Farmers warned to get ready as climate change threatens crops

The researchers, Michael Roberts (NCSU) and Wolfram Schlenker (Columbia U.), used massive amounts of data on crop yields and weather from 1950 to 2005 to look at yields from nearly every U.S. county. They focused on swings in temperature on individual days. They found the average U.S. yields for corn, soybeans, and cotton could plummet 30 percent to 46 percent by the end of the century under the slowest warming scenario, and 63 percent to 82 percent under the quickest.

While crop yields depend on a variety of factors, extreme heat is the best predictor of yields," Roberts said. "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."

Scientists are starting to look more closely at temperature spikes and dips because they can have outsized impact, said David Walter Wolfe, a Cornell University expert on the effects of climate change on crops who was not involved in the study.

A simple example, Wolfe said, is freezing. A study using the average of lows for several days might not even show below-freezing temperatures, and yet farmers may have suffered a catastrophe. At the other end of the temperature scale, one day of mid-90s temperatures can kill all the flowers on a crop of pepper plants.*

* A similar situation is with tomato plants.

What the study fails to recognise, is that crops in other areas could double.
Not that I expect a rational approach to climate change or its effect.

Wolfe (Cornell U.)frequently speaks to farmers and said his message is always the same: They are the first generation of growers who can't count on historical climate information to help them plan things such as when to plant and what varieties to choose.

"They're no longer farming in a static environment," he said. "They can't rely on the calendar to tell them when to plant, they can't rely on the variety of seeds they have always used, and they can't rely on dealing with the same insect pests, because it's all a moving target now."

P.S. Climate change is harmful to Farmer's Almanac as I said before on another thread.

Any one who disagrees with this science study is invited to post their science study. This is the abstract of the publication cited above:

The United States produces 41% of the world's corn and 38% of the world's soybeans. These crops comprise two of the four largest sources of caloric energy produced and are thus critical for world food supply. We pair a panel of county-level yields for these two crops, plus cotton (a warmer-weather crop), with a new fine-scale weather dataset that incorporates the whole distribution of temperatures within each day and across all days in the growing season. We find that yields increase with temperature up to 29° C for corn, 30° C for soybeans, and 32° C for cotton but that temperatures above these thresholds are very harmful. The slope of the decline above the optimum is significantly steeper than the incline below it. The same nonlinear and asymmetric relationship is found when we isolate either time-series or cross-sectional variations in temperatures and yields. This suggests limited historical adaptation of seed varieties or management practices to warmer temperatures because the cross-section includes farmers' adaptations to warmer climates and the time-series does not. Holding current growing regions fixed, area-weighted average yields are predicted to decrease by 30–46% before the end of the century under the slowest (B1) warming scenario and decrease by 63–82% under the most rapid warming scenario (A1FI) under the Hadley III model.

Given: "The United States produces 41% of the world's corn and 38% of the world's soybeans. These crops comprise two of the four largest sources of caloric energy produced and are thus critical for world food supply."

Only an irrational poster would contradict the topic study by merely saying in #2, "What the study fails to recognise, is that crops in other areas could double. Not that I expect a rational approach to climate change or its effect."

Earthling wrote:

What the study fails to recognise, is that crops in other areas could double.

Or manna could fall fromthe skies. Or H1N1 could make food suply a non-issue. Or any other fantasy you want to pull out of your..

Earthling wrote:

Not that I expect a rational approach to climate change or its effect.

A rational approach would be to read the article and assess its impact. Note that tropical yields are expected to fall as well.

Current equatorial zone temperatures are pretty close to optimal for yield in the heavily populated tropics.

Either colder OR warmer is going to drop yield and that is where the bulk of the food is grown and consumed.

The temperate zone farms were at least hoped to compensate a bit but this study shows that it is less likely to happen that way.

A rational approach to reading this article would be to realize that there is no effort spent on studying BOTH the positive and negative impacts of warmer weather on food crops. Which means that there was a pre-judgment that warming is bad or that there was a desired conclusion at the start of the study. Or maybe another explanation...

From the horse's mouth, the good, the bad and the ugly:

The overall impact of these effects will vary by elevation, soil type, crop and other local factors. This variability, along with the
uncertainties of very long-term climate forecasting, especially at the regional level, makes discussion of the effects of climate
change on crop production tentative at best. Generalizations can usually only indicate ranges of possible scenarios. Overall, there may be benefits for agriculture in many temperate zones, where the length of the growing period will increase, costs of overwintering livestock will fall, crop yields may improve and forests may grow faster.

http://www.unep.org/geo/yearbook/yb2006/063.a...

Actually what this means is a longer growing season with more yield per acre. Crops like corn, wheat, soybeans can be planted earlier and later with other crops like cotton or truck crops in between. Or the fields could lie fallow for a while during the season.

Farming has been less about planting according to a calander and more about planting according to conditions. All the relatives I grew up with start preping the fields as soon as they are dry enought to start supporting the equiptment. Thier wives start the seedlings for a truck garden in small green houses so that by the time the garden soil has been prepped and ready for planting they can have those seedlings in the soil and the root veggies in at the same time.

What this all means is the farmers will adapt and may even be able to grow crops tehy were not able to before.

dont drink the koolaid wrote:

A rational approach to reading this article would be to realize that there is no effort spent on studying BOTH the positive and negative impacts of warmer weather on food crops.

Data rules. You can't find positives if you don't find positives. Grow up and stop drinking that right wing koolaid.

dont drink the koolaid wrote:

Which means that there was a pre-judgment that warming is bad or that there was a desired conclusion at the start of the study. Or maybe another explanation...

Like the data rules?

LessHypeMoreFact wrote:

<quoted text>
Data rules. You can't find positives if you don't find positives. Grow up and stop drinking that right wing koolaid.
<quoted text>
Like the data rules?

Why don't you stop drinking left wing koolaid.

Also using only half the data is called spin. Make sure you look at all the data.

tina anne wrote:

<quoted text>
Why don't you stop drinking left wing koolaid.

I'm a centrist. I get to bitch at both sides..

tina anne wrote:

<quoted text>
Also using only half the data is called spin.

Id call that junk science. Spin is where you misrepresent the data. Like you do.

tina anne wrote:

<quoted text>
Make sure you look at all the data.

And you have not shown any missing data yet. So I am not sure what you are on about. Probably just spewing to make yourself look 'busy'.

LessHypeMoreFact wrote:

Data rules. You can't find positives if you don't find positives. Grow up and stop drinking that right wing koolaid.
...Like the data rules?

There is no experimental data. You can't pretend a computer model data set has the same value as data recorded from an experimental run where CO2 density and time were systematically varied. Obviously empirical tests take precedence over model projections. When there are no experimental tests, the science is stagnant and dying.

LessHypeMoreFact wrote:

<quoted text>
I'm a centrist. I get to bitch at both sides..
<quoted text>
Id call that junk science. Spin is where you misrepresent the data. Like you do.
<quoted text>
And you have not shown any missing data yet. So I am not sure what you are on about. Probably just spewing to make yourself look 'busy'.

Your only in the center in your mind. In the real world your on the left.

Spin requires you to start with something that actually happens unlike AGW which was junk scince because you started with garbage.

We skeptics were the ones sho showed that the data was missing. Those who supported AGW were the ones busy trying to deny it.

tina anne wrote:

<quoted text>
Your only in the center in your mind. In the real world your on the left.

Ah.. Tina. You say the nicest things. I wish I could agree but I tested myself at http://www.politicalcompass.org/

And considering that this is a U.S. test and most Americans are slightly to the right of Attila the Hun, that makes my centrist score slightly right wing in global context or in terms of Canadian values.

Q. Do you think the rain will hurt the rhubarb?

A. Only if it rains.

Q. Do you think the rain will hurt the rhubarb?

A. Not if it's in cans.

Brian_G wrote:

Q. Do you think the rain will hurt the rhubarb?
A. Only if it rains.
Q. Do you think the rain will hurt the rhubarb?
A. Not if it's in cans.

http://www.theglobeandmail.com/news/world/ken...

LessHypeMoreFact wrote:

<quoted text>
Ah.. Tina. You say the nicest things. I wish I could agree but I tested myself at http://www.politicalcompass.org/
And considering that this is a U.S. test and most Americans are slightly to the right of Attila the Hun, that makes my centrist score slightly right wing in global context or in terms of Canadian values.

Or the test was skewed hard to the left. Believe me I have been tested many times and found most test reflect the views of the person writing it.

NobodyYouKnow wrote:

<quoted text>
Or manna could fall fromthe skies. Or H1N1 could make food suply a non-issue. Or any other fantasy you want to pull out of your..
<quoted text>
A rational approach would be to read the article and assess its impact. Note that tropical yields are expected to fall as well.
Current equatorial zone temperatures are pretty close to optimal for yield in the heavily populated tropics.
Either colder OR warmer is going to drop yield and that is where the bulk of the food is grown and consumed.
The temperate zone farms were at least hoped to compensate a bit but this study shows that it is less likely to happen that way.

CNN says today: Earth's oceans had warmest summer on record

Summer temperatures for the globe's ocean surface ranked as the warmest on record, according to a report released Wednesday by the National Climatic Data Center.

Overall, when the Earth's land areas and oceans are included together, the three-month June-August period measured as the third-warmest summer on record. Global climate records go back to 1880.

Climatologists measure summer from June 1 to Aug. 31. The climate center is a branch of the National Oceanic and Atmospheric Administration (NOAA).

"During the season, warmer-than-average temperatures engulfed much of the planet's surface," the center wrote in an online report. One exception to the warmth was the north-central USA and central Canada, which had an unusually cool summer due to a persistent trough of low pressure that kept the area cloudy and cool.

The ocean's summer temperature was 62.5 degrees, 1 degree above the 20th-century average of 61.5 degrees.

The cause of the warmth? Deke Arndt, chief of the climate monitoring branch at the climate center, says it's due to a combination of man-made global warming and El Nino, a natural periodic warming of the tropical Pacific Ocean that affects weather around the world. "Each of those is a component in this summer's temperatures, he said.

"If El Nino continues to mature as projected by NOAA, global temperatures are likely to continue to threaten previous record highs," noted the center's report.

What really jumped out at Arndt, he says, was the heat in the Southern Hemisphere. "The warmth in Australia and South America in August was striking," he says. "Land areas in the Southern Hemisphere in August broke their previous record by a large amount."

Overall, it was the second-warmest winter on record in the Southern Hemisphere.(June-August is winter in the Southern Hemisphere.)

Additionally, according to the National Snow and Ice Data Center, Arctic sea ice covered an average of 2.42 million square miles during August. This is 18.4% below the 1979-2000 average extent and is consistent with a decline of August sea ice extent since 1979.
http://www.usatoday.com/weather/climate/2009-...

truthist wrote:

CNN says today: Earth's oceans had warmest summer on record
Summer temperatures for the globe's ocean surface ranked as the warmest on record, according to a report released Wednesday by the National Climatic Data Center...

This has got to be your weakest argument yet. The Keeling Curve, the ever increasing CO2 content of the air can only be caused by one thing, warming oceans. Man's contribution is insignificant. Henry’s Law dictates more CO2 emissions from the sea, than man could ever manage. It’s all in the math.