Global warming could significantly impact US wine and corn production, scientists say

Dec 14, 2009

When it comes to nature, timing is everything. Spring flowers depend on birds and insects for pollination. But if spring-like weather arrives earlier than usual, and flowers bloom and wither before the pollinators appear, the consequences could be devastating for both the plants and the animals that feed on them.

Global warming has made the early arrival of spring commonplace across the planet, say climate scientists. Plants are blooming earlier, birds are nesting sooner and mammals are breaking hibernation earlier than they were a few decades ago.

Understanding how global warming altered the timing of natural cycles in the past can provide important insights about the impact of in the future, said Noah Diffenbaugh, an assistant professor of environmental Earth system science at Stanford University.

"In recent years, there has been quite a bit of work in phenology, which is the study of the timing of lifecycles - when do birds migrate, trees drop their leaves, crops mature, etc.," said Diffenbaugh, a center fellow at Stanford's Woods Institute for the Environment. "Many of these natural events are tied to the climate."

Using a very high-resolution computer model, Diffenbaugh's research group has conducted a new experiment that uses phenological observations from the past to project future impacts of global warming at local and regional scales. "Our experiment is unprecedented," he said. "It's the first time that a climate model has been applied at such spatial and temporal detail over such a long period of time."

The experiment focuses on the regional impact of climate change on agriculture in the United States over the next three decades, from wine grapes on the West Coast to maple syrup in the Northeast. Diffenbaugh will present his 30-year forecast at the fall meeting of the American Geophysical Union (AGU) in San Francisco. He is among several scientists invited to speak at a session entitled, "Toward Phenological Assessments: Regional, National, Global."

Drilling down

One of the shortcomings of large-scale climate experiments is that they use relatively low-resolution computer models, Diffenbaugh said. He points to the United Nations Intergovernmental Panel on Climate Change (IPCC) as an example. "A typical climate model used in the last IPCC assessment had a 155-mile (250-kilometer) horizontal resolution," he explained. "However, the climate can vary quite a bit across that distance. My group takes the IPCC models and drills down to a 15-mile (25-kilometer) resolution."

Diffenbaugh's model also relies on data collected at intervals of 24 hours or less. "To really understand climate change impacts, we need to look at the sub-daily scale," he said. "In our simulations, we store data every three-to-six hours. That level of detail is not available from most global , because it's very data intensive to store that much information."

At the AGU meeting, Diffenbaugh will focus on the influence of climate change in the U.S. from 1950 to 2039. "We're using climate and phenological data from 1950 to 1999 as our historical period, and then providing a projection of what we expect the changes will be two-to-three decades from now," he said.

The forecast is based on a suite of climate variables that are crucial to agriculture, such as first freeze, last freeze, snowmelt timing and heat accumulation. "Some crops need to accumulate a certain amount of heat during the year," Diffenbaugh said. "With general global warming, we'd expect those thresholds to be reached earlier in the calendar year, say earlier in the spring. That's something we can observe in the historical records. We can also look at our climate model to see if it accurately captures past changes, and then look forward and project future changes at higher greenhouse gas concentrations."

Wine and corn production

A complicating factor in any forecast is predicting how crops will respond to different climate cues. "For example, in a managed system like premium wine on the West Coast, we look at several variables - seasonal heat accumulation, whether there are hard frosts in the winter or spring, how many severe heat days occur during the growing and ripening seasons," he said.

In a 2006 study, Diffenbaugh and his colleagues analyzed historical records from the principal wine regions of California, Oregon and Washington and found that temperatures in the growing season had increased about 1.6 degrees Fahrenheit (0.9 Celsius) from 1948 to 2002. Using these data and observations of how temperature affects the lifecycle of wine grapes, the researchers concluded that global warming could reduce the current U.S. wine grape region by 81 percent by the end of the century - primarily because of a projected sharp increase in the frequency of extremely hot days where the temperature reaches 95 degrees Fahrenheit (30 Celsius) or above.

"A key question now is how soon will that severe heat emerge," Diffenbaugh said. "In our new near-term climate projections, we're finding that the hottest temperatures on record will become commonplace within the next 30 years, even if is less than the 3.6 degrees Fahrenheit (2 C) currently being targeted by national governments at the U.N. climate conference in Copenhagen."

Diffenbaugh also used observational data in a 2008 study on U.S. corn production, which concluded that by the end of the 21st century, warmer growing seasons and milder winters could increase the population and geographic range of the corn earworm, an insect that preys on corn, tomatoes and other cash crops. "In the case of agricultural pests, many of their ranges are limited by severe cold tempertaures," he said. "In our new simulations, we find that those temperatures could disappear over the next few decades, potentially leading to an expansion of pest pressure."

The Stanford research team is now using historical data to project the impact of climate change on maple syrup production in the northeastern U.S.

According to Diffenbaugh, the success of climate forecasting will continue to depend on accurate data collection by organizations such as the National Phenology Network, a group of scientists and citizen-scientists that monitors the influence of climate on plants and animals by observing and recording information about egg-laying, flowering and other natural events. "As these large networks of observers gather information, we can test how well the climate models are predicting the real world and whether they can be applied in the future," Diffenbaugh said.

Source: Stanford University (news : web)

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User comments : 11

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omatumr
2.3 / 5 (12) Dec 14, 2009
Global warming could, . . .
if this globe were warming,
significantly impact many things.

However in distance from its heat source Earth is the third ball of dirt orbiting the Sun, and the Sun seems to have shut down after solar cycle #23.

But continue your tale.

With kind regards,
Oliver K. Manuel
Noumenon
2.7 / 5 (12) Dec 14, 2009
"Using a very high-resolution computer model, Diffenbaugh's research group has conducted a new experiment....."

First off, Computer models are NOT experiments!!! Only a crank would ever suggest this. Isolating the effect under study inorder that all variables are known, so that it can be compared to a controlled case, takes great care. The AGW theorists just dig their data from a trash can. This is why climate research will never be a fundamental science. That co2 absorbs infrared radiation is physics,... that one suggests they have a precise handle on global climate as is being claimed is wild speculation at best.

That being said there is nothing wrong with reducing co2 emissons within the existing framework of free market capitalism. The core problem is that anti-capitalists and socialists have claimed this science as their own, and are pushing for political change and mass global redistribution of wealth.
Noumenon
2.5 / 5 (11) Dec 14, 2009
To these people computer models are experiments,.. while skepticism (fundamentally necessary in science) is cranks.

Global weather is dynamic, always has been. There is no "proper gobal" temperature where it "should be". The earth adapts to us and we in turn adapt to it.
mikiwud
3.4 / 5 (10) Dec 15, 2009
Noumenon,
Global weather is dynamic, always has been. There is no "proper gobal" temperature where it "should be". The earth adapts to us and we in turn adapt to it.

Please stop talking common sense, it confuses the sheeple.
mysticshakra
3 / 5 (4) Dec 15, 2009
Actually, there is no such thing as common sense, only commonly held misconceptions.
marjon
3 / 5 (4) Dec 15, 2009
Since the ground has finally frozen in SD, farmers can get out into the fields and harvest their corn and beans without getting stuck in the mud.
Going
2.3 / 5 (3) Dec 17, 2009
Models are theories. They make a prediction about how the system will behave. They are run against known historic data to judge if the model matches they way the system has behaved in the past and whether it is useful to make prediction in the future. Poor models, which are poor theories, cant match past data and are improved or discarded. The best models fit the past data and are the only things we have to predict how systems are likely to behave in the future.
That's the scientific process that got us into the 21st century. Lets not abandon science now because its starting to say things which are unpalatable to the way we live.
Velanarris
3 / 5 (4) Dec 18, 2009
Models are theories.
No, they're not.

Models are complex calculations with variables entered by human beings using the best of their knowledge to set up a realtively accurate picture of what could happen in the real world.

Models are limited by our knowledge of the system being modeled. If we know nothing about the system, the model is entirely worthless.

Science uses hypothesis, test, verify. The problem is you think the model satisfies "test", when a model is really nothing more than a long engrossed example of what could happen if the hypothesis is correct.
Parsec
not rated yet Dec 20, 2009
It is true that models are not really theories in and of themselves. However, models are really fundamental tools along with a lot of other things to help us understand what is going on. Models can also be tested, in the sense that we can check to see if model predictions match reality. In addition, if they do not match, we know that either we don't understand something or we have left something important out. So in fact they can be verified using a variety of means.

A model that predicts the 'future' uses whatever future the modeler wants. So for example if I prime the model with data from 1948 till 1999, and then use it to predict the future starting in 1999, I have 10 years of real data to compare the predictions against.

I think that is what Going was saying and he is absolutely and precisely correct. Modeling is an essential part of all kinds of scientific endeavors. Since you do not know this Velanarris, I accept this as evidence you do not understand how science works.
Parsec
not rated yet Dec 20, 2009
Noumenon and mikiwud, I find it truly amazing that I agree with you. There really isn't any proper global temperature and it has been changing with or without mankind's help for about 4.53 billion years.

On the other hand, every species and every human society has a differing capacity to adjust to global temperature changes depending on circumstance and location. Changes of any given speed kill or seriously damage everything with a slower adaptation time. If the change is rapid enough, the number of species and people killed rises to a very substantial percentage of what is left after man's depredations of the last 10 or 20 thousand years.
marjon
3 / 5 (2) Dec 20, 2009
Noumenon and mikiwud, I find it truly amazing that I agree with you. There really isn't any proper global temperature and it has been changing with or without mankind's help for about 4.53 billion years.

On the other hand, every species and every human society has a differing capacity to adjust to global temperature changes depending on circumstance and location. Changes of any given speed kill or seriously damage everything with a slower adaptation time. If the change is rapid enough, the number of species and people killed rises to a very substantial percentage of what is left after man's depredations of the last 10 or 20 thousand years.

Is this not called survival of the fittest?
Many species in the USA are growing in numbers, like rats, deer and coyotes because they have adapted.