Posts tagged wildfire
Evidence of global climate in Southern Hemisphere
Aug 22nd
SOUTHERN SOUTH AMERICAN WILDFIRES
EXPECTED TO INCREASE, SAYS CU STUDY
A new University of Colorado Boulder study indicates a major climate oscillation in the Southern Hemisphere that is expected to intensify in the coming decades will likely cause increased wildfire activity in the southern half of South America.
The research team used tree rings dating to 1506 to track past wildfire activity in the forests of Patagonia tied to the Southern Annular Mode, or SAM, a climate oscillation that creates low atmospheric pressure in the Antarctic that is tied to warmer and drier conditions in southern South America. The tree rings showed that when SAM was in its positive phase, there were widespread fires in both dry woodlands and rainforests in Patagonia, a region that straddles Argentina and Chile, said CU-Boulder Research Associate Andres Holz, lead study author.
“Our study shows for about the past 250 years, the Southern Annular Mode has been the main driver in creating droughts and fires in two very different ecosystems in southern South America,” said Holz. “Climate models suggest an increase in SAM beginning in the 1960s due to greenhouse gas increases and Antarctic ozone depletion probably will cause this region to be drought-prone and fire-prone for at least the next 100 years.”
A paper on the subject by Holz and CU-Boulder geography Professor Thomas Veblen was published in Geophysical Research Letters.
Holz and Veblen compared past wildfire records for two ecologically distinct regions in Patagonia — the relatively dry region of southern Patagonia in Argentina and the temperate rainforest of Patagonia in northern Chile. While the tree ring historical record showed increased fires in both regions correlated with a positive SAM, the trend has been less pronounced in northern Patagonia in the past 50 years, likely because of fire-suppression efforts there, Holz said.
But the decades of fire suppression have caused the northern Patagonian woodlands to become denser and more prone towildfire during hot and dry years, Holz said.
“Even in areas of northern Patagonia where fire suppression previously had been effective, record surface areas of woodlands and forests have burned in recent years of extreme drought,” said Veblen. “And since this is in an area of rapid residential growth into wildland-urban interface areas, this climate-driven trend towards increasing fire risk is becoming a major problem for land managers and homeowners.”
The two CU-Boulder researchers studied reconstructions of tree rings going back more than 500 years from 432 trees at 42 sample sites in northern Argentina and southern Chile — the largest available data set of annual, readable tree ring records in the Southern Hemisphere. The tree rings, which indicate climate cycles and reveal the scars of old fires, showed that wildfires generally increased in both regions when SAM was in its strong, positive phase.
Although the Antarctic ozone hole stopped growing in about 2000 as a result of a ban on ozone-depleting gases and now appears to be slowly repairing itself, a 2011 paper by researchers at the National Center for Atmospheric Research in Boulder indicates ozone recovery and greenhouse gas influences essentially will cancel each other out, preventing SAM from returning to its pre-1960s levels.
“Before the Industrial Revolution, SAM intensified naturally at times to create drought situations in Patagonia,” Holz said. “But in the last 80 years or so, the natural variation has been overwhelmed by a bias toward a positive SAM phase because of ozone-depleting chemicals and greenhouse gases we have put in the atmosphere.”
The research effort was supported by the National Geographic Society, the National Science Foundation, the CU Beverly Sears Small Grants Program and the Council on Research and CreativeResearch of the CU Graduate School.
“As warming and drying trends continue, it is likely that wildfire activity will increase even in woodland areas where fire suppression has previously been effective,” Holz and Veblen wrote in Geophysical Research Letters.
Boulder Fire Department reminds residents that fireworks are illegal
Jun 28th
City officials are teaming up with the University of Colorado to remind Boulder residents that all fireworks are illegal within city limits. Illegal fireworks include: sparklers, snaps, snakes, bottle rockets, Roman candles and smoke bombs. The fireworks ban has been in place since 1985.
Boulder police will have extra patrols out over the July 4th holiday. Anyone caught using fireworks could face penalties that include arson charges, heavy fines, court costs, loss of property, possible jail time and personal injury damages. CU students who violate the ban could be sanctioned by the University of Colorado’s Office of Judicial Affairs.
Fireworks were outlawed because they pose dangers to humans, pets, property, and the environment. Boulder Fire Chief Larry Donner encourages residents to celebrate the holiday safely. “Fireworks can be very dangerous and unpredictable. They often cause serious injuries. Nationally, children suffer the lion’s share of fireworks related injuries. In addition, there is the ever-present danger of starting a disastrous wildfire on our open space,” says Chief Donner.
The city will host a professional fireworks show on July 4th at Folsom Field. Admission to Ralphie’s Independence Day Blast is free. Gates open at 8:00 p.m., and the show is scheduled to begin around 8:30 p.m.
Anyone who has illegal fireworks and who wants to dispose of them will be granted amnesty if the fireworks are brought to any Boulder fire station. To report fireworks violations, residents are encouraged to call the non-emergency dispatch line at 303-441-3333. To report a fire, always call 9-1-1 and give the location.
NEWLY DETECTED CHEMICAL IN SMOKE MAY HAVE SERIOUS HEALTH IMPLICATIONS, SAYS NEW STUDY
May 16th
Cigarette smoking, burning forests and even cooking fires all release a chemical compound not previously known to exist in significant quantities in smoke and which may have potential human health impacts, says a new study involving the National Oceanic and Atmospheric Administration and the University of Colorado Boulder.
The study was conducted by scientists at the Cooperative Institute for Research in Environmental Sciences, or CIRES — a joint institute of CU-Boulder and NOAA — along with researchers from NOAA’s Earth System Research Laboratory.
The molecule, isocyanic acid, is similar to methyl isocyanate, the gas that leaked from a pesticide plant in Bhopal, India, in 1984 killing more than 3,000 people within weeks. “The molecule has hardly been measured before — certainly not in the atmosphere,” said CIRES Fellow Joost de Gouw, coauthor of the new paper published May 16 in the Proceedings of the National Academy of Sciences. “So it was a complete surprise to find it in such large quantities.”
De Gouw and his colleagues were first able to detect isocyanic acid when they developed and tested a new instrument, a mass spectrometer designed to measure gaseous acids in the air. In the laboratory, they found biomass burning — the burning of trees or plant material — produced levels of the molecule approaching 600 parts per billion by volume, or ppbv.
“There is this molecule in smoke that we can now measure and it is there in significant quantities,” de Gouw said. “There are good reasons to believe that it can have significant health impacts.”
In the human body, isocyanic acid dissolves to form charged cyanate molecules, and the researchers found that the acid was very soluble at the pH level of human blood. This means it could potentially enter the bloodstream, said de Gouw. When the exposure levels of isocyanic acid are greater than 1 ppbv, the charged cyanate molecules are expected to be present at levels that can contribute to a variety of human health problems like cardiovascular disease, cataracts and rheumatoid arthritis.
Once the researchers discovered that fires produced the gas at the U.S. Forest Service Fire Sciences Laboratory in Missoula, Mont., they then took their instruments out of the lab to see whether smoke in a “real” environment also gave off this chemical. “We had a new tool to look around us and we just explored,” de Gouw said. “It was basically our chemical curiosity at work.”
Previous studies have shown that burning coal produces isocyanic acid, and the CIRES researchers have discovered the chemical also is present in tobacco smoke and smoke from the combustion of other plant materials. In rural areas of developing countries where biofuels are used for cooking and heating, exposure levels of the acid could be harmful, according to the research team.
But does a real fire, as opposed to a lab fire, give off the acid? The team didn’t have to wait long to find out. Starting on Labor Day 2010, the Fourmile Canyon wildfire raged in the foothills above Boulder, Colo., burning more than 6,000 acres and destroying 169 homes. Scientists at the NOAA Earth System Research Laboratory in Boulder wasted no time in learning what they could about the event.
The team’s spectrometer detected levels of the acid up to 200 pptv in the air at the site, which was downwind from the fire. “Boulder has a world-class atmospheric chemistry building and only once in its lifetime is it going to have a full-on hit from a wildfire,” de Gouw said. “So just about everyone in that building turned on their instruments.”
One possibility was that the acid would only be prevalent in the immediate vicinity of a fire, de Gouw said. “But that didn’t happen,” he said. “We were miles away and it was still there.”
The researchers didn’t constrain their measurements to wildfires. They also used their equipment to find the levels of isocyanic acid in the urban environment of Los Angeles. “In LA we find even when there are no fires there is a little of this acid,” de Gouw said. “So smoke may not be the only source of it in the atmosphere.”
Since more isocyanic acid was measured in the atmosphere during the day, sunlight could be sparking the chemical reactions that make it, de Gouw said. Another potential source in urban air could be emissions from diesel engines outfitted with the latest generation of pollution control equipment that is now being introduced in California and Europe, he said.
“We know so little about isocyanic acid’s behavior in the atmosphere that we want to do a number of follow-up studies, “ de Gouw said. “We have some data in our paper but that is just the beginning and we need to do a lot more work.”
Other authors on the PNAS paper included Jim Roberts, Patrick Veres, Anthony Cochran, Carsten Warneke, Ian Burling, Robert Yokelson, Brian Lerner, Jessica Gilman, William Kuster and Ray Fall.