A changing climate, growing human populations and widespread fires contributed to the last major extinction event − can we prevent another?

Emily Lindsey, Associate Curator, La Brea Tar Pits; Adjunct Faculty, Institute of the Environment and Sustainability, UCLA, University of California, Los Angeles, 

Regan E. Dunn, Adjunct Professor of Earth Sciences, USC Dornsife College of Letters, Arts and Sciences, 

and Lisa N. Martinez, Ph.D. Candidate in Geography, University of California, Los Angeles

Thu, August 17, 2023 

THE CONVERSATION 

Over the past decade, deadly wildfires have become increasingly common because of both human-caused climate change and disruptive land management practices. Southern California, where the three of us live and work, has been hit especially hard.

Southern California also experienced a wave of wildfires 13,000 years ago. These fires permanently transformed the region’s vegetation and contributed to Earth’s largest extinction in more than 60 million years.

As paleontologists, we have a unique perspective on the long-term causes and consequences of environmental changes, both those linked to natural climate fluctuations and those wrought by humans.

In a new study, published in August 2023, we sought to understand changes that were happening in California during the last major extinction event at the end of the Pleistocene, a time period known as the Ice Age. This event wiped out most of Earth’s large mammals between about 10,000 and 50,000 years ago. This was a time marked by dramatic climate upheavals and rapidly spreading human populations.

The last major extinction

Scientists often call the past 66 million years of Earth’s history the Age of Mammals. During this time, our furry relatives took advantage of the extinction of the dinosaurs to become the dominant animals on the planet.

During the Pleistocene, Eurasia and the Americas teemed with enormous beasts like woolly mammoths, giant bears and dire wolves. Two species of camels, three species of ground sloths and five species of large cats roamed what is now Los Angeles.

Then, abruptly, they were gone. All over the world, the large mammals that had characterized global ecosystems for tens of millions of years disappeared. North America lost more than 70% of mammals weighing more than 97 pounds (44 kilograms). South America lost more than 80%, Australia nearly 90%. Only Africa, Antarctica and a few remote islands retain what could be considered “natural” animal communities today.

The reason for these extinctions remains obscure. For decades, paleontologists and archaeologists have debated potential causes. What has befuddled scientists is not that there are no obvious culprits but that there are too many.

As the last ice age ended, a warming climate led to altered weather patterns and the reorganization of plant communities. At the same time, human populations were rapidly increasing and spreading around the globe.

Either or both of these processes could be implicated in the extinction event. But the fossil record of any region is usually too sparse to know exactly when large mammal species disappeared from different regions. This makes it difficult to determine whether habitat loss, resource scarcity, natural disasters, human hunting or some combination of these factors is to blame.

A deadly combination

Some records offer clues. La Brea Tar Pits in Los Angeles, the world’s richest ice age fossil site, preserves the bones of thousands of large mammals that were trapped in viscous asphalt seeps over the past 60,000 years. Proteins in these bones can be precisely dated using radioactive carbon, giving scientists unprecedented insight into an ancient ecosystem and an opportunity to illuminate the timing – and causes – of its collapse.

Our recent study from La Brea Tar Pits and nearby Lake Elsinore has unearthed evidence of a dramatic event 13,000 years ago that permanently transformed Southern California’s vegetation and caused the disappearance of La Brea’s iconic mega-mammals.

Sediment archives from the lake’s bottom and archaeological records provide evidence of a deadly combination – a warming climate punctuated by decadeslong droughts and rapidly rising human populations. These factors pushed the Southern California ecosystem to a tipping point.

Similar combinations of climate warming and human impacts have been blamed for ice age extinctions elsewhere, but our study found something new. The catalyst for this dramatic transformation seems to have been an unprecedented increase in wildfires, which were probably set by humans.

The processes that led to this collapse are familiar today. As California warmed coming out of the last ice age, the landscape became drier and forests receded. At La Brea, herbivore populations declined, probably from a combination of human hunting and habitat loss. Species associated with trees, like camels, disappeared entirely.

In the millennium leading up to the extinction, mean annual temperatures in the region rose 10 degrees Farenheit (5.5 degrees Celsius), and the lake began evaporating. Then, 13,200 years ago, the ecosystem entered a 200-year-long drought. Half of the remaining trees died. With fewer large herbivores to eat it, dead vegetation built up on the landscape.

At the same time, human populations began expanding across North America. And as they spread, people brought with them a powerful new tool – fire.

Humans and our ancestors have used fire for hundreds of thousands of years, but fire has different impacts in different ecosystems. Charcoal records from Lake Elsinore reveal that before humans, fire activity was low in coastal Southern California. But 13,200 to 13,000 years ago, as human populations grew, fire in the region increased by an order of magnitude.

Our research suggests that the combination of heat, drought, herbivore loss and human-set fires had pushed this system to a tipping point. At the end of this period, Southern California was covered in chaparral plants, which thrive after fires. A new fire regime had become established, and the iconic La Brea megafauna had disappeared.

Lessons for the future

Studying the causes and consequences of the Pleistocene extinctions in California can provide valuable context for understanding today’s climate and biodiversity crises. A similar combination of climate warming, expanding human populations, biodiversity loss and human-ignited fires that characterized the ice age extinction interval in Southern California are playing out again today.

The alarming difference is that temperatures today are rising 10 times faster than they did at the end of the ice age, primarily because of the burning of fossil fuels. This human-caused climate change has contributed to a fivefold increase in fire frequency and intensity and the amount of area burned in the state of California in the past 45 years.

While California is now famous for extreme fires, our study reveals that fire is a relatively new phenomenon in this region. In the 20,000 years leading up to the extinction, the Lake Elsinore record shows very low incidence of any fire even during comparable periods of drought. Only after human arrival does fire become a regular part of the ecosystem.

Even today, downed power lines, campfires and other human activities start over 90% of wildfires in coastal California.

The parallels between the late Pleistocene megafaunal extinctions and today’s environmental crises are striking. The past teaches us that the ecosystems we depend upon are vulnerable to collapse when stressed by multiple intersecting pressures. Redoubling efforts to eliminate greenhouse gas emissions, prevent reckless fire ignitions and preserve Earth’s remaining megafauna can help avert another, even more catastrophic transformation.

This article is republished from The Conversation, an independent nonprofit news site dedicated to sharing ideas from academic experts. Like this article? Subscribe to our weekly newsletter.

It was written by: Emily Lindsey, University of California, Los Angeles; Lisa N. Martinez, University of California, Los Angeles, and Regan E. Dunn, USC Dornsife College of Letters, Arts and Sciences.

Read more:

• A volcanic eruption 39 million years ago buried a forest in Peru – now the petrified trees are revealing South America’s primeval history

• Wooded grasslands flourished in Africa 21 million years ago – new research forces a rethink of ape evolution

Emily Lindsey receives funding from the National Science Foundation, which funded some of the research reported in this article.

Lisa N. Martinez receives funding from the National Science Foundation and the UCLA Endowed Chair in Geography of California and the American West.

Regan E. Dunn receives funding from National Science Foundation and NASA.

Should governments be blamed for climate change? How one lawsuit could change US policies

Marc Ramirez, USA TODAY
Updated Wed, August 16, 2023

A landmark ruling saying Montana has a constitutional duty to guard residents from the harmful effects of climate change could have wider implications, environmental experts said.

In a decision Monday lauded by activists as a potential turning point for the environmental movement, District Court Judge Kathy Seeley sided with young plaintiffs who claimed state policies used to evaluate requests for fossil-fuel projects are unconstitutional because they don't allow for agencies to consider the effects of greenhouse gas emissions – a practice she said had detrimental effects on the environment and the mental and physical health of young people in Montana.

The case marks the first time a U.S. court has held a government liable for disregarding the harmful effects of climate change and thereby violating its children's constitutional rights, according to a statement from Julia Olsen, chief legal counsel and executive director for Our Children's Trust, an Oregon environmental group that has filed similar lawsuits in every state over the past 12 years.

Nate Bellinger, who also represented the plaintiffs, called the ruling "historic."

“It’s the first-ever ruling of its kind in our nation’s nearly 250-year history. So it’s big, and it’s great.”

Environmental activist Maya van Rossum, founder of the Green Amendment movement, said the decision marks the first time a constitutional right to a clean and healthful environment has been determined to include the right to a safe climate.

"The oil and gas industry, and their friends in Montana's government, are now on notice that the people of Montana have the higher power of the Constitution to help them ensure protection of their climate," van Rossum said in a statement.

Robert Bullard, known as the father of the environmental justice movement, hailed the ruling in Held v. Montana as "a breath of fresh air."

"This ruling is really bigger than Montana," said Bullard, founding director of the Bullard Center for Environmental and Climate Justice and professor of urban planning and environmental policy at Texas Southern University in Houston. "Hopefully it will have a ripple effect across the country in getting more rulings that will somehow mirror reality."


Robert D. Bullard, distinguished orofessor of urban planning and environmental policy in the Barbara Jordan-Mickey Leland School of Public Affairs at Texas Southern University. He is a co-chair of the National Black Environmental Justice Network.

He said it was important that young people had been behind the case, calling the 16 plaintiffs, ages 5 to 22, "brave and courageous."

"They recognize that we can’t continue to do damage to the planet and keep ruining this earth," Bullard said.
Montana climate case is about environmental responsibility

Patrick Christie, a professor of marine and environmental affairs at the University of Washington in Seattle, called Seeley's decision "a precedent-setting ruling that with have impacts throughout the U.S. and beyond."

"This ruling makes it clear that stonewalling and ignoring the best available science is no longer tenable," Christie said.

He said safe, reliable and economically viable energy alternatives are available to Montana and other states looking for more environmentally friendly sources.

"The least that can be done in the midst of this climate crisis is to recognize, mitigate and then reverse the harm done by our over-reliance on fossil fuels," Christie said. "The minimum society can do is to take seriously the concerns of youth and the needs of future generations who are not responsible for this climate crisis, but who carry the greatest burden of climate change."

Montana has never denied a permit for a fossil fuel project, and its Legislature recently passed laws favoring oil, gas and coal over renewable energy. In the three years since the lawsuit was filed, the scope of the case narrowed to consider whether Montana’s Environmental Policy Act − which requires state agencies to weigh environmental health against resource development − is unconstitutional because it doesn't require officials to consider greenhouse gas emissions or their effects on the climate.

Oday Salim, director of the environmental law and sustainability clinic at the University of Michigan Law School, said the judge’s ruling means other state legislatures will have to proceed with caution.

“The state Legislature (in Montana) went out of its way to single out climate change and to punish the public for doing anything about it,” Salim said. “They enacted provisions that said you cannot raise arguments about climate change and greenhouse gas emissions when making a complaint.”

The right to a clean and healthful environment has been enshrined in Montana’s Constitution since 1972. The state is among the major sources of coal in the United States accounting for about 5% of the nation’s coal production.

“Now, you have an example of a state court judge saying people have the right to a healthy climate and that you can’t take away legal pathways based on achieving that,” Salim said. “That’s really significant and we haven’t seen that in other state courts.”

Lead plaintiff Rikki Held listens to testimony during a hearing in the climate change lawsuit, Held vs. Montana, at the Lewis and Clark County Courthouse on, June 20, 2023, in Helena, Montana.

Bellinger said the ruling affirmed not only the need to reduce greenhouse gas emissions but also the availability of renewable resources as an alternative.

“Those are things we’ve been talking about in the climate sphere for a long time, but it’s the first time a judge has included these in a legally binding court order,” Bellinger said. “So to have those findings of fact, that this harms the plaintiffs and that you have government conduct that is exacerbating those harms is really significant – and applicable beyond Montana.”
Young people say fossil fuels are hurting their future

Attorneys for the plaintiffs argued that the state’s pro-fossil fuel policies endangered their health and livelihoods and threatened future generations and presented evidence showing rising carbon dioxide emissions were pushing temperatures upward, exacerbating drought and wildfires and reducing snowpack.

Montana’s policies to promote and perpetuate fossil fuels, they said, violated residents’ fundamental rights to a stable climate system. They argued that the state should no longer permit new fossil fuel projects and should instead shift toward available renewable energies.

Youth plaintiffs in the climate change lawsuit, Held vs. Montana, arrive at the Lewis and Clark County Courthouse, on June 20, 2023, in Helena, Montana, for the final day of the trial.

The state had maintained that the role of its greenhouse gas emissions in global climate change was negligible and shouldn’t be held accountable.

That the judge had rejected that defense was important, Bellinger said, because he expects states to employ such arguments in similar cases.

“This is a really important precedent that says each state does have an obligation to reduce emissions and that those individual actors are collectively causing climate change,” he said.
Will similar climate change lawsuits be successful?

While Montana officials say they will appeal the case, Bellinger said, the state Supreme Court will have to review the evidence and testimony presented. The state’s defense, he said, was surprisingly abrupt, consisting of one expert on the stand “for about 10 minutes” and two state employees.

“The state had zero evidence contradicting our expert testimony,” he said. “There really isn’t another side to the story here. The overwhelming evidence supports the decision we got and makes clear that fossil fuels are harming young people and degrading the environment, and that there are alternatives.”

A Montana judge on Monday sided with young environmental activists who said state agencies were violating their constitutional right to a clean and healthful environment by permitting fossil fuel development without considering its effect on the climate.

Environmental advocates said the case had laid possible groundwork for similar cases in other states.

“This court has done a lot of the hard work already,” Salim said. “While it’s not binding precedent, it’s literally a blueprint. Other courts can look at that and decide what they can borrow for themselves.”

Bellinger said his organization’s strategy is unique in that it targets the government’s role in the climate crisis as opposed to, say, fossil fuel companies.

“Governments are issuing permits for everything the fossil fuel companies do,” he said. “This decision really affirms that governments do have an important role when it comes to permitting activities and should not be doing so when they harm plaintiffs and violate constitutional rights. That’s the blueprint we will continue to pursue.”

Contributing: The Associated Press

This article originally appeared on USA TODAY: Could the Montana youth climate case help stop global warming?

America’s richest 10% are responsible for 40% of planet-heating pollution, new report finds

Laura Paddison, CNN
Thu, August 17, 2023 

America’s wealthiest people are also some of the world’s biggest polluters – not only because of their massive homes and private jets, but because of the fossil fuels generated by the companies they invest their money in.

A new study published Thursday in the journal PLOS Climate found the wealthiest 10% of Americans are responsible for almost half of planet-heating pollution in the US, and called on governments to shift away from “regressive” taxes on the carbon-intensity of what people buy and focus on taxing climate-polluting investments instead.

“Global warming can be this huge, overwhelming, nebulous thing happening in the world and you feel like you’ve got no agency over it. You kind of know that you’re contributing to it in some way, but it’s really not clear or quantifiable,” said Jared Starr, a sustainability scientist at the University of Massachusetts Amherst and a report author.

This study helps build a clearer picture of individual responsibility by going beyond what people consume, he told CNN.

A private jet at Santa Fe Municipal Airport in Santa Fe, New Mexico. Traditionally analyses of climate footprints of the very rich have focused on what they buy. - Robert Alexander/Getty Images

To do this, the researchers analyzed huge datasets spanning 30 years to connect financial transactions to carbon pollution.

They looked at the planet-heating pollution produced by companies’ direct operations, as well as those relating to companies’ climate impacts further down the supply chain – for example, the bulk of an oil company’s emissions comes when its customers burn the oil it extracts.

That gave a carbon footprint for each dollar of economic activity in the US, which the researchers linked to households using population survey data that showed the industries people work for and their income from wages and investments.

They found the wealthiest 10% in the US, households making more than about $178,000, were responsible for 40% of the nation’s human-caused, planet-heating pollution. The income of the top 1% alone – households making more than $550,000 – was linked to 15% to 17% of this pollution.



The report also identified “super-emitters.” They are almost exclusively among the wealthiest top 0.1% of Americans, concentrated in industries such as finance, insurance and mining, and produce around 3,000 tons of carbon pollution a year. To put that in perspective, it’s estimated people should limit their carbon footprint to around 2.3 tons a year to tackle climate change.

“Fifteen days of income for a top 0.1% household generates as much carbon pollution as a lifetime of income for a household in the bottom 10%,” Starr said.

Climate impact is not just about the size of the people’s income but the industries that generate it. A household making $980,000 from certain fossil fuel industries, for example, would be considered a super-emitter, according to the report. But a household making money from the hospital industry would need to bring in $11 million to produce the same amount of planet-heating pollution.

 

The report’s authors call on policymakers to rethink how they use taxes to tackle the climate crisis.

Carbon taxes that focus on what people buy – the food we eat, the cars we drive, the clothes we buy – “disproportionately punish the poor while having little impact on the extremely wealthy,” said Starr. They also miss the chunk of wealth rich people spend on investments rather than buying things.

Governments instead should focus on taxes that target shareholders and carbon-intensive investments, the report said. Although it will be “a hard political ask,” Starr acknowledged, especially as the wealthiest tend to have disproportionate political power.

Many ideas for taxing carbon have been floated around the world including windfall taxes on fossil fuel companies and wealth taxes, but few have been politically viable.

Kimberly Nicholas, associate professor of sustainability science at Lund University in Sweden, who was not involved in the report, said the study helps reveal how closely income, especially from investments, is tied to planet-heating pollution.

Sometimes when people talk about ways to tackle the climate crisis, they bring up population control, said Mark Paul, a political economist at Rutgers University who was also not involved in the study. But studies like this “shine light on the outsized responsibility that the rich have in generating and perpetuating the climate crisis,” he told CNN.

Identifying the main actors behind the climate crisis is vital for governments to develop policies that cut planet-heating pollution in a fair way, he added. Although he disagreed with the study’s assertion that carbon taxes on consumption disproportionately affect the poor, saying there were ways to implement them fairly.

The outsized climate impact of the rich is, of course, far from just a US problem.

Globally, the planet-heating pollution produced by billionaires is a million times higher than the average person outside the world’s wealthiest 10%, according to a report last year from the nonprofit Oxfam.

“At the moment, the way the economy works is that it takes money and turns it into climate pollution that is destabilizing life on Earth,” Nicholas said. “And that fundamentally has to change.”

The scale of emissions inequality in U.S. society

Emissions inequality across economic and racial lines, with the top 1% of households’ investment holdings accounting for 40% of their emissions

Peer-Reviewed Publication

PLOS

 

IMAGE: FIG 4. MEAN HOUSEHOLD T CO2E EMISSIONS (2019) PER INCOME GROUP UNDER THE PRE-TAX SUPPLIER FRAMEWORK. THE WIDTH OF EACH INCOME GROUP, ON THE X-AXIS, CORRESPONDS WITH EACH GROUP’S SHARE OF NATIONAL EMISSIONS. COLOR INDICATES INCOME CATEGORY. BLACK ERROR BARS ARE BOOTSTRAPPED 95% CONFIDENCE INTERVALS FOR TOTAL T CO2E FROM ALL THREE SOURCES. SIMILARLY, GRAY ERROR BARS ARE BOOTSTRAPPED 95% CONFIDENCE INTERVALS ON THE TOTAL T CO2E GIVEN AN ASSUMED ±20% ERROR IN CARBON INTENSITY PER DOLLAR. (PRODUCER-BASED RESULTS ARE PRESENTED IN S8 FIG). view more 

CREDIT: STARR ET AL., 2023, PLOS CLIMATE, CC-BY 4.0 (HTTPS://CREATIVECOMMONS.ORG/LICENSES/BY/4.0/)

Researchers have linked US household income data to greenhouse gas emissions generated in creating that income, and found that 40% of total emissions are associated with income for the highest 10% of households. The paper, published in PLOS Climate suggests that an income or shareholder-based carbon tax focused on investments may have equity advantages over traditional consumer-facing cap-and-trade or carbon tax options.

Human created climate change is an existential threat, and there is a disconnect between those facing the worst impacts and those that drive the greatest greenhouse gas emissions.

Jared Starr of the University of Massachusetts Amherst, and colleagues, took 30 years of US household-level income data, from 1990-2019, and linked it to the emissions generated in that income. They look at both income from direct emissions, such as industries like power plants, and income related to industries supplying services or commodities to those industries - such as finance or fossil fuel suppliers.

In general, white non-Hispanic households had the highest emissions linked to income, and Black households had the lowest, predominantly because of the racial inequity of income distribution. In terms of age, emissions tend to increase with age until peaking within the 45 – 54 age group before declining again.

Among the highest earning 1% of households, whose income is linked to 15 - 17% of national emissions, investment holdings account for 38 - 43% of their emissions. The team also identifies “super emitters” with extremely high overall emissions, and these are almost exclusively among the top 0.1% of households, which are overrepresented in finance, real estate, and insurance; manufacturing; mining and quarrying.

The research offers a new perspective on emissions responsibility and climate finance and could be a useful policy tool to encourage decarbonization while raising revenue for climate finance.

Starr adds: “The scale of emission disparity is quite striking. Just fifteen days of income-based emissions from an average top 0.1% household is equal to a lifetime of emissions from a bottom decile household. I find that morally troubling, especially since low-income households face disproportionate climate harms.

I think we need to make sure that our climate policies take these disparities into account. One way to do that is to make sure that those who are financially benefitting thanks to emissions are properly incentivized to both reduce their emissions and pay for the damage caused by those emissions. I believe that an income or asset-based carbon tax would focus the minds of corporate executives, board members, and large shareholders to decarbonize their industries in order to reduce their taxes. In essence it is decarbonization and divestment out of self-interest. At the same time it would generate much needed revenue for climate finance. While no tool is perfect, I think this could be a useful new approach to encourage the most economically and politically powerful in our society to focus their minds on decarbonization.”

#####

In your coverage please use this URL to provide access to the freely available article in PLOS Climate: https://journals.plos.org/climate/article?id=10.1371/journal.pclm.0000190

Citation: Starr J, Nicolson C, Ash M, Markowitz EM, Moran D (2023) Income-based U.S. household carbon footprints (1990–2019) offer new insights on emissions inequality and climate finance. PLOS Clim 2(8): e0000190. https://doi.org/10.1371/journal.pclm.0000190

Author Countries: Norway, US

Funding: The authors received no specific funding for this work.

---

JOURNAL

PLOS Climate

DOI

10.1371/journal.pclm.0000190 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Income-based U.S. household carbon footprints (1990–2019) offer new insights on emissions inequality and climate finance

ARTICLE PUBLICATION DATE

17-Aug-2023

A carbon tax on investment income could be more fair and make it less profitable to pollute – a new analysis shows why

Jared Starr, Sustainability Scientist, UMass Amherst
Thu, August 17, 2023 

Investor pressure could drive down greenhouse gas emissions. Tippapatt/iStock/Getty Images Plus

About 10 years ago, a very thick book written by a French economist became a surprising bestseller. It was called “Capital in the 21st Century.” In it, Thomas Piketty traces the history of income and wealth inequality over the past couple of hundred years.

The book’s insights struck a chord with people who felt a growing sense of economic inequality but didn’t have the data to back it up. I was one of them. It made me wonder, how much carbon pollution is being generated to create wealth for a small group of extremely rich households? Two kids, 10 years and a Ph.D. later, I finally have some answers.

In a new study, colleagues and I investigated U.S. households’ personal responsibility for greenhouse gas emissions from 1990 to 2019. We previously studied emissions tied to consumption – the stuff people buy. This time, we looked at emissions used in generating people’s incomes, including investment income.

If you’ve ever thought about how oil company CEOs and shareholders get rich at the expense of the climate, then you’ve been thinking in an “income-responsibility” way.

While it may seem intuitive that those getting rich from fossil fuels bear responsibility for the emissions, very little research has been done to quantify this. Recent efforts have started to look at emissions related to household wages in France, global consumption and investments of different income groups and billionaires’ investments. But no one has analyzed households across a whole country based on the emissions used to generate their full range of income, including wages, investments and retirement income, until now.

We linked a global data set of financial transactions and emissions to microdata from the U.S. Census Bureau and Bureau of Labor Statistics’ monthly labor force survey, which includes respondents’ job, demographics and income from 35 categories, including wages and investments. People’s wages we connected to the emission intensity of the industries that employ them, and we based the emissions intensity of investment income on a portfolio that mirrors the overall economy.

The results of our analysis were eye-opening, and they could have profound implications for producing more effective and fair climate policies in the future.

A view from the top 1%

Both our consumption- and income-based approaches reveal that the highest-earning households are responsible for much more than an equitable share of carbon emissions. What’s more surprising is how different the level of responsibility is depending on whether you look at consumption or income.

In the income-based approach, the share of national emissions coming from the top 1% of households is 15% to 17% of national emissions. That’s about 2.5 times higher than their consumer-related emissions, which is about 6%.

In the bottom 50% of households, however, the trend is the exact opposite: Their share of consumption-based national emissions is 31%, about two times larger than their income-based emissions of 14%.

Why is that?

A couple things are going on here. First, the lowest earning 50% of U.S. households spend all that they earn, and often more via social assistance or debt. The top income groups, on the other hand, are able to save and reinvest more of their income.

Second, while high-income households have very high overall spending and emissions, the carbon intensity – tons of carbon dioxide emitted per dollar – of their purchases is actually lower than that of low-income households. This is because low-income households spend a large share of their income on carbon-intensive basic necessities, like home heating and transportation. High-income households spend more of their income on less-carbon-intensive services, like financial services or higher education.

Implications for a carbon tax

Our detailed comparison could help change how governments think about carbon taxes.

Typically, a carbon tax is applied to fossil fuels when they enter the economy. Coal, oil and gas producers then pass this tax on to consumers. More than two dozen countries have a carbon tax, and U.S. policymakers have proposed adding one in recent years. The idea is that raising the price of these products by taxing them will get consumers to shift to cheaper and presumably less carbon-intensive alternatives.

But our studies show that this kind of tax would disproportionately fall on poorer Americans. Even if a universal dividend check was adopted, consumer-facing carbon taxes have no impact on saved income. Generating that income likely contributed to greenhouse gas emissions, but as long as the money is used to buy stocks rather than consumables, it is excluded from carbon taxes. So, this kind of carbon tax disproportionately affects people whose income goes primarily toward consumption.

A profit-focused carbon tax

What if, instead of focusing on consumption, carbon taxes addressed greenhouse gases as an outcome of profit generation?

The vast majority of American corporations operate under the principle of “shareholder primacy,” where they see a fiduciary duty to maximize profit for their investors. Products – and the greenhouse gases used to make them – are not created for the benefit of the consumer, but because the sale of those products will benefit the shareholders.

If carbon taxes were focused on shareholder income linked to greenhouse gas emissions rather than consumption, they could target those receiving the most economic benefits resulting from these emissions.

The impact

A couple of interesting things might result, particularly if the tax was set based on the carbon intensity of the company.

Corporate executives and boards would have incentive to reduce emissions to lower taxes for shareholders. Shareholders would have incentive, out of self-interest, to pressure companies to do so.

Investors would also have incentive to shift their portfolios to less-polluting companies to avoid the tax. Pension and private wealth fund managers would have incentive to divest from carbon-polluting investments out of a fiduciary duty to their clients. To keep the tax focused on large shareholders, I could see retirement accounts being excluded from the tax, or a minimum asset threshold before the tax applies.

Revenue generated from the carbon tax could help fund adaptation and the transition to clean energy.

Instead of putting the responsibility for cutting emissions on consumers, maybe policies should more directly tie that responsibility to corporate executives, board members and investors who have the most knowledge and power over their industries. Based on our analysis of the consumption and income benefits produced by greenhouse gas emissions, I believe a shareholder-based carbon tax is worth exploring.

This article is republished from The Conversation, a nonprofit news site dedicated to sharing ideas from academic experts. 

It was written by: Jared Starr, UMass Amherst.

Read more:

Taxing carbon may sound like a good idea but does it work?

What if carbon border taxes applied to all carbon – fossil fuels, too?

A carbon tax can have economic, not just environmental benefits for Australia

Opinion: One thing we know about the Maui wildfires: Some of those most responsible won't pay a cent

Caroline Levine
Thu, August 17, 2023 

Destroyed homes and cars in Lahaina, Hawaii. (Rick Bowmer / Associated Press)


Maui faces devastating economic costs beyond its intolerable human loss and suffering from recent wildfires. Scorched homes and businesses reduced to rubble won’t be rebuilt quickly; cleaning up their remnants, some of them toxic, won’t be cheap. Rebuilding costs have been estimated at $5.5 billion.

Who will pay for this? Most of us will, to varying degrees, but some of those most responsible — the fossil fuel companies that play a key role in such climate-related disasters — won’t.

Extreme weather events always take their highest economic toll on the communities directly hit. Maui’s families, many of whom live paycheck to paycheck, have suddenly lost both jobs and homes. They’ll now struggle to meet their most basic needs. Even those who have some savings will have to figure out how to make them last through long delays for inspections, insurance payments and federal aid.

Taxpayers will keep some emergency shelters and food supplies going and fund longer-term federal assistance. Over the past 10 years, the U.S. government has spent $350 billion on climate-related disasters.

Insurance companies will cover much of the property damage. They’ll probably hike rates across the state, too, passing on the costs to ordinary Hawaiians. Some may even stop selling homeowner coverage in Hawaii, as State Farm and others have done in wildfire-prone California, exposing residents to even greater costs.

Hawaiian Electric already faces legal action over the possibility that the utility's equipment started the fires. If California residents’ experience attempting to extract compensation from Pacific Gas and Electric Co. is any guide, the results will be mixed.

The fossil fuel companies, however, won’t be paying a cent. That’s despite the fact that their products created the climate conditions that made such fires more likely and more catastrophic. Less rain, higher temperatures and other factors related to climate change have made Hawaii, like California, more vulnerable to wildfires.

Read more: Opinion: What Hawai’i needs now from California, our sister state

As Naomi Oreskes and Erik M. Conway have shown, major oil, gas and coal companies foresaw the catastrophic climatic consequences of fossil fuel use. But instead of leading an energy transition, they opted to sow public doubt about the link between fossil fuels and global warming and continued to invest in new mines and oilfields.

Cannily, fossil fuel companies have also turned public attention away from themselves by encouraging ordinary people to feel guilty about our own “carbon footprints,” pointing the finger at you and me.

And it’s you and I and the struggling citizens of Maui who are left to pick up the ever-mounting bill for climate disasters.

It doesn’t have to be this way.

One solution is to put a price on carbon to account for “externalities,” the term economists use for costs that aren’t reflected in the prices consumers pay.

Let’s say I buy a fertilizer for my crops that assures me a great yield. But when that fertilizer leaches into a nearby lake, it spawns lethal algae blooms, contaminates drinking water and kills plants and fish. I may be delighted by my profits, but I’m costing my neighbors substantial sums in healthcare, tourism and fishing revenue. These are the fertilizer’s dispersed costs — its externalities.

According to 28 Nobel laureate economists and 15 former chairs of the Council of Economic Advisors, it makes good economic sense to charge fossil fuel companies for the real costs of their products through a carbon tax. That cost would include much of the billions of dollars of damage to Maui.

Of course, raising fuel prices could make life harder for Americans who already struggle to fill their gas tanks. But there’s an excellent economic solution to that too. The group Citizens Climate Lobby has proposed to return carbon pricing revenue through regular dividends to all U.S. households. This model would reduce emissions, create jobs and stimulate innovation without burdening low- and middle-income families.

Read more: We survived the Paradise fire. For Lahaina survivors, escape from hell will mark them forever

Another solution is divestment from fossil fuel companies. Investors can force these companies to bear more of the social costs of their products by declining to buy and own their stocks.

Your own savings may have played role in the cause of the devastation in Hawaii. Just 23 investors are responsible for 50% of worldwide investments in fossil fuels. The biggest culprits are asset management giants Vanguard and BlackRock, with Fidelity Investments, JPMorgan Chase, T. Rowe Price, Bank of America and Berkshire Hathaway also making the list. My own retirement fund, TIAA, a nonprofit founded for teachers, manages at least $78 billion in fossil fuel-related holdings, according to one analysis.

Once investors have sunk our money into fossil fuels, they join the chorus lobbying politicians to protect fossil fuel profits. Coal, oil and gas companies are wielding massive influence in the political arena to manipulate the economy to their benefit at our expense. After giving millions of dollars to Senate Republicans this year, fossil fuel companies lobbied for cuts to the Energy Department’s renewables office and reductions in energy efficiency standards.

What if these companies had acknowledged the need for an energy transition 10 or 20 years ago? For the sake of their own bottom lines, they would be championing renewable energy and climate regulation, and we would have a different political landscape.

As long as we keep investing in, subsidizing and cleaning up after the fossil fuel companies, they’ll keep happily passing on these exorbitant costs to us. Isn’t it time to send this bill to the right address?

Caroline Levine is a professor of the humanities at Cornell University, where she teaches in the Environment and Sustainability program, and the author of “The Activist Humanist: Form and Method in the Climate Crisis.”

This story originally appeared in Los Angeles Times.

US investor group clinches tax credit deal for $1.5 billion renewable power acquisition

Its fellow investors include Canada's Caisse de depot et placement du Quebec.

Isla Binnie
Wed, August 16, 2023 

FILE PHOTO: Power-generating Siemens 2.37 megawatt (MW) wind turbines are seen at the Ocotillo Wind Energy Facility as the spread of the coronavirus disease (COVID-19) continues in this aerial photo taken over Ocotillo, California

By Isla Binnie

NEW YORK (Reuters) - Invenergy Renewables, Blackstone and Canada's second-largest pension fund said on Wednesday they struck a deal with Bank of America to help buy wind and solar plants worth $1.5 billion, capitalising on a new tax structure included in President Joe Biden's landmark climate law.

Developers and investors are working on ways to take advantage of a provision in the 2022 Inflation Reduction Act(IRA) which gives companies tax breaks for funding the clean energy projects which can help wean the world off fossil fuels.

Invenergy said in a statement it agreed to sell tax credits worth $580 million to Bank of America, and put those funds towards buying 14 projects from American Electric Power.

Policymakers hope the new system will bring more money from fresh sources into renewables projects which have long relied on a limited group of large banks which can handle the process of buying equity stakes and taking the associated tax breaks.

This is the first large-scale transaction of its kind to be publicly announced, Bank of America's global head of sustainable finance Karen Fang said in the statement.

It "creates a financeable transferability product that will be used to scale the growth of renewable energy," Fang said.

Around $4 trillion will need to be spent on clean energy development globally each year by 2030 to allow the world's economies to cut greenhouse gas emissions to net zero, meaning no more than can be captured by natural sinks like forests or using technology, the International Energy Agency said.

Analysts at investment bank Credit Suisse have estimated the IRA could lead to the generation of tax credits worth $576 billion by 2031.

Treasury Department and Internal Revenue Service published rules on how to regulate tax credit transfers in June, and they are expected to launch an online registry by the end of 2023.

Private equity firm Blackstone has invested around $4 billion in Invenergy. Its fellow investors include Canada's Caisse de depot et placement du Quebec.

(Reporting by Isla Binnie; Editing by Marguerita Choy)

Wood Mackenzie: govts' 'unrealistic' offshore wind expansion target would require $100 billion by 2026

Reuters
Thu, August 17, 2023

Turbines of the WindFloat Atlantic Project, a floating offshore wind-power generating platform, are seen 20 kilometers off the coast in Viana do Castelo

(Reuters) - Government targets to increase wind power installations would see annual capacity additions reach 80 gigawatts (GW) per year by 2030, requiring $100 billion in secured investment in the supply chain by 2026, Wood Mackenzie said in a report.

The research and consultancy firm forecast annual capacity is more likely to increase by 30 gigawatts (GW) a year by 2030, which would require $27 billion of secured investment by 2026.

"The supply chain is struggling to scale up and will be an impediment to achieving decarbonisation targets if change does not happen," said Chris Seiple, vice chair, power and renewables at Wood Mackenzie.

"Nearly 80 GW of annual installations to meet all government targets is not realistic, even achieving our forecasted 30 GW in additions will prove unrealistic if there isn't immediate investment in the supply chain," Seiple said.

Wood Mackenzie noted that the low profit margins on offshore wind production and uncertainty about project timings resulting in very different supply-chain needs are making it hard to drum up investment in the sector.

According to the Statistical Review of World Energy report in June, global wind and solar power grew to a record share of 12% of power generation last year, surpassing nuclear.

Target setting and plans for power market infrastructure to support offshore wind need to extend beyond 2030 to scale up the offshore wind supply chain, analysts at Wood Mackenzie said.

(This story has been corrected to say that an investment of $100 billion, not $27 billion, would be required by 2026 in the headline and paragraphs 1 and 2)

(Reporting by Anushree Mukherjee in Bengaluru; Editing by Susan Fenton)

INDIA

Himachal Pradesh floods: More rain, less snow are turning Himalayas dangerous

Navin Singh Khadka -

 Environment correspondent, 

BBC World Service
Thu, August 17, 2023 

Increased rain and melting of snow and ice has made the mountain regions more dangerous, a new study finds


Torrential rains and unabated construction are frequently triggering disasters in India's Himalayan region.

But an unusual increase in rainfall is making the terrain even more dangerous.

Landslides and flash floods have already killed dozens in the area this month, burying homes and buildings. Parts of Nepal and Pakistan have also suffered damage.

A new study has found that mountains across the globe, including the Himalayas, are now seeing more rainfall at elevations where it has mostly snowed in the past.

The change has made the mountains more dangerous, scientists say, as increased temperatures not only bring rain but also accelerate melting of snow and ice. The rainwater also loosens the soil resulting in landslides, rockfalls, floods and debris-flows.

"Our findings provide several lines of evidence demonstrating a warming-induced amplification of rainfall extremes at high altitudes, specifically in snow-dominated regions of the Northern Hemisphere," says the study, published in June in the Nature journal.

The finding is consistent with a special report of the Intergovernmental Panel on Climate Change (IPCC) in 2019 which said that snowfall had decreased, at least in part because of higher temperatures, especially at lower elevations of mountain regions.

The Himalayan hazards nobody is monitoring

There are more instances of extreme precipitation events occurring now in the form of rainfall even at a high elevation and in all seasons, says Samuel Morin, executive director of the National Centre for Meteorological Research in France and one of the authors of the special IPCC report.

This is mainly because the zero-degree isotherm, the freezing level at which precipitation falls as snow, has moved to a higher elevation because of global warming

"As a result, these [mountain] regions are regarded as hotspots that are vulnerable to high risk of extreme rainfall events and related hazards of flooding, landslides and soil erosion," the study says.

Himalayan states in India have suffered from increased frequency and intensity of landslides and floods

This risk is higher for the Himalayan region compared with other mountainous regions like the Alps and the Rockies in the northern hemisphere, Mohamed Ombadi, the study's lead author, told the BBC.

"That's because there are additional warming-related processes [in the Himalayas] that change wind patterns and storm tracks, leading to an increase in the intensity of storms."

Mountains in the Himalayas, which span India, Bhutan Nepal and Pakistan, hardly have any weather stations, which often leads to a lack of accurate data on precipitation levels.

There are a few stations located in the lower elevations of the mountains but they do not show whether the precipitation recorded is rain or snowfall.

However, a weather station installed at the base camp of Mount Everest showed that 75% of the 245.5mm precipitation on the mountain between 1 June and 10 August this year had fallen as rain. The remaining was snow or a combination of rain and snow.

This is a huge jump from the 32% of rain recorded between June and September in 2022, 43% in 2021 and 41% in 2020.

"We believe the dominance of rain vs snow is a relatively recent phenomenon but do not have longer term data to fully quantify that," said National Geographic explorers Baker Perry and Tom Matthews who were part of the National Geographic and Rolex Perpetual Planet Expeditions that installed the station.

The trauma of living in India's sinking Himalayan town

The changes in precipitation are evident on the mountains of the Himalayan state of Uttarakhand, says Bikram Singh, head of the regional weather office.

"We can definitely say snowfall frequency has decreased and this is usually at elevations below 6,000m. During monsoon, the lower elevations receive heavy rainfall."

The dwindling snowfall and increased rainfall mean that the nature of rivers in the region has changed, says Professor JS Rawat, former head of Kumaun University's geography department.

"There are now lots of flash floods after extreme rainfall and rivers that were once glacier-fed in the region have now turned into rain-fed [water bodies]."

Dozens have been killed in landslides and flash floods in Uttarakhand and Himachal Pradesh this month

Rising temperatures have added to the problem as they have accelerated the melting of Himalayan glaciers. This leads to rapid filling up of glacial lakes that then become prone to overflowing and causing floods. The thinning of glaciers also destabilises mountain slopes.

The Himalayas are estimated to be warming at three times the rate of the global average - and several studies have projected this will lead to substantive increase in rainfall there.

Locals in the states of Uttarakhand and Himachal Pradesh say they have noticed that the frequency and intensity of landslides and floods during the monsoon season have increased.

"Our village Ganai was already threatened by landslides because of increased rainfall on the mountains, so we had to abandon it and move," says Prabhakar Bhatta, 25, a resident of Mayapur village in Uttarakhand's Chamoli district. "But even here we have become homeless."

'Hanging' glacier broke off to trigger India flood

On 14 August, a little before midnight, a huge flash flood hit Mr Bhatta's two-storey house, burying it under debris of rock, silt and mud.

"We managed to survive because we were warned by people in villages at higher elevations that it was raining very heavily and there could be a flash flood coming our way," he says.

Mr Bhatta says his family stayed up that night and fled when they heard "odd sounds".

"My father built the house with his lifetime savings, and now that too is gone," he says. "This region is becoming unliveable."

Locals say the region has become uninhabitable

Experts say that rampant development of infrastructure like road, tunnels and hydropower projects in the ecologically sensitive region also leads to these disasters. Located in a seismic zone as the Himalayas are, they are subject to earthquakes which make matters worse.

The impact of increased rainfall is also visible across the Indian border.

In northern Pakistan, where the Himalayas meet Karakoram and Hindukush mountains, debris flows and flash floods have become increasingly common, officials say.

There were 120 flash floods in the region's Gilgit Baltistan area during the last monsoon - a huge jump from 10-20 years ago, says Kamal Qamar, director general of the regional disaster management authority.

"It's raining in high altitudes at around 4,000m both in summer and winter, when it should have snowed," he says.

Is India-China race to build damaging the Himalayas?

In the eastern Himalayas in Nepal, flash floods and debris flows are destroying vital infrastructure like hydropower and drinking water plants, apart from local settlements, roads and bridges.

According to the country's Independent Power Producers Association, 30 hydropower plants have been damaged in eastern Nepal this monsoon.

Experts say cascading events on Himalayan regions' mountains are also becoming frequent and intense.

That's when an event triggers something else further downstream, says Jakob Steiner, a researcher with the International Centre for Integrated Mountain Development, based in Kathmandu.

"And higher rainfall intensity is often the start or a sub-trigger in these chains."

As glaciers melt, a new study seeks protection of ecosystems that emerge in their place

JAMEY KEATEN
Updated Thu, August 17, 2023

FILE - A team member of Swiss Federal Institute of Technology glaciologist and head of the Swiss measurement network 'Glamos', Matthias Huss, passes the Rhone Glacier covered by sheets near Goms, Switzerland, on June 16, 2023. A new scientific study suggests the world should start preparing to protect the ecosystems that emerge from under the disappearing ice as warming planet is inevitably causing glaciers to melt. (AP Photo/Matthias Schrader) (ASSOCIATED PRESS)More


GENEVA (AP) — A new scientific study published Thursday suggests the world should start preparing to protect the ecosystems that emerge from under the disappearing ice, as a warming planet is inevitably causing glaciers to melt.

If nothing is done to stop global warming, the world could lose glaciers totaling the size of Finland by 2100. Even a best-case scenario — if the targets of the Paris Agreement to stop climate change are met — foresees glacier shrinkage the size of Nepal, according to the study published in the scientific journal Nature.

The analysis from Swiss and French scientists adds to worries about glacier melt and a growing call to step up efforts to protect the planet from climate change.

In their research, the scientists say humans have grown to live with glaciers for millennia, and the worrying retreat of the ice cover — currently amounting to 10 percent of the Earth’s land surface — will require both action to stop it and adaptation for its impact.

Glaciers play a key role on the planet, by reflecting sunlight or providing fresh water for irrigation, power generation and consumption, says study co-author Jean-Baptiste Bosson, a French-Swiss glacier expert with the National Council for the Protection of Nature in Annecy, France.

He said work is being done to slow down the retreat of glaciers, though it won't be “decisive” in saving them.

“But after the glaciers (melt) not everything is lost,” Bosson said in an interview. “We especially need to protect the nature that will follow the glaciers: we need to protect the forests of tomorrow, the great lakes of tomorrow, the great fjords of tomorrow."

The areas where glaciers once were will be “degraded” when the ice melts, Bosson said, adding that nature should be left to do its work: “There is a chance for ecosystems to rebound if we leave them space and time ... nature itself will find solutions: It will capture carbon, purify fresh water, create habitats for biodiversity."

Glacier retreat hit unprecedented high levels in Europe last year, especially in Switzerland.

The team behind the Nature study analyzed some 210,000 glaciers on Earth, not including the gigantic Greenland and Antarctic ice sheets, and found that glaciers covered some 665,000 square kilometers (257,000 square miles), about the size of Afghanistan, in 2020.

Depending on the different scenarios, which the experts slice up from worst-case to best-case, the world could lose between roughly 149,000 square kilometers (58,000 square miles) to some 339,000 square kilometers (131,000 square miles), by 2100. The team accounts for possible statistical variance. The loss could be much larger.

“Melting glaciers have become icons of climate change. People are mostly worried about the impact glacier melt will have on sea-level rise, seasonal water availability, and geohazards,” said Prof. Ben Marzeion, of the Institute of Geography at Germany’s University of Bremen.

“This study shows that there is more we need to be prepared for. It also shows that we are still in the process of uncovering the multitude of impacts climate change will have,” said Marzeion, who was not involved in the research.

Twila Moon, deputy lead scientist at the U.S. National Snow and Ice Center, laid out the challenges that policymakers will face as landscapes change with glacier retreat.

“There is no question that ice loss around the world is a serious issue, from influencing water availability to raising our sea levels,” Moon, who wasn’t involved in the study, said in an email. “This research highlights another impact — the uncovering of new land as glaciers shrink.”

“Glacier retreat can cause increasing hazards, like the outburst flood that destroyed homes in Juneau earlier this summer, or change water availability for drinking and crops,” Moon wrote. “We must plan ahead while also work hard to reduce heat-trapping gas emissions and limit future damage.”

Bosson says that record high temperatures reached this year in the northern hemisphere are producing worrisome outcomes that could have an even greater impact in the future – though not all data is in yet.

“We try to tell the story of the future of the surfaces today occupied by glaciers on Earth,” he said in a video call from the French Alpine town of Annecy. “Then we ask: Will tomorrow still see big glaciers, or smaller glaciers depending on the climate scenarios?”

More Snow Can Actually Cause Tundra to Thaw Faster, Unleashing Buried Carbon

Yale Environment 360
Thu, August 17, 2023 

The International Tundra Experiment at Toolik Lake in Alaska.

 Amanda Young / Toolik Field Station

With climate change, parts of the Arctic are seeing greater snowpack. Paradoxically, a thick blanket of snow can speed the melting of permafrost underneath, releasing buried stores of carbon, new research shows.

The insight comes from a decades-long experiment near Toolik Lake in northern Alaska. Starting in 1994, scientists there began covering a swath of tundra in three to four times the usual amount of snowpack, finding that, as the region warmed, this patch actually thawed faster than other areas. Scientists said the added snow acted like a blanket during the cold months, holding in summer heat while keeping out frigid air.

As permafrost melted, microbes began to consume long-frozen plant matter in the ground, producing carbon dioxide as a byproduct. The patch of tundra with extra insulation became a year-round source of emissions. Even as shrubs began to grow on the once-frozen ground and soak up some carbon dioxide, the emissions from microbes remained greater still, according to the new study, published in AGU Advances.

The new findings, authors write, show that greater snowfall “will cause earlier-than-expected losses of ancient carbon from permafrost and further accelerate climate change.”

ALSO ON YALE E360

How Thawing Permafrost Is Beginning to Transform the Arctic

US escalates trade dispute with Mexico over limits on genetically modified corn
Associated Press
Updated Thu, August 17, 2023

Central Illinois farmers deposit harvested corn on the ground outside a full grain elevator in Virginia, Ill. The U.S. government said Thursday, Aug. 17, 2023, it is formally requesting a dispute settlement panel in its ongoing row with Mexico over its limits on genetically modified corn.

 (AP Photo/Seth Perlman, File) (ASSOCIATED PRESS)


MEXICO CITY (AP) — The U.S. government said Thursday it is formally requesting a dispute settlement panel in its ongoing row with Mexico over its limits on genetically modified corn.

Mexico's Economy Department said it had received the notification and would defend its position. It claimed in a statement that “the measures under debate had no effect on trade,” and thus do not violate the United States-Mexico-Canada free trade agreement, known as the USMCA.

The U.S. Trade Representatives Office, or USTR, objected to Mexico’s ban on GM corn for human consumption and plans to eventually ban it as animal feed.

The USTR said in a statement that “Mexico’s measures are not based on science and undermine the market access it agreed to provide in the USMCA."

The panel of experts will now be selected and will have about half a year to study the complaint and release its findings. Trade sanctions could follow if Mexico is found to have violated the U.S.-Mexico Canada free trade agreement.

The U.S. government said in June that talks with the Mexican government on the issue had failed to yield results.

Mexico wants to ban biotech corn for human consumption and perhaps eventually ban it for animal feed as well, something that both its northern partners say would damage trade and violate USMCA requirements that any health or safety standards be based on scientific evidence.

Mexico is the leading importer of U.S. yellow corn, most of which is genetically modified. Almost all is fed to cattle, pigs and chickens in Mexico, because Mexico doesn’t grow enough feed corn. Corn for human consumption in Mexico is almost entirely domestically-grown white corn, though corn-meal chips or other processed products could potentially contain GM corn.

Mexico argues biotech corn may have health effects, even when used as fodder, but hasn’t yet presented proof.

Mexico had previously appeared eager to avoid a major showdown with the United States on the corn issue — but not eager enough to completely drop talk of any ban.

In February, Mexico’s Economy Department issued new rules that dropped the date for substituting imports of GM feed corn. The new rules say Mexican authorities will carry out “the gradual substitution” of GM feed and milled corn, but sets no date for doing so and says potential health issues will be the subject of study by Mexican experts “with health authorities from other countries.”

Under a previous version of the rules, some U.S. growers worried a GM feed corn ban could happen as soon as 2024 or 2025.

While the date was dropped, the language remained in the rules about eventually substituting GM corn, something that could cause prices for meat to skyrocket in Mexico, where inflation is already high.

U.S. farmers have worried about the potential loss of the single biggest export market for U.S. corn. Mexico has been importing GM feed corn from the U.S. for years, buying about $3 billion worth annually.