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Around 42 percent of all ride-hailing driving time on average is spent waiting for and driving to pick up passengers. Asia-Pacific Images Studio / E+ / Getty Images

Ride-hailing services such as Lyft and Uber are creating more climate pollution and road congestion per trip than the transportation options they displace, according to a new report from the Union of Concerned Scientists.

Looking at data from seven major U.S. cities, the authors found that a non-pooled trip from a ride-hailing service creates 47 percent more emissions than the equivalent trip in a private vehicle with average fuel efficiency, partially due to the "deadhead" miles without a passenger that a ride-hailing car travels in between trips.

Ride-hailing services such as Lyft and Uber are creating more climate pollution and road congestion per trip than the transportation options they displace, according to a new report from the Union of Concerned Scientists.


Looking at data from seven major U.S. cities, the authors found that a non-pooled trip from a ride-hailing service creates 47 percent more emissions than the equivalent trip in a private vehicle with average fuel efficiency, partially due to the “deadhead” miles without a passenger that a ride-hailing car travels in between trips.

Around 42 percent of all ride-hailing driving time on average is spent waiting for and driving to pick up passengers, Reuters reported.

Worse still, ride-hailing trips create 69 percent more carbon emissions than if the passengers had opted to travel via public transportation, biking or walking. The authors said the increase stems from ride-hailing services increasing, not replacing, the total number of car trips by pulling passengers away from other, more climate-friendly methods.

“While ride-hailing trips today are higher emitting than other types of trips, we were encouraged by the fact that they can be significantly lower polluting with efforts to electrify and pool rides,” Don Anair, report author and research director of the Union of Concerned Scientists’ Clean Transportation program, told The Hill.

For the report, the authors analyzed publicly available data gathered in New York, Chicago, Los Angeles, Boston, Seattle, San Francisco and Washington. They also looked at previously published studies, including one commissioned last year by Uber and Lyft.

The ride-sharing industry has grown tremendously since Uber’s launch in 2010. Citing data from both companies, the report authors note that Uber and Lyft have accumulated a combined 11 billion trips as of 2018. At the same time, the transportation sector is now the U.S.’s largest source of human-generated greenhouse gases, according to the U.S. Environmental Protection Agency.

The report marks the first time researchers have tried to quantify the pollution impact of ride-hailing services, Reuters reported.

“Certainly the evidence to date points to an overall increase in greenhouse gas emissions associated with ride-hailing under current market conditions,” Giovanni Circella, director of the 3 Revolutions Future Mobility Program within UC Davis’ Institute of Transportation Studies, told Axios. The Institute of Transportation Studies provided some of the data used in the Union of Concerned Scientists report.

The authors found that ride-hailing companies can reduce emissions and congestion by switching more of their fleet to electric vehicles, encouraging customers to take more pooled rides, improving connections to mass transit and collaborating with governments on policy.

For instance, a pooled and electrified trip could reduce emissions by 68 percent compared to a private vehicle trip with average fuel efficiency, or by 79 percent when compared to a non-pooled trip in a ride-hailing vehicle. Currently, however, the authors estimate that only 15 percent of ride-hailing trips in the U.S. are pooled.

“When combined with robust public transit and safe places to bike and walk, electric, pooled ride-hailing has the potential to reduce the need to own a car and reduce overall emissions from transportation,” Jeremy Martin, director of Fuels Policy and senior scientist in the Union of Concerned Scientists’ Clean Vehicles Program, told EcoWatch. “But we’re currently a long way from that future.”

A Lyft spokesperson called the report “misleading” and touted the company’s efforts to electrify its fleet, encourage shared rides and partner with cities on sustainable transportation, The Verge reported.

In its own statement, Uber did not acknowledge the report, but referenced its existing sustainability goals which include support for reduced car ownership and greater use of green transportation, CityLab reported.

For ride-hailing to become truly green, the authors emphasized the need for more collaboration on these efforts.

“Companies, governments, and individuals all need to take action to make sure ride-hailing services like Uber and Lyft are part of a clean transportation system, rather than continuing to contribute to climate change and congestion,” Martin said.

Update, March 3: This story has been updated to include a quote by Union of Concerned Scientists along with some minor changes for clarity.

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Yet another reason to avoid the typical western diet: eating high-fat, highly processed junk food filled with added sugars can impair brain function and lead to overeating in just one week.

The western diet has already been connected to a number of health issues, such as obesity, cardiovascular disease and even lower sperm counts in men. Now, researchers from Australia, the UK and U.S. may have identified why the diet is so difficult to quit — it disrupts proper function of the hippocampus, a region in the brain important for memory and regulating food intake.

Yet another reason to avoid the typical western diet: eating high-fat, highly processed junk food filled with added sugars can impair brain function and lead to overeating in just one week.


The western diet has already been connected to a number of health issues, such as obesity, cardiovascular disease and even lower sperm counts in men. Now, researchers from Australia, the UK and U.S. may have identified why the diet is so difficult to quit — it disrupts proper function of the hippocampus, a region in the brain important for memory and regulating food intake.

The researchers found that when otherwise healthy young adults followed the western diet for seven days, they tended to perform worse on memory tests and craved more junk food, even after eating a full meal, The Guardian reported.

“After a week on a western-style diet, palatable food such as snacks and chocolate becomes more desirable when you are full,” study author Richard Stevenson, a professor of psychology at Macquarie University in Sydney, told The Guardian. “This will make it harder to resist, leading you to eat more, which in turn generates more damage to the hippocampus and a vicious cycle of overeating.”

Stevenson explained to The Guardian that a functioning hippocampus could be blocking memories related to food when we are full so that we are not as tempted at the site of a delicious snack. When it is impaired, however, the food becomes more appealing as memories related to it flood in.

For the study, published in the journal Royal Society Open Science, the researchers split 110 lean and healthy students between the ages of 20-23 into two groups: one group ate their normal diet for a week, while the other were given a Western diet full of fast food, Belgian waffles and sugary foods. This group kept a food diary and provided receipts and photographs of their food intake.

The participants ate breakfast in the lab at the beginning and end of the week, which included a milkshake and toasted sandwich. Before and after breakfast, they took word memory tests and were asked to rate how much they wanted to eat six food samples, including sugary cereals such as Froot Loops, Coco Pops. After eating each sample, they also indicated how much they liked it and if they could eat more of it, ScienceAlert reported.

“Across these pre- and post-meal tests, wanting ratings declined far more than ratings of taste liking,” the researchers concluded. “This manifestation of appetitive control — that is the expectation that food is less desirable than it actually tastes — changed in participants following the Western-style dietary intervention.”

Essentially, the researchers found that for participants on the western diet, the more appealing they found the food samples when they were already full, the worse they did on the other tests — though three weeks after their diets returned to normal, the group that had been on the western diet showed results that resembled the control group, suggesting a balanced diet can reverse the hippocampal damage, News-Medical reported.

According to the Independent, the findings resembled previous research in rats and other animals, which first exposed the link between hippocampal function and junk food.

While the researchers believe more investigation must first be done to strengthen the link, Stevenson told The Guardian that the findings “should be a worrying finding for everyone,” and he can envision public health officials someday calling for restrictions on processed junk food in the same way they have done for tobacco.

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A coal-fired power plant on river in eastern Wyoming. Wyoming is one of the largest "net exporters" of deadly air pollution, a new study has found. PhilAugustavo / E+ / Getty Images

On average, around half of all early deaths from poor air quality in the U.S. are associated with pollution produced out-of-state, a new study has found.

The findings are especially concerning for New Yorkers: ozone and fine particulate matter from emitters in other states accounted for 60 percent of air pollution-related premature deaths, The New York Times reported, leading researchers to term the Empire State the "biggest importer of air pollution deaths." In 2018, that amounted to 3,800 deaths.

On average, around half of all early deaths from poor air quality in the U.S. are associated with pollution produced out-of-state, a new study has found.


The findings are especially concerning for New Yorkers: ozone and fine particulate matter from emitters in other states accounted for 60 percent of air pollution-related premature deaths, The New York Times reported, leading researchers to term the Empire State the “biggest importer of air pollution deaths.” In 2018, that amounted to 3,800 deaths.

On the other hand, the largest “net exporters” of premature deaths were mostly located in the northern Midwest, such as Wyoming and North Dakota, which have lower populations but higher emissions.

“This situation is a bit like secondhand smoke, but on a national scale,” study co-author Steven Barrett, director of the Laboratory for Aviation and the Environment at the Massachusetts Institute of Technology, told CNN. The researchers said estimates show between 90,000 and 360,000 deaths per year in the U.S. are linked to air pollution.

Experts have long been aware of air pollution’s ability to spread far from its source. but this new study, published in Nature, is the first to model its spread and resulting health impacts according to its source, Bloomberg reported.

The researchers developed a computer model of winds and chemical reactions in the atmosphere to track the movement of pollution created by the power generation, aviation, rail, road transportation, commercial and residential sectors, and other sectors to and from all 48 contiguous states. The model included U.S. Environmental Protection Agency (EPA) reports and health data to track air pollution and effects for the years 2005, 2011 and 2018.

They found that after air pollution is created in one state, winds may carry as much as half of it across the border to another state hundreds of miles away, according to MIT News. A separate study in January found that even low levels of air pollution exposure can lead to deadly health effects.

The results did show some progress over the course of the study, however.

For instance, there were 30,000 fewer early deaths caused by air pollution in 2018 than in 2015, driven by significant declines in deaths from power plant and road transportation pollution, the study found. Deaths from air pollution created in a different state also dropped from 53 percent to 41 percent.

Much of that progress was tied to EPA regulations such as the 2011 Cross-State Air Pollution Rule and reduced coal use, Barrett told Science Magazine. But the Cross-State rule only applies to some states and emissions from just a few sectors, The New York Times reported.

Meanwhile, the researchers did find that deaths related to emissions from heating homes and businesses increased by nearly 40 percent since 2005, as the ammonia and nitrogen oxide byproducts are more likely to become toxic particles in the atmosphere.

“They may not have seemed so important 10 or 20 years ago, but these commercial and residential emissions now look really important, in big part because progress has been made in other sectors,” Barrett told The New York Times. “Future research and future policy are going to have to bear down on these emissions and start controlling them.”

An October report by the National Bureau of Economic Research found that U.S. air pollution has actually become worse since President Donald Trump took office, during which time his administration has since moved to roll back a number of environmental regulations, including those related to air quality and fossil fuel extraction.

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