Posts Tagged: climate change
Keeping global warming below 2 degrees C (3.6 F) can be achieved only by reducing greenhouse gas emissions from all sectors, including land and food, said the United Nations' Intergovernmental Panel on Climate Change in a report released Aug. 8, 2019.
The panel of scientists said agriculture, deforestration and other land use - such as harvesting peat and managing grasslands and wetlands - generate about one-third of human greenhouse gas emissions and 44% of methane emissions. The panel suggests that farmland be reduced and forestland increased to keep the earth from getting more than 1.5 degrees C hotter than in the pre-industrial era. Global temperatures have already risen about 1 degree C in the past 150 years.
Currently, about 50% of the globe's vegetated land is dedicated to agriculture — and about 30% of cropland is used to grow grain for animal feed. Given how much land it takes to grow food to feed livestock, meat production is a leading cause of deforestation, reported National Public Radio.
Cattle ranchers dispute the UN report that links cows to climate change, said a story on CBS This Morning, which quoted UC Cooperative Extension animal science specialist Frank Mitloehner. Mitloehner studies livestock and air quality. He told the news station that Americans should focus on the energy wasted on food they don't consume.
“Forty percent of all food produced in this country goes to waste and you know who the main culprit is? You and I,” Mitloehner said. “So if you're really concerned about your personal environmental footprint around food, well, waste less.”
One of the forces driving agricultural experiments in California's fertile San Joaquin Valley is climate change, reported Mark Schapiro on Grist.org. Although some sources still don't feel completely comfortable with the concept.
"Whether it's carbon built up in the atmosphere or just friggin' bad luck, the conditions are straining us," said John Duarte, president of Duarte Nursery.
The state's fruit and nut orchards are taking the most heat as conditions change. A fruit or nut tree planted today may be ill-suited to climatic conditions by the time it begins bearing fruit in 5 or 10 years. Between 1950 and 2009, “chill” hours trees needed annually to reboot trees' metabolic system for the spring bloom had already declined by as much as 30 percent, according to a California Department of Food and Agriculture study.
“If trees haven't had that low-chill period when they wake up in the spring, it's like being up all night and then trying to go to work.” said Mae Culumber, a nut crop advisor with UC Cooperative Extension in Fresno County.
Researchers have already observed that cherry, apricot, pear, apple, pecan and almond trees are often less productive than they used to be.
The article said farmers may turn to pistachio trees to weather a warmer and dryer California. Pistachio trees require one-third to one-half as much water as almond trees. During droughts, pistachio tree metabolism slows and when water returns, they start producing nuts again. And they can produce nuts for 80 years or longer, almost four times the life span of an average almond tree.
For field crops, scientists are looking at improving the soil and transforming growing systems to help farmers adapt to the warming climate.
“When I drive to the Central Valley, I get goosebumps; I feel the urgency,” UC Davis agronomist Amélie Gaudin said. “I see an agriculture that is basically hydroponics. It's like a person being fed/kept alive by an IV.”
“What happens when you no longer have the sugar-water?” she adds.
Gaudin is focusing on using agroecological principles to develop efficient and resilient cropping systems. Planting cover crops and reducing tillage show promise for mitigating the impact of climate change in the valley.
KQED reporter Mark Schapiro discovered a "center of insurrection" at the UC West Side Research and Extension Center in Five Points, where UC Cooperative Extension cropping systems specialist Jeff Mitchell has been building soil on a research plot for 20 years.
Schapiro's story was part of a series titled "Reckoning in the Central Valley," a collaboration between Bay Nature magazine and KQED Science examining how climate change is exposing the vulnerabilities of California agriculture.
In the Central Valley, climate change is disrupting the predictability that is key to maintaining a profitable industrial agriculture system. Mitchell believes that employing practices that build soil - such as reducing or eliminating tillage and planting cover crops - will help farmers ride the wave of climate change.
It's that cover-cropped field “that is the real disruptor here," Mitchell said.
The soil in test plots where cover crops were grown are loaded with far more organic matter than soil in fields where cover crops were not grown. The organic matter improves water absorption, making the land more resilient to drier conditions. Fields with cover crops also sequester carbon and produce crops that may be more nutritious.
“What you see in Five Points,” said Daphne Miller, a physician who studies the links between the health of the foods we eat and the soil in which they're grown, “is that the plots with the greatest diversity of cover crops had the most diverse microbiome in the soil.”
Scientific evidence of a warming climate in California and across the globe is clear, but the impacts on ecosystems and agriculture are still difficult to predict.
Sophisticated computer models are used to forecast future climate. Understanding that temperature and precipitation levels will change in the future does not tell the full story: UC Agriculture and Natural Resources researchers also want real-world experience under those future conditions.
Moreover, some agricultural operations have higher sensitivity to the changes than others. Rangeland forage is particularly sensitive to climate changes since, unlike irrigated agriculture, ranchers rely solely on precipitation. They have no control over how much and when it rains.
“It's tricky business,” said rangeland expert Jeremy James, the director of the UC Sierra Foothill Research and Extension Center in Browns Valley. “It's not easy to forecast. We have to address the uncertainty in a realistic manner.”
Discovering climate change impact on rangeland
In order to study different climate projections on rangeland, James and Maggi Kelly, director of the UC ANR Informatics and Global Information Systems special program, have begun development of a research site that will allow scientists to manipulate the temperature and rainfall on sections of rangeland to understand what would happen under predicted weather scenarios.
“We need to know how rangelands will respond when conditions change,” James said. “Will we grow more, but dry out earlier? Will we have more medusahead (an undesirable rangeland weed) or more soft chess (a high quality forage)?”
When complete, 16 shelters on steel tracks will be connected to computer systems and hydraulic motors to move them up or down a research plot. The shelters and other equipment will allow scientists to precisely control the amount of precipitation (or irrigation water) that rains onto the plot. Other systems will give researchers control of air temperature.
“This facility isn't designed for one type of research,” James said. “It is designed to conduct a wide variety of research by scientists over the next several decades. With this setup, we can look at the effect of climate change on soil biological communities, soil carbon, insect communities, plant-insect interactions and oak seedling recruitment.”
The research results from the project should provide ranchers and land managers a better understanding of how climate change may impact agriculture and ecosystem function on rangeland while also providing important information on how to minimize impacts of these changes.
Some aspects of the research facility's development are not covered with funding from the National Science Foundation. The scientists are looking for additional support to complete the project.
For more information, contact James at firstname.lastname@example.org.
Current work underway at the Sierra Foothill Research and Extension Center
The Sierra Foothill REC, a 5,000-acre facility on the Yuba River, has supported research, education and outreach in the Sierra foothills since 1960. Multiple lines of research are being conducted at SFREC. During a recent workshop, scientists from UC Davis, UC Berkeley and UC Cooperative Extension shared a sampling of their work at SFREC.
UCCE livestock and natural resources advisor Dan Macon described a project aimed at helping ranchers make decisions about maintaining a cattle herd when faced with impending drought. Ranchers are reluctant to sell off their cattle even when the near future weather forecast is dire.
“Science tells us you shouldn't feed your way out of a drought,” Macon said. “But you want everything to stay the same. You want to maintain your genetic potential and keep cows that are familiar with the area.”
Working with ranchers, the research project will compare management practices to determine the best way forward when the future looks meteorologically bleak.
“We're assigning cows to a traditional weaning and early weaning groups,” Macon said. “They'll be out on the range from March to early September under different parameters. We're also tying in economics, the value of genetic potential and the value of having cows who know the landscape.”
Research by University of Oregon post doctorate researcher Ashley Shaw is looking into whether compost applied to rangeland will help mitigate climate change by sequestering more carbon, and also benefit forage under drought by increasing the soil's water-holding capacity and improving nutrient delivery.
Preliminary results are promising. A single application of 1/4-inch of compost resulted in forage production that was higher than areas where no amendment was applied and areas that were treated with a chemical fertilizer.
“The biggest impact was under drought shelters,” said Shaw, referring to PVC frames that were covered with plastic during rain events to understand the impact of the treatment under dry conditions. “In the drought plots, the areas where compost was applied are staying green longer.”
A defining research tool at SFREC is a dataset that includes information on monthly rainfall and forage production going back 40 years.
A review of the data shows surprising variations and correlations at the center, where forage production averages 3,000 pounds per acre, but ranges from about 1,000 pounds per acre in 1987, to over 5,000 pounds per acre in 2018, when there was so much growth, “we didn't have enough animals to graze,” James said.
The dataset paints a spectrum of the variation that ranchers across the state must navigate to manage their livestock and rangeland in a way that is profitable and ecologically sound. Research at the Sierra Foothill REC offers invaluable information to help them better understand the ecosystem and make informed decisions.
In the California agriculture industry, the climate change discussion is less about whether disruption is coming than it is about how farmers will adapt, reported John Cox in the Bakersfield Californian.
Cox spoke to a Delano farmer who doesn't like debating climate change, but he has thought a lot about how to deal with it.
"As a grower, you just take it as it comes," he said.
"Everybody I know in agriculture says, 'Yes, the climate's changing and adaptation to that climate change is crucial.' So that's not controversial," said Dan Sumner, director of the Agricultural Issues Center, a UC Agriculture and Natural Resources statewide program. "At the same time, that doesn't mean they buy into every public policy proposal for mitigating the climate change."
Climate change is likely to prompt farmers to grow different varieties or different crops.
But even as California agriculture may struggle to adjust to climate change, so will its competitors overseas, Sumner said. The real question is whether the state's farming climate will remain superior in relation to that of other countries producing the same crops, he said.
In the Washington Post, Adrian Higgins reported on the impact of climate change to agriculture across the nation. From Appalachia to North Carolina to California, milder winters are inducing earlier flowering of temperate tree fruits, exposing the blooms to increasingly erratic frost, hail and other adverse weather.
Breeders are working to develop new varieties, said Katherine Jarvis-Shean, a UC Cooperative Extension orchard systems advisor in Yolo County. But new trees typically take two decades of methodical breeding to create, exposing existing varieties to the vagaries of shifting winters and springs.
“The consumer will begin to know it's happening in the coming 10 to 20 years,” Jarvis-Shean said.