (even assuming temperature changes do cause a change in yield) is not very reliable, especially given a complicated system.
It seems to me the best way to confirm or refute this paper is just to do some good old fashioned science: dig up all those economic and climate variables for other locations and years (it may not be so bad since some variables are assumed insignificant and thus are not needed), plug in the model, and, assuming the standard error of the prediction is reasonably small (if it isn’t, the model isn’t all that useful), see how good the predictions are.
Also, having not read the paper itself, for all I know the actual authors of this paper may well have been appropriately cautious in their presentation of the data; this may simply be a case of publicity gone awry. They at least deserve the presumption of innocence until proven otherwise.
Steve in SC says:
Economists have no knowledge of agriculture.
Can we lose the “economist bashing”? I am a California Economist and I do have a decent knowledge of agriculture. My Alma Mater even has a specific Agricultural Economics major. It’s a BIG part of econ, and has been since the founding of the field (See Jevons, of Jevons Paradox fame, for example, who showed crop yields and prices correlated with sun spot cycles via rather intensive study of the yields of grains in India … which will have included rice.)
http://www.gradschools.com/search-programs/agricultural-economics
claims 177 schools with an Ag Econ program.
http://en.wikipedia.org/wiki/Agricultural_economics has:
and even a non-Ag Economist studies endless examples of ag related economics due to all the government programs involving food and agriculture and all the industries involved in it.
That SOME economists are a bit clueless about plants does not mean all of them are, or even most of them…
FWIW, I grew up in the middle of the N. California Rice region in a town dominated by raising “Peaches, Rice, and Kids; all for export” 😎
@amicus curiae: Glad you liked it!
OldBruin says:
The idea that higher temperature thwarts the production of rice is pure hogwash.
Well, more like ‘impure hogwash’… At SOME POINT higher temperatures do thwart production. It’s just that that point is way higher than just about everywhere on the planet, that’s all…
So I have to ‘nit-pick’ the point that it isn’t Strictly True, just true for all practical purposes and your conclusion is correct. Until everywhere is as hot as Phoenix or the Sahara, we’ve got no problem (and more total production up to that point).
Oddly, if the world gets hotter, we could likely grow lots of rice IN the Sahara:
http://chiefio.wordpress.com/2010/08/10/cold-dry-sahara-hot-wet-savanna/
when it’s 2 to 3 degrees hotter than now, the Sahara was a savanna… the rains return when there is enough heat to pull in the storms.
pat says:
August 10, 2010 at 9:31 am
“…..A far bigger problem is water. That has significantly impacted yields in California, India, and Australia.”
Yes…. But don’t forget that the lack of water may not be climate related either, but instead infrastructure related.
Especially concerning where it concerns Australia. Lack of investment in well sited dams and water storage, has meant that water is being taken from farmers to water cities…. also there are “environmental flows” that are flushed down the rivers at the cost of water to farmland and crops.
My thoughts exactly.
I actually helped start a climate skeptics’ wiki which looked really promising but then foundered because the owner of the website simply disappeared into the Great Blue Yonder – and all the considerable work I’d done just disappeared. So unlike me to fail to make backups for such a situation! Now my situation is changed and I have little time for that idea. But it has come back as potentially viable if it is limited and defined eg just one article. And it has to be “no admission” to warmistas, since they already hold Wikipedia gagged and trussed.
In fact I’m having a go at putting Cook’s Skeptical Science 119
debatesstrawmen and putdown points into the three-column format that’s needed ie(1) “Skeptic argument” [note inverted commas]
(2) What the “science” says
(3) What skeptics actually say – with hyperlinks from each of the 119 issues to a “crowdsourced” wiki article
and I’d like to see THIS done in wiki form, to be added to the iPhone “Our Climate” app. But I can only kick-start this idea, I don’t have the wiki platform, time, or knowledge to do the answers up to speed. But as Anthony says, we have the opportunity here to “crowdsource” the article(s) needed. And I know someone who just may have a wiki platform.
If somebody sees this post and thinks “great, I’ll do that right away”, fine. If not, I’ll be working away at this steadily until it’s up to WUWT article standard.
I wondered what had happened to your wiki project, Lucy! I posted the famous Washington Post 1922 “Arctic Warms, Seals Vanish” article there.
See it also here http://thesequal.proboards.com/index.cgi?board=climate&action=display&thread=31
Rice yields Indochina. Data up to 2008.
http://i599.photobucket.com/albums/tt74/MartinGAtkins/Rice-Yield-IndoChi.jpg
Randy Westcott says:
August 10, 2010 at 5:03 pm
Randy, I was just going on the state’s claim. Which goes to show never trust a government claim. (No I do not live there either, but it is a nice place to visit).