Coal vs. natural gas climate forcing, projected to the year 2100. Adapted from Figure 3 of Hausfather, 2015. Graphic: Yale Climate Connections

[cf. Our leaders thought fracking would save our climate – ‘Methane emissions are substantially higher than we’ve understood’]

By Zeke Hausfather
23 August 2016

(Yale Climate Connections) – For the past century, coal has been king, providing the majority of U.S. energy for electricity generation.

But a combination of new federal and state environmental policies and a glut of cheap natural gas (mostly from hydraulic fracturing, or fracking) have led to a dramatic shift during the past decade, with coal dropping from 50 percent to 32 percent of our electricity generation and gas increasing from 18 percent to 33 percent.

Just under a third of existing coal-based power generation in the United States has been shut down, and the Obama administration has aggressively embraced the replacement of coal with gas as a key part of meeting its 2030 climate targets. We are quickly traveling down a gas bridge away from coal. But will this shift actually be a good thing for the climate? […]

How much methane leaks from the natural gas system is very much an open question. For a long time official Environmental Protection Agency numbers suggested the emissions were small and falling fast, only amounting to around 1.5 percent of total production.

But dozens of independent academics doing research using aircraft, satellite data, and other instruments have consistently found higher emissions than officially reported.

Adam Brandt at Stanford University published a high-profile paper in the journal Science in 2014 summarizing all the research to date. He found that overall emissions were likely between 25 and 75 percent higher than reported by EPA, suggesting that actual natural gas leakage rates are probably somewhere between 2 and 4 percent of gas production. (Some researchers have found leakage as high as 10 percent for individual fields, but there isn’t evidence that those findings are characteristic of the sector as a whole.) […]

If leakage is higher than 3 percent, there are some periods in the next 30 years when gas will result in more climate impact than new coal plants. If leakage is higher than 4 percent, there are some periods when gas will be worse for the climate than existing coal plants.

But no matter what the leakage rate is, gas will still cut the climate impact by 50 percent in 2100 compared to new coal and 66 percent compared to existing coal. So whether switching from coal to gas is beneficial in this simple example depends on how you value near-term or longer-term warming.

The importance of near-term warming is tough to assess. Climate models, by and large, don’t predict any irreversible changes in periods as short as 30 years, and potential tipping points in the climate generally depend more on the peak warming that occurs (which in nearly all foreseeable cases would occur after 2050). […]

Renewables are getting cheaper, and although it might not be practical to replace all coal plants with renewables immediately, it’s definitely possible to do so in the next decade if renewables continue to fall in price. If we replace coal with gas today, we’ve sunk costs into new gas infrastructure that we might be loath to replace a few years later with renewables. In this way, a gas bridge could delay the widespread adoption of renewables. [more]

Is Natural Gas a Bridge Fuel?

Simulated rise in atmospheric CO2 concentrations during the most recent deglaciation event, resulting from the release of a Southern Ocean carbon pool (red line) and the breakdown of the permafrost and Southern Ocean carbon pools (blue line). Inclusion of the permafrost carbon pool results in a better match with CO2 reconstructions from the EPICA Dome C ice core (black diamonds), suggesting a plausible role of permafrost carbon in the deglacial CO2 rise during the Mystery Interval. The error bars are the 2σ error estimates taken from the EPICA Dome C ice core data. Graphic: Crichton, et al., 2016 / Nature Geoscience

By Andrew H. MacDougall
22 August 2016

(Nature Geoscience) – Between 17,500 and 14,500 years ago, a period sometimes referred to as the Mystery Interval1, atmospheric CO2 concentrations began their post-glacial rise from about 190 ppm in glacial times to approximately 270 ppm by the beginning of the Holocene. The rise in CO2 during the Mystery Interval is associated with large negative anomalies in the carbon isotopic composition of CO2 (refs 2,3). These anomalies suggest that a long-isolated carbon pool that was formed from a biological source was released to the atmosphere. A large pool of old 13C-depleted carbon in the Southern Ocean has been invoked as the source, but questions over the timing and magnitude of this release remain. Writing in Nature Geoscience, Crichton and colleagues5 report evidence from numerical simulations that suggest the primary source of the deglacial carbon during the Mystery Interval was instead a permafrost carbon pool.

Soil and bedrock that have temperatures below 0 °C for longer than two years are considered to be permafrost6. Permafrost soils hold an immense quantity of carbon in the form of partly decayed organic matter: carbon held in permafrost-affected soils is estimated to comprise ~35% of the total terrestrial carbon pool in the modern world7. Much of this carbon is held in permafrost soil horizons and is therefore frozen and protected from microbial decay7. Permafrost carbon — like all organic matter — has a low δ13C value and, because it can be locked in frozen soils for thousands of years, permafrost carbon typically has very little radiocarbon remaining6.

Extensive permafrost regions are thought to have existed during the Last Glacial Maximum. Under this cold climate, even though terrestrial productivity was half that of the pre-industrial period, the carbon pool housed in soils and vegetation was only ~10% smaller than that of the late Holocene8. However, the inactive fraction of the terrestrial carbon pool was about 45% larger than that of which exists today8. There is no palaeoclimate proxy to directly estimate the size of the permafrost carbon pool during the Last Glacial Maximum. Nonetheless, a large glacial permafrost carbon pool fits the criteria of a large inert carbon pool in a low primary productivity world.

Crichton and colleagues5 use an Earth system model of intermediate complexity to simulate the evolution of atmospheric CO2 concentration from the Last Glacial Maximum until the year 1850. In model simulations, the dissipation of the enhanced Southern Ocean carbon pool enlarges the atmospheric carbon pool by over 100 ppm of CO2 (red line, Fig. 1). However, the rise in CO2 concentrations occurs roughly 3,000 years after the rise observed in the ice-core record. Adding a permafrost carbon module to the Earth system model narrows the difference between the model simulation and palaeoclimate CO2 record, with simulated CO2 and δ13C closely matching the data until the onset of the Holocene (blue line, Fig. 1).

The simulations suggest a simplified storyline for the deglacial rise in atmospheric CO2. At the end of the Last Glacial Maximum, changes in Earth's orbit caused Northern Hemisphere summertime insolation to rise. These warmer summer conditions induced thaw of permafrost soils, which began to release long-sequestered carbon as CO2. The liberated permafrost carbon further warmed the climate, inducing deglaciation and further release of carbon from permafrost soils. Sea-level rise and a warming climate then triggered changes in brine formation and sinking in the Southern Ocean, which resulted in the dissipation of the glacial Southern Ocean carbon pool. However, regrowth of the terrestrial biosphere sequestered more carbon than was released from the terrestrial realm. Thus in net terms, although deglaciation was promoted by the release of permafrost carbon to the atmosphere, the ocean carbon pool was the dominant source of the glacial–interglacial rise in atmospheric CO2 concentrations. [more]

Permafrost carbon: Catalyst for deglaciation


ABSTRACT: The atmospheric concentration of CO2 increased from 190 to 280 ppm between the last glacial maximum 21,000 years ago and the pre-industrial era1, 2. This CO2 rise and its timing have been linked to changes in the Earth’s orbit, ice sheet configuration and volume, and ocean carbon storage2, 3. The ice-core record of δ13CO2 (refs 2,4) in the atmosphere can help to constrain the source of carbon, but previous modelling studies have failed to capture the evolution of δ13CO2 over this period5. Here we show that simulations of the last deglaciation that include a permafrost carbon component can reproduce the ice core records between 21,000 and 10,000 years ago. We suggest that thawing permafrost, due to increasing summer insolation in the northern hemisphere, is the main source of CO2 rise between 17,500 and 15,000 years ago, a period sometimes referred to as the Mystery Interval6. Together with a fresh water release into the North Atlantic, much of the CO2 variability associated with the Bølling-Allerod/Younger Dryas period ~15,000 to ~12,000 years ago can also be explained. In simulations of future warming we find that the permafrost carbon feedback increases global mean temperature by 10–40% relative to simulations without this feedback, with the magnitude of the increase dependent on the evolution of anthropogenic carbon emissions.

Permafrost carbon as a missing link to explain CO2 changes during the last deglaciation

A mural of murdered forest-rights and indigenous-rights activist Berta Cáceres in Tegucigalpa, Honduras. Photo: disoniador / Pixabay

By Lindsay Fendt
11 August 2016

(mongabay.com) – On a Tuesday in March, indigenous activist Nelson García was shot in the face in northwest Honduras. The next day, in Guatemala, unknown attackers found environmentalist Walter Méndez outside his home and filled his chest with bullets. Two weeks earlier gunmen killed Berta Cáceres, an internationally renowned environmental campaigner, in her Honduran home. And in the months before, similar killings were reported in Brazil, Mexico, and Peru.

Since 2010, murders over land disputes have been on the rise worldwide, but the problem is especially severe in Latin America, according to U.K.-based NGO Global Witness. The group documented more than 900 environmentalists killed in the region between 2002 and 2015. Last year was the deadliest year on record, with 185 murders worldwide, nearly two-thirds of them in Latin America, according to a report the group released in June.

“There is an increase in pressure to exploit resources that have not been exploited yet,” John Knox, a Special Rapporteur on human rights and the environment for the United Nations, told Mongabay. “You have very powerful economic interests on one hand and marginalized communities on the other and that seems to be leading to these conflicts [worldwide].”

Though in Latin America the reasons for the killings vary, many are related to a surge in development in remote parts of the region. Seeking out foreign investment, governments have been granting concessions to foreign-funded hydroelectric dams, mines, and other projects, often without consulting the communities already occupying the land. Meanwhile, landless ranchers, poachers, and illegal loggers are also pushing into remote areas in search of untapped resources.

Most of the encroached-upon areas have been inhabited by indigenous groups or subsistence farmers for generations, but many communities lack titles or deeds for their land. With little government assistance, some members of these communities are opposing environmental destruction on their own and paying the ultimate price.

“It is one of the most serious injustices in the world,” said Bill Kovarik, a professor at Radford University in Virginia who tracks murders of green activists. “For every one of these very serious deaths there are dozens of others that face violence.” [more]

In Latin America, environmentalists are an endangered species

By John Vidal
21 April 2016

(Guardian) – A documentary about the murder of a rainforest activist has been viewed tens of thousands of times online after being banned by the Cambodian government.

The film, I Am Chut Wutty, was due to be shown this week in a Phnom Penh cinema to coincide with the fourth anniversary of the killing of the environmentalist by an unidentified military police officer in April 2012.

But the Cambodian Department of Cinema and Cultural Diffusion refused the cinema a licence, stating that the British director had no permission to make the film.

Movie poster for the film, 'I Am Chut Wutty', which was banned by the government of Cambodia in April 2016. Graphic: Journeyman Pictures

The ban may have backfired, with sections of the Khmer language version of the film being viewed nearly 100,000 times in the last three days and private screenings reportedly being shown across Cambodia. An English version will be released next week.

Cambodian human rights and environment groups condemned what they said was suppression of the stories of people trying to save the country’s rainforest. [more]

Cambodia bans film about murdered rainforest activist

This Sunday, 21 August 2016, photo shows dead whitefish floating in the Yellowstone River near Emigrant, Montana. Montana wildlife officials closed a stretch of the river and numerous tributaries after a massive fish kill that is blamed on the contagious parasite Tetracalsula bryosalmonae. Photo: Matthew Brown / AP

By Sarah Jane Keller
25 August 2016

(smithsonian.com) – It was the kind of clear late-August day that anglers live for. Yet at the Yellowstone River near Livingston, Montana, not a single oar boat or even a fishing line broke the river’s calm surface. All was still, save for an osprey scavenging the corpses of pale, shimmering whitefish along the gravelly shoreline. A light breeze carried the sweetish smell of aquatic decay.

Earlier this month, the Yellowstone River made national headlines with the news of an unprecedented fish die-off in its usually healthy waters. Starting in mid-August, biologists counted 4,000 dead whitefish floating on the Yellowstone or washed ashore, but they estimate that the true number is in the tens of thousands. As if that wasn’t enough, they’ve recently spotted rainbow trout and Yellowstone cutthroat trout—both economically important species—go belly-up as well.

This devastating scene has state officials so worried that, on August 19, they closed a 183-mile stretch of the river and all of its tributaries until further notice. Fishing boats, inner tubers, even swimming dogs: none are allowed to get into the water.

The culprit is a tiny, highly contagious parasite called Tetracalsula bryosalmonae, which exclusively attacks fish. It worms its way into fishes’ kidneys, where it causes proliferative kidney disease and can obliterate fish populations, according to state biologists. (Science writer Ed Yong explains how this scientifically elusive parasite evolved from a jellyfish-like creature at The Atlantic.)

Those biologists note that it’s been a hot summer, and streamflows have been historically low—stressful conditions that make cold-adapted fish populations ripe for a deadly disease outbreak. The river closure is meant to keep the parasite out of other rivers and to keep fishers and boaters from further taxing sick fish. […]

News of the whitefish kill didn’t surprise Clint Muhlfeld, a U.S. Geological Survey aquatic ecologist and University of Montana researcher who studies climate change impacts on cold-water ecosystems. “We’re seeing severe impacts on Montana’s waters, mainly increases in stream temperatures and decreases in flows. These climate-induced changes are likely going to begin to interact with existing stressors such as habitat loss and invasive species,” he says. “The climate is warming, and there are going to be consequences for our freshwater ecosystems.” [more]

The Massive Yellowstone Fish Die-Off: A Glimpse Into Our Climate Future?

The spirit riders at Standing Rock show support for keeping the Missouri River waters clean, as the Great Sioux Nation defends its waters from the Dakota Access Pipeline. Photo: Steve Sitting Bear

By David Archambault II
24 August 2016

Near Cannon Ball, North Dakota (The New York Times) – It is a spectacular sight: thousands of Indians camped on the banks of the Cannonball River, on the edge of the Standing Rock Sioux Reservation in North Dakota. Our elders of the Seven Council Fires, as the Oceti Sakowin, or Great Sioux Nation, is known, sit in deliberation and prayer, awaiting a federal court decision on whether construction of a $3.7 billion oil pipeline from the Bakken region to Southern Illinois will be halted.

The Sioux tribes have come together to oppose this project, which was approved by the State of North Dakota and the United States Army Corps of Engineers. The nearly 1,200-mile pipeline, owned by a Texas oil company named Energy Transfer Partners, would snake across our treaty lands and through our ancestral burial grounds. Just a half-mile from our reservation boundary, the proposed route crosses the Missouri River, which provides drinking water for millions of Americans and irrigation water for thousands of acres of farming and ranching lands.

Our tribe has opposed the Dakota Access pipeline since we first learned about it in 2014. Although federal law requires the Corps of Engineers to consult with the tribe about its sovereign interests, permits for the project were approved and construction began without meaningful consultation. The Environmental Protection Agency, the Department of the Interior and the National Advisory Council on Historic Preservation supported more protection of the tribe’s cultural heritage, but the Corps of Engineers and Energy Transfer Partners turned a blind eye to our rights. The first draft of the company’s assessment of the planned route through our treaty and ancestral lands did not even mention our tribe.

The Dakota Access pipeline was fast-tracked from Day 1 using the Nationwide Permit No. 12 process, which grants exemption from environmental reviews required by the Clean Water Act and the National Environmental Policy Act by treating the pipeline as a series of small construction sites. And unlike the better-known Keystone XL project, which was finally canceled by the Obama administration last year, the Dakota Access project does not cross an international border — the condition that mandated the more rigorous federal assessment of the Keystone pipeline’s economic justification and environmental impacts.

The Dakota Access route is only a few miles shorter than what was proposed for the Keystone project, yet the government’s environmental assessment addressed only the portion of the pipeline route that traverses federal land. Domestic projects of this magnitude should clearly be evaluated in their totality — but without closer scrutiny, the proposal breezed through the four state processes.

Perhaps only in North Dakota, where oil tycoons wine and dine elected officials, and where the governor, Jack Dalrymple, serves as an adviser to the Trump campaign, would state and county governments act as the armed enforcement for corporate interests. In recent weeks, the state has militarized my reservation, with road blocks and license-plate checks, low-flying aircraft and racial profiling of Indians. The local sheriff and the pipeline company have both called our protest “unlawful,” and Gov. Dalrymple has declared a state of emergency. [more]

Taking a Stand at Standing Rock

The image above shows the Blue Cut fire at 10:36 p.m. Pacific Daylight Time on 17 August 2016, as observed by Thermal Infrared Sensor (TIRS) on the Landsat 8 satellite. TIRS observes in wavelengths of 10.9 micrometers and 12.0 micrometers, showing the amount of heat (thermal energy) radiating from the fiery landscape. Cooler areas are dark, while warmer areas are bright. The thermal data was overlaid on a daytime image for added geographic detail. Photo: Joshua Stevens / NASA Earth Observatory

By Pola Lem
18 August 2016

(NASA) – California’s Blue Cut fire has burned homes, caused power outages, and prompted more than 82,000 evacuations in San Bernardino County. The extent of the damage, however, remains unclear. Firefighters have been focused on containing the fire’s perimeter, The Los Angeles Times reported.

The image above shows the Blue Cut fire at 10:36 p.m. Pacific Daylight Time on 17 August 2016, as observed by Thermal Infrared Sensor (TIRS) on the Landsat 8 satellite. TIRS observes in wavelengths of 10.9 micrometers and 12.0 micrometers, showing the amount of heat (thermal energy) radiating from the fiery landscape. Cooler areas are dark, while warmer areas are bright. The thermal data was overlaid on a daytime image for added geographic detail.

The blaze started mid-morning on August 16, 2016 in the Cajon Pass, west of Interstate 15, according to CalFire. By midday on August 18, it had grown to 31,689 acres. At least 1,584 firefighting personnel were on the scene working with 178 engines, 10 air tankers, 2 Very Large Air Tankers (VLATS), and 17 helicopters.

Cameras captured video of at least one fire whirl, a “spinning vortex column of ascending hot air and gases rising from a fire and carrying aloft smoke, debris, and flame,” according to the Bureau of Land Management. The Blue Cut fire was one of ten major fires burning in the United States on 18 August 2016, according to the National Interagency Fire Center.

References

Blue Cut Fire at Night

Tariq Brown Otter holds a sign that reads, 'Respect Our Land - No Dakota Access', to protest the Army Corps of Engineers issuing a construction permit that allows Dakota Access LLC to build a massive oil pipeline through Standing Rock Sioux land. Photo: Last Real Indians

By Xeni Jardin
24 August 2016 

(Boing Boing) – In Washington today, District Judge James E. Boarsberge said he will not issue a decision on a legal challenge by the Standing Rock Sioux tribe against the U.S. Army Corps of Engineers and Dakota Access, LLC, the private firm behind a nearly $4 billion oil project Native people say will destroy their land and cause unprecedented damage to human, plant, and animal life in the region.

From Native News Online, on the judge's decision late Wednesday:

He indicated that the central legal issue is whether or not proper tribal consultation occurred between the tribes and U.S. Army Corps of Engineers.

Judge Boarsberge said there appears to have been a lack of communication between the Corps of Engineers and the tribes and the failure on the Corps of Engineers’ part to perform the due diligence in the process in the development of the project.

The judge will render his decision on September 9, 2016 and he set September 14 as a date for appeal if either side is not happy with his decision.

Standing Rock Sioux Reservation Chairman David Archambault described the court hearing as an encouraging victory.

“For our children that are not even here yet, this is something that is very powerful, very special,” he told Indian Country Today Media Network after Judge Boasberg said he needed time to weigh the evidence presented at Wednesday’s hearing on the lawsuit brought by the Tribe against the U.S. Army Corps of Engineers. [more]

Dakota Pipeline decision delayed to Sept. 9, thousands of indigenous activists continue protest


Dear President Obama and First Lady Michelle Obama,

It has been two years already since I met you during your visit to Standing Rock. When you were here, you sat and listened to what we had to say. You made us feel like we mattered, we didn’t feel invisible anymore.

I am writing this letter to you because I am concerned about the wellbeing of my people. The Army Corps of Engineers just issued a construction permit allowing Dakota Access LLC to build a massive pipeline through our Missouri River. This pipeline will transport 570,000 barrels of crude oil through our water every day. In 2012-2013 alone, there were 300 oil pipeline breaks in the state of North Dakota. When the Dakota Access Pipeline breaks, it will not only contaminate our water but it will also destroy our sacred land and threaten our individual, societal and community’s health.

A few months ago, the youth from my Tribe started speaking out against the Dakota Access Pipeline. We created a petition to raise awareness about the potential damages this pipeline could do to our people, and our Rezpect Our Water campaign now has over One Hundred and Forty Thousand (140,000) supporters, both across the country and around the world. Our campaign has been successful. Sadly, it was not enough to dissuade the Army Corps of Engineers from issuing the construction permit.

Throughout history, our people have used messenger runners to deliver valuable information between tribes. In the spirit of our ancestors we have started a Relay Race to bring our message to Washington DC. Thirty of us, from the Oceti Sakowin Youth (Standing Rock Sioux Tribe), will be running almost 2000 miles over three weeks to raise further awareness about the pipeline and to deliver our 140,000 petition signatures to the headquarter of the Army Corps of Engineers. Our final stop will be at your doorstep, Mr. President. We hope you can join us and listen to what we have to say.

As the native children of this country, we are asking you to stand with us on August 6, 2016 at Lafayette Square and help us fight the Dakota Access Pipeline. Enough has been taken away from our people. We want to thrive and we want a bright future. One that embraces our cultural heritage and our deep communion with our lands. By helping us fight for our water and for our ancestral lands, you confirm our common humanity and dignity. This is what we ask for.

After your visit to Standing Rock you said you felt we were like your own children. Mr. President and First Lady we have no doubt you meant every word you said and we know you have not forgotten us. We hope that your schedule allows you to greet us and show your support upon our arrival in Washington DC.

Thank you very much, Tariq and the Oceti Sakowin Youth

Letter to Obama ‘Rezpect Our Water’ Standing Rock Youth Reach out to Stop Dakota Access Pipeline

Number of smoke waves in the U.S.West, based on (a) the primary smoke wave definition (cutoff= 6 μg/m3), (b) smoke wave definition with cutoff =10 μg/m3, and (c) smoke wave definition with cutoff =20 μg/m3. Maps on the left represent the present day (based on 2004-2009 data). Maps on the right represent the future under climate change (based on projected data for the years 2046-2051). Graphic: Liu, et al., 2016 / Climatic Change

By Kevin Dennehy
15 August 2016

(Yale News) – A surge in major wildfire events in the western United States as a consequence of climate change will expose tens of millions of Americans to high levels of air pollution in the coming decades, according to a new Yale-led study conducted with collaborators from Harvard.

The researchers estimated air pollution from past and projected future wildfires in 561 western counties, and found that by mid-century more than 82 million people will experience “smoke waves,” or consecutive days with high air pollution related to fires.

The regions likely to receive the highest exposure to wildfire smoke in the future include northern California, western Oregon, and the Great Plains.

The findings, published in the journal Climatic Change, point to the need for new or modified wildfire management and evacuation programs in the nation’s high-risk regions, said Jia Coco Liu, a recent Ph.D. graduate at the Yale School of Forestry & Environmental Studies (F&ES) and lead author of the study.

“Our study illustrates that smoke waves are likely to be longer, more intense, and more frequent under climate change,” Liu said. “This raises critical health, ecological, and economic concerns. Identifying communities that will be most affected in the future will inform development of fire management strategies and disaster preparedness programs.”

Other authors include Michelle Bell, the Mary E. Pinchot Professor of Environmental Health at F&ES; Keita Ebisu, a former doctoral student with Bell; as well as colleagues at Harvard, Colorado State University, and the University of Michigan.

Smoke from wildfires, which are becoming more frequent and intense in the U.S. West as the climate changes, contains large amounts of fine particulate matter, or PM2.5, which can have profound impacts on human health.

But while wildfires are estimated to contribute about 18% of the total PM2.5 emissions in the United States, many questions remain about how these emissions will affect human populations, including how overall air quality will be affected, how these levels will change under climate change, and which regions are most likely to be impacted.

Using sophisticated atmospheric and climate models, the researchers estimated the levels of PM2.5 directly attributable to wildfires during a recent six-year period, 2004 to 2009, as well as under projected future climate change conditions (2046 to 2051).

Twenty counties that are currently free from smoke waves are expected to experience at least one in the future six-year period. The length of the smoke wave season is estimated to increase by an average of 15 days in more than 62.5% of the counties.

About 56% of the counties currently affected by smoke waves — including most located in the forests of the northern Rocky Mountains and coastal counties — will likely face more intense smoke waves in the future. About 19% will have less intense smoke waves.

The researchers also developed an interactive map to illustrate their findings.

“We hope these results will advance the understanding of the impacts of an increasing threat of wildfire smoke, and aid in the design of early warning systems, fire suppression policies, and public health programs,” Liu said.

Health risks from wildfires in U.S. West to increase under climate change


Difference in Fire Smoke Risk Index (FSRI) between future and present day in the U..S. West. Graphic: Liu, et al., 2016 / Climatic Change

ABSTRACT: Wildfire can impose a direct impact on human health under climate change. While the potential impacts of climate change on wildfires and resulting air pollution have been studied, it is not known who will be most affected by the growing threat of wildfires. Identifying communities that will be most affected will inform development of fire management strategies and disaster preparedness programs. We estimate levels of fine particulate matter (PM2.5) directly attributable to wildfires in 561 western US counties during fire seasons for the present-day (2004–2009) and future (2046–2051), using a fire prediction model and GEOS-Chem, a 3-D global chemical transport model. Future estimates are obtained under a scenario of moderately increasing greenhouse gases by mid-century. We create a new term “Smoke Wave,” defined as ≥2 consecutive days with high wildfire-specific PM2.5, to describe episodes of high air pollution from wildfires. We develop an interactive map to demonstrate the counties likely to suffer from future high wildfire pollution events. For 2004–2009, on days exceeding regulatory PM2.5 standards, wildfires contributed an average of 71.3 % of total PM2.5. Under future climate change, we estimate that more than 82 million individuals will experience a 57 % and 31 % increase in the frequency and intensity, respectively, of Smoke Waves. Northern California, Western Oregon, and the Great Plains are likely to suffer the highest exposure to widlfire smoke in the future. Results point to the potential health impacts of increasing wildfire activity on large numbers of people in a warming climate and the need to establish or modify US wildfire management and evacuation programs in high-risk regions. The study also adds to the growing literature arguing that extreme events in a changing climate could have significant consequences for human health.

Particulate air pollution from wildfires in the Western US under climate change

 

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