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‘Green Revolution’ changes breathing of the biosphere: Stronger seasonal oscillations in carbon dioxide linked to intensive agriculture

The intense farming practices of the “Green Revolution” are powerful enough to alter Earth’s atmosphere at an ever-increasing rate, boosting the seasonal amplitude in atmospheric carbon dioxide to about 15 percent over the past five decades.

That’s the key finding of a new atmospheric model developed by University of Maryland researchers, which estimates that on average, the amplitude of the seasonal oscillation of carbon dioxide in the atmosphere is increasing at a rate of 0.3 percent every year. A study based on the results of the model, called VEGAS, was published Nov. 20, 2014 in the journal Nature.

“What we are seeing is the effect of the Green Revolution on Earth’s metabolism,” said UMD Atmospheric and Ocean Science Professor Ning Zeng, the lead developer of VEGAS, a terrestrial carbon cycle model that, for the first time, factors in changes in 20th and 21st century farming practices. “Changes in the way we manage the land can literally alter the breathing of the biosphere.”

Scientists have known since the 1950s that carbon dioxide levels in the atmosphere hit an annual low during late summer and early fall in the Northern Hemisphere, which has a greater continental landmass than the Southern Hemisphere, and therefore has more plant life. The atmosphere’s carbon dioxide level falls in spring and summer as all the hemisphere’s plants reach their maximum growth, taking in carbon dioxide and releasing oxygen. In the autumn, when the hemisphere’s plants are decomposing and releasing stored carbon, the atmosphere’s carbon dioxide levels rapidly increase.

In a set of historic observations taken continuously since 1958 at Hawaii’s Mauna Loa Observatory, and later in other places including Barrow, Alaska, researchers have tracked these seasonal peaks and valleys, which clearly show an increase in the atmosphere’s overall level of carbon dioxide, Earth’s main greenhouse gas. Between 1961 and 2010, the seasonal variation has also become more extreme. Carbon dioxide levels are currently about 6 parts per million higher in the Northern Hemisphere’s winter than in summer.

While the forces driving the overall increase in carbon dioxide are well understood, the reasons behind the steepening of the seasonal carbon dioxide cycle are harder to pin down. Because plants breathe in carbon dioxide, higher atmospheric levels of the gas can stimulate plant growth, and this so-called “carbon dioxide fertilization effect” probably plays a role. Climate scientists also point to the warming in the Northern Hemisphere high latitudes that makes plants grow better in cold regions as an important factor. But even taken together, those factors cannot fully account for the trend and spatial patterns toward increasing seasonal change, said Zeng.

Zeng points out that between 1961 and 2010, the amount of land planted with major crops grew by 20 percent, but crop production tripled. The combination of factors known as the Green Revolution–improved irrigation, increased use of manufactured fertilizer, and higher-yield strains of corn, wheat, rice and other crops–must have led not only to increased crop productivity, but also to increases in plants’ seasonal growth and decay and the amount of carbon dioxide they release to the atmosphere, he reasoned.

UMD graduate student Fang Zhao and other collaborators worked with Zeng, who developed the first of several versions of the VEGAS model in 2000, to add information on worldwide crop production. The researchers combined country-by-country statistics collected yearly by the United Nations Food and Agricultural Organization (FAO) with climate data and observations of atmospheric carbon dioxide levels from several sites. To ensure that their results did not overstate the Green Revolution’s effect, the researchers ran their model using an estimate of worldwide crop production slightly lower than the FAO statistics.

Once the Green Revolution was factored in, VEGAS’ results generally tracked the actual carbon dioxide peaks and valleys recorded at Mauna Loa. Between 1975 and 1985, carbon dioxide levels rose faster at Mauna Loa than they did in the model, but this could be due to regional weather patterns, Zeng said.

Other atmospheric models factor in changes in land use, from natural vegetation to cropland, Zeng said, but the VEGAS results described in Nature are the first to track the effect of changes in the intensity of farming methods. There are still many unknowns. For example, the Green Revolution has not affected all parts of the world equally, and there isn’t enough detailed information about changing farming practices over the past 50 years to build those detailed variations into the model.

“We dealt with the unknowns by keeping it simple,” said Zeng. “My education was mostly in physics, and physicists are brave about making the simplifying assumptions you have to make to reach a general understanding of some important force. Our goal was simply to represent the intensification of agriculture in a model of the carbon cycle, and we have accomplished that.”

Story Source:

The above story is based on materials provided by University of Maryland. The original article was written by Heather Dewar. Note: Materials may be edited for content and length.

Agriculture and Food News — ScienceDaily

Sunkist seasonal citrus brightens CPMA Convention & Trade Show

After a long, cold winter, Sunkist Growers is brightening up the greatly awaited spring by showcasing fresh, seasonal citrus from California and Arizona at the 2014 Canadian Produce Marketing Association Convention & Trade Show in Vancouver.

“Spring is here and what better way to celebrate than with bright, healthy and delicious Sunkist citrus,” Sunkist Advertising & Public Relations Manager Joan Wickham said in a press release. “There are many Sunkist varieties in peak season right now and we are pleased to be sharing them with our customers and industry partners at CPMA.”CA-Star-Ruby-363Sunkist Growers Inc.’s California-sourced Star Ruby grapefruit.

Sunkist will be highlighting grapefruit at its show booth, emphasizing the exceptional taste and color of this year’s California Star Ruby crop by sampling freshly squeezed Star Ruby grapefruit juice. The cooperative is continuing to educate younger consumers about this delicious, nutrient-rich superfood by emphasizing the nutrition and weight loss benefits of grapefruit with the “Not Your Mother’s Grapefruit” campaign. An online brochure with more information about the campaign is available on Sunkist’s website,

The weight-loss benefits of both grapefruit and lemons are also being promoted with Sunkist’s “Peel Away the Pounds” promotion with “The Biggest Loser.” Joining forces with the hit TV. series that airs on NBC in the U.S. and on CTV in Canada, Sunkist is running a national sweepstakes offering consumers a chance to win one of two trips to The Biggest Loser Resort, an award-winning immersive weight-loss program with locations in Chicago, Ivins, UT, Malibu, CA, and Niagara, NY.* The agreement between Sunkist and “The Biggest Loser” is licensed by Universal Partnerships & Licensing and Shine America, the producers of “The Biggest Loser.”

“Following a harsh winter, consumers are motivated to make healthier choices as the weather improves,” said Sunkist Director of Retail Marketing Julie DeWolf. “Sunkist is proud to be teaming up with ‘The Biggest Loser’ this spring to provide an extra incentive for consumers seeking a healthier lifestyle to reach their weight-loss goals.”

The sweepstakes, which runs through May 21, is being promoted with specially marked Sunkist lemon and grapefruit packaging featuring “The Biggest Loser” logo and information about the health and wellness benefits of citrus. Consumers can enter the sweepstakes online at, a site where they can also access information on healthy living and find a forum to connect with other like-minded individuals for support, motivation and ideas for living a healthier lifestyle.

Now at the peak of season, Sunkist is also highlighting Gold Nugget variety Mandarins at the show. Branded by Sunkist as Nature’s Treasure and available from April to mid-May, the Gold Nugget variety Mandarin is a sweet, easy-peel late-season variety that received its name from its beautiful, bright and bumpy rind. Consumers, in a U.S. taste test of six varieties of citrus easy-peelers, ranked Gold Nugget’s taste as outstanding with 96 percent saying they would purchase the variety. Sunkist Gold Nuggets are available in two-, three- and five-pound giro bags and bulk packs.

To demonstrate some of the delicious ways that citrus can be used in cooking, Chef Jill Davie will be at the Sunkist booth serving Sunkist Lemon Pesto Shrimp Crostini and Sunkist Orange Chipotle Turkey Tacos.

The Produce News | Today’s Headlines – The Produce News – Covering fresh produce around the globe since 1897.

Europe: Better circumstances for seasonal workers

Europe: Better circumstances for seasonal workers

For seasonal workers from the third world better working and living circumstances apply in the European Union, as announced on the German website The European Parliament confirmed an agreement with the European Council and the European Commission.

The workers are entitled to, amongst others things, a fitting shelter and a set limit of the maximum number of working hours. At the same time the new regulations must prevent temporary stays becoming permanent ones. The member states can decide for themselves how many third world people will be allowed into their country. Each government, however, will have to record the maximum period seasonal workers may stay, which is between five and nine months each twelve months period. Within this period seasonal workers can renew their contracts or change to other employers. Everybody willing to come to the EU must supply a valid contract of work or a binding offer of employment, in which offered workd and salary are recorded. When shelter is supplied by or organised via the employer the rent is not allowed to be excessively high or be deducted automatically from the wages of the employee.

Publication date: 2/17/2014

Fresh Hires: Seasonal Staffing in Fresh Foods

Graduation season is a time of celebration for students and families in Minot, N.D., and that means big business for the cake department at Marketplace Food & Drug. There, manager Nyla Stromberg and her team of decorators work long hours turning out the hundreds of cakes customers have ordered to commemorate the occasion. “The month of May we’re working around the clock,” she said. “It’s insane.” So insane, in fact, that Stromberg has to hire …

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