Half the matter in the universe was missing – we found it hiding in the cosmos — The Conversation


Diligence, technological progress and a little luck have together solved a 20 year mystery of the cosmos.
CSIRO/Alex Cherney, CC BY-ND

J. Xavier Prochaska, University of California, Santa Cruz and Jean-Pierre Macquart, Curtin University

In the late 1990s, cosmologists made a prediction about how much ordinary matter there should be in the universe. About 5%, they estimated, should be regular stuff with the rest a mixture of dark matter and dark energy. But when cosmologists counted up everything they could see or measure at the time, they came up short. By a lot.

The sum of all the ordinary matter that cosmologists measured only added up to about half of the 5% what was supposed to be in the universe.

This is known as the “missing baryon problem” and for over 20 years, cosmologists like us looked hard for this matter without success.

It took the discovery of a new celestial phenomenon and entirely new telescope technology, but earlier this year, our team finally found the missing matter.

Origin of the problem

Baryon is a classification for types of particles – sort of an umbrella term – that encompasses protons and neutrons, the building blocks of all the ordinary matter in the universe. Everything on the periodic table and pretty much anything that you think of as “stuff” is made of baryons.

Since the late 1970s, cosmologists have suspected that dark matter – an as of yet unknown type of matter that must exist to explain the gravitational patterns in space – makes up most of the matter of the universe with the rest being baryonic matter, but they didn’t know the exact ratios. In 1997, three scientists from the University of California, San Diego, used the ratio of heavy hydrogen nuclei – hydrogen with an extra neutron – to normal hydrogen to estimate that baryons should make up about 5% of the mass-energy budget of the universe.

Yet while the ink was still drying on the publication, another trio of cosmologists raised a bright red flag. They reported that a direct measure of baryons in our present universe – determined through a census of stars, galaxies, and the gas within and around them – added up to only half of the predicted 5%.

This sparked the missing baryon problem. Provided the law of nature held that matter can be neither created nor destroyed, there were two possible explanations: Either the matter didn’t exist and the math was wrong, or, the matter was out there hiding somewhere.

Remnants of the conditions in the early universe, like cosmic microwave background radiation, gave scientists a precise measure of the unverse’s mass in baryons.
NASA

Unsuccessful search

Astronomers across the globe took up the search and the first clue came a year later from theoretical cosmologists. Their computer simulations predicted that the majority of the missing matter was hiding in a low-density, million-degree hot plasma that permeated the universe. This was termed the “warm-hot intergalactic medium” and nicknamed “the WHIM.” The WHIM, if it existed, would solve the missing baryon problem but at the time there was no way to confirm its existence.

In 2001, another piece of evidence in favor of the WHIM emerged. A second team confirmed the initial prediction of baryons making up 5% of the universe by looking at tiny temperature fluctuations in the universe’s cosmic microwave background – essentially the leftover radiation from the Big Bang. With two separate confirmations of this number, the math had to be right and the WHIM seemed to be the answer. Now cosmologists just had to find this invisible plasma.

Over the past 20 years, we and many other teams of cosmologists and astronomers have brought nearly all of the Earth’s greatest observatories to the hunt. There were some false alarms and tentative detections of warm-hot gas, but one of our teams eventually linked those to gas around galaxies. If the WHIM existed, it was too faint and diffuse to detect.

The red circle marks the exact spot that produced a fast radio burst in a galaxy billions of light-years away.
J. Xavier Prochaska (UC Santa Cruz), Jay Chittidi (Maria Mitchell Observatory) and Alexandra Mannings (UC Santa Cruz), CC BY-ND

An unexpected solution in fast radio bursts

In 2007, an entirely unanticipated opportunity appeared. Duncan Lorimer, an astronomer at the University of West Virginia, reported the serendipitous discovery of a cosmological phenomenon known as a fast radio burst (FRB). FRBs are extremely brief, highly energetic pulses of radio emissions. Cosmologists and astronomers still don’t know what creates them, but they seem to come from galaxies far, far away.

As these bursts of radiation traverse the universe and pass through gasses and the theorized WHIM, they undergo something called dispersion.

The initial mysterious cause of these FRBs lasts for less a thousandth of a second and all the wavelengths start out in a tight clump. If someone was lucky enough – or unlucky enough – to be near the spot where an FRB was produced, all the wavelengths would hit them simultaneously.

But when radio waves pass through matter, they are briefly slowed down. The longer the wavelength, the more a radio wave “feels” the matter. Think of it like wind resistance. A bigger car feels more wind resistance than a smaller car.

The “wind resistance” effect on radio waves is incredibly small, but space is big. By the time an FRB has traveled millions or billions of light-years to reach Earth, dispersion has slowed the longer wavelengths so much that they arrive nearly a second later than the shorter wavelengths.

Fast radio bursts originate from galaxies millions and billions of light-years away and that distance is one of the reasons we can use them to find the missing baryons.
ICRAR, CC BY-SA

Therein lay the potential of FRBs to weigh the universe’s baryons, an opportunity we recognized on the spot. By measuring the spread of different wavelengths within one FRB, we could calculate exactly how much matter – how many baryons – the radio waves passed through on their way to Earth.

At this point we were so close, but there was one final piece of information we needed. To precisely measure the baryon density, we needed to know where in the sky an FRB came from. If we knew the source galaxy, we would know how far the radio waves traveled. With that and the amount of dispersion they experienced, perhaps we could calculate how much matter they passed through on the way to Earth?

Unfortunately, the telescopes in 2007 weren’t good enough to pinpoint exactly which galaxy – and therefore how far away – an FRB came from.

We knew what information would allow us to solve the problem, now we just had to wait for technology to develop enough to give us that data.

Technical innovation

It was 11 years until we were able to place – or localize – our first FRB. In August 2018, our collaborative project called CRAFT began using the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope in the outback of Western Australia to look for FRBs. This new telescope – which is run by Australia’s national science agency, CSIRO – can watch huge portions of the sky, about 60 times the size of a full Moon, and it can simultaneously detect FRBs and pinpoint where in the sky they come from.

ASKAP captured its first FRB one month later. Once we knew the precise part of the sky the radio waves came from, we quickly used the Keck telescope in Hawaii to identify which galaxy the FRB came from and how far away that galaxy was. The first FRB we detected came from a galaxy named DES J214425.25–405400.81 that is about 4 billion light-years away from Earth, in case you were wondering.

The technology and technique worked. We had measured the dispersion from an FRB and knew where it came from. But we needed to catch a few more of them in order to attain a statistically significant count of the baryons. So we waited and hoped space would send us some more FRBs.

By mid-July 2019, we had detected five more events – enough to perform the first search for the missing matter. Using the dispersion measures of these six FRBs, we were able to make a rough calculation of how much matter the radio waves passed through before reaching earth.

We were overcome by both amazement and reassurance the moment we saw the data fall right on the curve predicted by the 5% estimate. We had detected the missing baryons in full, solving this cosmological riddle and putting to rest two decades of searching.

Sketch of the dispersion measure relation measured from FRBs (points) compared to the prediction from cosmology (black curve). The excellent correspondence confirms the detection of all the missing matter.
Hannah Bish (University of Washington), CC BY-ND

This result, however, is only the first step. We were able to estimate the amount of baryons, but with only six data points, we can’t yet build a comprehensive map of the missing baryons. We have proof the WHIM likely exists and have confirmed how much there is, but we don’t know exactly how it is distributed. It is believed to be part of a vast filamentary network of gas that connects galaxies termed “the cosmic web,” but with about 100 fast radio bursts cosmologists could start building an accurate map of this web.

This article was updated to indicate that Australia’s national science agency, CSIRO, operates the new telescope.

[Insight, in your inbox each day. You can get it with The Conversation’s email newsletter.]The Conversation

J. Xavier Prochaska, Professor of Astronomy & Astrophysics, University of California, Santa Cruz and Jean-Pierre Macquart, Associate Professor of Astrophysics, Curtin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

GDP measures the wrong things: Here’s something better — Marilyn Waring, TEDxChristchurch

“Because humankind and our planet need another way” — Marylyn Waring

In 1953, a group of economists got together to create the Gross Domestic Product: a way to measure everything that involves a market transaction. But GDP doesn’t measure the single biggest contributor to almost every nation’s economy—the unpaid labour performed every day in homes, in families, and by volunteers—and it doesn’t account for the cost of externalities like the environment. In this funny, engaging and enlightening talk, noted economist Dr Marilyn Waring makes a compelling and accessible argument for finding a better way to measure what counts.

Dr Marilyn Waring is a prominent New Zealand economist and feminist, and a leading activist for human rights.

At 23 years old, Marilyn was one of the youngest New Zealanders ever elected to Parliament. She pushed to have marital rape criminalised and threatened to cross the floor to vote with Labour on a nuclear-free New Zealand, precipitating the 1984 snap election.

On leaving Parliament, Marilyn earned a PhD in Political Economy; her research has been influential in establishing the field of feminist economics. She argues for the economic importance of women’s unpaid work and the environment, revealing the serious policy consequences caused by ignoring these when calculating national economic measures such as GDP.

More recently, Marilyn’s work has focused on the inequities of globalisation and the importance of acknowledging women’s work as an international human rights issue. She has undertaken a range of projects dealing with these issues for the United Nations. This talk was given at a TEDx event using the TED conference format but independently organized by a local community. Learn more at https://www.ted.com/tedx

@ColoradoStateU atmospheric scientists identify cleanest air on Earth in first-of-its-kind study

Aerosol filter samplers probe the air over the Southern Ocean on the Australian Marine National Facility’s R/V Investigator. Photo by Kathryn Moore via Colorado State University

Here’s the From Colorado State University (Jayme DeLoss):

Colorado State University Distinguished Professor Sonia Kreidenweis and her research group identified an atmospheric region unchanged by human-related activities in the first study to measure bioaerosol composition of the Southern Ocean south of 40 degrees south latitude. Kreidenweis’ group, based in the Department of Atmospheric Science, found the boundary layer air that feeds the lower clouds over the Southern Ocean to be pristine – free from particles, called aerosols, produced by anthropogenic activities or transported from distant lands. Their findings are published in Proceedings of the National Academy of Sciences.

Weather and climate are complex processes connecting each part of the world to every other region, and with climate changing rapidly as a result of human activity, it’s difficult to find any area or process on Earth untouched by people. Kreidenweis and her team suspected the air directly over the remote Southern Ocean that encircles Antarctica would be least affected by humans and dust from continents. They set out to discover what was in the air and where it came from.

“We were able to use the bacteria in the air over the Southern Ocean as a diagnostic tool to infer key properties of the lower atmosphere,” said research scientist Thomas Hill, coauthor on the study. “For example, that the aerosols controlling the properties of SO clouds are strongly linked to ocean biological processes, and that Antarctica appears to be isolated from southward dispersal of microorganisms and nutrient deposition from southern continents. Overall, it suggests that the SO is one of very few places on Earth that has been minimally affected by anthropogenic activities.”

CSU researcher Kathryn Moore collected bioaerosol samples aboard the R/V Investigator, an Australian Marine National Facility research vessel. Photo by Kendall Sherrin (CSIRO, AU) via Colorado State University

Samples were collected during the NSF-funded SOCRATES field campaign, led by research scientist and coauthor Paul DeMott. Graduate student Kathryn Moore sampled the air in the marine boundary layer, the lower part of the atmosphere that has direct contact with the ocean, aboard the Research Vessel Investigator as it steamed south from Tasmania to the Antarctic ice edge. Research scientist and first author Jun Uetake examined the composition of airborne microbes captured from the ship. The atmosphere is full of these microorganisms dispersed over hundreds to thousands of kilometers by wind.

Using DNA sequencing, source tracking and wind back trajectories, Uetake determined the microbes’ origins were marine, sourced from the ocean. Bacterial composition also was differentiated into broad latitudinal zones, suggesting aerosols from distant land masses and human activities, such as pollution or soil emissions driven by land use change, were not traveling south into Antarctic air.

These results counter all other studies from oceans in the subtropics and northern hemisphere, which found that most microbes came from upwind continents. Plants and soil are strong sources of particles that trigger freezing of supercooled cloud droplets, known as ice-nucleating particles. This process reduces cloud reflectivity and enhances precipitation, increasing the amount of sunlight reaching the surface and altering Earth’s radiative balance.

A wave breaks off the side of the Australian Marine National Facility research vessel, the R/V Investigator, during the SOCRATES field campaign. CSU researchers found sea spray emissions dominate cloud-forming material over the Southern Ocean. Photo by Peter Shanks (CSIRO, AU) via Colorado State University.

Over the Southern Ocean, sea spray emissions dominate the material available for forming liquid cloud droplets. Ice-nucleating particle concentrations, rare in seawater, are the lowest recorded anywhere on the planet.

The air over the Southern Ocean was so clean that there was very little DNA to work with. Hill attributed the quality of their results to Uetake and Moore’s clean lab process.

“Jun and Kathryn, at every stage, treated the samples as precious items, taking exceptional care and using the cleanest technique to prevent contamination from bacterial DNA in the lab and reagents,” Hill said.

Your guide to #Colorado Bike Month 2020 — @BicycleColorado #bikemonth

The “Emerald Mile” at Centennial Gardens in Denver, May 2020.

Click here for all the inside skinny:

National Bike Month aims to celebrate all that the bike is and can be, and create a movement of people organizing together for better bicycling (albeit, this year it is mostly virtual organization!). Our friends at the League of American Bicyclists say, “Whether you’re riding for fun, fitness or with family, or taking essential trips to work or shop, you are part of our movement for safer streets, connected communities, a healthier planet, and happier people.”

Though most of the country and the Western Slope of Colorado celebrate Bike Month in May each year, the Bike Month celebration is in June for the Colorado central mountains and Front Range. This is when the snow has melted enough for our mountain towns to join the fun!

Summer at America’s national parks kicks off with long lines and crowded trails — National Geographic

Lily Lake via Rocky Mountain National Park

Here’s an in-depth look at the opening of national parks from Krista Langlois that’s running in National Geographic. Click through for all the photos and graphics. Here’s an excerpt:

Despite these concerns—and questions of whether it’s premature to open parks at all—the Park Service is doing some things right. Rocky Mountain National Park is implementing a “timed entry” system to spread out crowds by giving people a specific time slot when they’re allowed to enter the park. Other parks may follow suit.

Yosemite, which plans to reopen in June, is among a number of parks limiting visitors to roughly half its typical capacity. Yellowstone has spent $135,000 on sanitation, protective gear, and educational signs. The Park Service is distributing masks and gloves to employees, albeit unevenly, and trying to educate visitors on safe practices: staying six feet apart, choosing parks close to home, and avoiding traveling long distances to get to a park.

(Related: Trespassing and vandalism abound at national parks that remain open during the pandemic.)

Some parks, like Yosemite, remain closed, while others were relatively quiet over Memorial Day weekend. A visitor from Big Cypress National Preserve in Florida said the park was practically empty, perhaps because of rain. A hiker in Washington’s Olympic National Park, where many roads remained closed, reported seeing few crowds. A ranger at Virginia’s George Washington Memorial Parkway, which connects trails around Washington, D.C. and is administered by the Park Service, said that the people he saw hiking were mostly in small groups spaced well apart.

Still, some parks just aren’t set up for social distancing. It’s nearly impossible to stay six feet apart on the boardwalks around Yellowstone’s geysers, for example, or the narrow hiking trails in Zion. That means that the responsibility to stay safe falls both to parks and individual travelers. “It’s really important for visitors to go online and check the park’s website before they go so they can make sure they’re prepared,” Brengel said. “If a park is going to be too crowded or a trail is closed, they should have a plan B.”

Having a backup plan—such as visiting a less-busy national forest—is one of the recommendations of the new #RecreateResponsibly initiative, a collaboration between nonprofits, outdoor businesses, and land managers. Other recommendations include adventuring with members of your household; choosing low-risk activities to decrease the chances of needing already-strained emergency services, such as hiking instead of rock climbing; and being self-sufficient, such as packing your own lunch instead of counting on a park restaurant to be open. The #RecreateResponsibly initiative emphasizes staying close to home, because non-essential travel is still discouraged by the nation’s top health officials.

Gold rush, mercury legacy: Small-scale mining for gold has produced long-lasting toxic pollution, from 1860s California to modern Peru — The Conversation


Artisanal small-scale gold mining polluted this stream and deforested sections of the Madre de Dios area of Peru.
Mario Tama/Getty Images

Jacqueline Gerson, Duke University; Austin Wadle, Duke University, and Jasmine Parham, Duke University

Gold is everywhere in modern life, from jewelry to electronics to smartphones. The global electronics industry alone uses 280 tons annually. And that demand keeps growing.

But most people know little about the environmental impacts of gold mining. About 15% of world gold production is from artisanal and small-scale mining in over 70 countries throughout Asia, Africa and South America. These operations employ 10 to 19 million workers. They often are poorly policed and weakly regulated.

Artisanal mining might sound quaint, but it is usually criminal activity and results in widespread environmental damage. It also is the largest source of mercury pollution in the world today, far exceeding other activities such as coal combustion and cement manufacturing. While mercury is an element that occurs naturally in the Earth’s crust, it has many toxic effects on humans and animals, even at very low exposure levels.

We have studied mercury pollution from artisanal gold mining for the past five years. The extraction methods that these operations use today are not drastically different from processes that miners employed in the California gold rush in the mid-1800s. Today we see history repeating itself in places like the Peruvian Amazon, where small-scale gold mining threatens to leave behind long-lasting social, economic and environmental consequences.

Mercury contamination from gold mining

Mercury has been used for centuries as an inexpensive and easy way to collect gold. The process begins when miners pump a mixture of water and sediment from a riverbed into a trough, where the sediment can be suspended into a slurry – a technique known as hydraulic mining.

Next they add mercury, which binds to the gold particles, forming an amalgam. Mercury is heavier than pure gold, so the balls of amalgam sink to the bottom of buckets or holding ponds where they can be collected. Finally, workers burn off the mercury – often with a hand torch or in a crude stove – leaving gold metal behind.

This process releases mercury to the environment in two forms. First, tailings, or waste material, can contaminate nearby land and aquatic ecosystems. Second, mercury vapor enters the atmosphere and can travel long distances before being deposited to land and water via rainfall or small dust particles.

In the environment, microbes can transform mercury into a more potent form known as methylmercury. Methylmercury can be taken up by bacteria, plankton and other microorganisms that are then consumed by fish and build up to dangerous concentrations in animals higher on the food chain.

When artisanal gold miners burn mercury, it is released into the atmosphere and can end up on land or in water. Mining tailings (solid waste) also deposit mercury onto land or into water. Microbes in the environment can convert mercury into methylmercury, which can be taken up by living organisms, including fish and people.
Arianna Agostini, Rand Alotaibi, Arabella Chen, Annie Lee, Fernanda Machicao, Melissa Marchese, CC BY-ND

Methylmercury is a potent neurotoxin that is harmful to humans and wildlife, such as endangered giant otters that feed high on the food web within these contaminated environments. It can cause severe central nervous system damage that results in sensory and motor deficits, as well as behavioral impairments such as difficulty swimming in aquatic animals and flying in birds.

A lasting legacy in California

During the U.S. gold rush, hydraulic mining operations in California completely denuded forested landscapes, altered the course of rivers, increased sedimentation that clogged river beds and lakes and released enormous amounts of mercury onto the landscape. California wildcat miners used an estimated 10 million pounds of mercury from the 1860s through the early 1900s. Most of it was released to the environment as tailings and mercury vapor.

Panning for gold in California, 1850.
Unknown/Wikipedia

A century later, water, soil and sediments in the Sierra Nevada region still have high concentrations of mercury and methylmercury, often exceeding thresholds set by the U.S. Environmental Protection Agency. Studies show that fish, birds and other organisms living near historically mined sites in California have high mercury concentrations in their bodies compared to those inhabiting nearby unmined landscapes. Extreme erosion on mountain slopes can continuously mobilize mercury deposited decades ago.

History repeats itself

Like men who traveled to California in 1849 hoping to strike it rich, today’s artisanal miners around the world are mainly low-skilled workers hoping to support themselves and their families.

In Peru, where we have studied this process, artisanal miners produce an estimated 35,000 to 40,000 pounds of gold per year. The industry offers an opportunity for upward mobility for substantial numbers of Peruvians, who generally migrate to mining sites from coastal and mountain towns.

As a result, gold rush towns have boomed over the past 20 years. The Inter-Oceanic Highway, which was completed in 2012 and runs from Brazil’s Atlantic coast to Peru’s Pacific coast, has connected these towns to larger cities and increased access to the Peruvian Amazon.

Producing a pound of gold requires about 6 pounds of mercury. Given that at least 50% of the mercury used in these operations is lost to the environment, we estimate that artisanal gold mining in Peru alone releases nearly 50,000 pounds of mercury annually.

Mining in this region is producing impacts that are strikingly similar to the hallmarks of the California gold rush. For example, miners in the Peruvian Amazon have cleared more than 250,000 acres of forest since 1984.

The Madre de Dios River, which runs through a zone that has seen substantial mining, will likely continue to erode the landscape, carrying mercury-laden particles downstream. Long-lasting mercury contamination in this region threatens the highest biodiversity on the planet and many indigenous communities.

Comparison of landscape change from gold mining during the California gold rush (left) and modern artisanal mining in Peru (right).
Bancroft Library, UC Berkeley (left); Arabella Chen (right)

Gold mining in 19th-century California sparked a wave of western migration and helped drive settlement of what we now refer to as the western United States at a time when mining and environmental pollution were unregulated. Today, use of mercury in artisanal gold mining is regulated by the 2013 Minamata Convention on Mercury, which has been signed by 128 countries – including Peru. Yet there is little on-the-ground regulation in most countries. Nor have governments addressed legacy pollution and deforestation from gold mining.

Illegal artisanal gold mining is a major source of income for local communities in places like the Madre de Dios region of Peru. As long as people all over the world continue to demand more gold, we believe that they are just as responsible as miners and local policymakers for the environmental degradation gold mining causes.

[You’re smart and curious about the world. So are The Conversation’s authors and editors. You can get our highlights each weekend.]The Conversation

Jacqueline Gerson, Ph.D. Candidate in Ecology, Duke University; Austin Wadle, Ph.D. Student in Civil and Environmental Engineering, Duke University, and Jasmine Parham, Ph.D. Student in Biology, Duke University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

#Colorado joins multistate lawsuit challenging federal government’s reckless rollback of national clean car standards — @PWeiser #ActOnClimate #KeepItInTheGround

Denver’s Brown Cloud via the Denver Regional Council of Governments.

Here’s the release from Phil Weiser’s office (Lawrence Pacheco):

Attorney General Phil Weiser today joined a multistate coalition in filing a lawsuit challenging the federal government’s final rule rolling back the national clean car standards.

“The administration’s illegal rollback rejects sound science, ignores environmental harms caused by carbon pollution, and will cost consumers more at the pump. Colorado is joining this lawsuit challenging the administration’s illegal action in order to defend our state’s fuel emission standards that are stronger than the national standards,” Weiser said. “By making more zero-emission vehicles available to Coloradans, we can address climate change and protect our air quality.”

In 2010, the EPA, states and automakers established a unified national program harmonizing improvements in fuel economy and reductions in greenhouse gas emissions from passenger cars and light trucks and then applied those standards to vehicle model years 2017-2025. The administration took its first step toward dismantling the national clean car standards in 2018, alleging that the standards were no longer appropriate or feasible despite the fact that the auto industry was on track to meet them.

On March 31, 2020, the EPA announced its final rule rolling back the clean car standards. The rule takes aim at the corporate average fuel efficiency standards, requiring automakers to make only minimal improvements to fuel economy on the order of 1.5 percent annually instead of the previously anticipated annual increase of 5 percent. The rule also diminishes the requirements to reduce vehicles’ greenhouse gas emissions, allowing hundreds of millions of metric tons of avoidable carbon emissions into our atmosphere over the next decade.

In the lawsuit filed today, the coalition argues that the final rule unlawfully violates the Clean Air Act, the Energy Policy and Conservation Act, and the Administrative Procedure Act.

Attorney General Weiser joins the attorneys general of California, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, Nevada, New Jersey, New Mexico, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, Vermont, Virginia, Washington, Wisconsin, and the District of Columbia. The California Air Resources Board and the Cities of Los Angeles, New York, San Francisco, and Denver also joined the coalition in filing the lawsuit.

From The Denver Post (Bruce Finley) via The Broomfield Enterprise:

Led by California, the states and major cities — including Denver — have asked federal judges to reverse Trump’s Safer Affordable Fuel Efficient Vehicle Rule, which was finalized in March and loosened requirements set under the Obama administration to make cars and light pickup trucks about 5% more efficient each year.

Trump’s rule means vehicles over the next decade would emit hundreds of millions more tons of carbon dioxide and other heat-trapping gases into the atmosphere. Instead of making cars that can cover 54 miles per gallon by 2025, automakers could make cars that cover 40 mpg by 2026.

Federal officials argue this will make new cars more affordable, encouraging more Americans to upgrade to relatively cleaner cars.

This lawsuit, filed in the U.S. Court of Appeals for the District of Columbia Circuit, contends the Trump rule violates the Clean Air Act, the Energy Policy and Conservation Act, and the Administrative Procedure Act.

“We so depend on protecting our land, air and water for our lifestyle,” Weiser said in a conference call Wednesday with attorneys general Xavier Becerra of California and Dana Nessel of Michigan.

“Climate change is not a theoretical, looming challenge. It is there today,” Weiser said, referring to “less natural snowpack than ever before” and a growing burden on future generations to deal with climate change impacts.

He cited a U.S. Supreme Court case that, more than a decade ago, established EPA power to regulate pollution that causes climate change.

“It is the job of the courts to get the EPA on track,” Weiser said.

Denver Mayor Michael Hancock, in a prepared statement, noted that vehicle emissions are a top contributor to air pollution over the city and are fueling climate change — causing harm to the public’s health and prosperity.

“If these rules are rolled back, the Trump administration will negate the progress that has happened across the country in these areas during a critical point in history,” Hancock said. “We are past due for our country taking more meaningful action, which is why Denver joined this important lawsuit.”

In 2010, EPA officials, state leaders and automakers began working to improve vehicle fuel efficiency and reduce emissions of heat-trapping gases and other pollution from passenger cars and light trucks made after 2017. Automakers have been working to meet these standards. Since 2018, Trump administration officials have been saying the standards are inappropriate and no longer feasible.

Rush hour on Interstate 25 near Alameda. Screen shot The Denver Post March 9, 2017.

Here’s a release about a coalition that has also filed a lawsuit from Environment Colorado (Ellen Montgomery, Hannah Collazo, Mark Morgenstein):

Environment America, an affiliate of Environment Colorado, along with ten other public interest organizations, filed a lawsuit today in the U.S. Court of Appeals for the D.C. Circuit opposing the Trump administration’s action to weaken federal clean car standards. This lawsuit follows litigation that Environment America and the other public interest groups previously filed challenging part one of the action, which attempts to block California and other states from setting stronger tailpipe emissions standards.

The petition challenges a final rule issued jointly by the Environmental Protection Agency (EPA) and the Department of Transportation’s National Highway Traffic Safety Administration (NHTSA). The agencies’ action violates several federal statutes, including the Energy Policy and Conservation Act, the Clean Air Act, and the Administrative Procedure Act.

“The EPA’s own analysis shows that this will reverse climate progress. The clean car standards should protect our climate, our health and the future of our children and grandchildren,” said Hannah Collazo, State Director with Environment Colorado. “This plan is unacceptable. Not only does it fail to adequately address the climate crisis — it sets us back years when we have no time to lose.”

The previous federal clean car standards would have doubled vehicular fuel economy and would have cut global warming pollution in half for cars sold in 2025. The weakened standards could result in more than 900 million additional metric tons of global warming pollution in our atmosphere.

The other petitioners are the Center for Biological Diversity, Communities for a Better Environment, Consumer Federation of America, Conservation Law Foundation, Environmental Defense Fund, Environmental Law & Policy Center, Natural Resources Defense Council, Public Citizen, the Sierra Club, and the Union of Concerned Scientists.

Denver photo courtesy of Michael Levine-Clark, Flickr Creative Commons.