Wednesday, April 20, 2022

Energy shift creates opening for 'world's largest batteries'

by John Flesher

Sprawled like a gigantic swimming pool atop a bluff overlooking Lake Michigan is an asphalt-and-clay pond holding enough water to produce electricity for 1.6 million households.

It's part of the Ludington Pumped Storage Plant, which uses simple technology: Water is piped from a lower reservoir—the lake, in this case—to an upper one, then released downhill through supersized turbines.

Supporters call these systems "the world's largest batteries" because they hold vast amounts of potential energy for use when needed for the power grid.

The hydropower industry considers pumped storage the best answer to a question hovering over the transition from fossil fuels to renewable energy to address climate change: where to get power when the sun isn't shining or the wind isn't blowing.

"I wish we could build 10 more of these. I love 'em," Eric Gustad, community affairs manager for Consumers Energy, said during a tour of the Ludington facility.

But the utility based in Jackson, Michigan, has no such plans. Environmental and logistical challenges and potential costs in the billions led Consumers to sell another would-be site near the lake years ago. It's now upgrading the existing plant with co-owner DTE Energy.

Constructing a new one "doesn't make financial sense," Gustad said. "Unless we get some help from the state or federal government, I don't see it happening any time soon."

STUCK IN NEUTRAL

The company's decision illustrates the challenges facing pumped storage in the U.S., where these systems account for about 93% of utility-scale energy in reserve. While analysts foresee soaring demand for power storage, the industry's growth has lagged.

The nation has 43 pumped storage facilities with a combined capacity of 22 gigawatts, the output of that many nuclear plants. Yet just one small operation has been added since 1995—and it's unknown how many of more than 90 planned can overcome economic, regulatory and logistical barriers that force long delays.

Three projects have obtained licenses from the Federal Energy Regulatory Commission, but none are being built. Developers of a long-planned Oregon facility expect work to begin in 2023. A Montana company that got a license five years ago needs a utility to operate the plant and buy its storage capacity before construction starts.

By contrast, more than 60 are being built worldwide, mostly in Europe, India, China and Japan.

"The permitting process is crazy," Malcolm Woolf, president of the National Hydropower Association, complained during a January hearing of the Senate Energy and Natural Resources Committee, saying it involves too many agencies.

Although FERC permits new facilities and relicenses existing ones, other federal, state and tribal offices have roles, spokesperson Celeste Miller said. "Every project is unique. All have various case-specific issues," she said.

The industry is lobbying for an investment tax credit similar to what solar and wind get. President Joe Biden's Build Back Better plan includes the tax break but is stuck in Congress.

Pumped storage dates from the early 1930s. But most systems were built decades later to warehouse excess electricity from nuclear plants and release it when needed.

The storage facilities also serve as a safety net in sudden power interruptions. When a New England nuclear unit tripped offline in 2020, Woolf said, "the lights in Boston didn't flicker" because two pumped storage stations provided backup power.

While nuclear, coal and natural gas plants can operate continuously, wind and solar can't—so the market for reserve power likely will grow. National Renewable Energy Laboratory models show U.S. storage capacity may rise fivefold by 2050.

"We're going to bring hundreds of gigawatts of clean energy onto the grid over the next few years and we need to be able to use that energy wherever and whenever it's needed," Energy Secretary Jennifer Granholm said last year.

LOCATION, LOCATION, LOCATION

Using computer mapping, Australian National University engineers identified more than 600,000 "potentially feasible" pumped storage sites worldwide—including 32,000 in the U.S.—that could store 100 times the energy needed to support a global renewable electricity network.

But the study didn't examine whether sites would meet environmental or cultural protection standards or be commercially viable. Its website acknowledged, "Many or even most ... may prove to be unsuitable."

Environmentalists are cool toward pumped storage because reservoirs typically are formed by hydropower dams, which block fish pathways, damage water quality and emit methane, a potent greenhouse gas. Also, most plants continuously draw water from rivers.

But recent designs envision "closed-loop" systems that tap a surface or underground supply, then repeatedly cycle that water between reservoirs. Water would be added only to make up for evaporation or leaks.

The Hydropower Reform Coalition, representing conservation groups, says it might support such projects under "very limited circumstances."

Yet some are drawing resistance, including the Goldendale Energy Storage Project in Washington state. It would pipe water between two 60-acre (24.3-hectare) reservoirs on opposite sides of a hill.

The facility could power nearly 500,000 homes for up to 12 hours, according to Rye Development, spearheading the project. It's seeking FERC licensing and is scheduled to go online in 2028 but still needs a state water quality permit.

Environmental groups fear harm to wetlands and wildlife habitat, while tribes say the project would encroach on a sacred site.

"What are we willing to sacrifice to get this technology online?" said Bridget Moran, an associate director of American Rivers.

Developers say the project would include cleanup of the polluted lower reservoir area.

The U.S. Department of Energy has launched a web-based tool to help developers find the best locations.

A recent Michigan Technological University study identified hundreds of abandoned U.S. mines that could host pumped storage, with upper reservoirs at or near the surface and lower ones below ground.

They are close enough to transmission and distribution infrastructure and to solar and wind generating facilities, the report says.

"All these holes in the ground are ready to go," said study co-leader Roman Sidortsov, an energy policy associate professor.

But while some decommissioned mines might be better for the environment, a project in New York's Essex County stalled over water pollution concerns.

COMPETITIVE FUTURE

As the market for stored energy grows, new technologies are emerging.

Texas-based Quidnet Energy has developed a pumped storage offshoot that forces water underground, holds it amid rock layers and releases it to power turbines. The company announced a project in March with San Antonio's municipal utility.

Energy Vault, a Swiss startup, devised a crane powered by renewable energy to lift and stack 35-ton bricks. When energy is needed, the bricks are lowered by cables that spin a generator.

For now, batteries are the leading competitor to pumped storage plants, which can generate power for eight to 16 hours. Lithium-ion batteries typically last up to four hours but longer-duration ones are in the works.

"Are we going to get to the point where an eight-hour battery is cheaper than a pumped storage plant? That's the billion-dollar question," said Paul Denholm, an analyst with the National Renewable Energy Laboratory.

A 2016 Energy Department report said the U.S. network has a potential for 36 gigawatts of new pumped storage capacity.

"We don't think pumped storage is the be-all, end-all but it's a vital part of our storage future," said Cameron Schilling, vice president of markets for the hydropower association. "You can't decarbonize the system without it."Pumped hydro provides the vast majority of long-term energy storage

Stars align for fintech, but regulators are wary of dangerous risks

by Steven Harras

Commercials featuring NBA legend LeBron James, comedy icon Larry David and movie star Matt Damon touting digital assets were prominent on this year's telecast of the Super Bowl played at California's SoFi Stadium, named for a financial technology service company.

But as the stars promote the digitalization of financial services, tossing phrases such as fintech, blockchain, artificial intelligence, digital assets, Bitcoin and machine learning into popular culture, regulators and lawmakers are moving more slowly, worried about the downside of innovations that could transform daily life.

Among the fears are that the technology is too complicated for many consumers; poses security, privacy, consumer protection and discrimination risks; and consumes too much energy as politicians, companies and consumers increasingly worry about climate change. The decentralized character of some of the technology even raises questions about what entity can be regulated.

"The velocity and magnitude of marketplace change coming in the crypto space—cryptoassets, blockchains, central bank digital currencies, DeFi, Web3, DAOs, the metaverse—is unlike anything we've seen in our lifetimes," said Jo Ann Barefoot, CEO of the Alliance for Innovative Regulation.

A former deputy comptroller of the currency and staff member for the Senate Banking Committee, Barefoot said industry and regulators don't even agree on a catchall term for all the innovations, much less on how to regulate it.

"These innovations are also mold-breakers, in terms of who is supposed to regulate what at the federal, state and international level, and in terms of how to get leverage on them," she said.

Government reports, including from international organizations, hint at the challenge.

"Economies rely on central authorities and trusted intermediaries to facilitate business transactions. Blockchain is a technology that could reduce the need for such entities," the Government Accountability Office said in a March report. It also said blockchain-based financial applications can facilitate illicit activity and may reduce consumer and investor protections compared to traditional finance.

The GAO found that blockchain is useful for some applications but limited or even problematic for others. Blockchain's resistance to tampering, for example, may make it suitable for applications with many participants who don't trust each other, but it may be too complex for uses where the participants trust each other, the GAO said.

The International Organization of Securities Commissions warned last month that decentralized finance, or DeFi, may remove intermediaries such as banks and brokers, institutions that are closely regulated. The result may be investors deprived of advice, lack of capital controls and compliance measures, it said.

"Absent these intermediaries—and without appropriate substitute mechanisms—the risk for investor and market harm may be exacerbated," IOSCO said. "Most of the new services which are emerging replicate more traditional financial services and activities, but with weaker regulation and increased risks for investors."

The IOSCO DeFi Working Group is led by the Securities and Exchange Commission and includes two other U.S. regulators, the Commodity Futures Trading Commission and the Financial Industry Regulatory Authority, which oversees brokers.

Melissa Koide, the CEO of FinRegLab, a Washington research group, and Kelly Thompson Cochran, the group's deputy director, are trying to use their ties to the fintech industry and to Capitol Hill to draw attention to the technology's potential benefits, but also to raise red flags about over-reliance.

Koide said by email and in an interview that artificial intelligence and machine learning, combined with new types of data, present enormous potential to improve financial inclusion and equality but also enormous risk of deepening bias and exclusion.

"Careful, use-case specific research to understand how AI/ML with new data may affect consumers is essential to getting the rules of the road right in terms of how we regulate to protect people while making sure the benefits of the more complex analytics are trustworthy, inclusive, and beneficial," she said.

Koide said FinRegLab will release empirical research evaluating just those questions in the context of consumer credit this month at a symposium on artificial intelligence that the group is co-hosting with the Commerce Department, the National Institute of Standards and Technology, and the Stanford Institute for Human-Centered Artificial Intelligence.

She said the symposium will have representatives of government, industry, advocacy and academia address how these technologies, particularly in sectors like financial services and health care, relate to ensuring inclusive economic growth, supporting diversity and financial inclusion, and mitigating risks such as bias and unfairness.

Before establishing FinRegLab, Koide spent four-and-a-half years in President Barack Obama's administration as the Treasury Department's assistant secretary for consumer policy. She helped lead the creation of Treasury's "myRA" program, designed to help low- and middle-income earners begin saving for retirement. The Trump administration shut down the program in 2017, saying it wasn't cost effective.

Utopia or dystopia?

Barefoot said the technology is offering a utopian versus dystopian moment.

"New financial technologies, broadly defined, are either going to make financial services a lot better or a lot worse, depending on how we regulate them," she said.

"Every innovation, from AI to encryption to blockchain, has potential to bring breakthroughs in fixing longstanding problems like financial access, inclusion and fairness," she said. "They also could make everything worse by introducing or exacerbating bias and eroding privacy."

Barefoot said Congress and regulators face challenges that are arguably even greater than those in the financial crisis because the issues are more novel.

"Regulators are facing incredible challenges in figuring out how best to regulate new technologies in finance. Speaking as a former bank regulator, I think the single best step they can take is to use these technologies, themselves. That will be the fastest way to understand them."

As regulators and the industry assess the financial strengths and weaknesses of the innovation, others are seeing it against a backdrop of climate change and global warming.

The GAO report noted evidence that blockchains use more energy than traditional centralized databases because they must store copies of transactions across several or many computers.

A 2019 study in the energy journal Joule estimated that Bitcoin, the most popular cryptocurrency, had annual emissions between 22 million and 22.9 million metric tons of carbon dioxide, about as much as the nations of Jordan and Sri Lanka combined. A 2021 report by Galaxy Digital Holdings Ltd., an asset management company, estimated that Bitcoin networks consume around half the energy of the banking or gold industries.

Bitcoin's electricity use also results from its miners' need for high-powered computers to solve the complex mathematical equations that unlock new bitcoins, of which there is a finite amount. Unlocking Bitcoins gives the miners a big payout, which in turn provides the incentive to maintain the network.

The influx of Bitcoin miners to areas with access to cheap and plentiful energy has brought attention from Congress. Energy costs and demands of blockchain technology are of particular concern to lawmakers from states that have access to cheap power. Bitcoin miners have flooded to areas such as Washington state, New York and Montana because of the availability of low-cost hydroelectricity.

Washington state is experiencing "a tremendous increase in electricity demand attributed to mining of Bitcoin," Sen. Maria Cantwell, D-Wash., said at a Senate Energy and Natural Resources Committee hearing in August 2018. "To put this into context, a recent estimate found that a single bitcoin transaction uses as much electricity as an average household in the Netherlands uses in a month."

Montana Sen. Steve Daines, a Republican, said at the same hearing that his state has two Bitcoin mining facilities that collectively require about 80 megawatts of electricity, "sometimes surpassing even traditional mining projects." He expressed concern that as the demand from Bitcoin miners increases, it could pose a threat to energy supply and prices for Montana as a whole.

Brandon Dalling, a partner at the New York office of the international law firm King & Spalding, agreed that coin-mining is "energy intensive." He said the Pacific Northwest's cheap, low-cost hydro power has made it an attractive location for crypto-mining. This has proved popular with some segments of the local population who see the miners adding to the tax baseBitcoin carbon emissions rise as mining moves to US and other countries

Journal information: Joule

Distributed by Tribune Content Agency, LLC.

Amazon taps former Attorney General Loretta Lynch to run racial equity audit

by Lauren Rosenblatt

Amazon is launching a racial equity audit to examine any uneven effects of its policies, programs and practices on hourly employees.

Facing pressure from shareholders to provide more information about pay gaps, working conditions and procedures that may be negatively affecting women, people of color and other minorities, Amazon announced in a recent legal filing it had hired former U.S. Attorney General Loretta Lynch to conduct an audit to "evaluate any disparate racial impacts on our nearly one million U.S. hourly employees resulting from our policies, programs and practices."

The audit is part of its "existing commitment to human and civil rights, racial equity, diversity and inclusion and nondiscrimination," the filing read.

Amazon said it would publicly release the results of the audit but declined to share when it would be completed or specifics about what the audit would study.

The audit will include only hourly employees and will not include workers at Whole Foods or PillPack, Amazon's pharmaceutical centers where workers pack and ship prescriptions.

Attorneys at Paul, Weiss, Rifkind, Wharton & Garrison, a law firm based in New York City, will conduct the audit, and Lynch will lead it. The firm also recently represented Amazon in an antitrust lawsuit filed by Washington, D.C., Attorney General Karl Racine challenging Amazon's pricing policies. In March, a D.C. Superior Court judge dismissed the case.

Amazon tucked the announcement of the racial equity audit into an annual filing with the Securities and Exchange Commission, ahead of its quarterly earnings call with investors next week and its meeting with shareholders in May.

A shareholder proposal requesting a similar audit failed to pass at Amazon's last annual meeting, but 44% of stakeholders voted in favor of it. This year, shareholders again introduced a proposal for a diversity and equity audit, asking for a report that would analyze the effects of its policies, practices, products and services "through a racial equity lens." It asks for an assessment of Amazon's diversity, equity and inclusion strategy and its effectiveness as well as how the company is addressing any implicit biases.

"Because of the pattern and magnitude of controversies repeatedly facing Amazon, we believe that it is in shareholders' best interests for Amazon to proactively identify and mitigate risks through an independent racial equity audit," the proposal reads.

Ahead of Amazon's annual meeting, shareholders also introduced several other proposals to study how the company's policies and products could be contributing to racial and gender divides, including:

Whether Amazon's health and safety practices give rise to any racial and gender disparities in workplace injury rates, affecting long-term earnings and career advancement for women and minority warehouse workers
More information on gender and racial pay gaps to address "structural bias" that women and minorities face regarding job opportunity and pay
A public report on the risk to Amazon of using contract clauses, like nondisclosure agreements, related to harassment and discrimination
And an independent study of Rekognition, a facial recognition system that Amazon Web Services markets and sells to government and shareholders say is "worse at identifying Black women than white men and misgenders nonbinary people."

Amazon's board of directors is recommending shareholders vote against all those proposals, as well as one that asks more broadly for a study on working conditions in its warehouses.

The board pointed to a report it released earlier this year that found the rate of injury at its facilities has declined and noted its investment in new technologies, research and procedures to protect warehouse employees.

When it comes to its facial recognition product offering, the board said Amazon is "committed to the responsible use of artificial intelligence and machine learning," and had never received a report of the technology being misused "in the manner posited in this proposal." Related to pay gaps and racial and gender disparities, the board said it regularly reviews employee well-being and workplace safety, and that Amazon is "committed to supporting and increasing diversity."

Amazon's board of directors is comprised of six men and five women, according to the SEC filing. Of 11 total members, it includes nine white people, one Black person and one Asian person.

It employs 1.6 million people worldwide.Amazon CEO Jassy says he wants to improve warehouse safety

Workers at New York Apple store launch union campaign

Workers at Apple's Grand Central Station store are organizing to try to form the

Workers at Apple's Grand Central Station store announced Monday they are organizing to establish a union, in what would be a first at one of the tech giant's retail locations in the United States.

The effort, calling itself "Fruit Stand Workers United," aims to garner signatures from at least 30 percent of the New York store, the minimum needed to qualify for a unionization election.

The campaign is connected to Workers United, an affiliate of the national Service Employees International Union, which was established in 2009 from several earlier unions.

Workers United confirmed its involvement.

"Like so many recent campaigns, this has been worker-driven, and worker led," Workers United said in an email. "We recognize the tremendous bravery and courage these workers have taken to stand up for their rights, and we will support them every step of the way."

Organizers of the Grand Central campaign described themselves as working in "extraordinary times with the ongoing Covid-19 pandemic and once-in-a-generation consumer price inflation," though their website did not disclose the name of staff members leading the effort.

"Grand Central is an extraordinary store with unique working conditions that make a union necessary to ensure our team has the best possible standards of living," the workers said on the campaign website for the prospective union.

The Apple effort comes as a Starbucks unionization drive backed by Workers United has spread nationally after election victories last year in New York.

Amazon is also facing a growing challenge from unions after an upstart campaign won an election at a warehouse in nearby Staten Island earlier this month. A vote at a second Staten Island Amazon site is scheduled for later in April.

On Monday, the National Labor Relations Board, which oversees union elections, indicated it received enough signatures from another Amazon warehouse to hold a vote in Bayonne, New Jersey at a site with about 200 workers.

Employees working in at least three other Apple stores are also attempting to organize, according to The Washington Post.

Apple did not immediately respond to a request for comment from AFP.

Yes or No? Amazon union vote gets underway in New York

#BANHYPERSONICWEAPONS

How Hypersonic Missiles Work and the Significant Threats They Pose

By IAIN BOYD, UNIVERSITY OF COLORADO AT BOULDER APRIL 18, 2022

Hypersonic missiles can change course to avoid detection and anti-missile defenses. Credit: U.S. Air Force

On March 18, 2022, Russia launched a hypersonic missile against a Ukrainian arms depot in the western part of the country. That may sound frightening, but the Russian technology used in that attack was not particularly advanced. However, Russia, China, and the United States are developing next-generation hypersonic missiles, which pose a significant threat to national and global security.

I am an aerospace engineer who studies space and defense systems, including hypersonic systems. Because of their maneuverability throughout their trajectory, these new systems pose a significant challenge. These missiles must be tracked throughout their flight because their flight paths can change as they travel.

Another important challenge is that they operate in a different part of the atmosphere than other existing threats. The new hypersonic weapons fly much higher than slower subsonic missiles but much lower than intercontinental ballistic missiles (ICBMs). The United States and its allies do not have good tracking coverage for this in-between region. Neither does Russia or China.

Destabilizing effect

Russia claims that some of its hypersonic weapons are capable of carrying nuclear weapons. Whether true or not, this statement alone is cause for concern. If Russia were to use this system against an adversary, that country would have to decide the probability of the weapon being conventional or nuclear.

How hypersonic missiles threaten to upend the relative stability of the current era of nuclear weapons.

In the case of the U.S., if the determination were made that the weapon was nuclear, then there is a very high likelihood that the U.S. would consider this a first-strike attack and respond by unloading its nuclear weapons on Russia. The hypersonic speed of these weapons increases the precariousness of the situation because the time for any last-minute diplomatic resolution would be severely reduced.

It is the destabilizing influence that modern hypersonic missiles represent that is perhaps the greatest risk they pose. I believe the U.S. and its allies should rapidly field their own hypersonic weapons to bring other nations such as Russia and China to the negotiating table to develop a diplomatic approach to managing these weapons.

What is hypersonic?

Describing a vehicle as hypersonic means that it flies much faster than the speed of sound, which is 761 miles per hour (1,225 kilometers per hour) at sea level and 663 mph (1,067 kph) at 35,000 feet (10,668 meters) where passenger jets fly. Passenger jets travel at just under 600 mph (966 kph), whereas hypersonic systems operate at speeds of 3,500 mph (5,633 kph) – about 1 mile (1.6 kilometers) per second – and higher.

Hypersonic systems have been in use for decades. When John Glenn came back to Earth in 1962 from the first U.S. crewed flight around the Earth, his capsule entered the atmosphere at hypersonic speed. All of the intercontinental ballistic missiles in the world’s nuclear arsenals are hypersonic, reaching about 15,000 mph (24,140 kph), or about 4 miles (6.4 km) per second at their maximum velocity.

Hypersonic missiles are not as fast as intercontinental ballistic missiles but are able to vary their trajectories. Credit: U.S. Government Accounting Office

ICBMs are launched on large rockets and then fly on a predictable trajectory that takes them out of the atmosphere into space and then back into the atmosphere again. The new generation of hypersonic missiles fly very fast, but not as fast as ICBMs. They are launched on smaller rockets that keep them within the upper reaches of the atmosphere.

Three types of hypersonic missiles

There are three different types of non-ICBM hypersonic weapons: aero-ballistic, glide vehicles and cruise missiles. A hypersonic aero-ballistic system is dropped from an aircraft, accelerated to hypersonic speed using a rocket and then follows a ballistic, meaning unpowered, trajectory. The system Russian forces used to attack Ukraine, the Kinzhal, is an aero-ballistic missile. The technology has been around since about 1980.

The type of hypersonic missile Russia has used in Ukraine, the Kinzhal aero-ballistic missile, is essentially a ballistic missile launched from aircraft. It is not as advanced as other types of hypersonic missiles that Russia, China and the U.S. are developing. Credit: Russian Defense Ministry Press Service

A hypersonic glide vehicle is boosted on a rocket to high altitude and then glides to its target, maneuvering along the way. Examples of hypersonic glide vehicles include China’s Dongfeng-17, Russia’s Avangard, and the U.S. Navy’s Conventional Prompt Strike system. U.S. officials have expressed concern that China’s hypersonic glide vehicle technology is further advanced than the U.S. system.

A hypersonic cruise missile is boosted by a rocket to hypersonic speed and then uses an air-breathing engine called a scramjet to sustain that speed. Because they ingest air into their engines, hypersonic cruise missiles require smaller launch rockets than hypersonic glide vehicles, which means they can cost less and be launched from more places. Hypersonic cruise missiles are under development by China and the U.S. The U.S. reportedly conducted a test flight of a scramjet hypersonic missile in March 2020.

Difficult to defend against

The primary reason nations are developing these next-generation hypersonic weapons is how difficult they are to defend against due to their speed, maneuverability and flight path. The U.S. is starting to develop a layered approach to defending against hypersonic weapons that includes a constellation of sensors in space and close cooperation with key allies. This approach is likely to be very expensive and take many years to implement.

With all of this activity on hypersonic weapons and defending against them, it is important to assess the threat they pose to national security. Hypersonic missiles with conventional, non-nuclear warheads are primarily useful against high-value targets, such as an aircraft carrier. Being able to take out such a target could have a significant impact on the outcome of a major conflict.

However, hypersonic missiles are expensive and therefore not likely to be produced in large quantities. As seen in the recent use by Russia, hypersonic weapons are not necessarily a silver bullet that ends a conflict.

Written by Iain Boyd, Professor of Aerospace Engineering Sciences, University of Colorado Boulder. Iain Boyd receives funding from the U.S. Department of Defense, the U.S. Department of Energy, NASA, Lockheed-Martin, and L3-Harris.

This article was first published in The Conversation.

Changing Vegetation a Key Driver of Global Temperatures Over Last 10,000 Years

By WASHINGTON UNIVERSITY IN ST. LOUIS APRIL 16, 2022

Aerial Forest Stream

Follow the pollen. Records from past plant life tell the real story of global temperatures, according to research from a climate scientist at Washington University in St. Louis.

Warmer temperatures brought plants — and then came even warmer temperatures, according to new model simulations published in Science Advances.

Alexander Thompson, a postdoctoral research associate in earth and planetary sciences in Arts & Sciences, updated simulations from an important climate model to reflect the role of changing vegetation as a key driver of global temperatures over the last 10,000 years.

Thompson had long been troubled by a problem with models of Earth’s atmospheric temperatures since the last ice age. Too many of these simulations showed temperatures warming consistently over time.

But climate proxy records tell a different story. Many of those sources indicate a marked peak in global temperatures that occurred between 6,000 and 9,000 years ago.

Aerial Forest

Thompson had a hunch that the models could be overlooking the role of changes in vegetation in favor of impacts from atmospheric carbon dioxide concentrations or ice cover.

“Pollen records suggest a large expansion of vegetation during that time,” Thompson said.

“But previous models only show a limited amount of vegetation growth,” he said. “So, even though some of these other simulations have included dynamic vegetation, it wasn’t nearly enough of a vegetation shift to account for what the pollen records suggest.”

In reality, the changes to vegetative cover were significant.

Early in the Holocene, the current geological epoch, the Sahara Desert in Africa grew greener than today — it was more of a grassland. Other Northern Hemisphere vegetation including the coniferous and deciduous forests in the mid-latitudes and the Arctic also thrived.

Thompson took evidence from pollen records and designed a set of experiments with a climate model known as the Community Earth System Model (CESM), one of the best-regarded models in a wide-ranging class of such models. He ran simulations to account for a range of changes in vegetation that had not been previously considered.

Alexander Thompson

“Expanded vegetation during the Holocene warmed the globe by as much as 1.5 degrees Fahrenheit,” Thompson said. “Our new simulations align closely with paleoclimate proxies. So this is exciting that we can point to Northern Hemisphere vegetation as one potential factor that allows us to resolve the controversial Holocene temperature conundrum.”

Understanding the scale and timing of temperature change throughout the Holocene is important because it is a period of recent history, geologically speaking. The rise of human agriculture and civilization occurred during this time, so many scientists and historians from different disciplines are interested in understanding how early and mid-Holocene climate differed from the present day.

Thompson conducted this research work as a graduate student at the University of Michigan. He is continuing his research in the laboratory of climate scientist Bronwen Konecky at Washington University.

“Overall, our study emphasizes that accounting for vegetation change is critical,” Thompson said. “Projections for future climate change are more likely to produce more trustworthy predictions if they include changes in vegetation.”

Reference: “Northern Hemisphere vegetation change drives a Holocene thermal maximum” by Alexander J. Thompson, Jiang Zhu, Christopher J. Poulsen, Jessica E. Tierney and Christopher B. Skinner, 15 April 2022, Science Advances.
DOI: 10.1126/sciadv.abj6535

New Ancient DNA Study Reveals 5,000-Year Population History of Xinjiang, China

By CHINESE ACADEMY OF SCIENCES APRIL 17, 2022

Overlook of Tombs in High Altitudes Tashikuergan Kashi

Overlook of Tombs in high altitudes. Excavated from Jierzankale site in Tashikuergan, Kashi region. Credit: YAN Xuguang, Kashi Daily

Xinjiang, in northwest China, lays at an important junction between east and west Eurasia and has played a historically important role in the exchange of goods and technologies between these two regions along the Silk Road. It is a complex mix of cultures and populations.

However, the interflow and blending of these diverse populations in Xinjiang can be traced further back. Bronze Age mummies discovered in Tarim Basin were purported to have western features and textiles, and the discovery of 5^th century C.E. texts of an extinct Indo-European language group, Tocharian, has spurred great interest in archeologists, linguists, and anthropologists.

Now, a research team led by Prof. FU Qiaomei from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences has unravel the past population history of Xinjiang, China, based on information from 201 ancient genomes from 39 archeological sites.

Their findings were published in the journal Science on March 31, 2020.

Principal Component and Admixture Analysis of Xinjiang Populations

Principal Component (PCA) (A) and ADMIXTURE (B) analysis of Xinjiang populations. Credit: Kumar et al. 2022, Science

A mix of local northern Asian and western Steppe ancestry in Bronze Age

The peopling of Bronze Age Xinjiang is key to understand the later population dynamics of the region. It had been proposed that the Bronze Age settling of the Tarim Basin was originally by people related to either western Steppe Cultures (“Steppe hypothesis”) or Central Asian populations related to the Bactria Margiana Complex (BMAC) (“Bactrian oasis hypothesis”).

FU and her team discovered the earliest inhabitants of Xinjiang showed genomic similarities with both of these groups, but broadly mixed with a unique ancestry found in the local Tarim Basin mummies, who were recently shown to be linked to a population found 25,000 years ago in southern Siberia known as the Ancient North Eurasians (ANE).

“In all, Bronze Age Xinjiang populations were found to contain ancestral components of the ‘local’ Tarim Basin population mixed to varying degrees with those of three groups from the surrounding regions: the Afanasievo, an Indo-European-associated Steppe culture, a group called the Chemurchek, who contained BMAC ancestry from Central Asia, and ancestry from a Northeast Asian population called the Shamanka,” said Prof. FU, the last corresponding author of this paper.

The appearance of an individual with almost exclusive Northeast Asian ancestry in northern Xinjiang at this time indicated these early populations may have been already highly mobile. This evidence fits a scenario where incoming Steppe, Chemurchek and Northeast Asian populations entered the region and mixing with the existing inhabitants, who are closest to the oldest Tarim Basin mummies.

In the later part of the Bronze Age, they found the existing genomic profiles shifted to include an influx of a newer western Steppe group linked to the Steppe Middle-Late Bronze Age (MLBA) Andronovo culture, as well as an increasing influx of ancestry from East Asia found in southern Siberia. Furthermore, an expansion of ancestry related to Central Asia (BMAC) at this time indicated an increase in interactions with Central Asia across the Inner Asian Mountain Corridor.

The qpAdm admixture proportions for all Xinjiang populations. Each bar represents admixture proportion of the listed subgroups for BA, LBA, IA and HE populations. Credit: Kumar et al. 2022, Science

Early entry of Indo-European speakers in Bronze Age Xinjiang

Interestingly, they also found ancestry of several Early Bronze Age individuals identified as unmixed Afanasievo ancestry. This finding corroborates an early entry of these Indo-Europeans, who may have played a role in introducing Tocharian languages to Xinjiang, the easternmost Indo-European languages recorded. This early date would make the appearance of Indo-European languages in Xinjiang roughly contemporary with their entrance into Western Europe, clarifying the origin and spread of the language family with the largest number of speakers today.

Iron Age influx of East and Central Asians established the ancestry still present today

Compared to the Bronze Age, Iron Age populations showed an increased influx of people from East and Central Asia, with the presence of the East Asian component following a West-to-East gradient of increasing East Asian ancestry. Unlike the Northeast Asian ancestry present during the Bronze Age, the East Asian ancestry entering during the Iron Age showed more diverse origins including mainland East Asia.

These Iron Age populations could be linked to populations such as the Xiongnu and Han, which coincided with a historically documented westward expansion of Xiongnu in ~2200 BP after the defeat of Yuezhi in Gansu region. Additional Iron Age movements of people from Central Asia or the Indus periphery region into Xinjiang supported early activity along routes such as the Inner Asian Mountain Corridor.

The Iron Age appearance of ancestry linked to the Sakas, a nomadic confederation derived from the Iranian peoples, helps to date the entrance of Indo-Iranian languages like Khotanese, known to be spoken by the Sakas, into Xinjiang. This Iron Age genetic profile of the region, linking Steppe, East Asian, and Central Asian people, was found to have been maintained into the Historical Era (HE). Despite the cultural shifts of the past millennia, similar ancestries to those established in the Iron Age are still observed in present-day Xinjiang populations.

Phenotypic analysis of several remains, the first reported for ancient Xinjiang, gave depth to the genetic results. The majority of individuals investigated had dark brown to black hair and brown eye color throughout Bronze Age, Iron Age, and HE. Corresponded with the appearance of Andronovo Steppe ancestry, a small proportion of the Iron Age individuals are marked blond hair, blue eyes and lighter skin tone in the west and north of Xinjiang. Two Early Bronze Age Tarim Basin mummies in east Xinjiang were found likely to have had dark brown to black hair and darker skin, despite their archeologically-identified “western” features, and a more recent third mummy from the Late Bronze Age was likely to have had a more intermediate skin tone.

“With the widespread population movements documented in the study, it is intriguing to see the degree of genetic continuity that has been maintained in Xinjiang over the past 5000 years,” said Associate Prof. Vikas KUMAR from IVPP, the first author of this study.

“What is striking about these results is that the demographic history of a cross-roads region as Xinjiang has been marked not by population replacements, but by the genetic incorporation of diverse incoming cultural groups into the existing population, making Xinjiang a true ‘melting-pot’,” said Prof. FU.

This detailed aspect had not been so clear looking only at archeological and cultural evidence. These findings suggest the importance of combining genetic and archaeological evidence to provide a more comprehensive insight into population history.

The current ancient DNA analysis highlights a holistic approach to unraveling the complex history of locations like Xinjiang, where the many interactions between different groups and cultures in the past make detailed demographic studies difficult. Future studies in this area could reveal more about the finer points of Xinjiang’s history.

Reference: “Bronze and Iron Age population movements underlie Xinjiang population history” by Vikas Kumar, Wenjun Wang, Jie Zhang, Yongqiang Wang, Qiurong Ruan, Jianjun Yu, Xiaohong Wu, Xingjun Hu, Xinhua Wu, Wu Guo, Bo Wang, Alipujiang Niyazi, Enguo Lv, Zihua Tang, Peng Cao, Feng Liu, Qingyan Dai, Ruowei Yang, Xiaotian Feng, Wanjing Ping, Lizhao Zhang, Ming Zhang, Weihong Hou, Yichen Liu, E. Andrew Bennett and Qiaomei Fu, 31 March 2022, Science.
DOI: 10.1126/science.abk1534

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