Renowned British naturalist and broadcaster David Attenborough has warned that we are facing “global catastrophe” if we do not act rapidly to deal with climate change.

Attenborough, 92, made the comments in a new one-off program for the BBC titled Climate Change: The Facts, which airs in the U.K tonight.

“In the 20 years since I first started talking about the impact of climate change on our world, conditions have changed far faster than I ever imagined,” Attenborough says in the film, Radio Times reported.

“It may sound frightening, but the scientific evidence is that if we have not taken dramatic action within the next decade we could face irreversible damage to the natural world and the collapse of our societies,” he said. “We’re running out of time but there’s still hope. I believe that if we better understand the threat we face, the more likely it is that we can avoid such a catastrophic future.”

Using interviews with several leading researchers in the field, the program investigates the science of climate change; the impact it could have on humans and the natural world if major reductions in carbon emissions are not made; and potential solutions to this “global threat.”

“One degree Celsius global warming may not sound like much, but it’s having a dramatic effect on our weather,” Peter Stott from the U.K. Met Office says in the film. “We’re seeing extreme heat in southern Africa, Japan, North America, in the U.K. as well. So it doesn’t mean to say that every single weather event is due to climate change. But what [it] does mean, is that with the baseline climate having changed, then the frequency of the extreme temperatures is increasing.”

Richard Black, from the Energy and Climate Change Intelligence Unit, adds: “Often the question is did climate change cause a certain event, and you can never really answer that question. But what scientists do is to look at whether climate change made a certain event more or less likely or more or less intense.”

As well as climate experts, the program also briefly features Swedish teen activist Greta Thunberg, who sparked a global movement last year when she began striking on school days.

Thunberg began her “School Strike for the Climate” by protesting alone—initially—outside the Swedish parliament in Stockholm every Friday. Her activism soon attracted the attention of the media, inspiring similar protests by young people around the world.

“My future and everyone else’s future is at risk and nothing is being done, no one is doing anything, so then I have to do something,” Thunberg says in the film, Radio Times reported. “So I sat myself down on the ground outside the Swedish parliament, and I decided that I wasn’t going to go to school.

“The first day I sat all alone. Then the second day people started joining me. I wouldn’t have imagined in my wildest dreams that this would happen. It happened so fast.”

David AttenboroughDavid Attenborough on stage during UKTV Live 2016 at BFI Southbank on September 6, 2016, in London.DAVE J HOGAN/DAVE J HOGAN/GETTY IMAGES

Climate change: Sir David Attenborough warns of ‘catastrophe’

Media captionViewers can watch Climate Change – The Facts on BBC One, Tonight at 9pm

Sir David Attenborough has issued his strongest statement yet on the threat posed to the world by climate change.

In the BBC programme Climate Change – The Facts, the veteran broadcaster outlines the scale of the crisis facing the planet.

Sir David says we face “irreversible damage to the natural world and the collapse of our societies”.

But there is still hope, he says, if dramatic action to limit the effects is taken over the next decade.

Sir David’s new programme lays out the science behind climate change, the impact it is having right now and the steps that can be taken to fight it.

“In the 20 years since I first started talking about the impact of climate change on our world, conditions have changed far faster than I ever imagined,” Sir David states in the film.

“It may sound frightening, but the scientific evidence is that if we have not taken dramatic action within the next decade, we could face irreversible damage to the natural world and the collapse of our societies.”

Speaking to a range of scientists, the programme highlights that temperatures are rising quickly, with the world now around 1C warmer than before the industrial revolution.

“There are dips and troughs and there are some years that are not as warm as other years,” says Dr Peter Stott from the Met Office.

“But what we have seen is the steady and unremitting temperature trend. Twenty of the warmest years on record have all occurred in the last 22 years.”

The programme shows dramatic scenes of people escaping from wildfires in the US, as a father and son narrowly escape with their lives when they drive into an inferno.

Scientists say that the dry conditions that make wildfires so deadly are increasing as the planet heats up.

GreenlandImage copyrightGETTY IMAGES
Image captionGreenland is losing ice five times as fast as it was 25 years ago

Some of the other impacts highlighted by scientists are irreversible.

“In the last year we’ve had a global assessment of ice losses from Antarctica and Greenland and they tell us that things are worse than we’d expected,” says Prof Andrew Shepherd from the University of Leeds.

“The Greenland ice sheet is melting, it’s lost four trillion tonnes of ice and it’s losing five times as much ice today as it was 25 years ago.”

These losses are driving up sea levels around the world. The programme highlights the threat posed by rising waters to people living on the Isle de Jean Charles in Louisiana, forcing them from their homes.

“In the US, Louisiana is on the front line of this climate crisis. It’s losing land at one of the fastest rates on the planet – at the rate of of a football field every 45 minutes,” says Colette Pichon Battle, a director of the Gulf Coast Center for Law & Policy.

LouisianaImage copyrightJULIE DERMANSKY
Image captionPeople are moving from parts of Louisiana in the US as a result of rising waters

“The impact on families is going to be something I don’t think we could ever prepare for.”

Hope rising

Sir David’s concern over the impacts of climate change has become a major focus for the naturalist in recent years.

This has also been a theme of his Our Planet series on Netflix.

His new BBC programme has a strong emphasis on hope.

Sir David argues that if dramatic action is taken over the next decade then the world can keep temperatures from rising more than 1.5C this century. This would limit the scale of the damage.

“We are running out of time, but there is still hope,” says Sir David.

“I believe that if we better understand the threat we face the more likely it is we can avoid such a catastrophic future.”

The programme says that rapid progress is being made in renewable energy, with wind now as cheap as fossil fuels in many cases. It shows how technologies to remove and bury carbon dioxide under the ground are now becoming more viable.

But politicians will need to act decisively and rapidly.

“This is the brave political decision that needs to be taken,” says Chris Stark from the UK’s Committee on Climate Change.

GretaImage copyrightGETTY IMAGES
Image captionTeenage campaigner Greta Thunberg has helped spark school strikes all over the world

“Do we incur a small but not insignificant cost now, or do we wait and see the need to adapt. The economics are really clear on this, the costs of action are dwarfed by the costs of inaction.”

The programme also highlights the rising generation of young people who are deeply concerned about what’s happening to the planet.

Swedish teenager Greta Thunberg explains that things can change quickly, despite the scale of the challenge on climate change.

“The first day I sat all alone,” she says, speaking of her decision to go on strike from school and sit outside the Swedish parliament to highlight the climate crisis.

“But on the second day, people started joining me… I wouldn’t have imagined in my wildest dreams that this would have happened so fast.”

“Change is coming whether you like it or not.”

Follow Matt on Twitter@mattmcgrathbbc

Climate Change – The Facts is on BBC One on Thursday 18 April at 9pm

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6 pressing questions about beef and climate change, answered

Cattle feed at a shed belonging to Kim Jin-cheon, 56, a farmer raising about 120 domestic cows, in Gapyeong, about 60 km (37 miles) east of Seoul, April 23, 2008. South Korea's decision to gradually open up to U.S. beef imports are set to hit local farmers hard, with some experts expecting around 14 percent fall this year in prices of home-grown cattle from a year earlier.  REUTERS/Jo Yong-Hak (SOUTH KOREA) - GM1E44N0XWA01

How friendly is your food?
Image: REUTERS/Jo Yong-Hak
This article is published in collaboration withEcoWatch

Beef and climate change are in the news these days, from cows’ alleged high-methane farts (fact check: they’re actually mostly high-methane burps) to comparisons with cars and airplanes (fact check: the world needs to reduce emissions from fossil fuels and agriculture to sufficiently rein in global warming). And as with so many things in the public sphere lately, it’s easy for the conversation to get polarized. Animal-based foods are nutritious and especially important to livelihoods and diets in developing countries, but they are also inefficient resource users. Beef production is becoming more efficient, but forests are still being cut down for new pasture. People say they want to eat more plants, but meat consumption is still rising.

All of the above statements are true even if they seem contradictory. That’s what makes the beef and sustainability discussion so complicated — and so contentious.

Here we look at the latest research (including from our recent World Resources Report) to address six common questions about beef and climate change:

1. How does beef production cause greenhouse gas emissions?

The short answer: Through the agricultural production process and through land-use change.

The longer explanation: Cows and other ruminant animals (like goats and sheep) emit methane, a potent greenhouse gas, as they digest grasses and plants. This process is called “enteric fermentation,” and it’s the origin of cows’ burps. Methane is also emitted from manure, and nitrous oxide, another powerful greenhouse gas, is emitted from ruminant wastes on pastures and chemical fertilizers used on crops produced for cattle feed.

More indirectly but also importantly, rising beef production requires increasing quantities of land. New pastureland is often created by cutting down trees, which releases carbon dioxide stored in forests.

2013 study by the U.N. Food and Agriculture Organization (FAO) estimated that total annual emissions from animal agriculture (production emissions plus land-use change) were about 14.5 percent of all human emissions, of which beef contributed 41 percent. That means emissions from beef production are roughly on par with those of India. Because FAO only modestly accounted for land-use-change emissions, this is a conservative estimate.

Beef-related emissions are also projected to grow. Building from an FAO projection, we estimated that global demand for beef and other ruminant meats could grow by 88 percent between 2010 and 2050, putting enormous pressure on forests, biodiversity and the climate. Even after accounting for continued improvements in beef production efficiency, pastureland could still expand by roughly 400 million hectares, an area of land larger than the size of India, to meet growing demand. The resulting deforestation could increase global emissions enough to put the global goal of limiting temperature rise to 1.5-2 degrees C (2.7-3.6 degrees F) out of reach.

2. Is beef more resource-intensive than other foods?

The short answer: Yes.

The longer explanation: Ruminant animals have lower growth and reproduction rates than pigs and poultry, so they require a higher amount of feed per unit of meat produced. Animal feed requires land to grow, which has a carbon cost associated with it, as we discuss below. All told, beef is more resource-intensive to produce than most other kinds of meat, and animal-based foods overall are more resource-intensive than plant-based foods. Beef requires 20 times more land and emits 20 times more GHG emissions per gram of edible protein than common plant proteins, such as beans. And while the majority of the world’s grasslands cannot grow crops or trees, such “native grasslands” are already heavily used for livestock production, meaning additional beef demand will likely increase pressure on forests.

3. Why are some people saying beef production is only a small contributor to emissions?

The short answer: Such estimates commonly leave out land-use impacts, such as cutting down forests to establish new pastureland.

The longer explanation: There are a lot of statistics out there that account for emissions from beef production but not from associated land-use change. For example, here are three common U.S. estimates we hear:

  • The U.S. Environmental Protection Agencyestimatedtotal U.S. agricultural emissions in 2017 at only 8 percent of total U.S. emissions;
  • 2019 studyin Agricultural Systems estimated emissions from beef production at only 3 percent of total U.S. emissions; and
  • 2017 studypublished in the Proceedings of the National Academy of Sciences estimated that removing all animals from U.S. agriculture would reduce U.S. emissions by only 3 percent.

While all of these estimates account for emissions from U.S. agricultural production, they leave out a crucial element: emissions associated with devoting land to agriculture. An acre of land devoted to food production is often an acre that could store far more carbon if allowed to grow forest or its native vegetation. And when considering the emissions associated with domestic beef production, you can’t just look within national borders, especially since global beef demand is on the rise. Because food is a global commodity, what is consumed in one country can drive land use impacts and emissions in another. An increase in U.S. beef consumption, for example, can result in deforestation to make way for pastureland in Latin America. Conversely, a decrease in U.S. beef consumption can avoid deforestation (and land-use-change emissions) abroad.

When these land-use effects of beef production are accounted for, we found that the GHG impacts associated with the average American-style diet actually come close to per capita U.S. energy-related emissions. A related analysis found that the average European’s diet-related emissions, when accounting for land-use impacts, are similar to the per capita emissions typically assigned to each European’s consumption of all goods and services, including energy.

4. Can beef be produced more sustainably?

The short answer: Yes, although beef will always be resource-intensive to produce.

The longer explanation: The emissions intensity of beef production varies widely across the world, and improvements in the efficiency of livestock production can greatly reduce land use and emissions per pound of meat. Improving feed quality and veterinary care, raising improved animal breeds that convert feed into meat and milk more efficiently, and using improved management practices like rotational grazing can boost productivity and soil health while reducing emissions. Boosting productivity, in turn, can take pressure off tropical forests by reducing the need for more pastureland.

Examples of such improved practices abound. For example, some beef production in Colombiaintegrates trees and grasses onto pasturelands, helping the land produce a higher quantity and quality of feed. This can enable farmers to quadruple the number of cows per acre while greatly reducing methane emissions per pound of meat, as the cows grow more quickly. A study of dairy farms in Kenyafound that supplementing typical cattle diets with high-quality feeds like napier grass and high-protein Calliandra shrubs — which can lead to faster cattle growth and greater milk production — could reduce methane emissions per liter of milk by 8–60 percent.

There are also emerging technologies that can further reduce cows’ burping, such as through feed additives like 3-nitrooxypropan (3-NOP). Improving manure management and using technologies that prevent nitrogen in animal waste from turning into nitrous oxide can also reduce agricultural emissions.

5. Do we all need to stop eating beef in order to curb climate change?

The short answer: No.

The longer explanation: Reining in climate change won’t require everyone to become vegetarian or vegan, or even to stop eating beef. If ruminant meat consumption in high-consuming countries declined to about 50 calories a day or 1.5 burgers per person per week — about half of current U.S. levels and 25 percent below current European levels, but still well above the national average for most countries — it would nearly eliminate the need for additional agricultural expansion (and associated deforestation), even in a world with 10 billion people.

Diets are already shifting away from beef in some places. Per capita beef consumption has already fallen by one-third in the United States since the 1970s. Plant-based burgers and blended meat-plant alternatives are increasingly competing with conventional meat products on important attributes like taste, price and convenience. The market for plant-based alternatives is growing at a high rate, albeit from a low baseline.

There are also other compelling reasons for people to shift toward plant-based foods. Some studieshave shown that red meat consumption is associated with increased risk of heart disease, type 2 diabetes, stroke and colorectal cancer, and that diets higher in healthy plant-based foods (such as whole grains, fruits, vegetables, nuts and legumes) are associated with lower risks. In high-income regions like North America and Europe, people also consume more protein than they need to meet their dietary requirements.

6. Would eating less beef be bad for jobs in the food and agriculture sector?

The short answer: Not necessarily.

The longer explanation: Given projected future growth in meat demand across the developing world, even if people in higher-income countries eat less beef, the global market for beef will likely continue to grow in the coming decades. The scenario in the chart above leads to a 32 percent growth in global ruminant meat consumption between 2010 and 2050, versus 88 percent growth under business-as-usual. In the U.S., despite declining per capita beef consumption, total beef production has held steadysince the 1970s. Burgeoning demand in emerging markets like China will lead to more export opportunities in leading beef-producing countries, although building such markets takes time.

In addition, major meat companies — including Tyson Foods, Cargill, Maple Leaf Foods and Perdue — are starting to invest in the fast-growing alternative protein market. They’re positioning themselves more broadly as “protein companies,” even as they work to reduce emissions from beef production in their supply chains through improved production practices.

Moving Toward a Sustainable Food Future

Beef is more resource-intensive than most other foods and has a substantial impact on the climate. A sustainable food future will require a range of strategies from farm to plate. Food producers and consumers alike have a role to play in reducing beef’s emissions as the global population continues to grow. And as we all work on strategies to curb climate change — whether in the agriculture sector, the energy sector or beyond — it’s important we rely on the best available information to make decisions.

Extinction Rebellion want to get arrested to fight climate change

An Extinction Rebellion protester blocking Blackfriars Bridge, in London, November 2018.

London (CNN)Earlier this month a group of climate change activists stripped down to their underwear in British parliament and glued their hands to the glass of the House of Commons’ public gallery.

Why? To get arrested.
Extinction Rebellion, a grassroots environmental group based in the UK, is responsible for a series of stunts that deliberately break the law to highlight the threat of climate change.
Since launching last year they have caused disruption by holding a “Funeral for our Future” outside Buckingham Palace, which led to 14 arrests, poured200 liters of fake blood outside Downing Street, and brought London to a standstill by shutting down five bridges.
So far Extinction Rebellion has counted 222 arrests — and thousands have declared they are willing to be arrested, or even go to prison, to demand action on climate change.

Method to the madness

Extinction Rebellion claims their actions are based on research into how to use “non-violent civil disobedience to achieve radical change.”
An Extinction Rebellion protester, London, November 2018

They estimate that significant numbers of people will have to get arrested and cause disruption for the government to pay attention to their demands. These include the UK government declaring a climate change emergency, reducing greenhouse gas emissions to net zero by 2025 and starting a citizen’s assembly.
“People making decisions have to pay attention to a mass of people that come out on to the streets to demand action in the face of this crisis we are in,” said Roman Paluch-Machnik, an Extinction Rebellion activist who has been arrested more than once.
“You put the police in a dilemma,” explained Nuala Gathercole Lam, another protester. “If you have got thousands of people refusing to move, they either have to let you do it, which is hugely economically disruptive, or they have to arrest you.”
According to the group, research shows that non-violent uprisings involving 3.5% of the public participating in acts of civil disobedience force a political response because they cannot be ignored.
“Every non-violent uprising since 1900, if it achieves that threshold, succeeds in its aims,” said Paluch-Machnik. “One of our main principles is to get this 3.5% mobilized.”
That would need about 2 million people to get involved in the UK.

Willing to get arrested

Almost 10,000 people worldwide have signed up as “willing to get arrested,” as of April 8, 2019, according to the group. Around 3,000 are based in the UK.
Of those people, over 80% are also “willing to go to prison.” The group holds prison workshopsand training sessions to prepare people for what to do if they end up at a police station.
Pictured, a protest outside Downing Street, March 2019.

“Nothing has been achieved after 30 years of regular environmental campaign,” said Paluch-Machnik. “People are so motivated by what is happening right now because there is not really another option.”
“I’ve always been very worried about continuous news about the government not addressing the situation,” said Alanna Byrne, an activist for Extinction Rebellion. “I felt very isolated in the way that I felt.”
Along with 25 others, Paluch-Machnik, Lam and Byrne have quit their jobs to work for Extinction Rebellion full time.

How far are you willing to go to demand action?

Since the UN Intergovernmental Panel on Climate Change (IPCC) warned last year that the planet only has 11 years before it reaches disastrous levels of global warming, Extinction Rebellion isn’t the only group to launch radical climate activism.
Extinction Rebellion activists threw 200 liters of fake blood outside Downing Street in March 2019.

School students around the world have been skipping school to demand that world leaders take action on climate change.
The movement has spanned more than 100 countries and 1,500 cities, with teenagers missing out on their education to show how worried they are about the threat to their future.
In response to critics, who say Extinction Rebellion is causing unnecessary disruption and wasting police time, the activists say the “climate and ecological emergency” demands their actions.
“I think that any suffering that is caused as a result of a few hours sitting in a traffic jam is incomparable to what is going to happen in a few years” said Paluch-Machnik.
London’s Metropolitan Police Service told CNN that it is aware of a number of Extinction Rebellion demonstrations and protests planned over the coming weeks, and that “Appropriate policing plans are in place.”
It added: “We will always provide a proportionate policing plan to balance the right to a peaceful protest, while ensuring that disruption to communities is kept to a minimum.”
This Monday, the group plans to shut down London in their biggest action yet. They plan to meet at five London locations and block traffic by playing music, hosting discussions and refusing to move from the street.
Demonstrators blocked Waterloo Bridge by bringing trees and solar panels.
Extinction Rebellion  demonstrating on Waterloo Bridge, London, April 15, 2019.

The group says hundreds of people have taken time off work to camp for as long as it takes get their demands heard by the government. Read more coverage of the protest.

Climate change made the Arctic greener. Now parts of it are turning brown.

Warming trends bring more insects, extreme weather and wildfires that wipe out plants

7:00AM, APRIL 11, 2019
Alaska landscape

TUNDRA IN TROUBLE  In southern Alaska in 2012, geometrid moths and other insects heavily defoliated alder bushes and other shrubs (brown patches in this aerial photo).

The Chugach people of southern Alaska’s Kenai Peninsula have picked berries for generations. Tart blueberries and sweet, raspberry-like salmonberries — an Alaska favorite — are baked into pies and boiled into jams. But in the summer of 2009, the bushes stayed brown and the berries never came.

For three more years, harvests failed. “It hit the communities very hard,” says Nathan Lojewski, the forestry manager for Chugachmiut, a nonprofit tribal consortium for seven villages in the Chugach region.

The berry bushes had been ravaged by caterpillars of geometrid moths — the Bruce spanworm (Operophtera bruceata) and the autumnal moth (Epirrita autumnata). The insects had laid their eggs in the fall, and as soon as the leaf buds began growing in the spring, the eggs hatched and the inchworms nibbled the stalks bare.

Chugach elders had no traditional knowledge of an outbreak on this scale in the region, even though the insects were known in Alaska. “These berries were incredibly important. There would have been a story, something in the oral history,” Lojewski says. “As far as the tribe was concerned, this had not happened before.”

At the peak of the multiyear outbreak, the caterpillars climbed from the berry bushes into trees. The pests munched through foliage from Port Graham, at the tip of the Kenai Peninsula, to Wasilla, north of Anchorage, about 300 kilometers away. In summer, thick brown-gray layers of denuded willows, alders and birches lined the mountainsides above stretches of Sitka spruce.

Salmonberries are widely harvested during the summer in southern Alaska’s coastal regions. The shrubs have been hit hard by moth damage in recent years. 


Two summers ago, almost a decade after the first infestation, the moths returned. “We got a few berries, but not as many as we used to,” says Chugach elder Ephim Moonin Sr., whose house in the village of Nanwalek is flanked by tall salmonberry bushes. “Last year, again, there were hardly any berries.”For more than 35 years, satellites circling the Arctic have detected a “greening” trend in Earth’s northernmost landscapes. Scientists have attributed this verdant flush to more vigorous plant growth and a longer growing season, propelled by higher temperatures that come with climate change. But recently, satellites have been picking up a decline in tundra greenness in some parts of the Arctic. Those areas appear to be “browning.”

Like the salmonberry harvesters on the Kenai Peninsula, ecologists working on the ground have witnessed browning up close at field sites across the circumpolar Arctic, from Alaska to Greenland to northern Norway and Sweden. Yet the bushes bereft of berries and the tinder-dry heaths (low-growing shrubland) haven’t always been picked up by the satellites. The low-resolution sensors may have averaged out the mix of dead and living vegetation and failed to detect the browning.

Scientists are left to wonder what is and isn’t being detected, and they’re concerned about the potential impact of not knowing the extent of the browning. If it becomes widespread, Arctic browning could have far-reaching consequences for people and wildlife, affecting habitat and atmospheric carbon uptake and boosting wildfire risk.

Growing greenbelt

The Arctic is warming two to three times as fast as the rest of the planet, with most of the temperature increase occurring in the winter. Alaska, for example, has warmed 2 degrees Celsius since 1949, and winters in some parts of the state, including southcentral Alaska and the Arctic interior, are on average 5 degrees C warmer.

An early effect of the warmer climate was a greener Arctic. More than 20 years ago, researchers used data from the National Oceanic and Atmospheric Administration’s weather satellites to assess a decade of northern plant growth after a century of warming. The team compared different wavelengths of light — red and near-infrared — reflecting off vegetation to calculate the NDVI, the normalized difference vegetation index. Higher NDVI values indicate a greener, more productive landscape. In a single decade — from 1981, when the first satellite was launched, to 1991 — the northern high latitudes had become about 8 percent greener, the researchers reported in 1997 in Nature.

The Arctic ecosystem, once constrained by cool conditions, was stretching beyond its limits. In 1999 and 2000, researchers cataloged the extent and types of vegetation change in parts of northern Alaska using archival photographs taken during oil exploration flyovers between 1948 and 1950. In new images of the same locations, such as the Kugururok River in the Noatak National Preserve, low-lying tundra plants that once grew along the riverside terraces had been replaced by stands of white spruce and green alder shrubs. At some of the study’s 66 locations, shrub-dominated vegetation had doubled its coverage from 10 to 20 percent. Not all areas showed a rise in shrub abundance, but none showed any decrease.

In 2003, Howard Epstein, a terrestrial ecologist at the University of Virginia in Charlottesville, and colleagues looked to the satellite record, which now held another decade of data. Focusing on Alaska’s North Slope, which lies just beyond the crown of the Brooks Range and extends to the Beaufort Sea, the researchers found that the highest NDVI values, or “peak greenness,” during the growing season had increased nearly 17 percent between 1981 and 2001, in line with the warming trend.

Brown among the green

As the Arctic warms up, it’s getting greener, but some pockets have been going brown instead. Satellite imagery and ecologists on the ground have observed browning in the circled areas on this map.


Earth-observing satellites have been monitoring the Arctic tundra for almost four decades. In that time, the North Slope, the Canadian low Arctic tundra and eastern Siberia have become especially green, with thicker and taller tundra vegetation and shrubs expanding northward. “If you look at the North Slope of Alaska, if you look at the overall trend, it’s greening like nobody’s business,” says Uma Bhatt, an atmospheric scientist at the University of Alaska Fairbanks.

Yet parts of the Arctic, including the Yukon-Kuskokwim Delta of western Alaska, the Canadian Arctic Archipelago (the islands north of the mainland that give Canada its pointed tip) and the northwestern Siberian tundra, show extensive browning over the length of the satellite record, from the early 1980s to 2016. “It could just be a reduction in green vegetation. It doesn’t necessarily mean the widespread death of plants,” Epstein says. Scientists don’t yet know why plant growth there has slowed or reversed — or whether the satellite signal is in some way misleading.

“All the models indicated for a long time that we would expect greening with warmer temperatures and higher productivity in the tundra, so long as it wasn’t limited in some other way, like [by lower] moisture,” says Scott Goetz, an ecologist and remote-sensing specialist at Northern Arizona University in Flagstaff. He is also the science team lead for ABoVE, NASA’s Arctic-Boreal Vulnerability Experiment, which is tracking ecosystem changes in Alaska and western Canada. “Many of us were quite surprised … that the Arctic was suddenly browning. It’s something we need to resolve.”

Freeze-dried tundra

While global warming has propelled widespread trends in tundra greening, extreme winter weather can spur local browning events. In recent years, in some parts of the Arctic, extraordinary warm winter weather, sometimes paired with rainfall, has put tundra vegetation under enormous stress and caused plants to lose freeze resistance, dry up or die — and turn brown.

From 2002 to 2009, two moth species defoliated as much as a third of the mountain birch trees that stretch across northern Norway, Sweden and Finland. By 2014, some trees had recovered (top) while others had not (bottom).


Gareth Phoenix, a terrestrial ecologist at the University of Sheffield in England, recalls his shock at seeing a series of midwinter timelapse photos taken in 2001 at a research site outside the town of Abisko in northern Sweden. In the space of a couple of days, the temperature shot up from −16° C to 6° C, melting the tundra’s snow cover.“As an ecologist, you’re thinking, ‘Whoa! Those plants would usually be nicely insulated under the snow,’ ” he says. “Suddenly, they’re being exposed because all the snow has melted. What are the consequences of that?”

Arctic plants survive frigid winters thanks to that blanket of snow and physiological changes, known as freeze resistance, that allow plants to freeze without damage. But once the plants awaken in response to physical cues of spring — warmer weather, longer days — and experience bud burst, they lose that ability to withstand frigid conditions.

Top: Healthy crowberry shrubs grow among mountain cranberry in Abisko, Sweden, in September 2005. Bottom: A 2013 midwinter warming event near Tromsø, Norway, melted the snow. By May, these crowberry plants turned reddish brown from severe stress. When this happens, the leaves eventually turn brown, then wilt, turn gray and fall off.


That’s fine if spring has truly arrived. But if it’s just a winter heat wave and the warm air mass moves on, the plants become vulnerable as temperatures return to seasonal norms. When temporary warm air covers thousands of square kilometers at once, plant damage occurs over large areas. “These landscapes can look like someone’s gone through with a flamethrower,” Phoenix says. “It’s quite depressing. You’re there in the middle of summer, and everything’s just brown.”Jarle Bjerke, a vegetation ecologist at the Norwegian Institute for Nature Research in Tromsø, saw browning across northern Norway and Sweden in 2008. The landscape — covered in mats of crowberry, an evergreen shrub with bright green sausagelike needles — was instead shades of brown, red-brown and grayish brown. “We saw it everywhere we went, from the mountaintops to the coastal heaths,” Bjerke says.Bjerke, Phoenix and other researchers continue to find brown vegetation in the wake of winter warming events. Long periods of mild winter weather have rolled over the Svalbard archipelago, the cluster of islands in the Arctic Ocean between Norway and the North Pole, in the last decade. The snow melted or blew away, exposing the ground-hugging plants. Some became encrusted in ice following a once-unheard-of midwinter rainfall. In 2015, the Arctic bell heather, whose small white flowers brighten Arctic ridges and heaths, were brown that summer, gray the next and then the leaves fell off. “It’s not new that plants can die during mild winters,” Bjerke says. “The new thing is that it is now happening several winters in a row.”

Insect invasion

The weather needn’t always be extreme to harm plants in the Arctic. With warmer winters and summers, leaf-eating insects have thrived, defoliating bushes and trees beyond the insects’ usual range. “They’re very visual events,” says Rachael Treharne, an Arctic ecologist who completed her Ph.D. at the University of Sheffield and now works at ClimateCare, a company that helps organizations reduce their climate impact. She remembers being in the middle of an autumnal moth outbreak in northern Sweden one summer. “There were caterpillars crawling all over the plants — and us. We’d wake up with them in our beds.”

In northernmost Norway, Sweden and Finland in the mid-2000s, successive bursts of geometrid moths defoliated 10,000 square kilometers of mountain birch forest — an area roughly the size of Puerto Rico. The outbreak was one of Europe’s most abrupt and large-scale ecosystem disturbances linked to climate change, says Jane Jepsen, an Arctic ecologist at the Norwegian Institute for Nature Research.

Three effects

The Arctic is warming more than twice as fast as the rest of the world. The higher temperatures have led to browning in some areas due to:

Extreme weather
Midwinter warming awakens plants, which then freeze as temperatures dive.
Moth infestations
Insects thrive and move into new areas to eat plants.
Dry plants plus more lightning leads to blackened land.

“These moth species benefit from a milder winter, spring and summer climate,” Jepsen says. Moth eggs usually die at around −30° C, but warmer winters have allowed more eggs of the native autumnal moth to survive. With warmer springs, the eggs hatch earlier in the year and keep up with the bud burst of the mountain birch trees. Another species — the winter moth (O. brumata), found in southern Norway, Sweden and Finland — expanded northward during the outbreak. The spring and summer warmth favored the larvae, which ate more and grew larger, and the resulting hardier female moths laid more eggs in the fall.

While forests that die off can grow back over several decades, some of these mountain birches may have been hammered too hard, Jepsen says. In some places, the forest has given way to heathland. Ecological transitions like this could be long-lasting or even permanent, she says.

Smoldering lands

Once rare, wildfires may be one of the north’s main causes of browning. As grasses, shrubs and trees across the region dry up, they are being set aflame with increasing frequency, with fires covering larger areas and leaving behind dark scars. For example, in early 2014 in the Norwegian coastal municipality of Flatanger, sparks from a power line ignited the dry tundra heath, destroying more than 100 wooden buildings in several coastal hamlets.

Sparsely populated places, where lightning is the primary cause of wildfires, are also seeing an uptick in wildfires. Scientists say lightning strikes are becoming more frequent as the planet warms. The number of lightning-sparked fires has risen 2 to 5 percent per year in Canada’s Northwest Territories and Alaska over the last four decades, earth system scientist Sander Veraverbeke of Vrije Universiteit Amsterdam and his colleagues reported in 2017 in Nature Climate Change.

In 2014, the Northwest Territories had 385 fires, which burned 34,000 square kilometers. The next year, 766 fires torched 20,600 square kilometers of the Alaskan interior — accounting for about half the total area burned in the entire United States in 2015.

In the last two years, wildfires sent plumes of smoke aloft in western Greenland (SN: 3/17/18, p. 20) and in the northern reaches of Sweden, Norway and Russia, places where wildfires are uncommon. Wildfire activity within a 30-year period could quadruple in Alaska by 2100, says a 2017 report in Ecography. Veraverbeke expects to see “more fires in the Arctic in the future.”

The loss of wide swaths of plants could have wide-ranging local effects. “These plants are the foundation of the terrestrial Arctic food webs,” says Isla Myers-Smith, a global change ecologist at the University of Edinburgh. The shriveled landscapes can leave rock ptarmigan, for example, which rely heavily on plants, without enough food to eat in the spring. The birds’ predators, such as the arctic fox, may feel the loss the following year.

The effects of browning may be felt beyond the Arctic, which holds about half of the planet’s terrestrial carbon. The boost in tundra greening allows the region to store, or “sink,” more carbon during the growing season. But carbon uptake may slow if browning events continue, as expected in some regions.

Treharne, Phoenix and colleagues reported in February in Global Change Biology that on the Lofoten Islands in northern Norway, extreme winter conditions cut in half the heathlands’ ability to trap carbon dioxidefrom the atmosphere during the growing season.

Yet there’s still some uncertainty about how these browned tundra ecosystems might change in the long-term. As the land darkens, the surface absorbs more heat and warms up, threatening to thaw the underlying permafrost and accelerate the release of methane and carbon dioxide. Some areas might switch from being carbon sinks to carbon sources, Phoenix warns.

On the other hand, other plant species — with more or less capacity to take up carbon — could move in. “I’m still of the view that [these areas] will go through these short-term events and continue on their trajectory of greater productivity,” Goetz says.

A better view

The phenomena that cause browning events — extreme winter warming, insect outbreaks, wildfires — are on the rise. But browning events are tough to study, especially in winter, because they’re unpredictable and often occur in hard-to-reach areas.

On Svalbard in the Arctic in 2015, extreme weather killed flowering mountain avens, but purple saxifrage survived.


Ecologists working on the ground would like the satellite images and the NDVI maps to point to areas with unusual vegetation growth — increasing or decreasing. But many of the browning events witnessed by researchers on the ground have not been picked up by the older, lower-resolution satellite sensors, which scientists still use. Those sensors oversimplify what’s on the ground: One pixel covers an area 8 kilometers by 8 kilometers. “The complexity that’s contained within a pixel size that big is pretty huge,” Myers-Smith says. “You have mountains, or lakes, or different types of tundra vegetation, all within that one pixel.”At a couple of recent workshops on Arctic browning, remote-sensing experts and ecologists tried to tackle the problem. “We’ve been talking about how to bring the two scales together,” Bhatt says. New sensors, more frequent snapshots, better data access and more computing power could help scientists zero in on the extent and severity of browning in the Arctic.

Researchers have begun using Google Earth Engine’s massive collection of satellite data, including Landsat images at a much better resolution of 30 meters by 30 meters per pixel. Improved computational capabilities also enable scientists to explore vegetation change close up. The European Space Agency’s recently launched Sentinel Earth-observing satellites can monitor vegetation growth with a pixel size of 10 meters by 10 meters. Says Myers-Smith: “That’s starting to get to a scale that an ecologist can grapple with.”

Earth’s carbon dioxide levels highest in 3 million years, study says


Who emits more methane in Colorado: natural gas producers or cows?

Posted: 6:43 PM, Mar 29, 2019
Updated: 6:02 PM, Mar 29, 2019

CU mobile Solar Occultation Flux

BOULDER, Colo. — While lawmakers at the Colorado state capitol debate a bill to change the way oil and gas production is regulated in the state, researchers at the University of Colorado Boulder have come up with a way to better track methane emissions.

Methane is a greenhouse gas that traps heat in the environment and contributes to climate change.

“Methane is kind of complicated because it’s a global problem,” said Rainer Volkamer, an associate professor of chemistry at CU Boulder. “We want to be able to keep track of it and what are the important sources.”

Methane lives in the atmosphere for about ten years, traveling from the North Pole to the South Pole before eventually being destroyed in the tropics.

Colorado has two main sources of methane emissions: natural gas production and livestock.

“Methane is the same whether it’s emitted from oil and gas or whether it’s emitted from a cow.” Volkamer said.

For years, it has been difficult for industries to determine whether livestock or natural gas production emits more methane.

“They need to know what their impact is on the environment,” Volkamer said.

In the past, methane emissions were measured by an airplane.

However, Volkamer and others created the CU mobile Solar Occultation Flux to help measure methane emissions from the ground and determine exactly where they are coming from. It was developed as part of the Cooperative Institute for Research in Environmental Sciences (CIRES).

“With our technique, we could show that the majority is produced from oil and gas and that the agricultural sources are a significant minor source for methane in the region,” Volkamer said.

The conclusion came from data Volkamer and study co-author Natalie Kille, a PhD student at CU Boulder, gathered over a five-day period in 2015 and have been working to analyze.

The researchers measured not only methane, but also ethane emissions, which is co-emitted from oil and gas producers. On the livestock side, the box measures ammonia that is co-emitted from the cows. By measuring all three, researchers can determine who is emitting what.

The machine is tiny compared to its predecessors; it’s about the size of a car engine. It’s also a much more cost-effective way to measure methane.

“This instrument is a tenth of the cost of another instrument that fills an entire room and it’s mobile, so it’s cost-effective for that reason,” Volkamer said.

It is also, in principle, able to perform the same functions inside of an airplane if researchers want to use that method.

Beyond that, the technique can determine exactly what methane was created in Colorado and which emissions were created elsewhere to give the state a better idea of its contributions to climate change.

Eventually, this data could help natural gas producers, cattle farmers and state regulators figure out how to mitigate air pollution. The researchers are hoping to build on this data with a long-term study over several seasons to see how methane emissions change over time.

Ocasio-Cortez: We reacted to 9/11, so where’s the reaction on climate change?

U.S. Rep. Alexandria Ocasio-Cortez, D-N.Y., appeared on MSNBC Friday to address the Green New Deal with host Chris Hayes and discussed the dire world she’s convinced lies ahead for Americans if climate change is not addressed.

“So this issue is not just about our climate. First and foremost we need to save ourselves. Period. There will be no future for the Bronx. There will be no livable future for generations coming, for any part of this country in a way that is better than the lot that we have today if we don’t address this issue urgently and on the scale of the problem,” said Ocasio-Cortez.


The freshman congresswoman believes America has seen dire situations before and mobilized, but mostly in connection with conflict and war. “Historically speaking, we have mobilized our entire economy around war. But I thought to myself it doesn’t have to be that way, especially when our greatest existential threat is climate change,” Ocasio-Cortez said.

“First and foremost we need to save ourselves. Period.”

— U.S. Rep. Alexandria Ocasio-Cortez, D-N.Y.

“And so to get us out of this situation, to revamp our economy to create dignified jobs for working Americans, to guarantee health care and elevate our educational opportunities and attainment, we will have to mobilize our entire economy around saving ourselves and taking care of this planet.”

Ocasio-Cortez also addressed critics of the Green New Deal legislation she’d co-sponsored, after MSNBC played a montage of Republicans and pundits, including some on Fox News, criticizing her and talking about “cow farts” and accusing her of wanting to take away their “hamburgers.”

“I didn’t expect them to make total fools of themselves,” Ocasio-Cortez said, saying she expected the criticism.


The congresswoman also said Hurricane Maria and the devastation caused on Puerto Rico was a sign that climate change problems are “here,” invoking the Sept. 11, 2001, terror attacks and criticizing the government for the lack of response.

“You know that this is here. This is not something that’s coming. … On the events of September 11 2001, thousands of Americans died in one of the largest terrorist attack on U.S. soil. And our national response — whether we agree with that or not — our national response was to go to war in one, then eventually two countries. Three thousand Americans died in Puerto Rico in the aftermath of Hurricane Maria. Where’s our response?” Ocasio-Cortez said to loud applause.

David Attenborough Isn’t Sure We Can Save the Natural World. But at 92, He’s Not Giving Up Trying

Sir David Attenborough poses for a portrait at the Royal Botanic Gardens, Kew, London, in February.

Sir David Attenborough poses for a portrait at the Royal Botanic Gardens, Kew, London, in February.
Jackie Nickerson for TIME

MARCH 28, 2019

Play Video


It’s the voice you notice first. In person, David Attenborough speaks in the same awestruck hush he has used in dozens of nature documentaries, a crisp half whisper that is often mimicked but seldom matched. Ninety-two years of use may have softened its edges, but still it carries the command of authority. Sitting in his home in the Richmond neighborhood of west London for one in a series of conversations, I feel compelled to drink a second cup of tea when he offers. It somehow seems wrong to say no.

In his native U.K., Attenborough is held in the kind of esteem usually reserved for royalty. Over decades–first as a television executive, then as a wildlife filmmaker and recently as a kind of elder statesman for the planet–he has achieved near beatific status. He was knighted by the Queen in 1985 and is usually referred to as Sir David. As he walked into the Royal Botanic Gardens for TIME’s portrait shoot on the day of our interview, the mere sight of him caused members of the public and staff alike to break into goofy smiles.

Attenborough pioneered a style of wildlife filmmaking that brought viewers to remote landscapes and gave them an intimate perspective on the wonders of nature. Frans de Waal, the renowned Dutch primatologist, says he regularly uses clips from Attenborough’s shows in lectures. “He has shaped the views of millions of people about nature,” he says. “Always respectful, always knowledgeable, he takes us by the hand to show us what is left of the nature around us.”

In the autumn of his life, Attenborough has largely retreated from filmmaking on location but lends his storytelling abilities to wildlife documentaries in collaboration with filmmakers he has mentored. His most famous work, the 2006 BBC series Planet Earth, set a benchmark in the use of high-definition cameras and had a budget equal to that of a Hollywood movie. Among its highlights was the first footage of a snow leopard, the impossibly rare Asian wildcat that hunts high in the Himalayas. More than a decade after its initial release, Planet Earth remains among the all-time best-selling nonfiction DVDs.

Attenborough with orangutans at the London Zoo

Attenborough with orangutans at the London Zoo

Now Attenborough is putting his voice and the weight of authority he has accumulated to greater moral purpose. In recent months he has stood in front of powerful audiences at the 2018 U.N. climate talks in Katowice, Poland, and the 2019 World Economic Forum at Davos, in Switzerland, to urge them into action on climate change. These kinds of events are not his chosen habitat, Attenborough tells TIME. “I would much prefer not to be a placard-carrying conservationist. My life is the natural world. But I can’t not carry a placard if I see what’s happening.”

Attenborough and his frequent collaborators, filmmakers Alastair Fothergill and Keith Scholey, will attempt to show the world exactly what is happening on April 5, when Netflix launches Our Planet–a new, blockbuster eight-part documentary series that aims not just to present the majesty of the world around us but also raise awareness of what the changing climate is doing to it.

Filmed across every continent over four years, the show takes viewers from remote steppes to lush rain forest to the ocean floor. It has vertiginous ambitions in both its scope and intent. “The idea was not just to make another landmark show, but also to move the dial,” says Scholey, who served as an executive producer. “Not only do we engage a large audience but also actually get to the point of changing policy that would lead to global change.”

It’s a show perfectly timed for a global moment in which politicians are prioritizing climate change as never before, students are skipping school to attend climate marches, and governments are attempting to rein in carbon emissions to meet Paris Agreement targets. Although he has been criticized for not speaking up earlier, Attenborough now says that if he has the opportunity to speak truth to power, he has to take it. “It is important, and it is true, and it is happening, and it is an impending disaster,” he says.

Attenborough promoting his BBC show 'The Tribal Eye'

Attenborough promoting his BBC show ‘The Tribal Eye’
Jeremy Grayson—Radio Times/Getty Images

Long before he was a world-famous documentarian, Attenborough was a trailblazer in the medium of television. He went from being a junior producer at the BBC in the 1950s, making programs about “gardening and cooking and knitting,” he says, to becoming one of the first controllers of BBC Two, the corporation’s eclectic second flagship channel. Among his commissions was a quirky comedy-sketch show called Monty Python’s Flying Circus. He was prouder, he recalls, of commissioning an opera by the composer Benjamin Britten.

Having studied natural sciences at the University of Cambridge, Attenborough juggled his TV duties with making wildlife films every few months; his series Zoo Quest, which ran from 1954 to 1963, followed the London Zoo’s attempts to gather rare animals for its menagerie from West Africa, South America and Southeast Asia. “I’d go away for three months and make some programs, which was lovely,” he says. “But in between, I had to do all these other things … politics and finance and engineering, which was never my bag.”

In the early 1970s, he resigned from the BBC to dedicate himself full time to wildlife filmmaking. He soon began work on Life on Earth, the seminal 1979 series that traced the arc of evolution from primordial ooze to Homo sapiens. The 13-part broadcast took viewers around the world, bringing them into close contact with a range of animals and using then cutting-edge filming techniques like the slow-motion capture of animal movements. Its most famous sequence shows Attenborough cavorting with a family of mountain gorillas in Rwanda.

But while Attenborough’s filmography made him a household name in the U.K., his fame didn’t immediately transfer stateside. He remembers being in a pitch session with a major U.S. network trying to describe Life on Earth to an executive. “I remember saying, ‘We’re going to start from the very beginning of the primordial oceans and see when life begins to appear.’ And he said, ‘You mean the first program’s all about green slime?’ I said, ‘Well, yes.’ ‘No, thank you,’ he said.”

Attenborough with Queen Elizabeth II

Attenborough with Queen Elizabeth II

This skepticism about his appeal would last for decades. When the Discovery Channel decided to broadcast Planet Earth in 2007, his voice-over was replaced with one by the actor Sigourney Weaver. Yet the incredible popularity of the DVD collection–carrying Attenborough’s narration, it sold 2.6 million copies in its first year of release–won him a narrow yet fervent U.S. fan base. Among his admirers was President Barack Obama, who invited him to the White House in 2015 to discuss the threat of climate change in a televised interview.

Attenborough initially assumed he would be the one interviewing Obama. But he was astonished to discover the President wanted it the other way round. “I thought, I mean apart from my work, what’s he doing talking to me?” he says. He desperately boned up on figures on climate change, even calling the U.K. environment ministry to check statistics.

His profile is evidently now high enough for Netflix to tout him as the narrator of Our Planet for English-speaking viewers (Penélope Cruz and Salma Hayek narrate for Spanish-language audiences), although he admits his creative role was mostly limited to the voice-over. He didn’t travel to remote locations for the new series, focusing his efforts instead on helping producers craft a script that would suit his signature narrative style while also fulfilling the show’s brief to sound the alarm about a changing planet. “In the old days I wrote every shot,” he says. “These days it’s a lot more … professional.”

Although Planet Earth, as well as his other acclaimed BBC series Blue Planetand Frozen Planet, did raise concerns among some viewers about the state of the environment, Our Planet is more explicit in its messaging. This is in part because the filmmakers, freed from the rigorous impartiality of the state-funded BBC, teamed up with the World Wide Fund for Nature (WWF), a conservation NGO. In one jaw-dropping sequence, after thousands of Pacific walruses are forced by vanishing ice sheets to crowd on a rocky strip of land, hundreds leap off a cliff to their doom, a scene Attenborough says is “almost heartbreaking” to watch.

Yet there are also scenes of hope that remind viewers that at least some environmental damage can be reversed. We see that Chernobyl–the Ukrainian region depopulated after a nuclear disaster in the 1980s–now has seven times more wolves than the surrounding countryside. Drone-mounted cameras show us one of the largest gatherings of humpback whales ever filmed, illustrating how marine preservation has permitted the species to bounce back from near extinction. To accompany the series, the WWF has created an online information hub so viewers can learn more about how to get involved in such efforts.

And yet even as he tries to spur action, Attenborough confesses that he has trouble staying optimistic. “The question is, Are we going to be in time, and are we going to do enough? And the answer to both of those is no,” he says. “We won’t be able to do enough to mend everything. But we can make it a darn sight better than it would be if we didn’t do anything at all.”

Attenborough with an anesthetized polar bear in Svalbard, Norway

Attenborough with an anesthetized polar bear in Svalbard, Norway

The reality of our changing planet is something Attenborough, who has seen more of it than most people alive, has long been aware of. For decades, he has decried the tendency of human development to crowd out natural habitats. He was present at the founding of the WWF in 1961, he says, even though he was just a “junior pipsqueak” at the time.

But it wasn’t until relatively recently that Attenborough became certain of mankind’s role in climate change. It sounds surprising given his body of work, but as he tells it, he didn’t want to base his judgment on observation alone. “It’s very dangerous to take a worldwide phenomenon and think you’re going to find just one scene in one locality that will prove it’s actually happening,” he says.

It was a 2004 presentation by the late U.S. environmental scientist Ralph Cicerone that convinced him of what was happening. “He showed a series of graphs that showed, with no doubt whatsoever, how population growth and industrial affluence had sent the content of noxious gases in the upper atmosphere,” he says. “And I had no hesitation after that.”

Still, some critics have argued that Attenborough and his colleagues have not done enough in their films to show the devastating effect of climate change. In a column for the Guardian in November, for instance, the environmental writer George Monbiot attacked the veteran broadcaster for “his consistent failure to mount a coherent, truthful and effective defense of the living world he loves,” and said wildlife television “cultivates complacency, not action,” by focusing on beauty rather than destruction.

“What George does is preach to the converted,” Attenborough says in response. By contrast, he explains, television makers have to speak to a wider audience. “You cannot do every program saying the world is in danger. Because they’ll say, ‘O.K., O.K., we get the message’ and go back to listening to something else. But we can say that the natural world is a wonder and a thrill and an excitement. And that’s what we do.”

A wild horse in 'Mongolia in Our Planet'

A wild horse in ‘Mongolia in Our Planet’
Ben Macdonald—Silverback Films/Netflix

There’s evidence this approach is as capable of sparking change as outright activism. Blue Planet II, the 2017 BBC series that explored life deep below the ocean’s surface, inspired a groundswell of activity after its final episode showed in detail how plastics are getting into the marine food chain. At the show’s conclusion, Attenborough told the audience “the future of all life now depends on us.” The resulting public outcry helped pressure the British government to enact restrictions on single-use plastics.

Blue Planet II moved the dial in this country more than anything I’ve ever seen,” says Fothergill, an executive producer on Our Planet. “For a long time, conservation and wildlife filmmaking was about pretty animals. Now it’s about saying that without this biodiversity there won’t be air to breathe or water to drink. It is about empowering people.”

At the age of 92, Attenborough remains committed to that mission. The BBC has announced new sequels to Planet Earth and Frozen Planet, and he says he was recently contacted about a show due to air in 2026, when he will turn 100. After seven decades in the business, Attenborough marvels at the life he’s still able to lead. “I’m very surprised I’m still employed,” he says. “But I’m just very grateful I am.”


Trees release flammable methane—here’s what that means for climate

There are more reasons than ever to conserve forests, but the surprising role of trees as a methane source adds a complication.

This article was created in partnership with the National Geographic Society.

In 1907, Francis W. Bushong, a chemistry professor at the University of Kansas, reported a novel finding in the journal Chemical and Physical Papers. He’d found methane, the main ingredient in natural gas, in a tree.

Years earlier, he wrote, he’d cut down some cottonwood trees and “observed the formation of bubbles in the sap upon the freshly cut trunk, stump and chips.” When he struck a match, the gas ignited in a blue flame. At the university, he replicated the flame test on a campus cottonwood and this time captured gas samples. The concentration of methane was not much below the level measured in samples from Kansas’s natural gas fields.

The finding was reported mainly as a novelty and faded into obscurity.

Tree methane is back, in a big way.


An expanding network of researchers has discovered methane flowing out of trees from the vast flooded forests of the Amazon basin to Borneo’s soggy peatlands, from temperate upland woods in Maryland and Hungary to forested mountain slopes in China.

Even as they strap $50,000 instruments to trees to record gas flows, more than a few of these researchers have been unable to resist using a lighter or match to produce the same blue flame that took Professor Bushong by surprise more than a century ago.

But the research now is driven by far more than novelty. Methane is second only to carbon dioxide in its importance as a greenhouse-gas emission linked to global warming. In a natural gas pipeline, methane is a relatively clean fossil fuel. But it is a powerful heat-trapping addition to the planet’s greenhouse effect when it accumulates in the atmosphere.

Methane released by a tree lights on fire.

Natural sources have always produced large amounts of the gas—currently on a par with those from agriculture. The main source is microbial activity in oxygen-deprived soggy soils and wetlands. (Increasingly, human-driven warming appears to be expanding wetlands, particularly in high latitudes, adding even more methane emissions.)

The full climate impact of methane from trees is nowhere near that of the tens of billions of tons of carbon dioxide released annually from smokestacks and tailpipes, or the methane from, say, humanity’s vast cattle herds or gas fields. But there is sufficient uncertainty in the estimates setting the “global methane budget” that trees could turn out to be a substantial source.

For the moment, this is a newly revealed frontier, said Kristofer Covey, a Skidmore College scientist focused on the chemistry and ecology of forests.

“At the global scale this could be huge”

“The emissions from an individual tree are small,” Covey said. “But there are several trillion trees. At the global scale this could be huge.” Covey organized an international workshop last spring to identify research priorities and just published a paper in New Phytologist that is, in essence, a call for help from a host of disciplines not yet focused on this issue. His coauthor is J. Patrick Megonigal, a tree researcher at the Smithsonian Environmental Research Center in Maryland.

New papers are being published month by month with remarkable rapidity, with each field measurement essentially constituting a new publishable finding.

“We’re very much still in the stamp collecting phase,” Covey said.

The findings are already challenging old norms. Dry upland forests were long assumed to be removing methane from the air through the action of a class of soil microbes called methanotrophs. But work by Megonigal and others is showing tree emissions can exceed that methane-scrubbing capacity.

Misled by “a flat world”

How did this effect, measured by Bushong in 1907 and noted informally by forestry scientists for generations, stay hidden so long?

For decades, scientists studying flows of methane between terrestrial ecosystems and the air had set their instruments on the ground, never thinking trees might be involved, said Vincent Gauci, a professor of global change ecology at Britain’s Open University and an author of a string of recent papers on trees’ methane role.

What everyone had missed is that the stems and trunks and leaves of trees are surfaces, too, and the gas can flow there as well. “We’d been looking at a flat world,” Gauci said.

No more. Much of the methane now found to be escaping from trees in such wet conditions is thought simply to be microbial methane pumped up and out as oxygen flows down to the roots. But Gauci and other scientists are finding many instances in which trees produce their own methane—sometimes from microbes in the heartwood or other tissues and in other cases from a remarkable direct photochemical reaction thought to be driven by the ultraviolet wavelengths in sunlight.

The tree emissions measured in some regions are enormous, with an international team led by Sunitha Pangala of Lancaster University last year estimating in Nature that just the trees in the Amazon’s seasonally flooded forests were the source of between 14 million and 25 million metric tons of the gas annually—an amount similar to estimates for methane emissions from tundra all around the Arctic.

It might not seem so surprising to think of trees in Amazon forests as conduits for this gas, given that soggy soils, peat bogs, and other low-oxygen environments are the domain of microbes that generate this gas. But other studies have found trees generating substantial methane even in dry upland ecosystems—in some cases within the trunk of the tree, not the soil.

Such findings have spurred even more work, and it seems that everywhere someone looks, the more consequential, and confounding, the picture becomes.

At every scale, from whole forests to clusters of similar trees in a forest to the dynamics in individual trees, the one constant is variation, said Megonigal, at the Smithsonian research center in Maryland.

Covey described forests where similar trees in similar soils have been measured with a fiftyfold difference in methane emissions.

Some trees have been measured to be emitting methane near the base and absorbing it higher up the trunk.

But that’s not the least of it. Closer analysis has found that a single tree can be absorbing methane near the base through microbial processes and emitting it higher up the trunk.

The study surveyed methane flows in trees in wet and dry soils from Central America and the Amazon to Britain and Sweden. Trees in wet soils uniformly were net emitters of methane but those in drier conditions in some regions actually were net absorbers of the gas.

Lessons for climate policy

The emerging findings on methane and forests are likely to stir discussions about next steps for climate policy related to forests, which has long focused on trees’ capacity to absorb and store carbon dioxide, with little attention to other properties.

“The thing we know about forests is that they sequester carbon,” Covey said. “That’s what you learn, what’s in a third grader’s cartoon drawing of a forest.”

The reality for climate is more complicated. “There is global warming but there’s no global forest,” he said.

The 2015 Paris Agreement on climate change supports forest projects as a way to draw down carbon dioxide emissions that countries have so far failed to constrain at the source. The United Nations has launched a Trillion Tree Campaign. There are a host of ways for companies and consumers to spend money on forest projects through “carbon offsets” to compensate for emissions from travel and the like.

In interviews, Covey and other researchers looking at the tree methane question stress they aren’t arguing that such efforts should pause, noting the many benefits of forest conservation, including carbon storage, resilience against floods, and safeguarding species-rich ecosystems.

Independent of climate diplomacy, countries around the world are working to accelerate forest conservation under a separate agreement, the Convention on Biological Diversity, to safeguard their value as home to vast arrays of species.

But the methane findings do highlight the importance of assessing the full range of climate impacts—for better or worse—of different forest and tree types in different regions. As with better understanding of forest ecology, this can then guide projects to maximize benefits and limit risks.

In recent years, other studies looking at the full impact of forests on the climate system have illuminated how a CO2-centered focus can miss significant additional cooling benefits of forests and—in some regions and forest properties—significant warming effects.

“For some forests all the arrows point in the same direction,” Covey said, describing the various ways trees can affect climate. “There are other places where the arrows don’t line up much.”

He and other researchers said a clearer view can improve climate models and also help insure that programs centered on the climate value of forests are as effective as possible.

In higher latitudes, the simple shift from light-reflecting open land to dark, rough-surfaced tree canopies can warm the local climate by absorbing more sunlight. Forests in the tropics are particularly valuable for local climate, cooling the air around them as their metabolic machinery results in enormous evaporation—and that also can result in more sun-blocking cloud cover and precipitation.

Other work has shown how a complicated array of volatile organic compounds emitted by trees react to create haze and clouds, influencing temperature and precipitation in a variety of ways. In 2014, debate erupted over over-distilled headlines implying that this work, particularly studies by the atmospheric chemist Nadine Unger, then at Yale, meant forests should not be saved.

No one interviewed for this story, including Unger, sees that as the case. Now at Exeter University, she said what’s needed are comprehensive assessments of forests and climate accounting for the full suite of properties.

What’s particularly notable now is that she and some of her past critics are all stressing that the prime focus of the world needs to be cutting emissions of carbon dioxide at the source, even as forests are saved for all the benefits they provide.

“Our best shot at achieving Paris Agreement global temperature targets is a laser focus on reducing CO2 emissions from energy-use in the wealthy mid-latitude countries,” Unger said.

Her point echoes a commentary by a range of scientists in the March 1 edition of Science on making sure “natural climate solutions”—including forest-focused projects—are not seen as an alternative to pursuing deep, prompt cuts in greenhouse-gas emissions. Both will be needed, they said.

William R. Moomaw, an emeritus professor of international environmental policy at Tufts University, said there will always be uncertainties in gauging the full mix of climate influences of forests. But that should not stand in the way of moving forward with programs to expand them or boost their carbon-holding capacity. The weight of evidence still points to forests as a key to maintaining a safe climate, Moomaw said.