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| Bolaleman... |
 Posted: Sat Oct 17, 2009 10:48 am |
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Guest
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Climate change could devastate US crop yields: Study from September 1,
2009
Climate change could result in severe shortages of two of America’s
most important grains, according to the authors of a new study
published online in the Proceedings of the National Academy of
Sciences (PNAS).
The research was conducted by two economists, Dr Michael Roberts of
North Carolina State University and Dr Wolfram Schlenker at Columbia
University, who used a well-known climate change prediction model to
assess how much yields could decline by the end of the century. They
found that corn, soy and cotton yields could fall by 30 to 46 percent
in this time under the slowest warming scenarios – if greenhouse gas
emissions are cut to 50 percent of 1991 levels by 2050 – and by 63 to
82 percent if emissions continue at current levels.
They wrote that although yields increase with temperature up to 29C
for corn and 30C for soybeans, there is a sharp decline in yield above
these thresholds.
Roberts said: "While crop yields depend on a variety of factors,
extreme heat is the best predictor of yields. There hasn't been much
research on what happens to crop yields over certain temperature
thresholds, but this study shows that temperature extremes are not
good."
Soaring food prices
And decreasing yields mean that prices of staple grains are likely to
skyrocket, bringing serious consequences for consumers as well as food
manufacturers, many of which are still reeling from last year’s record-
high input prices.
The study comes on the heels of a report released last week by the
Economic Research Service of the US Department of Agriculture, warning
Americans that food prices are once more on the rise. Overall it said
that grocery prices are likely to rise by two to three percent this
year, although that compares to a huge 6.4 percent jump in 2008, the
largest increase for nearly two decades.
This latest study adds to a bleak picture, considering that experts
estimate that global food supplies need to increase by at least 70
percent by 2050 in order to feed the world’s booming – and
increasingly urbanized – population.
Dramatic change
On his blog, Roberts wrote: “To my mind, what this study makes very
clear is that the worldwide face of agriculture is going to change
dramatically. Even in the best-case scenario, in which losses in areas
like the US are made up with gains elsewhere, we will see different
crops cultivated all around the world.”
He sees three ‘caveats’ which could ease the problem: The so-called
‘greening theory’ in which more CO2 could offset some negative
effects, which he mentions is still a topic of intense debate; the
development of heat tolerant crops by companies like Monsanto,
although he says that there is “little evidence of adaptation in the
past”, and by farmers shifting where they grow different kinds of
crops.
“But with projected damages this large for the world's biggest bread
basket, no clear evidence of adaptation to warmer temperatures in the
historical data, and with projections already rather dismal for much
of tropics and subtropics, at present I don't know why we should be
particularly optimistic,” he wrote.
Although the study focused on US crop yields alone, the authors said
that their findings have global implications due to the quantity of
grains exported from the US, which produces 41 percent of the world’s
corn and 38 percent of its soybeans.
Roberts said: "Effects of climate change on US crop production will
surely be felt around the globe, especially in developing countries.”
Source: Proceedings of the National Academy of Sciences,
http://www.bakeryandsnacks.com/On-your-radar/Wheat-and-grain-supply/Climate-change-could-devastate-US-crop-yields-Study
“Nonlinear temperature effects indicate severe damages to U.S. crop
yields under climate change”
Authors: M. Roberts and W. Schlenker
-------------------------
Bolaleman
Renewable Energy Jobs: http://2ajobguide.com/wind_jobs_solar_renewable_energy_jobs.aspx |
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| Frank... |
| Posted: Sat Oct 17, 2009 11:27 am |
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On Oct 17, 4:48 pm, Bolaleman <oswald_epp... at (no spam) hotmail.com> wrote:
[quote:63e0212a8c]Climate change could devastate US crop yields: Study from September 1,
2009
Climate change could result in severe shortages of two of America’s
most important grains, according to the authors of a new study
published online in the Proceedings of the National Academy of
Sciences (PNAS).
The research was conducted by two economists, Dr Michael Roberts of
North Carolina State University and Dr Wolfram Schlenker at Columbia
University, who used a well-known climate change prediction model to
assess how much yields could decline by the end of the century. They
found that corn, soy and cotton yields could fall by 30 to 46 percent
in this time under the slowest warming scenarios – if greenhouse gas
emissions are cut to 50 percent of 1991 levels by 2050 – and by 63 to
82 percent if emissions continue at current levels.
They wrote that although yields increase with temperature up to 29C
for corn and 30C for soybeans, there is a sharp decline in yield above
these thresholds.
Roberts said: "While crop yields depend on a variety of factors,
extreme heat is the best predictor of yields. There hasn't been much
research on what happens to crop yields over certain temperature
thresholds, but this study shows that temperature extremes are not
good."
Soaring food prices
And decreasing yields mean that prices of staple grains are likely to
skyrocket, bringing serious consequences for consumers as well as food
manufacturers, many of which are still reeling from last year’s record-
high input prices.
The study comes on the heels of a report released last week by the
Economic Research Service of the US Department of Agriculture, warning
Americans that food prices are once more on the rise. Overall it said
that grocery prices are likely to rise by two to three percent this
year, although that compares to a huge 6.4 percent jump in 2008, the
largest increase for nearly two decades.
This latest study adds to a bleak picture, considering that experts
estimate that global food supplies need to increase by at least 70
percent by 2050 in order to feed the world’s booming – and
increasingly urbanized – population.
Dramatic change
On his blog, Roberts wrote: “To my mind, what this study makes very
clear is that the worldwide face of agriculture is going to change
dramatically. Even in the best-case scenario, in which losses in areas
like the US are made up with gains elsewhere, we will see different
crops cultivated all around the world.”
He sees three ‘caveats’ which could ease the problem: The so-called
‘greening theory’ in which more CO2 could offset some negative
effects, which he mentions is still a topic of intense debate; the
development of heat tolerant crops by companies like Monsanto,
although he says that there is “little evidence of adaptation in the
past”, and by farmers shifting where they grow different kinds of
crops.
“But with projected damages this large for the world's biggest bread
basket, no clear evidence of adaptation to warmer temperatures in the
historical data, and with projections already rather dismal for much
of tropics and subtropics, at present I don't know why we should be
particularly optimistic,” he wrote.
Although the study focused on US crop yields alone, the authors said
that their findings have global implications due to the quantity of
grains exported from the US, which produces 41 percent of the world’s
corn and 38 percent of its soybeans.
Roberts said: "Effects of climate change on US crop production will
surely be felt around the globe, especially in developing countries.”
Source: Proceedings of the National Academy of Sciences,http://www.bakeryandsnacks.com/On-your-radar/Wheat-and-grain-supply/C...
“Nonlinear temperature effects indicate severe damages to U.S. crop
yields under climate change”
Authors: M. Roberts and W. Schlenker
-------------------------
Bolaleman
Renewable Energy Jobs:http://2ajobguide.com/wind_jobs_solar_renewable_energy_jobs.aspx
[/quote:63e0212a8c]
Offhand, I would think the trouble with this analysis is that it does
not consider effect on crops further north.
For example, here, you can double crop in a year, maybe following up
corn or soybeans with winter wheat.
in northern parts of US you may only get a single crop in every 2
years but if warmer, maybe a crop every year or even double crop. |
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| Thiophilus... |
| Posted: Sat Oct 17, 2009 6:10 pm |
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Guest
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On Sat, 17 Oct 2009 14:27:07 -0700 (PDT), Frank
<frank.logullo at (no spam) dol.net> wrote:
[quote:f53da2e679]On Oct 17, 4:48 pm, Bolaleman <oswald_epp... at (no spam) hotmail.com> wrote:
Climate change could devastate US crop yields: Study from September 1,
2009
Climate change could result in severe shortages of two of America’s
most important grains, according to the authors of a new study
published online in the Proceedings of the National Academy of
Sciences (PNAS).
The research was conducted by two economists, Dr Michael Roberts of
North Carolina State University and Dr Wolfram Schlenker at Columbia
University, who used a well-known climate change prediction model to
assess how much yields could decline by the end of the century. They
found that corn, soy and cotton yields could fall by 30 to 46 percent
in this time under the slowest warming scenarios – if greenhouse gas
emissions are cut to 50 percent of 1991 levels by 2050 – and by 63 to
82 percent if emissions continue at current levels.
They wrote that although yields increase with temperature up to 29C
for corn and 30C for soybeans, there is a sharp decline in yield above
these thresholds.
Roberts said: "While crop yields depend on a variety of factors,
extreme heat is the best predictor of yields. There hasn't been much
research on what happens to crop yields over certain temperature
thresholds, but this study shows that temperature extremes are not
good."
Soaring food prices
And decreasing yields mean that prices of staple grains are likely to
skyrocket, bringing serious consequences for consumers as well as food
manufacturers, many of which are still reeling from last year’s record-
high input prices.
The study comes on the heels of a report released last week by the
Economic Research Service of the US Department of Agriculture, warning
Americans that food prices are once more on the rise. Overall it said
that grocery prices are likely to rise by two to three percent this
year, although that compares to a huge 6.4 percent jump in 2008, the
largest increase for nearly two decades.
This latest study adds to a bleak picture, considering that experts
estimate that global food supplies need to increase by at least 70
percent by 2050 in order to feed the world’s booming – and
increasingly urbanized – population.
Dramatic change
On his blog, Roberts wrote: “To my mind, what this study makes very
clear is that the worldwide face of agriculture is going to change
dramatically. Even in the best-case scenario, in which losses in areas
like the US are made up with gains elsewhere, we will see different
crops cultivated all around the world.”
He sees three ‘caveats’ which could ease the problem: The so-called
‘greening theory’ in which more CO2 could offset some negative
effects, which he mentions is still a topic of intense debate; the
development of heat tolerant crops by companies like Monsanto,
although he says that there is “little evidence of adaptation in the
past”, and by farmers shifting where they grow different kinds of
crops.
“But with projected damages this large for the world's biggest bread
basket, no clear evidence of adaptation to warmer temperatures in the
historical data, and with projections already rather dismal for much
of tropics and subtropics, at present I don't know why we should be
particularly optimistic,” he wrote.
Although the study focused on US crop yields alone, the authors said
that their findings have global implications due to the quantity of
grains exported from the US, which produces 41 percent of the world’s
corn and 38 percent of its soybeans.
Roberts said: "Effects of climate change on US crop production will
surely be felt around the globe, especially in developing countries.”
Source: Proceedings of the National Academy of Sciences,http://www.bakeryandsnacks.com/On-your-radar/Wheat-and-grain-supply/C...
“Nonlinear temperature effects indicate severe damages to U.S. crop
yields under climate change”
Authors: M. Roberts and W. Schlenker
-------------------------
Bolaleman
Renewable Energy Jobs:http://2ajobguide.com/wind_jobs_solar_renewable_energy_jobs.aspx
Offhand, I would think the trouble with this analysis is that it does
not consider effect on crops further north.
For example, here, you can double crop in a year, maybe following up
corn or soybeans with winter wheat.
in northern parts of US you may only get a single crop in every 2
years but if warmer, maybe a crop every year or even double crop.
[/quote:f53da2e679]
Up here in Canada, and in Siberia too, there is a hell of a lot of
land that will only benefit from warming. |
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| RAB... |
| Posted: Mon Oct 19, 2009 8:16 am |
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Guest
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Thiophilus wrote:
[quote]On Sat, 17 Oct 2009 14:27:07 -0700 (PDT), Frank
frank.logullo at (no spam) dol.net> wrote:
On Oct 17, 4:48 pm, Bolaleman <oswald_epp... at (no spam) hotmail.com> wrote:
Climate change could devastate US crop yields: Study from September 1,
2009
Climate change could result in severe shortages of two of America’s
most important grains, according to the authors of a new study
published online in the Proceedings of the National Academy of
Sciences (PNAS).
The research was conducted by two economists, Dr Michael Roberts of
North Carolina State University and Dr Wolfram Schlenker at Columbia
University, who used a well-known climate change prediction model to
assess how much yields could decline by the end of the century. They
found that corn, soy and cotton yields could fall by 30 to 46 percent
in this time under the slowest warming scenarios – if greenhouse gas
emissions are cut to 50 percent of 1991 levels by 2050 – and by 63 to
82 percent if emissions continue at current levels.
They wrote that although yields increase with temperature up to 29C
for corn and 30C for soybeans, there is a sharp decline in yield above
these thresholds.
Roberts said: "While crop yields depend on a variety of factors,
extreme heat is the best predictor of yields. There hasn't been much
research on what happens to crop yields over certain temperature
thresholds, but this study shows that temperature extremes are not
good."
Soaring food prices
And decreasing yields mean that prices of staple grains are likely to
skyrocket, bringing serious consequences for consumers as well as food
manufacturers, many of which are still reeling from last year’s record-
high input prices.
The study comes on the heels of a report released last week by the
Economic Research Service of the US Department of Agriculture, warning
Americans that food prices are once more on the rise. Overall it said
that grocery prices are likely to rise by two to three percent this
year, although that compares to a huge 6.4 percent jump in 2008, the
largest increase for nearly two decades.
This latest study adds to a bleak picture, considering that experts
estimate that global food supplies need to increase by at least 70
percent by 2050 in order to feed the world’s booming – and
increasingly urbanized – population.
Dramatic change
On his blog, Roberts wrote: “To my mind, what this study makes very
clear is that the worldwide face of agriculture is going to change
dramatically. Even in the best-case scenario, in which losses in areas
like the US are made up with gains elsewhere, we will see different
crops cultivated all around the world.”
He sees three ‘caveats’ which could ease the problem: The so-called
‘greening theory’ in which more CO2 could offset some negative
effects, which he mentions is still a topic of intense debate; the
development of heat tolerant crops by companies like Monsanto,
although he says that there is “little evidence of adaptation in the
past”, and by farmers shifting where they grow different kinds of
crops.
“But with projected damages this large for the world's biggest bread
basket, no clear evidence of adaptation to warmer temperatures in the
historical data, and with projections already rather dismal for much
of tropics and subtropics, at present I don't know why we should be
particularly optimistic,” he wrote.
Although the study focused on US crop yields alone, the authors said
that their findings have global implications due to the quantity of
grains exported from the US, which produces 41 percent of the world’s
corn and 38 percent of its soybeans.
Roberts said: "Effects of climate change on US crop production will
surely be felt around the globe, especially in developing countries.”
Source: Proceedings of the National Academy of Sciences,http://www.bakeryandsnacks.com/On-your-radar/Wheat-and-grain-supply/C...
“Nonlinear temperature effects indicate severe damages to U.S. crop
yields under climate change”
Authors: M. Roberts and W. Schlenker
-------------------------
Bolaleman
Renewable Energy Jobs:http://2ajobguide.com/wind_jobs_solar_renewable_energy_jobs.aspx
Offhand, I would think the trouble with this analysis is that it does
not consider effect on crops further north.
For example, here, you can double crop in a year, maybe following up
corn or soybeans with winter wheat.
in northern parts of US you may only get a single crop in every 2
years but if warmer, maybe a crop every year or even double crop.
Up here in Canada, and in Siberia too, there is a hell of a lot of
land that will only benefit from warming.
[/quote]
Plant productivity depends on more than just temperature - hours of
daylight, rainfall, soil properties etc. While agriculture might well
transition to more northern latitudes, I don't think there have been
many serious studies of how such a transition would be likely to go.
Much of the talk about benefits of a warmer climate sound like trading
the devil you know for the devil you don't know but hope will be benevolent. |
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| Frank... |
| Posted: Tue Oct 20, 2009 5:05 am |
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Guest
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RAB wrote:
[quote]Thiophilus wrote:
On Sat, 17 Oct 2009 14:27:07 -0700 (PDT), Frank
frank.logullo at (no spam) dol.net> wrote:
On Oct 17, 4:48 pm, Bolaleman <oswald_epp... at (no spam) hotmail.com> wrote:
Climate change could devastate US crop yields: Study from September 1,
2009
Climate change could result in severe shortages of two of America’s
most important grains, according to the authors of a new study
published online in the Proceedings of the National Academy of
Sciences (PNAS).
The research was conducted by two economists, Dr Michael Roberts of
North Carolina State University and Dr Wolfram Schlenker at Columbia
University, who used a well-known climate change prediction model to
assess how much yields could decline by the end of the century. They
found that corn, soy and cotton yields could fall by 30 to 46 percent
in this time under the slowest warming scenarios – if greenhouse gas
emissions are cut to 50 percent of 1991 levels by 2050 – and by 63 to
82 percent if emissions continue at current levels.
They wrote that although yields increase with temperature up to 29C
for corn and 30C for soybeans, there is a sharp decline in yield above
these thresholds.
Roberts said: "While crop yields depend on a variety of factors,
extreme heat is the best predictor of yields. There hasn't been much
research on what happens to crop yields over certain temperature
thresholds, but this study shows that temperature extremes are not
good."
Soaring food prices
And decreasing yields mean that prices of staple grains are likely to
skyrocket, bringing serious consequences for consumers as well as food
manufacturers, many of which are still reeling from last year’s record-
high input prices.
The study comes on the heels of a report released last week by the
Economic Research Service of the US Department of Agriculture, warning
Americans that food prices are once more on the rise. Overall it said
that grocery prices are likely to rise by two to three percent this
year, although that compares to a huge 6.4 percent jump in 2008, the
largest increase for nearly two decades.
This latest study adds to a bleak picture, considering that experts
estimate that global food supplies need to increase by at least 70
percent by 2050 in order to feed the world’s booming – and
increasingly urbanized – population.
Dramatic change
On his blog, Roberts wrote: “To my mind, what this study makes very
clear is that the worldwide face of agriculture is going to change
dramatically. Even in the best-case scenario, in which losses in areas
like the US are made up with gains elsewhere, we will see different
crops cultivated all around the world.”
He sees three ‘caveats’ which could ease the problem: The so-called
‘greening theory’ in which more CO2 could offset some negative
effects, which he mentions is still a topic of intense debate; the
development of heat tolerant crops by companies like Monsanto,
although he says that there is “little evidence of adaptation in the
past”, and by farmers shifting where they grow different kinds of
crops.
“But with projected damages this large for the world's biggest bread
basket, no clear evidence of adaptation to warmer temperatures in the
historical data, and with projections already rather dismal for much
of tropics and subtropics, at present I don't know why we should be
particularly optimistic,” he wrote.
Although the study focused on US crop yields alone, the authors said
that their findings have global implications due to the quantity of
grains exported from the US, which produces 41 percent of the world’s
corn and 38 percent of its soybeans.
Roberts said: "Effects of climate change on US crop production will
surely be felt around the globe, especially in developing countries.”
Source: Proceedings of the National Academy of
Sciences,http://www.bakeryandsnacks.com/On-your-radar/Wheat-and-grain-supply/C...
“Nonlinear temperature effects indicate severe damages to U.S. crop
yields under climate change”
Authors: M. Roberts and W. Schlenker
-------------------------
Bolaleman
Renewable Energy
Jobs:http://2ajobguide.com/wind_jobs_solar_renewable_energy_jobs.aspx
Offhand, I would think the trouble with this analysis is that it does
not consider effect on crops further north.
For example, here, you can double crop in a year, maybe following up
corn or soybeans with winter wheat.
in northern parts of US you may only get a single crop in every 2
years but if warmer, maybe a crop every year or even double crop.
Up here in Canada, and in Siberia too, there is a hell of a lot of
land that will only benefit from warming.
Plant productivity depends on more than just temperature - hours of
daylight, rainfall, soil properties etc. While agriculture might well
transition to more northern latitudes, I don't think there have been
many serious studies of how such a transition would be likely to go.
Much of the talk about benefits of a warmer climate sound like trading
the devil you know for the devil you don't know but hope will be
benevolent.
[/quote]
I expected some Greenie to object because the northern planting of crops
would deprive the caribou of their lichen  |
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| RAB... |
| Posted: Tue Oct 20, 2009 10:21 am |
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Guest
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Frank wrote:
[quote]RAB wrote:
Thiophilus wrote:
On Sat, 17 Oct 2009 14:27:07 -0700 (PDT), Frank
frank.logullo at (no spam) dol.net> wrote:
On Oct 17, 4:48 pm, Bolaleman <oswald_epp... at (no spam) hotmail.com> wrote:
Climate change could devastate US crop yields: Study from September 1,
2009
Climate change could result in severe shortages of two of America’s
most important grains, according to the authors of a new study
published online in the Proceedings of the National Academy of
Sciences (PNAS).
The research was conducted by two economists, Dr Michael Roberts of
North Carolina State University and Dr Wolfram Schlenker at Columbia
University, who used a well-known climate change prediction model to
assess how much yields could decline by the end of the century. They
found that corn, soy and cotton yields could fall by 30 to 46 percent
in this time under the slowest warming scenarios – if greenhouse gas
emissions are cut to 50 percent of 1991 levels by 2050 – and by 63 to
82 percent if emissions continue at current levels.
They wrote that although yields increase with temperature up to 29C
for corn and 30C for soybeans, there is a sharp decline in yield above
these thresholds.
Roberts said: "While crop yields depend on a variety of factors,
extreme heat is the best predictor of yields. There hasn't been much
research on what happens to crop yields over certain temperature
thresholds, but this study shows that temperature extremes are not
good."
Soaring food prices
And decreasing yields mean that prices of staple grains are likely to
skyrocket, bringing serious consequences for consumers as well as food
manufacturers, many of which are still reeling from last year’s
record-
high input prices.
The study comes on the heels of a report released last week by the
Economic Research Service of the US Department of Agriculture, warning
Americans that food prices are once more on the rise. Overall it said
that grocery prices are likely to rise by two to three percent this
year, although that compares to a huge 6.4 percent jump in 2008, the
largest increase for nearly two decades.
This latest study adds to a bleak picture, considering that experts
estimate that global food supplies need to increase by at least 70
percent by 2050 in order to feed the world’s booming – and
increasingly urbanized – population.
Dramatic change
On his blog, Roberts wrote: “To my mind, what this study makes very
clear is that the worldwide face of agriculture is going to change
dramatically. Even in the best-case scenario, in which losses in areas
like the US are made up with gains elsewhere, we will see different
crops cultivated all around the world.”
He sees three ‘caveats’ which could ease the problem: The so-called
‘greening theory’ in which more CO2 could offset some negative
effects, which he mentions is still a topic of intense debate; the
development of heat tolerant crops by companies like Monsanto,
although he says that there is “little evidence of adaptation in the
past”, and by farmers shifting where they grow different kinds of
crops.
“But with projected damages this large for the world's biggest bread
basket, no clear evidence of adaptation to warmer temperatures in the
historical data, and with projections already rather dismal for much
of tropics and subtropics, at present I don't know why we should be
particularly optimistic,” he wrote.
Although the study focused on US crop yields alone, the authors said
that their findings have global implications due to the quantity of
grains exported from the US, which produces 41 percent of the world’s
corn and 38 percent of its soybeans.
Roberts said: "Effects of climate change on US crop production will
surely be felt around the globe, especially in developing countries.”
Source: Proceedings of the National Academy of
Sciences,http://www.bakeryandsnacks.com/On-your-radar/Wheat-and-grain-supply/C...
“Nonlinear temperature effects indicate severe damages to U.S. crop
yields under climate change”
Authors: M. Roberts and W. Schlenker
-------------------------
Bolaleman
Renewable Energy
Jobs:http://2ajobguide.com/wind_jobs_solar_renewable_energy_jobs.aspx
Offhand, I would think the trouble with this analysis is that it does
not consider effect on crops further north.
For example, here, you can double crop in a year, maybe following up
corn or soybeans with winter wheat.
in northern parts of US you may only get a single crop in every 2
years but if warmer, maybe a crop every year or even double crop.
Up here in Canada, and in Siberia too, there is a hell of a lot of
land that will only benefit from warming.
Plant productivity depends on more than just temperature - hours of
daylight, rainfall, soil properties etc. While agriculture might well
transition to more northern latitudes, I don't think there have been
many serious studies of how such a transition would be likely to go.
Much of the talk about benefits of a warmer climate sound like trading
the devil you know for the devil you don't know but hope will be
benevolent.
I expected some Greenie to object because the northern planting of crops
would deprive the caribou of their lichen
[/quote]
But then there would not be any lichen for the carbou in any case - if
there were caribou. But that was not an objection; it was just pointing
out that the wishful thinking of those who dismiss the problems out of
hand may not work out as simply as they imagine. It seems that while
Greenies may have knee-jerk reactions, so does the other side (Brownies?). |
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| Frank... |
| Posted: Wed Oct 21, 2009 5:28 am |
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Guest
|
RAB wrote:
[quote]Frank wrote:
RAB wrote:
Thiophilus wrote:
On Sat, 17 Oct 2009 14:27:07 -0700 (PDT), Frank
frank.logullo at (no spam) dol.net> wrote:
On Oct 17, 4:48 pm, Bolaleman <oswald_epp... at (no spam) hotmail.com> wrote:
Climate change could devastate US crop yields: Study from
September 1,
2009
Climate change could result in severe shortages of two of America’s
most important grains, according to the authors of a new study
published online in the Proceedings of the National Academy of
Sciences (PNAS).
The research was conducted by two economists, Dr Michael Roberts of
North Carolina State University and Dr Wolfram Schlenker at Columbia
University, who used a well-known climate change prediction model to
assess how much yields could decline by the end of the century. They
found that corn, soy and cotton yields could fall by 30 to 46 percent
in this time under the slowest warming scenarios – if greenhouse gas
emissions are cut to 50 percent of 1991 levels by 2050 – and by 63 to
82 percent if emissions continue at current levels.
They wrote that although yields increase with temperature up to 29C
for corn and 30C for soybeans, there is a sharp decline in yield
above
these thresholds.
Roberts said: "While crop yields depend on a variety of factors,
extreme heat is the best predictor of yields. There hasn't been much
research on what happens to crop yields over certain temperature
thresholds, but this study shows that temperature extremes are not
good."
Soaring food prices
And decreasing yields mean that prices of staple grains are likely to
skyrocket, bringing serious consequences for consumers as well as
food
manufacturers, many of which are still reeling from last year’s
record-
high input prices.
The study comes on the heels of a report released last week by the
Economic Research Service of the US Department of Agriculture,
warning
Americans that food prices are once more on the rise. Overall it said
that grocery prices are likely to rise by two to three percent this
year, although that compares to a huge 6.4 percent jump in 2008, the
largest increase for nearly two decades.
This latest study adds to a bleak picture, considering that experts
estimate that global food supplies need to increase by at least 70
percent by 2050 in order to feed the world’s booming – and
increasingly urbanized – population.
Dramatic change
On his blog, Roberts wrote: “To my mind, what this study makes very
clear is that the worldwide face of agriculture is going to change
dramatically. Even in the best-case scenario, in which losses in
areas
like the US are made up with gains elsewhere, we will see different
crops cultivated all around the world.”
He sees three ‘caveats’ which could ease the problem: The so-called
‘greening theory’ in which more CO2 could offset some negative
effects, which he mentions is still a topic of intense debate; the
development of heat tolerant crops by companies like Monsanto,
although he says that there is “little evidence of adaptation in the
past”, and by farmers shifting where they grow different kinds of
crops.
“But with projected damages this large for the world's biggest bread
basket, no clear evidence of adaptation to warmer temperatures in the
historical data, and with projections already rather dismal for much
of tropics and subtropics, at present I don't know why we should be
particularly optimistic,” he wrote.
Although the study focused on US crop yields alone, the authors said
that their findings have global implications due to the quantity of
grains exported from the US, which produces 41 percent of the world’s
corn and 38 percent of its soybeans.
Roberts said: "Effects of climate change on US crop production will
surely be felt around the globe, especially in developing countries.”
Source: Proceedings of the National Academy of
Sciences,http://www.bakeryandsnacks.com/On-your-radar/Wheat-and-grain-supply/C...
“Nonlinear temperature effects indicate severe damages to U.S. crop
yields under climate change”
Authors: M. Roberts and W. Schlenker
-------------------------
Bolaleman
Renewable Energy
Jobs:http://2ajobguide.com/wind_jobs_solar_renewable_energy_jobs.aspx
Offhand, I would think the trouble with this analysis is that it does
not consider effect on crops further north.
For example, here, you can double crop in a year, maybe following up
corn or soybeans with winter wheat.
in northern parts of US you may only get a single crop in every 2
years but if warmer, maybe a crop every year or even double crop.
Up here in Canada, and in Siberia too, there is a hell of a lot of
land that will only benefit from warming.
Plant productivity depends on more than just temperature - hours of
daylight, rainfall, soil properties etc. While agriculture might well
transition to more northern latitudes, I don't think there have been
many serious studies of how such a transition would be likely to go.
Much of the talk about benefits of a warmer climate sound like
trading the devil you know for the devil you don't know but hope will
be benevolent.
I expected some Greenie to object because the northern planting of
crops would deprive the caribou of their lichen ;)
But then there would not be any lichen for the carbou in any case - if
there were caribou. But that was not an objection; it was just pointing
out that the wishful thinking of those who dismiss the problems out of
hand may not work out as simply as they imagine. It seems that while
Greenies may have knee-jerk reactions, so does the other side (Brownies?).
[/quote]
I know. Just being facetious but I am remembering many years ago,
nuclear was defeated here by arguments such as excess heat dumped in the
water would kill fish. Now the greenies are constantly complaining
about the pollutants from the coal that the nuclear would have replaced. |
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