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
silly you … the percentage of annual increase has slowed … don’t get confused by raw yield numbers …
remember like any government budget, getting a 5% increase instead of last years 7% increase is a decrease or cut … depending on how well you cook the books it could be called a 29% decrease … think of the CHILDREN …
Rice paddies are the largest source of CH4 methane on the planet.
This rice issue is big. They use a lot of water.
When a field is flooded, it gets treated like a wetland and a new set of rules.
Note: “cut the yield growth rate by 10-20 percent”
I.e. they claim they’ve detected a second order effect, the first order still shows yield is increasing.
So how can they attribute a 2nd-order effect on minimum temperatures? Did they, perhaps, um, guess?
Another note: “the report analyzed six years of data”
and from this, they deduced that growth rates had been reducing for 25 years?
They’re dead clever, these guys!
Jeff beat me to it….
Key phrase from the Alert:
“The research team found evidence that the net impact of projected temperature increases will be to [b]slow the growth[/b] 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.”
If memory serves me, rice production struggled these last 5 years do to unseasonably COLD weather in these particular growing areas. The researchers appear to completely ignore weather related crop damage and instead simply say that it must be the global temperature rise whut dun it. As to PROJECTED temperature increases, I get to ignore that part of the research.
First thing to do is a Willis smell-check of the data presented in the press release. Does it make sense? Is it reliable?
Next, evaluate the assumptions. Are they reasonable or a stretch or just unknowable?
Third, follow the logic of argument.
Well, with regards to the rising crops, one confounding factor would be the increased use of modern farming practices – those would have an effect far beyond a 0.5 degree C change.
From the article:
“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.
Translation: Our data doesn’t match reality so, ignore the reality.
You have to factor in irrigation enhancements, fertilization and mechanization. If your output is increasing because you’re better at farming, then you yield goes up.
Examples:
– you provide better irrigation & fertilization: it grows faster, you can to higher-density farming. (every 10cm instead of 15, because the nutrients are there)
– you use machines to reap & sow, meaning the idle time of the fields drops.
Let me begin with a question. The student is economics to begin with and not a plant science person. Why? Macro economics is NOT how we study crop performance evah!!!
Since he is in economics, he doesn’t even mention other variables. Agriculture is like climate and we use multi variate stats and not ever presume we are dealing with only one variable and all the others are constants.
I could have the same study and results and claim that it was because they were buying more John Deere farm equipment in the last 6 years.
This sounds like Paul Ehrlich still yelling about how we’re all gonna starve by 1970.
From the study’s abstract:
” Higher minimum temperature reduced yield, whereas higher maximum temperature raised it; radiation impact varied by growth phase. Combined, these effects imply that yield at most sites would have grown more rapidly during the high-yielding season but less rapidly during the low-yielding season if observed temperature and radiation trends at the end of the 20th century had not occurred, with temperature trends being more influential.”
And from the linked summary:
“…cut the yield growth rate by 10-20 percent”
So, it would appear the press release:
1. Ignored potential benefits of warmer temperatures
2. Is confusing yield growth with yield growth rate
and,
At one point people were growing grapes in northern Europe and England.
Farmers are changing from wheat to corn, corn is more profitable.
Rice farmers are growing a better rice with a higher yield.
Rice farmers also practice crop rotation.
What’s the problem? All over a 1/2 degree increase in temperatures.
Are they referring to yield as the amount of crop planted, or the amount harvested?
And now for some sanity. World crop production report of gains and losses based on…wait for it…weather conditions.
http://www.usda.gov/oce/weather/pubs/Annual/CropProduction.pdf
I saw this article also and had the identical reaction. The claim that there was proof was particularly startling. Of course the evidence turned out to be suspect. Sure they used “real” rice fields. ie farms. But there was no direct collation of temperatures. When one pulls away from actual farm yields, which are actually pretty good and markedly increasing in China, there is no evident problem. Likewise when one looks at the rice belt, there is a considerable variation in temperatures with no impact on yield. For example, the difference in growing climate in Japan versus the Philippines is considerable, but both have extremely high yields of the medium grain rice they prefer.
A far bigger problem is water. That has significantly impacted yields in California, India, and Australia.
If this was true, solution is much cheaper than demonising CO2 and rationing society. The solution is GM, which creates a universe of opportunity.
Higher overnight low temperatures sound like urbanization to me.
Maybe when roads are built nearby, rice yield decreases because the people who used to work the fields can now take the bus to a job that pays better.
Rice farming is very labor intensive.
Maybe the hotter night temperatures make the laborers less willing to work hard during the day, decreasing the yield.
Maybe the study failed to account for seasonality – and the midsummer crop always has a lower yield than the early and late summer crops.
Maybe it is simple correlation. Asia is an economic boom, drawing the most fit workers away from the farms and into the city. During this time, evening temperatures and crop yields also fell.
But stupid is as stupid does. This idiot thinks climate change will affect crop production. Sorry. Gong the bell and get off the stage. Within growing season weather pattern variation trumps global average climate wriggles all to hell and back. But I give you the article as a comparison to the above post from the usda just for giggles.
http://www.unnayan.org/reports/Climate_Change_Impacts_on_Rice_Production_in_Bangladesh_Report.pdf
As the current extreme cooling (in the Southern hemisphere, where the bulk of the oceans lie) spreads over larger areas, and becomes worldwide for the next two decades or more, the graph will likely dip down, and over all, crop failures be the challenge.
But hopefully the increasing CO2 will help the rice stomata to close and counter the severe droughts to come-more prevlent during gloobal cooling than warming.
This from CO2 Science:
http://www.co2science.org/subject/n/nitrogenrice.php
Summary
Atmospheric CO2 Enrichment: Boosting Rice Yields of Asia
Elevated CO2 and Soil Nitrogen Enhance Radiation Use Efficiency in Rice
How Elevated CO2 Influences Grain Production in Rice at Different Levels of Soil Nitrogen Availability
Effects of Elevated CO2 and Nitrogen Supply on Rice
Anthropogenic CO2 is of course a GIGO hypothesis. But cereal-crop yields since about 1975 have been subject to the seminal Green Revolution fostered by Norman Borlaug (1914 – 2009), named a Peace Prize laureate in 1970.
To the intense chagrin of death-eating Luddite sociopaths such as Paul Ehrlich, John Holdren, James Hansen of GISS/NASA fame, Borlaug’s genetically modified (“GM”) seeds have prevented any naturally-caused (vs. politicized) mass famine over the last quarter century.
To the extent scientific intervention spares hundreds of millions from disease and death, Norman Borlaug’s name will live forever. As for climate cultists’ Green Gang of pseudo-science propagandists, their mendacious sabotage of global energy economies already bears comparison with Inquisitorial persecution of Copernicus’ adherents and of Galileo.
Isn’t rice production a large methane source? 🙂
Perhaps the operating quote is “cut the yield growth RATE” ?
So he calculates a growth RATE, based on data older than 25 years (might I guess that the highest yield growth RATE in Asia was prior to the mid 1980’s?), then any change that growth RATE can can be investigated.
Improved farming techniques, new rice hybrids and technological advances significantly improve yield growth RATES, but once in place, that growth RATE is not likely to remain as high at the locations where such techniques have been applied. But since you can measure temperature, you can also secure funding and write a paper to explain the “decline” in the yield growth RATE based on AGW. Brilliant.
So what did he find? That the growth RATE is lower by some “10-20 percent in several locations”. Growing, but a lower growth RATE. “Several locations” means it was not lower in ALL locations. I suspect that improvements in rice farming technology in these varied “locations” had something to do with the result.