Forest Fires Can Heat Up the Whole Planet
Forest Fires Can Heat Up the Whole Planet
23 June 2016
published by http://news.nationalgeographic.com
USA/Global– A monster forest fire that began in early May is still burning in Canadas vast, isolated north woods. That may seem of little consequence to anyone other than the 88,000 residents of Fort McMurray forced to flee as the blaze swept into the northern Alberta city.
Yet large fires like these matter immensely to the rest of the planet.
Fires so intense that they consume millions of acres of trees and scorch the soil on the forest floor have become the kind of extreme disruptors that are remaking the boreal forest and transforming its role as one of the worlds great protectors against global warming.
The boreal, which takes its name from Boreas, the Greek god of the North Wind, encircles the top of the globe in North America and Eurasia. Half lies in Siberia, another third in Canada, and the rest in Alaska and Scandinavia.
It is Earths single largest land habitat, and it stores about 30 percent of the carbon found on the planets surfacesmore than any other terrestrial ecosystem. The forest also provides refuge for animals and birds as they relocate from southern habitats that have become too warm.
Climate change is playing out twice as fast in the boreal forest than it is on the rest of the planet. Permafrost is thawing, and vegetation is changing as climatic zones migrate north faster than trees can adapt.
Already, dramatic change can be glimpsed from space: The tundra is turning green, while the boreal forest is turning brown.
Some scientists predict the boreal forest may reach a disastrousand irreversibletipping point this century and shift from carbon storehouse into a major source of greenhouse gas emissions. Others contend that the tipping point has already been reached.
These forests matter to the rest of us on Earth because of how they help regulate climate by keeping carbon in the soil and in the trees and out of the atmosphere, says Peter Griffith, founding director of NASAs Carbon Cycle and Ecosystems Office.
So where fires are getting bigger and happening more often, that impacts the rest of us. Its putting more greenhouse gases into the atmosphere that would have stayed locked up for perhaps hundreds of years.
View From ABoVE
Griffith is director of the Arctic Boreal Vulnerability Experiment (ABoVE), a decade-long NASA study that is using satellite imagery to examine the impact of climate change on the Arctic tundra and boreal forests.
The region under NASAs microscope spans 2.5 million square miles (6.4 million square kilometers). The project launched its first field research earlier this spring on nearly two dozen separate studies, which range from the changing migratory patterns of caribou and birds to the role of fire as a contributor to climate change.
Scott Goetz, deputy director and scientist at Woods Hole Research Center in Falmouth, Massachusetts, first documented the shifting colors of the tundra and boreal forest in 2005. The change happens as more vegetation grows in the warming Arctic, and forests struggle to survive against fire and insect infestations in warmer and drier conditions.
For the NASA study, Goetz will continue to examine this change. The boreal is expanding in the north, he says, and declining in the southern region. Evergreen stands of conifers are being replaced by deciduous trees, larch, and birch or, in some places, by less productive grassland.
That was a surprise, to see declining productivity, Goetz says of the struggle in the southern end of the forest. Most think they would be greater and more productive, but warmer and drier is not conducive to productivity.
Another natural focus of the NASA study is thawing permafrost, which, when melted, would release a mother lode of stored carbon and methane into the atmosphere. That would create more warming, which would in turn create more thawing. It becomes a vicious cycle, known as positive feedback.
Once you start thawing the permafrost out, you cant stop it. Its completely irreversible, says Kevin Schaefer, a scientist at the University of Colorados National Snow and Ice Data Center. Once organic matter thaws out, even if the permafrost refroze, you cant put it back. Its a climatic tipping point.
Feeling the Burn
Now, as forest fires become more intense and frequent, they are creating a similar cycle. Large fires are not only killing all the trees, they are burning through the peat, the rich organic soil on the forest floor that serves as a large reservoir for carbon.
The warmer the Earth gets, the more fire we get, and the more fire we get, the more greenhouse gases we get, says Mike Flannigan, director of the Western Partnership for Wildland Fire Science at the University of Alberta in Edmonton.
Conditions are ripe for more frequent fires in multiple ways. For every degree of global warming, the forest needs a 15 percent increase in precipitation to compensate for the increased drying caused by warming, according to a recent study. Instead, forests are getting less rain, not more.
Scientists also have found that every degree of warming sets off a 12 percent increase in lightning activity, Flannigan says. In the woods, lightning means more forest fires.
Fires in Canadas huge, largely unpopulated forest often burn for months, and are extinguished by the first snow of autumn. Last summer, fires in the Northwest Territories burned more than 3.4 million acres (1.375 million hectares)an area the size of Maryland.
So far, the Fort McMurray fire has burned more than 1.45 million acres (589,600 hectares) and is considered held, meaning it has stopped gaining in size but is still burning out of control. That could change if the weather turns hot and windy.
Investigators believe the first blaze was caused by humans, although its unclear whether that was deliberate or accidental. At times, it burned with such intensity that it spawned its own thunderstorms, complete with lightning that ignited new fires within the fire.
I have seen lightning before, says Flannigan. But spawning new fires? That is a new one for me.
Up in Smoke
The Fort McMurray fire turned out to be exactly the large, intense fire that scientists in the NASA study want to examine, although it didnt quite work out that way. Brendan Rogers, an Earth scientist at the Woods Hole Research Center, is studying how deeply large fires burn the layers of peat on the forest floor.
There have been a lot of studies about how climate affects fires, he says. We want to study how fire feedback affects climate.
Earlier last spring, Rogers and a team of five scientists chose the forest zone around Fort McMurray for a smoke-measuring experiment, because the area rates high for fire severity. Smoke would help determine the age of the carbon being released, which could then be compared to soil samples.
If you look at the smoke from these fires, you can look at the average of the carbon in that smoke, and since most comes from the soil, you can get an average of the burn depth, he says.
Fire season begins earlier these days, but the team did not expect a blaze to break out in early May.
The teams smoke sensors arrived in Fort McMurray the same day the city evacuated, and Rogers has not learned their fate. Some of the volunteers recruited to monitor the sensors lost their homes and are now preoccupied with rebuilding their lives.
It would have been perfect, so it is ironic and also a bit scary, he says. You need to be close, but not too close. We didnt expect one to happen right there in town.New Research on the California spotted owl has found that severely burned forests that have not been post-fire salvage logged are used by the threatened raptor when foraging for their small mammal prey. Stand-replacing fires, also called crown fires or high-intensity fires, do not harm spotted owl foraging habitat.
“We looked at spotted owl foraging behavior at multiple spatial extents and we found that whatever scale we used, the owls foraged in severely burned unlogged forests in proportion to their availability. In other words, they foraged in burned forest with the same likelihood as in unburned forest.” said Monica Bond, lead author of the study.
Wildfires over the past two decades have affected southern California spotted owl habitat to a greater extent than elsewhere in the range of the subspecies. From 2003 to 2007, spotted owl territories in the region were especially affected by wildfire, with more than 40% of 168 breeding sites in the San Bernardino and San Jacinto mountains experiencing at least one fire.
“These frequent and hot fires make southern California forests a good indicator of what may happen in more northerly forests of California in a warming climate,” said Bond. “Luckily, forests burned by high-severity fire can still be considered suitable foraging habitat for Californiaspotted owls.”
Bond continued, “We also found these spotted owls strongly selected foraging sites close to streambeds, so we recommend implementing protective measures and management activities that conserve water and streamside forests.”
The study was published this week by scientists from the Wild Nature Institute and the Center for Biological Diversity in theJournal of Wildlife Management, a peer-reviewed scientific journal for professional wildlife biologists.
This is the latest in a series of scientific papers that have documented how resilient spotted owls are to high-severity fires, including so-called megafires. Spotted owl pairs have been shown to survive and continue to reproduce in breeding sites that experienced severe fire, even megafire, with success that is the same or higher than unburned sites. Spotted owls have also shown a significant preference for foraging in severely burned forest patches in the Sierra Nevada. However, post-fire salvage logging, also called forest restoration by the US Forest Service, causes site abandonment and reduces survival. Logging in an attempt to reduce the risk of fire, often called thinning or fuels reduction, also has adverse effects on spotted owls. The only studies that claimed forest fires hurt spotted owls have had logging in large portions of the study area.
“It’s high time we stopped managing our forests with the futile and unnecessary goal of stopping severe fires. All the science from the field says fuel buildup and insects don’t make forest fires worse. It is extreme weather like the Santa Anna winds in southern California that push fires to become very large, but we will never be able to stop these weather-driven blazes, so we should not risk our firefighter’s lives out in the wildlands. Instead, we should repurpose the billions of dollars we waste each year fighting wildfires on making structures fire-safe in our forest communities,” said Dr. Derek Lee, a co-author of the study. “Many native plants and animals thrive in the severely burned unlogged forest, and that response tells us that this kind offire is natural and necessary to the ecology of theforest.”
Read more at: http://phys.org/news/2016-06-evidence-forest-threaten-owls.html#jCpNew Research on the California spotted owl has found that severely burned forests that have not been post-fire salvage logged are used by the threatened raptor when foraging for their small mammal prey. Stand-replacing fires, also called crown fires or high-intensity fires, do not harm spotted owl foraging habitat.
“We looked at spotted owl foraging behavior at multiple spatial extents and we found that whatever scale we used, the owls foraged in severely burned unlogged forests in proportion to their availability. In other words, they foraged in burned forest with the same likelihood as in unburned forest.” said Monica Bond, lead author of the study.
Wildfires over the past two decades have affected southern California spotted owl habitat to a greater extent than elsewhere in the range of the subspecies. From 2003 to 2007, spotted owl territories in the region were especially affected by wildfire, with more than 40% of 168 breeding sites in the San Bernardino and San Jacinto mountains experiencing at least one fire.
“These frequent and hot fires make southern California forests a good indicator of what may happen in more northerly forests of California in a warming climate,” said Bond. “Luckily, forests burned by high-severity fire can still be considered suitable foraging habitat for Californiaspotted owls.”
Bond continued, “We also found these spotted owls strongly selected foraging sites close to streambeds, so we recommend implementing protective measures and management activities that conserve water and streamside forests.”
The study was published this week by scientists from the Wild Nature Institute and the Center for Biological Diversity in theJournal of Wildlife Management, a peer-reviewed scientific journal for professional wildlife biologists.
This is the latest in a series of scientific papers that have documented how resilient spotted owls are to high-severity fires, including so-called megafires. Spotted owl pairs have been shown to survive and continue to reproduce in breeding sites that experienced severe fire, even megafire, with success that is the same or higher than unburned sites. Spotted owls have also shown a significant preference for foraging in severely burned forest patches in the Sierra Nevada. However, post-fire salvage logging, also called forest restoration by the US Forest Service, causes site abandonment and reduces survival. Logging in an attempt to reduce the risk of fire, often called thinning or fuels reduction, also has adverse effects on spotted owls. The only studies that claimed forest fires hurt spotted owls have had logging in large portions of the study area.
“It’s high time we stopped managing our forests with the futile and unnecessary goal of stopping severe fires. All the science from the field says fuel buildup and insects don’t make forest fires worse. It is extreme weather like the Santa Anna winds in southern California that push fires to become very large, but we will never be able to stop these weather-driven blazes, so we should not risk our firefighter’s lives out in the wildlands. Instead, we should repurpose the billions of dollars we waste each year fighting wildfires on making structures fire-safe in our forest communities,” said Dr. Derek Lee, a co-author of the study. “Many native plants and animals thrive in the severely burned unlogged forest, and that response tells us that this kind offire is natural and necessary to the ecology of theforest.”
Read more at: http://phys.org/news/2016-06-evidence-forest-threaten-owls.html#jCp
