Tag Archives: agriculture

Live longer? Save the planet? Better diet could nail both

New study shows healthier food choices could dramatically decrease environmental costs of agriculture


As cities and incomes increase around the world, so does consumption of refined sugars, refined fats, oils and resource- and land-intense agricultural products such as beef. A new study led by University of Minnesota ecologist David Tilman shows how a shift away from this trajectory and toward healthier traditional Mediterranean, pescatarian or vegetarian diets could not only boost human lifespan and quality of life, but also slash greenhouse gas emissions and save habitat for endangered species.

The study, published in the November 12 online edition of Nature by Tilman and graduate student Michael Clark, synthesized data on environmental costs of food production, diet trends, relationships between diet and health, and population growth. Their integrated analysis painted a striking picture of the human and environmental health costs of our current diet trajectory as well as how strategically modifying food choices could reduce not only incidence of type II diabetes, coronary heart disease and other chronic diseases, but global agricultural greenhouse gas emissions and habitat degradation, as well.

“We showed that the same dietary changes that can add about a decade to our lives can also prevent massive environmental damage,” said Tilman, a professor in the University’s College of Biological Sciences and resident fellow at the Institute on the Environment. “In particular, if the world were to adopt variations on three common diets, health would be greatly increased at the same time global greenhouse gas emissions were reduced by an amount equal to the current greenhouse gas emissions of all cars, trucks, planes, trains and ships. In addition, this dietary shift would prevent the destruction of an area of tropical forests and savannas as large as half of the United States.”

The researchers found that, as incomes increased between 1961 and 2009, people consumed more meat protein, empty calories and total calories per person. When these trends were combined with forecasts of population growth and income growth for the coming decades, the study predicted that diets in 2050 would contain fewer servings of fruits and vegetables, but about 60 percent more empty calories and 25 to 50 percent more pork, poultry, beef, dairy and eggs — a suite of changes that would increase incidence of type II diabetes, coronary heart disease and some cancers. Using life-cycle analyses of various food production systems, the study also calculated that, if current trends prevail, these 2050 diets would also lead to an 80 percent increase in global greenhouse gas emissions from food production as well as habitat destruction due to land clearing for agriculture around the world.

The study then compared health impacts of the global omnivorous diet with those reported for traditional Mediterranean, pescatarian and vegetarian diets. Adopting these alternative diets could reduce incidence of type II diabetes by about 25 percent, cancer by about 10 percent and death from heart disease by about 20 percent relative to the omnivore diet. Additionally, the adoption of these or similar alternative diets would prevent most or all of the increased greenhouse gas emissions and habitat destruction that would otherwise be caused by both current diet trends and increased global population.

The authors acknowledged that numerous factors go into diet choice, but also pointed out that the alternative diets already are part of the lives of countless people around the world. Noting that variations on the diets used in the scenario could potentially show even greater benefit, they concluded that “the evaluation and implementation of dietary solutions to the tightly linked diet-environment-health trilemma is a global challenge, and opportunity, of great environmental and public health importance.”

Tilman is a Regents Professor and McKnight Presidential Chair in Ecology in the College of Biological Sciences’ Department of Ecology, Evolution and Behavior and a resident fellow in the University of Minnesota’s Institute on the Environment, which seeks lasting solutions to Earth’s biggest challenges through research, partnerships and leadership development. Clark is currently a doctoral student in the College of Food, Agricultural and Natural Resource Sciences.

Source: University of Minnesota

Achieving agricultural sustainability through seawater

Even though our planet is called “Earth,” over 70% of its surface is composed of water. Our continued existence depends on this vital resource but it is a staggering fact that only 1% of that water is directly accessible for human use. That is mainly because about 98% of the world’s available water is salty. This means that merely “2% of the Earth’s water is fresh water; but half of it is frozen in the form of glaciers and icebergs,” as Mark Tester, Professor of Bioscience at KAUST and Principal Investigator of the Salt Lab, explains.

The scarcity of fresh water supplies, surface water found in lakes and rivers as well as underground sources, poses a major challenge in the face of a growing world population set to plateau at 9 billion people by 2050. Fresh water is an essential part of our agricultural production infrastructure required to feed ourselves. Indeed, no less than “70% of the water that we use on the planet is used for agriculture. Moreover, 40% of our food is produced under irrigation,” as Prof. Tester outlines.

Global climate change is compounding the problem of water scarcity by altering rainfall patterns, reducing rainfall in previously well watered regions. The already limited supply of fresh water is also increasingly affected by salinity. “It would be wonderful if we could unlock at least a fraction of the rest of the vast amount of the world’s water resources,” as Tester further posits.

“So, in the context of needing to produce 70% more food by 2050, we have to both stop the reduction of yield already suffered from brackish irrigation water, and also unlock some of the other 99% of the water that we’re not able to use at the moment. Both of these things call out for our ability to increase the salinity-tolerance of plants.”

Making Our Current Plants Better

Prof. Mark Tester and his group, as well as other KAUST faculty members’ groups, are actively conducting experimental research in the University’s well-equipped greenhouse to find solutions to tackle our expanding food security challenges.

“We need to raise our ability to increase food supply,” said Tester. “We need innovation in plant science, modern plant breeding (e.g. quantitative genetics) and genetic modification.”

Prof. Tester’s group is primarily focused on studying how salt-tolerant plants are able to survive in harsh environments and then using that knowledge to make less salt-tolerant plants grow better in difficult conditions.

“We are trying to improve plant yields in sub-optimal conditions – where the soil is salty or when the water used to irrigate the plants is salty,” as Prof. Tester clarifies. His group essentially looks at the “naturally occurring variability in plants.”

How are some plants naturally able to better grow in salty water while others are less able to thrive in saline conditions? “I want to know what genes are in those tough plants that are missing from the less tough plants,” said Tester.

A Greenhouse Like No Other

These efforts, combining the observation of naturally occurring variations, the discovery of characterizing genes, and the measuring of the salt tolerance of plants require that KAUST plant scientists be able to grow plants in a controlled environment. These tasks are performed in the KAUST Center for Desert Agriculture (CDA)’s high quality 1600-square-meter greenhouse.

Prof. Mark Tester pointed out a unique feature of the greenhouse: a seawater tank. “We can water plants with seawater in this greenhouse. That’s pretty unusual,” he exclaimed. The filtered seawater greatly facilitates salinity experiments.

Another particular feature of the CDA greenhouse, unique to it’s location in Saudi Arabia, is that the water is actually cooled as it arrives from the desalination plant. This is to prevent the water warming the roots of plants in the soil – roots are used to be in the cooler soil, and are particularly sensitive to being warmed.

Different Approaches to Tackling Abiotic Stress

Given the fact that a quarter of the food that we produce under irrigation is already affected by salinity, a number that is rising rapidly, finding effective ways to use seawater to grow plants is of primary importance.

Prof. Tester recognizes the value of research towards this common sustainable agriculture goal also being conducted by fellow KAUST faculty members such as Prof. Heribert Hirt, who looks at solutions to increase plants’ tolerance to drought and heat, and Prof. Magdy Mahfouz, whose research interests focus on genome-engineering across plant species.

“Together we form a package of different approaches. All the approaches are good. There’s no one right approach. One might be better than another for particular circumstances, but they can all make a valuable contribution to improving crop growth in tough conditions,” said Prof. Tester.

How Plant Science Can Improve Food Security

Among the plants being cultivated and studied in the CDA greenhouse are rice plants. Demonstrating some of the crops that have grown in this controlled environment, Prof. Tester points out how “this one species of rice feeds half of the planet. It’s really important because it feeds the poor half of the planet – mainly in Asia and Africa.”

Taking into account the vital importance of rice crops to continue feeding the world’s growing population, it’s particularly significant that rice plants, as most crop plants, are salt-sensitive. They are indeed easily negatively affected by high salinity.

So Prof. Mark Tester and his team are studying the more salt-tolerant crops, such as barley and tomatoes, in order to better understand how they tolerate salinity, and then use that knowledge to improve other vital crops for our increasing food demands.

For instance, his team is growing a particular type of tomatoes, found on the Galapagos Islands, which are amazingly able to grow right at the edge of the sea and flourish in saline water. “We’re trying to discover the genes that are in these Galapagos tomatoes that allow the plants to grow in these crazy tough conditions,” said Tester.

“We want to use that knowledge to make commercial tomatoes even tougher,” he adds. By extension, “we can then turn our attention to rice and potentially improve its salt-tolerance.”

Source : KAUST News