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Related: About this forumHow will crops fare under climate change? Depends on how you ask (Global Change Biology)
http://blogs.princeton.edu/research/2013/08/14/how-will-crops-fare-under-climate-change-depends-on-how-you-ask-global-change-biology/[font face=Serif][font size=5]How will crops fare under climate change? Depends on how you ask (Global Change Biology)[/font]
By Morgan Kelly, Office of Communications
[font size=3]The damage scientists expect climate change to do to crop yields can differ greatly depending on which type of model was used to make those projections, according to research based at Princeton University. The problem is that the most dire scenarios can loom large in the minds of the public and policymakers, yet neither audience is usually aware of how the model itself influenced the outcome, the researchers said.
The report in the journal Global Change Biology is one of the first to compare the agricultural projections generated by empirical models which rely largely on field observations to those by mechanistic models, which draw on an understanding of how crop growth and development are affected by the environment. Building on similar studies from ecology, the researchers found yet more evidence that empirical models may show greater losses as a result of climate change, while mechanistic models may be overly optimistic.
The researchers ran an empirical and a mechanistic model to see how maize and wheat crops in South Africa the worlds ninth largest maize producer, and sub-Saharan Africas second largest source of wheat would fare under climate change in the years 2046 to 2065. Under the hotter, wetter conditions projected by the climate scenarios they used, the empirical model estimated that maize production could drop by 3.6 percent, while wheat output could increase by 6.2 percent. Meanwhile, the mechanistic model calculated that maize and wheat yields might go up by 6.5 and 15.2 percent, respectively.
In addition, the empirical model estimated that suitable land for growing wheat would drop by 10 percent, while the mechanistic model found that it would expand by 9 percent. The empirical model projected a 48 percent expansion in wheat-growing areas, but the mechanistic reported only 20 percent growth. In regions where the two models overlapped, the empirical model showed declining yields while the mechanistic model showed increases. These wheat models were less accurate, but still indicative of the vastly different estimates empirical and mechanistic can produce, the researchers wrote.
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http://dx.doi.org/10.1111/gcb.12325By Morgan Kelly, Office of Communications
[font size=3]The damage scientists expect climate change to do to crop yields can differ greatly depending on which type of model was used to make those projections, according to research based at Princeton University. The problem is that the most dire scenarios can loom large in the minds of the public and policymakers, yet neither audience is usually aware of how the model itself influenced the outcome, the researchers said.
The report in the journal Global Change Biology is one of the first to compare the agricultural projections generated by empirical models which rely largely on field observations to those by mechanistic models, which draw on an understanding of how crop growth and development are affected by the environment. Building on similar studies from ecology, the researchers found yet more evidence that empirical models may show greater losses as a result of climate change, while mechanistic models may be overly optimistic.
The researchers ran an empirical and a mechanistic model to see how maize and wheat crops in South Africa the worlds ninth largest maize producer, and sub-Saharan Africas second largest source of wheat would fare under climate change in the years 2046 to 2065. Under the hotter, wetter conditions projected by the climate scenarios they used, the empirical model estimated that maize production could drop by 3.6 percent, while wheat output could increase by 6.2 percent. Meanwhile, the mechanistic model calculated that maize and wheat yields might go up by 6.5 and 15.2 percent, respectively.
In addition, the empirical model estimated that suitable land for growing wheat would drop by 10 percent, while the mechanistic model found that it would expand by 9 percent. The empirical model projected a 48 percent expansion in wheat-growing areas, but the mechanistic reported only 20 percent growth. In regions where the two models overlapped, the empirical model showed declining yields while the mechanistic model showed increases. These wheat models were less accurate, but still indicative of the vastly different estimates empirical and mechanistic can produce, the researchers wrote.
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How will crops fare under climate change? Depends on how you ask (Global Change Biology) (Original Post)
OKIsItJustMe
Aug 2013
OP
appal_jack
(3,813 posts)1. Interesting.
This link and the summary there are worth the read. I plan to try to find the full version next time I am in an academic library.
From what I could read at the link, it seems like the empirical models (i.e.- based upon actual historical/climatological data), while more pessimistic, should also be more realistic. The summary did not really address why mechanistic models confer any advantage in a field such as agriculture. Any one have any insights into this?
k&r,
-app