Methane, explained

Cows and bogs release methane into the atmosphere, but it’s by far mostly human activity that’s driving up levels of this destructive greenhouse gas.

Every time a cow burps or passes gas, a little puff of methane wafts into the atmosphere.

Each of those puffs coming out of a cow’s plumbing, added together, can have a big effect on climate because methane is a potent greenhouse gas—about 28 times more powerful than carbon dioxide at warming the Earth, on a 100-year timescale, and more than 80 times more powerful over 20 years. The effects aren’t just hypothetical: Since the Industrial Revolution, methane concentrations in the atmosphere have more than doubled, and about 20 percent of the warming the planet has experienced can be attributed to the gas.

There’s not that much methane in the atmosphere—about 1,800 parts per billion, about as much as two cups of water inside a swimming pool. That’s about 200 times less concentrated in the atmosphere than carbon dioxide, the most abundant and dangerous of the greenhouse gases. But methane’s chemical shape is remarkably effective at trapping heat, which means that adding just a little more methane to the atmosphere can have big impacts on how much, and how quickly, the planet warms.

Methane is a simple gas, a single carbon atom with four arms of hydrogen atoms. Its time in the atmosphere is relatively fleeting compared to other greenhouse gases like CO2—any given methane molecule, once it’s spewed into the atmosphere, lasts about a decade before it’s cycled out. That’s a blip compared to the centuries that a CO2 molecule can last floating above the surface of the planet. But there are many sources of methane, so the atmospheric load is constantly being regenerated—or increased.

Methane’s sources

Today, about 60 percent of the methane in the atmosphere comes from sources scientists think of as human caused, while the rest comes from sources that existed before humans started influencing the carbon cycle in dramatic ways.

Most of methane’s natural emissions come from a soggy source: wetlands, which includes bogs. Many microbes are like mammals in that they eat organic material and spit out carbon dioxide—but many that live in still, oxygen-deprived spots like waterlogged wetland soils produce methane instead, which then leaks into the atmosphere. Over all, about a third of all the methane floating in the modern atmosphere comes from wetlands.



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There are a variety of other natural methane sources. It seeps out of the ground naturally near some oil and gas deposits and from the mouths of some volcanoes. It leaks out of thawing permafrost in the Arctic and builds up in the sediments under shallow, still seas; it wafts away from burning landscapes, entering the atmosphere as CO2; and it is produced by termitesas they chow through piles of woody detritus. But all of these other natural sources, excluding wetlands, only make up about ten percent of the total emissions each year.

Human sources of methane

Today, human-influenced sources make up the bulk of the methane in the atmosphere.

Other agricultural endeavors pump methane into the atmosphere, too. Rice paddies are a lot like wetlands: When they’re flooded, they’re filled with calm waters low in oxygen, which are a natural home for methane-producing bacteria. And some scientists think they can see the moment when rice production took off in Asia, about 5,000 years ago, because methane concentrations—recorded in tiny bubbles of ancient air trapped in ice cores in Antarctica—rose rapidly.

The small flask holds as much methane as the large one, as a powder rather than a gas.PHOTOGRAPH BY MARK THIESSEN, NAT GEO IMAGE COLLECTION

Methane also leaks into the atmosphere at gas and oil drilling sites. There are strict rules in place in many states and countries about how much leakage is allowed, but those rules have proven difficult to enforce. Recent studies suggest that wells in the U.S. alone are producing about 60 percent more methane than previously estimated by the Environmental Protection Agency. Worldwide, the energy sector contributes about a quarter of the annual methane budget.

Another major source? Waste. Microbes in landfills and sewage treatment centers chomp through the detritus humans leave behind and in the process pump out tons of methane each year—about 14 percent of the U.S.’s annual footprint.

Methane’s impact on climate, past and future

Methane may also have been the cause of rapid warming events deep in Earth’s history, millions of years ago. Under high pressure, like the pressures found deep at the bottom of the ocean, methane solidifies into a slush-like material called methane hydrate. Vast amounts of methane are “frozen” in place at the bottom of the sea in this chemical state, though the exact amounts and locations are still being studied. The hydrates are stable unless something comes along to disturb them, like a plume of warm water.

massive warming event that occurred about 55 million years ago may have been kicked off by destabilized hydrates, some scientists think. Methane percolated up from the seafloor into the atmosphere, flooding it with the heat-trapping gas and forcing the planet to warm drastically and quickly.

In the modern atmosphere, methane concentrations have risen by more than 150 percent since 1750. It’s not clear whether this rise will continue, or at what rate, but the IPCC warns that keeping methane emissions in check is necessary in order to keep the planet from warming further.

Climate action: Should methane be measured the same as carbon dioxide?

Climate action: Should methane be measured the same as carbon dioxide?

A different metric should be used to measure methane emissions for climate change policy, according to a recent paper published by the Oxford Martin School, in the University of Oxford.

The paper, published last year, highlights that the current ‘one size fits all’ climate change policy does not take into account that there are two types of emissions that contribute to climate change – long-lived and short-lived pollutants.

Explaining the difference, Dr. Michelle Cain from the Oxford Martin Programme on Climate Pollutants, said: “Long-lived pollutants, like carbon dioxide, persist in the atmosphere, building up over centuries.

The CO2 created by burning coal in the 18th century is still affecting the climate today. Short-lived pollutants, like methane, disappear within a few years.

“Their effect on the climate is important – but very different from that of CO2: Yet current policies treat them all as ‘equivalent’.”

Prof. Myles Allen, who led the study, said: “We don’t actually need to give up eating meat to stabilise global temperatures.

“We just need to stop increasing our collective meat consumption. But we do need to give up dumping CO2 into the atmosphere.

“Every tonne of CO2 emitted is equivalent to a permanent increase in the methane emission rate. Climate policies could be designed to reflect this.”

Prof. Dave Frame, head of the Climate Change Research Institute at Victoria University of Wellington, added: “Under current policies, industries that produce methane are managed as though that methane has a permanently worsening effect on the climate.

But this is not the case. Implementing a policy that better reflects the actual impact of different pollutants on global temperatures would give agriculture a fair and reasonable way to manage their emissions and reduce their impact on the environment.

“Implementing a policy like this would show New Zealand to be leaders and innovators in climate change policy,” says Professor Allen.

“Implemented successfully, it could also completely stop New Zealand’s contribution to global warming.”

The work, which is a collaboration between researchers at Victoria University of Wellington, the Universities of Oxford and Reading, and the Centre for International Climate Research in Norway (CICERO), “shows a better way to think about how methane might fit into carbon budgets”, according to the Oxford Martin School.


Smoke rises above the Amazon rainforest, outside an indigenous reservation near Jundia, Roraima state. Brazil, on Monday, Jan. 28, 2019.
This story originally appeared on Yale Environment 360 and is part of the Climate Desk collaboration.

There are many mysteries in the Amazon. Until recently, one of the most troubling was the vast methane emissions emerging from the rainforest that were observed by satellites but that nobody could find on the ground. Around 20 million tons was simply unaccounted for.

Then Sunitha Pangala, a British postdoc researcher, spent two months traveling the Amazon’s waterways strapping gas-measuring equipment to thousands of trees. She found that trees, especially in the extensive flooded forests, were stimulating methane production in the waterlogged soils and mainlining it into the atmosphere.

Her 2014 expedition plugged a gaping hole in the planet’s methane budget. And she had discovered a hitherto ignored major source of the second most important greenhouse gas in the atmosphere. It now seems that most of the world’s estimated 3 trillion trees emit methane at least some of the time.

Nobody is arguing that trees are therefore bad for climate and should be cut down. Indeed, in most cases, their carbon storage capability easily outweighs their methane emissions. But in a world where corporations plant trees to offset their carbon emissions, we badly need to know if their numbers add up, or if they are undermined by the complex chemistry of trees and methane.

Forest scientists have long amused their students by cutting holes in tree bark and setting fire to gases hissing from the trunk. The first recorded measurements were made in 1907, when Francis Bushong of the University of Kansas cut a campus cottonwood and found the gas coming off was 60 percent methane. Yet “it was only about a decade ago that scientists thought to measure whether methane was actually emitting from trees growing in forests,” says Patrick Megonigal of the Smithsonian Environmental Research Center in Maryland, a pioneer in the work.

For a while, few forest researchers wanted to know. They were not keen to hear that trees might not be quite as good for the climate as they hoped. Perhaps they feared a rerun of the furor in 1981, when Ronald Reagan used research on the discovery of volatile organic compounds from trees to falsely claim that they “cause more pollution than automobiles.”

Similarly, climate scientists saw forests as absorbing methane, rather than releasing it. It only slowly dawned on anyone that trees might do both.

Among the first was Vincent Gauci, then at the UK’s Open University and now at Birmingham University. “When I was first working on this, it was poo-pooed,” he says. When Pangala, then also at The Open University, made her first measurements of trees emitting methane in the swamps of Borneo, she had the same experience. Despite finding that the trees increased standard estimates of emissions from the swamps sevenfold, “it took 18 months to get it published,” she says. “We were rejected by several journals. They just weren’t interested.”

“We found a consistent story that the trees all emit a lot of methane,” she says. “In the seasonally flooded part of the Amazon, the trees become a massive chimney for pumping out methane.” Emissions from individual trees were more than 200 times higher than any previously measured anywhere. This was not trivial. Every hectare of flooded forests was emitting several kilograms of methane each day. The on-the-ground findings doubled previous estimates of Amazon methane emissions to around 40 million tons a year. The trees were emitting as much methane as all the tundra ecosystems of the Arctic, whose permafrost contains huge amounts of the gas—a store that is expected to be released in ever-greater quantities as the region warms and its soils thaw.

Pangala’s “bottom-up” findings were confirmed by “top-down” measurements from aircraft flown by the US National Oceanic and Atmospheric Administration (NOAA) and others across the same areas. It was a game-changer. “She blew the story open,” says Kristofer Covey of Skidmore College in New York. “The work was very thorough and considered. She provided a full ecosystem picture, and showed the missing methane was coming from trees. It was very difficult to argue with.”

Not least because it explained a long-standing data gap, first identified by hydrologist Christian Frankenberg, now at the NASA Jet Propulsion Laboratory in California. He had pointed out in 2005 that remote sensing data from satellites suggested the Amazon was emitting twice as much methane as researchers on the ground could account for. Now the world knew why. “She closed the Amazon methane budget,” says Covey.

After water vapor and carbon dioxide, methane is the most important greenhouse gas. In fact, molecule for molecule, it is a much more potent planet-warmer than CO2. Human sources—most prominently rotting landfills, coal mines, rice paddies, cattle, and leaks from natural gas pipelines—have raised atmospheric concentrations by around 250 percent. They are reckoned to be responsible for around a fifth of global warming.

Because methane only lasts in the atmosphere for around a decade, removing major sources could have a quicker effect on global temperatures than removing CO2, which lasts for centuries. That does not mean that cutting down the world’s trees would cool the planet, however. Far from it. In most places at most times, trees’ ability to absorb and store carbon dioxide trumps any contribution their methane emissions make to the atmosphere.

But equally, it can’t be ignored, says Pangala. The numbers are too high. “We find a total footprint of 50-65 million tons of methane annually from wetland trees,” she says. “That is a third of the total from natural wetlands. A third we didn’t know about at all until recently.”

The most intense tree emissions are almost certainly from forested areas of tropical wetlands, such as the Amazon. But the role of trees outside wetlands cannot be discounted. “We know emissions from [non-wetland] trees are lower, but there is a far larger area of upland forests in the world to emit,” says Megonigal.

Likewise, trees outside the tropics do not generally emit on the scale of those in the tropics. Temperatures are too low. But even so, some forests in the mid-latitudes may at times emit enough methane to negate the methane-absorbing capacity of their soils, turning their ecosystems from net methane sinks to net sources, says Megonigal.

Some researchers see wetland tree trunks merely as passive conduits for methane generated by micro-organisms in the waterlogged soils. Tree trunks may look solid, but they contain spaces and channels through which gases travel up and down. “A large proportion of the volume of a tree stem is gas,” says Covey—anywhere between a quarter and half.

But it seems that wetland trees are much more than conduits. They also create the conditions, and provide the raw materials, for methane generation by micro-organisms. “In wetland systems, trees send a lot of carbon into their roots,” says Pangala. This delivery, known as rhizodeposition, provides the essential raw materials for methane-generating micro-organisms that congregate among the trees’ roots. “Trees are bioreactors”, says Gauci. “Without them, methanogenesis, even in wetlands, might be much less.”

Many trees, especially outside wetlands, also actively generate methane. Some methane comes from photochemical reactions in their foliage. More may be from microbes living in the trunks that themselves generate methane, says Gauci. Some researchers have termed trees as crypto-wetlands or vertical wetlands.

The scale of these processes remains unclear. But what we are learning, says Covey, is that the chemical interactions between trees and the atmosphere are extremely dynamic. “Until recently, in climate terms, we have seen forests mostly as carbon sinks,” he says. “ The reality is very different, there is much more going on.”

The bottom line, says Pangala, is that almost all trees can both emit and absorb methane. But finding out the net balance is very hard because it changes so much. And that methane is, of course, only part of a much bigger picture of the role of trees in climate.

“In the wider world of climate change, their benefits are almost always much greater,” says Pangala. “Even for an individual tree, the methane element usually turns out to be quite small compared to carbon storage.” And besides storing carbon, they recycle moisture, create shade, stimulate cloud formation, protect biodiversity, and cleanse the air.

But even if trees are rarely “bad” for the climate, clearly some can be better than others, says Pangala. So if the world is to embark on a sustained program of reforesting the planet as a means to fight climate change, then “let’s choose trees with a small methane footprint.”

Her former supervisor at The Open University is on the case. Gauci currently is working on the Indonesian island of Sumatra with the owners of huge plantations of acacia trees growing on drained peat bogs. Dried peat emits carbon dioxide, and to prevent that, the Indonesia government is requiring peatland concession holders to plug drains and raise the water table. But the risk, says Gauci, is that rising waters will trigger a burst of methane emissions from the waterlogged trees. He hopes to find a perfect combination of trees and water levels—a “sweet spot that will minimize carbon emissions but avoid a methane bomb.”

The need is all the greater, notes Covey, when governments and corporations are planting trees with the promise that they will thereby offset their industrial emissions by adding trees that soak up CO2, thus meeting their international obligations for cutting greenhouse gas emissions. The climate benefits could be inflated if methane emissions from the trees are ignored, he says: “The danger is that we end up trading real emissions on the carbon markets for perceived offsets.”

“Ultimately we want to get to the situation where if you… know the type of trees and soil and temperature and water table, we will be able to calculate how much methane gets into the atmosphere,” says Pangala. But that still requires a lot more science, and a lot more data.

Earlier this month, Pangala, now at Lancaster University, flew to Mexico with her young son, ready to clamp methane monitoring equipment to mangroves in the coastal swamps of the Yucatan. “It will be hard work,” she said before she departed. “The mangroves are dense. There are snakes to contend with. But it is wet and there are trees. So surely they will be releasing methane. The only question is how much.”

New research is out on thawing permafrost – and it’s worse than climate scientists thought

July 3 (UPI) — The problem of thawing permafrost is worse than climate scientists thought. New research suggests previous studies have underestimated the rate at which thawing permafrost is releasing carbon into the atmosphere.

Thawing permafrost is one of the many negative feedback loops caused by global warming. As temperatures rise, more and more frozen tundra melts, releasing previously trapped carbon into the atmosphere and accelerating climate change.

The new findings build on researchers’ ongoing efforts to track carbon storage and carbon cycling in Arctic ecosystems.

Climate 09 troubling bubbles

In this Aug. 10, 2009, photo, a hill of permafrost “slumping” from global warming near the remote, boggy fringe of North America, 2,200 kilometers (1,400 miles) from the North Pole, where researchers are learning more about methane seeps in the 25,000 lakes of this vast Mackenzie River Delta, in the Northwest Territories, Canada. (AP Photo/Rick Bowmer)

“This study was novel because we used new methods to directly track the soil carbon losses, and they were much higher than we previously thought,” Ted Schuur, a professor of ecology at Northern Arizona University, said in a news release. “This suggests that not only is carbon being lost through greenhouse gases directly to the atmosphere but also dissolved in waters that flow through the soil and likely carried carbon into streams, leaves and rivers.”

Thawing permafrost leaves traceable carbon footprint in Arctic rivers
Warming Arctic may lead to methane boost, abrupt permafrost thaw
42,000-year-old specimen believed to be ‘best preserved Ice Age animal ever found in the world’

Scientists established a consistent relationship between the amount of carbon and ash content in the Alaskan soil, allowing them to use the soil’s mineralogy as a proxy for tracking soil carbon changes over time.

The approach revealed an annual loss of 5 percent of soil carbon.

The study is bad news for the planet’s carbon reserves, more than a third of which are located in frozen tundra. Researchers estimate 5 to 15 percent of the soil carbon sequestered in permafrost could be relinquished to atmosphere by the end of the century — a development that would no doubt lead to accelerated warming.

“Our results demonstrate the potential for repeated measurements that quantify changes in soil carbon across the entire permafrost region to better understand its environmental fate,” researchers wrote in the new study, published this week in the journal Nature Geosciece. “An effort such as this is a critical and currently overlooked link to determine the magnitude of the terrestrial permafrost carbon to climate change.”

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Manipulating gut microbes in livestock could cut their methane emissions

Researchers have investigated the gut microbes of sheep to find ways to reduce agricultural methane emissions
Researchers have investigated the gut microbes of sheep to find ways to reduce agricultural methane emissions(Credit: bogdan.hoda/Depositphotos)

Fossil fuels cop the brunt of attention for reducing climate-changing emissions, but they’re far from the only culprit – livestock like sheep and cows are responsible for huge amounts of methane being released into the atmosphere. Now, an international team of researchers has analyzed the gut microbes of different sheep and found clues that may help us curb the problem.

While carbon dioxide is the most common greenhouse gas being emitted today, methane makes up for its smaller amounts by being more potent. Though it only accounts for 10 percent of emissions in the US, the gas can be up to 28 times more damaging, thanks to its prowess at trapping heat.

Methane is a by-product of coal, gas and oil processing, but the biggest source comes from the burps and farts of farm animals. And considering there are over a billion cattle in the world and about that many sheep as well, that’s a lot of gassy animals warming up the planet.

So researchers from Monash University, AgResearch, and the Universities of Otago, Illinois and Hokkaido investigated how to reduce the methane emissions where they begin – in the stomach of these animals.

The methane released in a hearty fart isn’t actually produced by the animal itself – blame it on the microbes in the gut. As they break down the animal’s food they release methane, which then builds up until it’s released out of one end of the digestive tract or the other.

The researchers on the new study looked at the microbes in the guts of two groups of sheep, one that produced high amounts of methane and one with low emissions. The biggest difference between the microbiomes of the two groups were in the bugs that consumed hydrogen.

In high methane emitters, a group of microbes called methanogens – which eat hydrogen and produce methane – were the most dominant. Unsurprisingly, in low emitters the more common bugs were those that didn’t produce methane, including acetogens, fumarate, nitrate and sulfate reducers.

Of the bugs that produced hydrogen, the team found that Clostridia were the most active, while a group called Ruminococcus albus was seen to alter its metabolism depending on the hydrogen levels in the sheeps’ guts.

Armed with this information, scientists could change up the types of food given to livestock in order to manipulate their gut microbiomes and reduce the amount of methane released into the atmosphere.

“Controlling the supply of hydrogen to the methanogens will lead to reduced ruminant methane emissions and allow us to divert the hydrogen towards other microbes that we know do not make methane,” says Chris Greening, an Associate Professor of Monash University’s School of Biological Sciences who led the study. “We’re excited about this research because it has strong potential to lead to new strategies that slow agricultural methane emissions, which will vital for the ongoing health of the planet and sustaining economies.”

In a similar vein, other studies have found that feeding livestock certain types of seaweed or tropical leaves can lead to reduced methane emissions.

The research was published in the International Society for Microbial Ecology Journal.


Making Cattle More Sustainable

By Amy Quinton on June 27, 2019 in Feeding a Growing Population


Inside the University of California, Davis, dairy barn, a Holstein cow has its head and neck sealed airtight inside a large, clear-plastic chamber that resembles an incubator for newborns. While giant tubes above the chamber pump air in and push air out, the cow calmly stands and eats her feed. Equipment inside a nearby trailer spits out data.

This is how Frank Mitloehner measures gases that come from cows’ stomachs and ultimately contribute to global warming. Quantifying these emissions is key to mitigating them, and Mitloehner is one of several UC Davis researchers investigating economical ways to make livestock production more environmentally sustainable around the globe.

Frank Mitloehner, UC Davis professor and air quality specialist, is researching ways to reduce greenhouse gas emissions from cows. In this experiment, he’s added an essential oil to the cow’s feed. (Karin Higgins/UC Davis)
The plastic chambers help measure the amount of gases coming from the cow’s stomach more precisely. Each year, one cow can belch 220 pounds of methane, which is 28 times more potent than carbon dioxide. (Karin Higgins/UC Davis)

Cattle are the No. 1 agricultural source of greenhouse gases worldwide. Each year, a single cow will belch about 220 pounds of methane, which is shorter lived than carbon dioxide but 28 times more potent in warming the atmosphere, said Mitloehner, a professor and air quality specialist in the Department of Animal Science.

With the escalating effects of climate change, that fact has advocates urging the public to eat less beef. They contend it’s an unsustainable diet in a world with a population expected to reach nearly 10 billion by 2050.

Mitloehner has openly challenged this view, writing in a recent commentary for The Conversation that “forgoing meat is not the environmental panacea many would have us believe.”

Cows and other ruminants account for just 4 percent of all greenhouse gases produced in the United States, he said, and beef cattle just 2 percent of direct emissions.

Better breeding, genetics and nutrition have increased the efficiency of livestock production in the U.S. In the 1970s, 140 million head of cattle were needed to meet demand. Now, just 90 million head are required. At the same time, those 90 million cattle are producing more meat.

“We’re now feeding more people with fewer cattle,” Mitloehner said.

The global problem

Shrinking livestock’s carbon hoofprint worldwide is a bigger challenge. Livestock are responsible for 14.5 percent of global greenhouse gases.

India, for example, has the world’s largest cattle population, but the lowest beef consumption of any country. As a result, cows live longer and emit more methane over their lifetime. In addition, cows in tropical regions produce less milk and meat, so it takes them longer to get to market.

“If you have hundreds of millions of cattle to achieve a dismal amount of product, then that comes with a high environmental footprint,” Mitloehner said.

beef sustainability uc davis
Professor and air quality specialist Frank Mitloehner sits in a trailer at the UC Davis dairy barn examining real-time greenhouse gas emission data coming from cows. (Karin Higgins/UC Davis)

Researchers at UC Davis have projects in Vietnam, Ethiopia and Burkina Faso to boost livestock productivity through better nutrition. That may be critical going forward as demand for meat is rising in developing countries.

“We expect by 2050 there is going to be a 300 percent increase in beef demand in Asia,” said Ermias Kebreab, a professor of animal science and director of the UC Davis World Food Center.

A new diet

Kebreab, Mitloehner and other UC Davis scientists are looking for ways to make cows more sustainable and less gassy. One way to do that is to make their high-fiber diet easier to digest, so scientists often turn to feed supplements for this purpose. It sounds simple, but finding an affordable and nutritious additive has proved difficult.

However, Kebreab has succeeded in finding such a supplement by feeding dairy cattle a plant way off the trough menu: seaweed.

“We’ve done one trial and showed that there is up to a 60 percent reduction in methane emissions by using 1 percent of seaweed in the diet,” Kebreab said. “This is a very surprising and promising development.”

beef sustainability uc davis
These black Angus cattle graze on a diversity of grasses at the Van Vleck Ranch near Rancho Murieta, California. Managed correctly, cows can help restore healthy soils. (Karin Higgins/UC Davis)

In addition to reducing methane output, the seaweed doesn’t make the cows’ milk taste bad. He’s now testing the diet on beef cattle.  It could be a relatively inexpensive solution for reducing emissions.

This type of red seaweed, called Asparagopsis taxiformis, has one big drawback: a wild harvest is unlikely to provide enough of a supply for broad adoption. Other scientists are looking for ways to grow it to scale, and Kebreab remains hopeful that feed additives hold the most promise.

“I believe that we will have a solution, two or three good candidates, that would reduce emissions quite substantially,” Kebreab said. “I can see that happening in the next few years.”

Jerry Spencer, Van Vleck ranch manager, rotates herds of cattle between pastures to give grasses opportunity to recover and allow healthy root systems to grow. (Karin Higgins/UC Davis)
Hundreds of black Angus cattle graze at the Van Vleck ranch near Rancho Murieta. Rangelands like these can help mitigate climate change by holding atmospheric carbon in the soil. (Karin Higgins/UC Davis)

Cows as part of the climate change solution

Besides emitting greenhouse gases, another common criticism of beef production is that cows take up nearly half the land in the United States. Overgrazing those lands can degrade soil health and biodiversity. Yet researchers argue that, managed correctly, cows help restore healthy soilsconserve sensitive species and enhance overall ecological function. Proper cattle grazing management can even help mitigate climate change.

On the Van Vleck Ranch east of Sacramento near Rancho Murieta, Jerry Spencer manages about 2,500 cattle. A good winter’s rain this year has left them a feast of green pastures. Spencer pays close attention to the grasses, making sure the animals have enough to eat but don’t overgraze. He maintains a diversity of native grasses to keep the cows healthy and rotates herds between pastures to give the plants a rest from grazing and opportunity to recover.

“You want to leave as much as grass as possible to allow water infiltration and healthy root systems,” Spencer said.

(Research at UC Davis indicates just a touch of the ocean algae in cattle feed could dramatically cut greenhouse gas emissions from California’s 1.8 million dairy cows.)

Maintaining healthy root systems isn’t just good for the plants. The longer and denser the roots, the more they can hold atmospheric carbon in the soil.

“One of the best and most simple things we can do on rangelands to help mitigate climate change is to conserve rangeland ecosystems and keep the carbon that’s already stored in rangeland soils safely stored there,” said Ken Tate, a UC Davis rangeland watershed management extension specialist. California is at particular risk of rangelands being converted to housing and other developments, he said.

Ranchers really have little financial incentive to let their herds overgraze or let their herd’s hooves compact and degrade soils. Spencer said if the land degrades, then the cattle’s health can suffer as well.

“Sustainability is keeping everything viable both economically and biologically,” said Spencer. “Ranchers don’t continue to exist if either one of those are really out of balance.”

While sustainable grazing practices won’t eliminate methane produced by the cows, they can offset it. According to Project Drawdown, this solution could sequester 16 gigatons of carbon dioxide by 2050.

“Proper grazing sustains working landscapes that support communities, food production and a healthy environment,” Tate said.

Researchers say sustainable grazing practices like those at Van Vleck ranch won’t eliminate methane produced by cows, but they can offset it. (Karin Higgins/UC Davis)
Jerry Spencer’s dogs help herd the black Angus cattle on the Van Vleck ranch. (Karin Higgins/UC Davis)

Meat-free movement

Environmental considerations may factor into people’s food choices, but those decisions are also based on religious and cultural beliefs and traditions, as well as personal tastes. In low-income countries, there may not be any choice. It’s why Tate and Mitloehner believe the meat-free movement can go only so far.

“There will never be a situation where some major part of our diet will be ruled out,” Mitloehner said.  “My job is not to judge people for their eating habits. My job is to look at how we can produce livestock and minimize those environmental impacts that do exist.”

A Glint Of Light And A Hint Of Life: Mars Is Getting Very Interesting Right Now

The bright spot in the distance was photographed days before the rover detected a possible sign of life on the Red Planet.

NASA’s Mars Curiosity rover spotted a strange glowing object that seemed to hover just above the surface of the Red Planet earlier this month.

While the glint on Mars has captured the imagination of folks on social media, it was likely just sunlight, a cosmic ray or a camera artifact. But in an unrelated development days later, the rover detected something else ― and it could be a long-sought signal of possible microbial life on or inside the planet.

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The glowing object was captured on camera ― look at the right side of this raw image taken from the NASA website on June 16:

Here it is zoomed in:

It doesn’t appear on any of the images snapped before or after, taken about 13 seconds apart, so if it was an object of some kind it moved quickly. More likely, however, it was nothing too out of the ordinary.

“In the thousands of images we’ve received from Curiosity, we see ones with bright spots nearly every week,” Justin Maki of NASA’s Jet Propulsion Laboratory said in 2014 when a similar flash of light made headlines. “These can be caused by cosmic-ray hits or sunlight glinting from rock surfaces, as the most likely explanations.”

So, the flash of light was unlikely to be a sign of activity on the planet.

But something else was detected on Mars last week that just might be a sign of life: methane. The New York Times reported that Curiosity detected a spike in methane, which, if confirmed, could hint of microbial life hidden beneath the surface of Mars.

There were other possible explanations:

Curiosity Rover


Something in the air tonight

I detected the largest amount of methane ever during my mission: ~21 parts per billion by volume. While microbial life can be a source of methane on Earth, methane can also be made by interaction between rocks and water. 

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The rover spent the weekend conducting follow-up tests in an attempt to confirm the results, with more analysis ongoing. NASA said the rover had detected methane in the past, and the planet seemed to have seasonal peaks and dips.

Definitive answers could be tough to come by.

“With our current measurements, we have no way of telling if the methane source is biology or geology, or even ancient or modern,” Paul Mahaffy of NASA’s Goddard Spaceflight Center said in a news release.

NASA is coordinating with the scientists working with the European Space Agency’s Trace Gas Orbiter, which is orbiting Mars, to find the origin of the gas.



Mars Photos

People are losing their homes to wildfires. They are dealing with floods. Their loved ones are dying in extreme heat. Their houses are falling into the sea.

Climate change is no longer theoretical. It’s in our backyard.

Here are four snapshots of this new reality — and what we’re doing about it.

The only thing I’m thinking is my mama burning alive, and she’ll be crying out my name.
When John Bino learned that a wildfire was closing in on his home in Fort McMurray’s Abasand neighbourhood on May 3, 2016, he was at work — one and a half hours away.

John Bino holds up the framed number of his house in Fort McMurray.
John Bino holds up the framed number of his house in Fort McMurray, which burned to the ground in the 2016 wildfire. (Craig Chivers/CBC)
He called home and told his wife, Jenny Solidum, to gather their two young boys and go to a friend’s place in nearby Timberlea. In the meantime, Bino would drive back to the house to retrieve his 76-year-old mother, who was visiting from India. She was a polio survivor and too heavy for his wife to lift.

But by the time he arrived at home, police had barricaded the road. Bino pleaded with them to let him through.

“I said, ‘My mom, she’s handicapped, she cannot move. She doesn’t speak the language. She’s stuck. She has no idea what’s happening. We need to rescue her and the door is locked.'”

Police assured him his mother would be rescued and told him to go. Bino waited hours at a nearby evacuation centre. But Solidum kept calling him, in a panic, as the fire approached Timberlea.

“I had to make a decision, right? To take care of my wife and kids or to take care of my mom.” Bino decided to rejoin his family. But as they fled north from evacuation centre to evacuation centre and eventually onto a flight to Calgary, Bino made frantic phone calls to 911 and the Red Cross. No one knew anything about his mother’s whereabouts.

Bino tried not to dwell on reports that Abasand was burning. “The only thing I’m thinking is my mama burning alive, and she’ll be crying out my name.”

Two days after being forced to abandon his home, Bino got a surprise phone call. A doctor at Leduc Community Hospital, just outside Edmonton, asked if he knew someone named Salimma Michael, who had been airlifted to safety.

“I was so relieved, my knees were shaking,” Bino said. The family rushed to Edmonton, and arrived at the hospital to visit Michael the next morning.

When Bino and Solidum bought the house in Abasand back in 2014, they loved the fact that the neighbourhood was on a hill surrounded by forest. “The trails were great. And it was peaceful and quiet,” Bino said. “No one ever mentioned [anything] about forest fires being a risk.”

Infographic showing the number of hectares burned by wildfires each year across Canada. Source: National Forestry Database
Growing wildfires
There has been a “significant increase” in the area burned by wildfires each year across Canada, Environment Canada reports. On average, wildfires in Canada have been burning 2.5 million hectares a year (nearly half the area of Nova Scotia) — double the 1970s average. B.C. and Alberta have been bearing the brunt of that increase.

Source: National Forestry Database

Climate change has increased the risk of major wildfires by extending the fire season by several weeks and generating hotter, drier conditions that support more extreme, fast-burning fires. The Fort McMurray fire in 2016, nicknamed “The Beast,” led to the largest wildfire evacuation in Canadian history. By the time it was extinguished that August, the fire had destroyed 6,000 square kilometres and caused $3.8 billion in insured damage alone.

When Bino and Solidum finally returned to the house, it was among 2,400 buildings that had burned to the ground. Almost everything the family owned was gone — from their children’s first locks of hair to a medal of valour Bino’s late father had received from the Indian navy.

The events of those few, intense days changed Bino’s perspective. “You know, we got our mom back. So to hell with the stuff, right?” But their struggles weren’t over. Solidum was so traumatized by the event, and the guilt of leaving Bino’s mother behind, that for more than a year, she became shell-shocked and unresponsive whenever she heard sirens or saw flashing lights.

Ashy remains of Bino’s neighbourhood after the wildfire had been extinguished.
This photo of the Abasand neighbourhood after the fire was taken by John Bino’s neighbour, Peter Fortna, when residents were allowed to return and look for belongings that may have survived. (Peter Fortna)
Bino also suffered. He was laid off from his engineering job, and once the family had settled in Edmonton, he got a position that required a five-hour commute back to Fort McMurray. Bino ended up quitting that job to care for his mother, but the situation eventually became untenable, and he was forced to send his mother back to India.

In spite of the trauma, Bino said the whole experience left him with a deep sense of gratitude for his family’s safety and care.

“The government, people — everybody was so helpful. It was amazing. It was like … how do people care about each other so damn much here?”

Adapting to wildfires
Climate change is the biggest and most significant factor behind the increase in wildfire risk and damage, said Laura Stewart, president of Firesmart Canada, which provides tools to communities to reduce the risks and impacts of wildfires.

But the development of industry and housing in forested or grassland areas also plays a role — as illustrated by Fort McMurray’s Abasand neighbourhood, which is surrounded by boreal forest.

Boreal forests contain trees like jack pine and lodgepole pine, whose seed cones only open when exposed to heat, and are reliant on wildfires to regenerate.

Natural Resources Canada estimates the cost of managing wildfires has been rising about $120 million per decade since 1970, to an annual cost of up to $1 billion in recent years.

Governments and communities can reduce the risks and impacts of wildfires by:

Imposing fire bans or even forest closures to shut down industrial operations when the risk of fires is high.
Thinning or removing conifer trees in surrounding communities to reduce the risk of crown fires, which spread from treetop to treetop, and are the most intense and dangerous wildland fires.
Creating fire breaks around communities, such as golf courses and soccer fields.
Burying power lines to eliminate the risk of them starting fires (as happened in California in 2018).

Seaweed feed additive cuts livestock methane but poses questions

June 17, 2019
Penn State
Supplementing cattle feed with seaweed could result in a significant reduction in methane belched by livestock, according to researchers, but they caution that the practice may not be a realistic strategy to battle climate change.

Supplementing cattle feed with seaweed could result in a significant reduction in methane belched by livestock, according to Penn State researchers, but they caution that the practice may not be a realistic strategy to battle climate change.

Asparagopsis taxiformis — a red seaweed that grows in the tropics — in short-term studies in lactating dairy cows decreased methane emission by 80 percent and had no effect on feed intake or milk yield, when fed at up to 0.5 percent of feed dry-matter intake,” said Alexander Hristov, distinguished professor of dairy nutrition. “It looks promising, and we are continuing research.”

If seaweed feed supplement is a viable option to make a difference globally, the scale of production would have to be immense, Hristov noted. With nearly 1.5 billion head of cattle in the world, harvesting enough wild seaweed to add to their feed would be impossible. Even to provide it as a supplement to most of the United States’ 94 million cattle is unrealistic.

“To be used as a feed additive on a large scale, the seaweed would have to be cultivated in aquaculture operations,” he said. “Harvesting wild seaweed is not an option because soon we would deplete the oceans and cause an ecological problem.”

Still, the capability of Asparagopsis taxiformis to mitigate enteric methane as a feed supplement demands attention, said Hannah Stefenoni, the graduate student working with Hristov on the research project, who will present the research to members of the American Dairy Science Association June 23 at their annual meeting in Cincinnati, Ohio. The findings of their research were published recently online in the Proceedings of the 2019 American Dairy Science Association Meeting.

“We know that it is effective in the short term; we don’t know if it’s effective in the long term,” Hristov explained. “The microbes in cows’ rumens can adapt to a lot of things. There is a long history of feed additives that the microbes adapt to and effectiveness disappears. Whether it is with beef or dairy cows, long-term studies are needed to see if compounds in the seaweed continue to disrupt the microbes’ ability to make methane.”

There are also questions about the stability over time of the active ingredients — bromoforms — in the seaweed. These compounds are sensitive to heat and sunlight and may lose their methane-mitigating activity with processing and storage, Hristov warned.

Palatability is another question. It appears cows do not like the taste of seaweed — when Asparagopsis was included at 0.75 percent of the diet, researchers observed a drop in the feed intake by the animals.

Also, the long-term effects of seaweed on animal health and reproduction and its effects on milk and meat quality need to be determined. A panel judging milk taste is part of ongoing research, Hristov said.

Cows burping — often incorrectly characterized as cows farting — methane and contributing to climate change has been the subject of considerable derision within the U.S., conceded Hristov, who is recognized as an international leader in conducting research assessing greenhouse gas emissions from animal agriculture. It is taken seriously in other countries, he explained, because the average dairy cow belches 380 pounds of the potent greenhouse gas a year.

“But methane from animal agriculture is just 5 percent of the total greenhouse gases produced in the United States — much, much more comes from the energy and transportation sectors,” Hristov said. “So, I think it’s a fine line with the politics surrounding this subject. Do we want to look at this? I definitely think that we should, and if there is a way that we can reduce emissions without affecting profitability on the farm, we should pursue it.”

And there may be a hidden benefit.

“It is pretty much a given that if enteric methane emissions are decreased, there likely will be an increase in the efficiency of animal production,” said Hristov. Seaweed used in the Penn State research was harvested from the Atlantic Ocean in the Azores and shipped frozen from Portugal. It was freeze-dried and ground by the researchers. Freeze drying and grinding 4 tons of seaweed for the research was “a huge undertaking,” Hristov said.

Also involved in the research at Penn State were Molly Young, research technician; and Audino Melgar Moreno and Susanna Raeisaenen, graduate assistants; all in animal science. Camila Lage, a graduate student at Federal University of Minas Gerais, Brazil, also was on the project.

The U.S. Department of Agriculture’s National Institute of Food and Agriculture and the Jeremy and Hannelore Grantham Environmental Trust funded this research.

Story Source:

Materials provided by Penn State. Original written by Jeff Mulhollem. Note: Content may be edited for style and length.

Pollution, anthrax – even nuclear waste – could be released by global warming

In 2012, Sue Natali arrived in Duvanny Yar, Siberia, for the first time. Then a postdoctoral research fellow studying the effects of thawing permafrost due to climate change, she had seen photos of this site many times. Rapid thawing at Duvanny Yar had caused a massive ground collapse – a “mega slump” – like a giant sinkhole in the middle of the Siberian tundra. But nothing had prepared her for seeing it in person.

As you walk along you see what look like logs poking out the permafrost. But they aren’t logs, they are the bones of mammoths and other Pleistocene animals – Sue Natali

“It was incredible, really incredible”, she recalls while speaking to me from The Woods Hole Research Center, Massachusetts, where she is an associate scientist. “I still get chills when I think about it… I just couldn’t believe the magnitude: collapsing cliffs the size of multi-storey buildings … and as you walk along you see what look like logs poking out the permafrost. But they aren’t logs, they are the bones of mammoths and other Pleistocene animals.”

What Natali describes is the visible, dramatic effects of a rapidly warming Arctic. The permafrost – up until now, permanently frozen land and soil – is thawing out, and revealing its hidden secrets. Alongside Pleistocene fossils are massive carbon and methane emissions, toxic mercury, and ancient diseases.

(Credit: Sue Natali)

The rapid thawing of permafrost causes “mega slumps” that puncture the landscape like the holes in swiss cheese (Credit: Sue Natali)

The organic-rich permafrost holds an estimated 15 billion tonnes of carbon. “That’s about twice as much carbon in the atmosphere, and three times as much carbon than that stored in all the world’s forests”, says Natali. She explains that between 30% and 70% of the permafrost may melt before 2100, depending on how effectively we respond to climate change. “The 70% is business as usual, if we continue to burn fossil fuels at our current rate, and 30% is if we vastly reduce our fossil fuel emissions… Of the 30-70% that thaws, the carbon locked up in organic matter will begin to be broken down by microbes, they use it as fuel or energy, and they release it as CO2 or methane.”

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Around 10% of the carbon that does defrost will probably be released as CO2, amounting to 130-150 billion tonnes. That is equivalent to the current rate of total US emissions, every year until 2100. Melting permafrost effectively introduces a new country at number two on the highest emitters list, and one that isn’t accounted for in current IPCC models. “People talk about a carbon bomb,” says Natali. “In geological timescales this is not a slow release. It is a pool of carbon that is locked away and is not accounted for in the carbon budget to keep rises below two degrees (Celsius).”

The Northern Hemisphere winter of 2018/2019 was dominated by headlines of the “polar vortex”, as temperatures plummeted unusually far south into North America. In South Bend, Indiana, it reached -29C in January 2019, almost twice as low as the city’s previous record set in 1936. What such stories masked, however, was that the opposite was happening in the far North, beyond the Arctic circle. January 2019 also saw Arctic sea ice average just 13.56 million square kilometres (5.24 million square miles), some 860,000 square kilometres (332,000 square miles) below the 1981 to 2010 long-term average, and only slightly above the record low reached in January 2018.

(Credit: Alamy)

Melting ice can release methane, which will exacerbate global warming (Credit: Alamy)

In November, when temperatures should have been -25C, a temperature of 1.2C above freezing was recorded at the North Pole. The Arctic is warming twice as fast as the rest of the world (in part due to the loss of solar reflectivity).

“We are seeing a big increase in the thaw of permafrost”, confirms Emily Osborne, program manager for the Arctic Research Program, NOAA, and editor of the Arctic Report Card, an annual peer-reviewed environmental study of the Arctic. As a direct result of rising air temperatures, she says, the permafrost is thawing and “the landscape is physically crumbling as a result… things are changing so fast, and in ways that researchers hadn’t even anticipated.”

The headline of the 2017 Arctic Report Card pulled no punches: “Arctic shows no sign of returning to a reliably frozen region”. One paper co-authored by Hanne Christiansen, professor and vice dean of education at University Centre Svalbard, Norway, studied permafrost temperatures at a depth of 20 metres (that’s 65ft, far enough down not to be affected by short-term seasonal changes) and found temperatures had risen by up to 0.7C since 2000. Christiansen, who is also president of the International Permafrost Association, tells me, “temperatures are increasing inside the permafrost at relatively high speed… then, of course, what was permanently frozen before can become released.” In 2016, the autumn temperatures in Svalbard remained above zero throughout November, “the first time this has happened in the records that we have, going back to 1898”, says Christiansen. “Then large amounts of rain came – the precipitation here is typically snow… we had mudslides crossing roads for 100s of metres… we had to evacuate some parts of the population.”

(Credit: Getty Images)

The melting permafrost is transforming Alaska’s landscapes (Credit: Alamy)

In some places in the Alaskan Arctic, you fly over a swiss cheese of land and lakes formed by ground collapse – Sue Natali

The rapid change in North American permafrost is equally alarming. “In some places in the Alaskan Arctic, you fly over a swiss cheese of land and lakes formed by ground collapse,” says Natali, whose fieldwork has moved from Siberia to Alaska. “Water that was close to the surface now becomes a pond.” Many of these ponds are bubbling with methane, as microbes suddenly find themselves with a feast of ancient organic matter to munch on, releasing methane as a by-product. “We often walk across the lakes because it’s so shallow and it’s like you’re in a hot tub in some places, there is so much bubbling,” says Natali.

(Credit: Alamy)

The melting permafrost released anthrax in Siberia (Credit: Alamy)

But methane and CO2 are not the only things being released from the once frozen ground. In the summer of 2016, a group of nomadic reindeer herders began falling sick from a mysterious illness. Rumours began circling of the “Siberian plague”, last seen in the region in 1941. When a young boy and 2,500 reindeer died, the disease was identified: anthrax. Its origin was a defrosting reindeer carcass, a victim of an anthrax outbreak 75 years previously. The 2018 Arctic report card speculates that, “diseases like the Spanish flu, smallpox or the plague that have been wiped out might be frozen in the permafrost.” A French study in 2014 took a 30,000 year-old virus frozen within permafrost, and warmed it back up in the lab. It promptly came back to life, 300 centuries later. (To read more, see BBC Earth’s piece on the diseases hidden in ice.)

Adding to this apocalyptic vision, in 2016 the Doomsday Vault – a sub-permafrost facility in Arctic Norway, which safeguards millions of crop seeds for perpetuity – was breached with meltwater. And listed amongst the membership of The Global Terrestrial Network for Permafrost, is Swedish Nuclear Waste Management who presumably also rely on a permanently frozen permafrost (when BBC Future approached them for comment on this point, they did not respond).

Long-preserved human archaeology may also be emerging, but just as quickly lost. A frozen Palaeo-Eskimo site in Greenland, preserved for some 4,000 years, is at risk of being washed away. This is just one of an estimated 180,000 archaeological sites preserved in the permafrost, often with soft tissues and clothing that uniquely remain intact but would rot quickly if exposed. Adam Markham, of the Union of Concerned Scientists has said, “with rapid, human-caused climate change, many sites or the artefacts they contain, will be lost before they have been discovered.”

More modern (and unwanted) human detritus will, however, not rot away: marine microplastics. Due to circular global marine currents, much plastic waste ends up in the Arcticwhere it becomes frozen in sea ice or permafrost. A recent study of marine micro-particles demonstrated that concentrations were higher in the Arctic Basin than all other ocean basins in the world. Microplastic concentrations in the Greenland Sea doubled between 2004 and 2015. “Scientists are finding that those microplastics are accumulating across the entire ocean and being dumped into the Arctic”, explains Osborne. “This is something we didn’t [previously] realise was a problem. What scientists are trying to find out now is the composition of these microplastics, what sort of fish are feeding on these… and whether we are essentially eating microplastics through eating these fish.”

(Credit: Alamy)

In 2016 the Doomsday Vault – a sub-permafrost facility in Arctic Norway, which safeguards millions of crop seeds for perpetuity – was breached with meltwater (Credit: Alamy)

Mercury is also entering the food chain, thanks to thawing permafrost. The Arctic is home to the most mercury on the planet. The US Geological Survey estimates there’s a total of 1,656,000 tonnes of mercury trapped in polar ice and permafrost: roughly twice the global amount in all other soils, oceans, and atmosphere. Natali explains that, “mercury often binds up with organic material in places where you have high organic matter content… organism’s bodies don’t remove it, so it bio-accumulates up the food web. Permafrost is almost the perfect storm – you have a lot of mercury in permafrost, it is released into wetland systems, those are the right environment for organisms to take them up, and then [it] heads up the food web. That’s a concern for wildlife, people, and the commercial fishing industry.”

Are there some positives of a thawing Arctic? Could a greener Arctic start to see more trees and vegetation take root, sequestering more carbon and offering new grazing land for animals? Osborne agrees that “the Arctic is greening”. But she adds that studies of animal populations actually suggest that, “warmer temperatures also increase the prevalence of viruses and disease, so we’re seeing a lot more caribou and reindeer becoming more sickly as a result of this warming climate… it is just not an environment that is suited to thrive at these warmer temperatures.” Natali also says that many areas are experiencing “Tundra browning”: the higher temperatures lead surface water to evaporate into the atmosphere, causing plants to die off. Other areas are experiencing sudden flooding due to the ground collapsing. “It’s not happening in 2100 or 2050, it’s now”, says Natali. “You hear people say ‘we used to pick blueberries over there’, and you look over there and it’s a wetland.”

Natali doesn’t want to end the conversation on a downer. There is a lot we can do, she says. The fate of the Arctic is not a foregone conclusion: “The actions taken by the international community will have a substantial impact on just how much carbon will be released and how much of the permafrost will thaw. We need to keep as much of the permafrost as we can frozen. And we do have some control of that.” Our emissions cannot remain “business as usual”. The Arctic depends on it. And we depend on the Arctic.

Tim Smedley is a sustainability writer, based in the UK. His first book is Clearing the Air: The Beginning and the End of Air Pollution. Join more than one million Future fans by liking us on Facebook, or follow us on Twitter or Instagram.

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