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Friday, April 12, 2024

Can Diet Diminish Climate Change? See Video.


UC Climate Video Questioned by UC Researchers

According to a video called “The diet that helps fight climate change” released by the Office of the UC President, everyone — including the 238,000 students across the UC system — can help combat climate change on their own. But not everyone is celebrating.

On Dec. 12 of last year, the University of California and Vox Media released an episode in a multi-video series describing one solution that everyone can do to help combat climate change: converting to a Mediterranean diet. This diet entails eating less meat and more vegetables. The research claims that the decision alone would reduce greenhouse gas emissions by up to 15 percent by 2050. The evidence for this conclusion has been questioned by multiple experts within the UC community.

“[The video] recommended for the global population a diet that only the top one percent can afford,” said Dr. Frank Mitloehner, a professor and air quality specialist at UC Davis. “We could not even satisfy a Mediterranean diet for the entire United States population today.”

With over two million views online, critics claim that the video hurts the UC brand because the piece lacks objective evidence and uses conflated methodologies to give audiences a false sense of reality. The scientists featured in the video, however, say that their research was peer reviewed and confirms previous studies on diet and climate change.

Each interviewee in the Climate Lab series is a volunteer, including the host, Dr. M. Sanjayan, a UCLA visiting researcher and CEO of Conservation International. The scientists in the video, Dr. Benjamin Houlton and Dr. Maya Almaraz, are aware of the criticisms.

Almaraz, a postdoc in Houlton’s lab, received her B.S. in conservation and resource studies and her B.A. in public health at UC Berkeley.

“We define the Mediterranean diet as being similar to the vegetarian diet, in that it is a diet that is heavy in plant based-foods.” Almaraz said, “The difference is that the Mediterranean diet allows the consumption of red meat and pork once a month, and poultry and fish once a week, whereas the vegetarian diet does not include meat consumption. While the world adopting a uniform Mediterranean diet is unlikely, it would benefit not only global health but also the climate –– and implies a fully nourished global society.”

According to a similar study in the Proceedings of the National Academies of Science, if every American went vegan, it would reduce GHG emissions by only 2.6 percent nationally –– compared to the 14 percent globally that the video mentions. And that is one of the main points of contention: when is it appropriate to draw conclusions based on global data?

“Diet doesn’t have to be a divisive issue,” Houlton said in a previous interview with The California Aggie. “Instead, there’s a symbiosis between people and the planet, that a healthy diet can go a long way toward reducing greenhouse gases.”

According to UCOP, the episode was developed in part because of viewer feedback. The partnership with Vox allowed the UC to reach Vox’s four million YouTube subscribers, two million Facebook followers and 50 million website visitors each month. In total, the Climate Lab videos have over 20 million views. The Climate Lab series itself was inspired by a 2015 report from the United Nations Climate Summit, in which 50 UC researchers presented at the conference.

Since the video series began in 2016, $152,000 has been spent to produce all nine Climate Lab episodes, which include the cost of researching, writing and editing each video. Episode eight, “The diet that helps fight climate change,” cost $6,067 to create. It is aimed to inspire engagement on climate change solutions on an individual level, but multiple researchers from UC Davis and across UC campuses are questioning the methods in which the speakers reached their conclusions –– even those working within UCOP.

Dr. Glenda Humiston, the vice president for the UC Division of Agriculture and Natural Resources, wrote in a public letter to UC colleagues, “[The video] states that if the world was to reduce its meat consumption, that decision alone could offset the emissions from a billion cars on the road by 2050. For the U.S., however, this contention is misleading, as the impact would be considerably smaller.”

For the entire U.S., livestock are responsible for 3.8 percent of GHG emissions, and transportation accounts for 26.4 percent, according to the EPA. In California, livestock are responsible for 5.4 percent of GHG emissions, and transportation makes up 37 percent according to the California Air Resources Board. These numbers are regionally based, and GHG percentages vary greatly from state to state and country to country.

For example, in 2010, agriculture contributed to 85 percent of Ethiopia’s GHG emissions, and livestock contributed to 40 percent of those emissions, while livestock emissions from the EU make up only 9.1 percent. Other GHG emitters such as transportation and electricity consumption explain the differences in percentage. In other words, Ethiopia does not have as many cars as France, which is why the percentages are so different.

Globally, however, the video says that livestock contributes to 14 percent of all greenhouse gases according to the UN Food and Agriculture Organization, and another 14 percent is from transportation according to the UN Intergovernmental Panel on Climate Change. Houlton’s model shows that if everyone on the planet switches to a Mediterranean diet, then that would reduce global greenhouse gas emissions by 15 percent, almost directly offsetting the emissions from transportation. However, the FAO and IPCC used two different metrics to reach their statistics: a life cycle assessment for livestock — including all feed, fertilizer production, land-use change, heating/cooling, manure — and a direct emissions assessment for transportation, including only tailpipe pollution.

“It’s a simple apples to oranges comparison,” said Dr. Frank Mitloehner, who served as chairman for an FAO partnership committee on livestock emissions. He is the expert in measuring and assessing the environmental impact of the livestock industry.

In 2006, a similar juxtaposition was made when a UN FAO global report claimed that the livestock industry contributed more to GHG emissions than transportation. According to Mitloehner, emissions from all aspects of caring for livestock were considered, but the same was not done for transportation.

“I must say honestly that [Mitloehner] has a point,” said FAO’s Dr. Pieer Gerber in 2006.

The report was deemed flawed and later corrected because of the unbalanced comparisons. Mitloehner was at the helm of the 2006 correction, and now he is concerned that the research presented in the UCOP video also used a derivative approach.

“This is not something the University of California should endorse,” Mitloehner said.  “Maybe something like this can be put out as an opinion piece by a faculty member, but not be produced by the University of California for the world to see.”

In 2012, as chairman of a global FAO partnership committee, Mitloehner helped create a program called the Livestock Environmental Assessment and Performance. LEAP developed a global gold standard for measuring the environmental footprint of livestock and, according to Mitloehner, those guidelines were ignored in the study.

Dr. Alison Van Eenennaam, an expert featured in “Food Evolution” from UC Davis, also claims that the Climate Lab video is misleading. With a combined 2.1 million views on YouTube and Facebook to date, Van Eenennaam expressed concern that the public is led to believe that diet is twice as important as transportation effects –– which is not true at all, she said.

“It’s not simple, and that video made it simple,” Van Eenennaam said.

According to the EPA, electricity contributes 29 percent of GHG emissions nationally and 25 percent globally.

“Our video states that reducing meat intake can offset emissions from all the cars on earth –– that’s one billion cars,” Almaraz said.

Critics of the video also said that the research did not fairly represent the data as it pertains to dietary choices in the U.S.

“The easy things [like diet] are more appealing to people, and overemphasizing that gives people a false security,” Van Eenennaam said.

Public institutions are obligated to present conclusions and data in an objective manner, but researchers are also entitled to academic freedom.

“Our study is global and that’s the context in which it should be considered,” Almaraz said.

Most viewers believed the U.S. was the intended target, including Molly Spencer, a second-year Ph.D. student in the UC Davis Food Science Department.

“I felt like the audience was targeting Americans,” Spencer said.

The video shows footage of planes, congested highways, freighters, mid-1900 family dinners and delis, large farms, ranches on the American-West and more. The video also mentions that the U.S. has one of the highest meat footprints per capita.

“Most of the images in here are U.S. images,” Mitloehner said. “I have not seen any images from Africa or from South America or Australia or Asia.”

Houlton’s study describes the effect of GHG emissions that would occur by 2050 if the entire world were to adopt a Mediterranean diet uniformly. Though unlikely, Almaraz said that the choice would not only improve global health but also the climate.  

“Our work implies that all people have access to food equally by 2050, something that is a major goal for the human race,” Houlton said.

According to U.S. News & World Report, the Mediterranean diet was voted to be the healthiest diet in the world.

“Not only does [the diet] provide adequate nutrients, but it reduces your risk of disease, prolongs your life, improves cognition, and hey, it also reduces greenhouse gas emissions,” Almaraz said. “So, eating in a way that is good for your health is also good for the health of the planet.”

Dr. Daniela Chifor and Dr. Alfredo Tura, physicians at the Washington Park Medical Clinic from British Columbia, both recommend the Mediterranean diet for their patients or ask them to consider at least these three aspects of it –– using olive oil as a method of fat reduction, balancing diet without taking extreme measures and avoiding fast food.

“I don’t believe there is a single accepted definition for the ‘Mediterranean diet,” Tura said.

Usually, the diet is high in fruit and vegetables, including whole grains, beans, nuts and seeds, with little red meat. Olive oil is a defining component for the diet since it is the main source of fat.  

“The public does not realize that in a typical Mediterranean diet there is hardly any other fat other than olive oil,” Tura said.

The diet is known to lower cholesterol levels by replacing saturated fats with olive oil, and was believed to help people live longer, but the latter claim was recently proved otherwise.

The 1962 National Diet Heart Study was the baseline for tracking the health benefits of the diet, and is considered to be one of the most rigorous diet trials ever conducted to date, monitoring over 100,000 people. Using controlled clinical trials where one group of people ate their normal diet and the other ate a Mediterranean-based diet, the National Diet Heart Study followed these two groups over their lifetimes to see what would happen.

As reported by The New Yorker’s Malcolm Gladwell, the patients who used olive oil for their diets did have lower cholesterol, but they did not live longer. In fact, the diet actually increased the risk of death for seniors –– which puzzled scientists. People over 65 years old who were on the Mediterranean diet for more than a year were the most vulnerable. A similar trial in Sydney, Australia also reached the same conclusion. Now, portions of the National Diet Heart Study are undergoing re-evaluations.

Dr. Ermias Kebreab specializes in ecological modeling and works with the IPCC. He said that it would be impossible for the world to fully adopt a Mediterranean diet even if we wanted.

“You cannot assume that everybody in the world has the same access to food,” Kebreab said. “That is just not feasible. It really depends on where you are and what you can grow.”

Almost 60 percent of the world’s agriculture is grazing land, which is unsuitable for producing crops. Various types of food are grown based on the agricultural resources in each country.

“Solutions are very much tailored to the region. There is no one fix-all approach,” Kebreab said.

Climate change is a complex issue, and one challenge is identifying regional methods that cumulatively reduce emissions without disrupting people’s culture and lifestyle. That is what Kebreab hopes to accomplish.

“What we have done in Vietnam, for example, is helping farmers balance their nutrition for animals that would lead to a significant reduction of greenhouse gases emissions per unit of product they are producing,” Kebreab said. “For the same amount of emission, they could double their productivity.”

The problem in many agricultural-based nations is that productivity is low because farmers are not feeding their animals effectively. In California, one cow produces six to seven gallons of milk per day, while a cow in a developing nation produces about half a gallon of milk per day.

In response to the criticisms, Stephanie Beechem, a UC spokesperson and member of the UCOP Media Relations team, said, “The intent of this video, and all UC Climate Lab videos, is not to explore every industry or behavior that contributes to global climate change, or to provide an overview of all research available on a certain climate-related topic, but rather to explain in an approachable and conversational way how individuals might make everyday changes to reduce their carbon footprint.”

Kebreab would like to see another video produced on diet, featuring people with backgrounds in nutrition and animal science. Since UC Davis has one of the best animal science and nutrition programs in the country, one does not have to go far.  

Months after the original video’s release, even some critics say the option seems unlikely.

“They’ve got themselves in a situation where there is no simple solution out of this problem,” Van Eenennaam said.

In the end, viewers watching this video don’t have the luxury of having comparable facts and figures, knowing whether or not these studies are global or regional.

“The few times they have used citations, they have conflated methodologies,” Mitloehner said. “You have to decide for yourself [as the viewer] whether or not the evidence that was provided justifies the statements that were made.”

Mitloehner and Van Eenennaam emailed Janet Napolitano, the president of the UC system, on Jan. 2 regarding their concerns over the UC endorsement of the research, requesting a correction be made. They have yet to hear back from Napolitano, but instead received UC Vice President Humiston’s public letter, also criticizing the research presented in the video.

“Encouraging people to focus on livestock, rather than on much larger sources of GHG emissions, can lead to policies that slow our efforts to develop more effective climate change solutions,” Humiston said.

Intellectual freedom lies at the heart of any research institution, and sometimes the same data can be interpreted differently.

“The discussion of findings and methods is an integral part of the scientific process,” Almaraz said. “Being able to have respectful and productive discussions about research findings related to climate change is key in progressing towards a more sustainable future.”

Conclusions have changed in the scientific community before. In the Time Magazine edition, “Eat butter and why they were wrong,” scientists showed that consuming margarine and butter had virtually the same effects. Previously, it was believed that margarine was healthier and, due to the updated study, there is now a butter shortage in France –– everyone wants to consume butter again.

“We don’t view this as the final word –– science is an ever evolving process and every study has uncertainty –– but our global model and data pointed to a large footprint of food production on greenhouse gases, something that really confirms what’s already known,” Houlton said.

According to Houlton, his results are similar to at least 18 other published studies, including papers from the National Center for Biotechnology Information, El Sevier’s Food Policy, The European Journal of Clinical Nutrition and others.

So what can individuals do concretely to help combat climate change? Besides reducing energy usage, selling your car and installing solar panels, the best way individuals can mitigate the effects of climate change, according a study in The Guardian, is to have fewer children. That solution has the greatest impact. While this idea may not be as popular as changing diets, the evidence is clear.

“What would really be good is if everybody ate less of everything,” Van Eenennaam said. “Whatever you are going to have, eat less. That would have been a simple thing to say.”

Critics hope that future UCOP outreach pieces are reviewed by specialists with expertise on the specific topic before release to ensure that the information presented to the public is objective and fair.

Previously, Mitloehner, Van Eenennaam and Kebreab spoke with Houlton and reached out to UCOP requesting a correction, a suspension, or at least a disclaimer be shown before the video. They want to indicate to the public that the conclusions presented in the video were based on global data. Neither Houlton nor UCOP wanted to make any changes. As of March 19, the UC researchers wrote a letter to UCOP calling for a full removal of the video.

“This is really a masterpiece with respect to teaching us how deceiving a video can be,” Mitloehner said.



Written by: David Madey — science@theaggie.org



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