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
Rice productivity is not sensitive to temperature rice as it is to water. Last year, production plunged 89.13 million tonnes in 2009-10 crop year (July-June) from record 99.18 million tonnes in the previous year due to severe drought. With good rains, India expects an all time bumper rice crop convincingly crossing 100 million tonnes threshold mark.
Rice is a highly water intensive crop. Much of rice production in the country are however rain-fed. So it is more accurate to call rice productivity more monsoon sensitive. Years of drought are also warmer years and the wet years are cooler years. So warmist exploit this super-imposition. So if productivity fell last year to an El Nino induced drought, it bounces back in a La Nina, like this year, when the country receives good rainfall. The expected bumper crop this season makes nonsense of the study claims.
I come from a rice farming family. (have been out of india for 30 some years. before that used to be on the farm most days ). in the years when we had hotter winters, the production will be significantly higher than other winters. in the summer, as long as we had good water supply and good sunlight, we had good crop. IT would not depend on the temperatures much at all.
Anthony also said
“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?”
what you see in the IRI chart, is the effect of increase in level of penetration of good practices, new varieties ( eg. IRnn — IR8, IR35 etc, a series of hybrid strains from IRI ), newer fertilizers ( DAP as opposed to Urea ), mechanization ( increases per squarfoot productive shoots ).
This book on Asian rice production highlights that fact that cold weather is one of the major limiting factors to yield.
http://books.google.com/books?id=LgKJXgAJ0sgC&pg=PA24&lpg=PA24&dq=freezing+temperatures+damage+rice+crops&source=bl&ots=RB2PgiTzOc&sig=VDcX0KcrsrwFev5maCvRMWEzPfk&hl=en&ei=K4BhTOTHKoymsQO40am_CA&sa=X&oi=book_result&ct=result&resnum=3&ved=0CB4Q6AEwAg#v=onepage&q&f=false
Cold weather is such a damaging event to rice yield that seminars are given on how to mitigate its affects.
http://www.ricecrc.org/research/programabstracts.pdf
I have no brief on rice, and have never grown the stuff, so I don’t know how it responds per function of temperature. However, 1988 was one hot year around here and I was farming at that time. We had the best yields in sugar beets and corn in 1988 of any year I recall. Here are several items that come to mind, besides the obvious one about rate of yield growth per Jeff, above, but were not covered in the article.
1) with increased nighttime and daytime temperatures there must be new ground for growing rice that will come available. Places where climate is not suitable or less than ideal now.
2) They analyzed only six years worth of data. Changes in local temperature during this time must be mainly due to typical fluctuations in year to year weather. This makes it hard to sell me on the applicability of this study to future climate.
Reading the original paper would lead to more…but I don’t see the paper yet on the PNAS site.
there have been dozens of papers in the last few years studying the effects of increased CO2 on rice production
here is a good place to start
http://jxb.oxfordjournals.org/cgi/content/full/ern288#BIB11
And another book on cold weather damage on rice, including the fact that Japan has quite a reliable history going back to the 1700’s on crop damage due to cold weather.
http://books.google.com/books?id=L2pIKl25aqkC&pg=PA21&lpg=PA21&dq=freezing+temperatures+damage+rice+crops&source=bl&ots=y5DNbKcY9o&sig=6UbsPW2ggTv9LORStEnqC1eT11k&hl=en&ei=HoJhTK7tCYPQsAO2w6W9CA&sa=X&oi=book_result&ct=result&resnum=10&ved=0CEAQ6AEwCQ#v=onepage&q&f=false
I thought I read somewhere that CO2 causes mole lice.
In some areas, like the Mekong delta, sea level rise may increase the salinity of the water and hence reduce yield.
You would also want to compare yield increases to population increases.
“Gains in land productivity have come primarily from three
sources—the growing use of fertilizer, the spread of irrigation,
and the development of higher-yielding varieties.”
…
“The third source of higher land productivity is higher-yielding
varieties. The initial breakthrough came when Japanese scientists
succeeded in dwarfing both wheat and rice plants in the
late nineteenth century. This decreased the share of photosynthate
going into straw and increased that going into grain, often
doubling yields.”
…
“Most recently, Chinese scientists have developed commercially
viable hybrid rice strains. While they have raised yields,
the gains have been small compared with the earlier gains from
dwarfing the rice plant.”
…
“In the Asian rice economy, the highest yields are in Japan,
China, and South Korea. All three have moved above 4 tons per
hectare, but moving above 5 tons is difficult. Japan reached 4 tons
per hectare in 1967 but has yet to reach 5 tons. In China, rice
yields appear to be plateauing as they approach the Japanese
level. South Korea has leveled off right around 5 tons.”
From Plan B 4.0 –
http://www.earth-policy.org/index.php?/books/pb4
In the graph shown above, you can certainly see this levelling off of yield from China in the last few decades.
Another quote:
“China’s double-cropped rice yields over 8
tons per hectare.”
So there are several different factors responsible for increasing yields, and it’s not hard to see that if the gains from breeding, irrigation, fertiliser and improved agricultural practices are beginning to level off, any decline in productivity from rising temperatures is going to have a more significant impact. Maybe more breeding will help with that too – developing plants which are more resistant to higher temperatures. Let’s hope so.
I should have said that rice production was damaged enough to warrent global concern in the winter of 03/04, so it was a bit more than these past 5 years. Taken all together, in the last decade, dry conditions (lack of monsoons which has nothing to do with CO2 related climate change) and cold weather has harmed rice production. Warmer temps in general are beneficial to multiple harvests in a single year.
Implementing all the features of modern industrial agriculture – improved strains, pesticides, herbicides, and fertilizers – will result in dramatic yield growth rate. After they have been implemented, the yield growth rate will approach zero because the yield is maximized.
The AGW cult strikes again.
Just looking at the graph of rice production by country, you could change the headline to “Socialism will reduce Asian Rice Production”. Vietnam took a 5+ year hit in the 1970s, as the North took over the South. Cambodia took a 25 year hit after Pol Pot.
Given that the measure here is yield per hectare (IOW, efficiency), this is entirely expected.
Somehow, though, I doubt that out Intellectual Superiors in the media will rush to highlight this.
Well, heck, the article on PNAS is behind a pay-wall, but here is something interesting. The biggest contributor to production of U.S. corn crop is not climate, but rather the number of acres planted/harvested. So, my question is what will be the trend in acres planted for rice; any connection with some amount of temperature rise?
Fromt he press release:
“Our study is unique because it uses data collected in farmers’ fields, under real-world conditions,” said Welch. “This is an important addition to what we already know from controlled experiments.”
What is known about the “real=world conditions” of growing rice in the Phillipines?
Consider “The Fertilizer Scam”:
http://tatlongtala.blogspot.com/2006/03/senate-report-on-fertilizer-scam.html
From the above report:
The Senate Committees on Agriculture and Food, and Accountability of Public Officers and Investigations (Blue Ribbon) have concluded that agricultural funds intended for farmers were diverted by Agriculture Undersecretary Jocelyn “Joc-joc” Bolante for the 2004 electoral campaign of President Gloria Arroyo.
Testimonies and corroborative statements of DA officials, 13 farmer groups (see attached list), Commission on Audit officials, Budget Secretary Emilia Boncodin, and alleged “runners” of Bolante concluded that farmers did not get a single “farm input or implement” in 2004. At least two LGU officials testified that their districts did not receive any fertlizer in spite of records showing that deliveries had
been made. Several Congressmen also denied having made requests for fertilizer assistance or receiving fertilizers.
Some facts about rice:
http://vasatwiki.icrisat.org/index.php/Climatic_Requirements_of_Rice_crop
From the above page:
Temperature:
· Need hot and humid climate;
· Best suited for the regions having high humidity, prolonged sunshine;
· Mean temperature around 22oC through out growing period;
· Tolerates day temperature up to 40oC;
· Minimum of 10oC for sprouting;
· Optimum of 22 to 23oC for flowering and 20 to 21oC for grain formation;
· Above 22oC respiration is accelerated and grain filling period is reduced.
If global circulation models are correct, the projected temperature increases are modest in the tropics. Anyone with experience measuring photosynthesis will tell you that, as CO2 concentrations increase, plants use less water at a given temperature and humidity, and that the rate of growth increases, though sometimes with very slightly lower nutrient content in the tissues, because the plant no longer needs nitrogen content to be as high. CO2 really is a fertilizer in terms of plant growth and there is not a photosynthesis researcher in the world who will tell you that CO2 is not an important limiting factor to productivity at the leaf scale. When it comes to carbon sequestration in natural ecosystems, it is hard to say how much this will increase carbon uptake, because cycling rates often increase, but it certainly enhances growth, and this is especially true of most C3 crops. Rice is one of them.
Notice the bump up in yield around 1979 and 1998. Seems to me that warming and increasing CO2 increases production. The alarmist enjoy pointing out the unbridled warming since the 1970s; yet here we see correlated increase in rice production as well.
Do they really think they can have it both ways?
Plant life either adapts or flourishes elsewhere. If the climate becomes warmer, rice cultivation will move to higher latitudes. Note this important qualification in the full length article (that I am sure will be ignored by the media and most blogs):
“Farmers can be expected to adapt to changing conditions, so real-world circumstances, and therefore outcomes, might differ from those in controlled experimental settings,” he added.
One final comment and I’ll shut up. The graphs of productivity are quite astounding, especially China going from 20t/ha to 70t/ha. The short term decline for Cambodia is interesting. I see mainly the influence of politics in this data. So, my next question would be: will the political environment be amenable to increasing food (and energy) production or not?
You’re being tricked by “Semantics,” again, just like you were on using “Median” Density when discussing Phytoplancton.
This article is discussing growth “Rates.”
“Rate” of growth.
Yields are still rising, just not as fast. Several things could be at work, here. Not being a rice farmer I wouldn’t want to speculate as to exactly which ones are the most important.
Perhaps they just plotted the average lattitude of each country vs. the rice yeild and found that the more northern country had higher yeilds than countries in more southern lattitudes. It would be a noisy graph but you could make an argument for that trend. (Of course this ignores rainfall, the intensity of the use of fertilizers, pesticides, mechanization and other such things.) But hey with the right statistical tools, anything is possible.
Obviously if temperature affects rice, other things affect rice MORE. Like, for instance, technology . . .
Rice production in the U.S. occurs in three regions: north-central California, the Texas/Louisiana Gulf coast and the Mississippi River valley.
http://www.nass.usda.gov/Charts_and_Maps/Crops_County/pdf/AR-YI08-RGBChor.pdf
In the U.S., yields have increased from roughly 4550 pounds per acre in 1979 to about 7157 pounds per acre today. This is an increase of about 57% in 31 years.
http://www.nass.usda.gov/Charts_and_Maps/Field_Crops/riceyld.asp
Here is the latest WASDE Report:
http://www.usda.gov/oce/commodity/wasde/latest.txt
First off I thought we just had a post on which warmists claimed
“How corn may be helping Michigan keep its cool”
http://wattsupwiththat.com/2010/08/09/corn-as-a-local-climate-forcing/
Now onto rice:
It would be hard to deconvolve the root causes of the rice prodcutivity increase; fertilization, mechanization, perhaps higher CO2 may all contribute. But that it is the point. Studies such as this are always bogus — always — because they assume that everything else is held constant. So for example, in the 70s, we were told to get ready for mass starvation on the Indian subcontinent as wheat productivity could not possibly keep up with exploding population. Enter hybird wheat strains, courtesy of Norman Baulaug, and a few years later India is exporting wheat.
The scare mongers are scarcity thinkers paid to get the “right” answer by their funding agencies. They deserve to be ignored, and they are.