This has been a devastating wildfire season. Nationwide, more acres have burned this summer than at this time in any other year on record. In May and June, New Mexico weathered the largest fire in its history. Hundreds of homes and tens of thousands of acres have burned in Colorado. As the summer wears on, fire season has moved west — as it tends to do – and now the Ponderosa Fire is raging near Redding.

Has it always been like this? A new NPR series by Christopher Joyce explores what a century of fire suppression has meant for forests in the Southwest.

By keeping forests from burning, the Forest Service has actually made them more susceptible to very large fires. Instead of more frequent brush fires, which help keep fuel to a minimum, now, when a forest begins burning, fires consume the ample fuel and are able to climb to the tops of trees, sweeping through thousands of acres. (Graphics in the second story in the series illustrate the difference.)

In addition to the video above and five radio pieces (the first two aired today), there’s a fire map that shows current large fires and fire conditions, and a series of photos showing the evolution of a forest where fire is suppressed.

Fire suppression is only a piece — though it’s a big one — of the wildfire puzzle. Beetles, disease, drought and logging are all in the mix, too. And then there’s climate change, which scientists project will bring more fires to the West — not just in the long-term, but within the next few decades.

Mike Kapusta / CTV

Flames and smoke from the 2011 Slave Lake fire in Alberta. Evacuations are likely to increase, partly from smoke.

Research continues to suggest that this century will be a brutal one for wildfires.

The reasons seem pretty straightforward: “The warmer it gets, the more fires we have,” fire scientist Mike Flannigan told reporters at a major science conference in Vancouver this weekend. Flannigan is a professor at the University of Alberta and also works for Canada’s natural resources agency.

Flannigan says fires already claim an area roughly the size size of India each year (If you’re wondering how that’s even possible, he says the acreage includes grasslands, which can actually burn more than once a year). And he says the toll will rise, driven by three main factors:

• The warmer it is, the longer the fire season
• The warmer it is, the more lightning strikes occur
• The warmer it is, the drier the “fuels” waiting to ignite

Flannigan’s colleague at Ontario’s Wilfrid Laurier University, Douglas Woolford, confirmed that in western Canada, the fire season has been growing steadily longer, something fire officials in California say have observed, also. And given the bone-dry winter we’re having, the 2012 fire season could be that much longer and more severe in California.

To monitor fire activity, Flannigan’s team uses an index called “cumulative daily severity,” which he says is rising globally. He says that in the northern hemisphere, that measure could double or even triple by 2070. “It’s going to be incredibly difficult in the future, to manage forest fires,” Flannigan told reporters at a news briefing. “The intensity of fires is going to be increasing and that changes the strategy of putting fires out.”

Flannigan explained that more intense fires can’t simply be confronted head-on. They have to be attacked “at the flanks,” which requires more equipment and manpower, and airborne assaults aren’t as effective. “I would argue that the standard way of doing fire management will no longer be effective in the future.”

As the burned acreage rises, so does the economic toll. Flannigan cited a single fire in Alberta that racked up more than $700 million in costs last year. He says there’s an urgent need for more public education on fire prevention, as most wildfires are caused by human activity.

Also revealed at the AAAS annual meeting was possibly the first-ever global estimate of fire-related mortality. Based on data collected over a ten-year period, Respiratory health researcher Fay Johnston puts the annual death toll related to “landscape fires” at about 340,000. Her work was published this weekend in the journal Environmental Health Perspectives. Johnson says nearly half the victims are typically in Asia and Africa, with 100,000 in southeast Asia alone. She says fires from deforestation are a major contributor — and unlike many other fires, are avoidable.

Photo: Tim Walton

Last year around this time, I asked some state fire officials what to expect in terms of the fire season and got a definite “It depends.” On the one hand, scant precipitation over the winter had left behind a dry landscape. On the other hand, spring rains had given a boost to rebounding vegetation, providing more fuel for later in the season. I was reminded of the old joke about politicians searching for a “one-handed economist” and found myself wishing for a one-handed forester.

Whether a good spring dousing is more likely to inhibit wildfires or feed them is a common source of confusion, which San Jose Mercury News writer Paul Rogers has sought to extinguish. By dipping into four decades of fire data, Rogers and his researchers at the Merc conclude that dry winters generally make for more intense fire seasons in California.

Rogers writes that “the worst fire seasons come after dry winters, not wetter ones like the one we’ve just had.” That would seem to bear out a conversation I had in 2007 with Crawford Tuttle, Chief Deputy Director at CalFire, fire protection arm of the state’s department of forestry. Walking through the burn zone of a Sierra wildfire that broke out in May of that year, Tuttle said that early-season fire was “a great demonstration of how (the) fire regime–fire severity is expanding in California.” Tuttle told me that when moisture levels in the air, vegetation and soil are lower, earlier in the season, it’s likely that the fire season will be intense.

The preceding winter had been dry by historical standards, with just over half the normal amount of precipitation and indeed, wildfires went on to char almost a million acres in the state that year.

Photo: Tim Walton

California’s Yosemite National Park has been scarred by several big fires in recent years—the latest contained less than two months ago. But new research affirms that this crown jewel among national parks is likely to have even more fire in its future.

In late August, when fire crews attacked the Big Meadow Fire in Yosemite, it was hard to blame nature for the 74-hundred acres lost. That was a “prescribed burn” that got out of hand (or “escaped,” as the official report puts it). But nine out of ten wildland fires in the Sierra start with a lightning strike. Newly published work suggests that as California’s climate changes, the combination of warmer temperatures, less snow and more lightning strikes could mean 20% more fires by mid-century.

USGS research forester emeritus Jan van Wagtendonk co-authored the study with James Lutz at the University of Washington. He says they studied 20 years of Yosemite fire data to identify a trend. The mechanism starts with the oft-cited warming scenario, causing more rain and less snow at upper elevations.

“What happens in the mountains is that, as snow recedes in the spring the moisture in the fuels follows,” says van Wagtendonk. “The fuel starts drying out earlier and we extend the fire season by having more days available for fires to burn.”

But there’s another wildcard in the deck: lightning. Separate studies suggest that higher concentrations of atmospheric carbon dioxide will set the stage for more lightning strikes.

The study assumes a 17% reduction in snowpack by 2050—under the relatively modest B1 warming scenario, drawn from IPCC models. The results are in line with other climate studies that imply not just more fires, but more intense fires as the climate warms. It’s a trend, says van Wagtendonk, that has already started:

“We were able to trace, through satellite imagery, the change that we’ve seen in the severity of those fires just over the past 20 years, so it’s been obvious to us from those data that whatever temperature trends are occurring today are already having an effect on increased severity.”

“We see more of the same,” said the forester, “and a continued increase in both size, number and severity of fires.”

Yosemite fires from 1984-2005. The black triangles indicate fires sparked by lightning. Image: International Journal of Wildland Fire.

Scott Stephens, an associate professor of fire science at UC Berkeley, says lightning is changing the landscape in more ways than one.

Stephens recently told KQED’s Central Valley Bureau Chief, Sasha Khokha: “In Yosemite and Sequoia-Kings Canyon, they manage quite a few lighting fires in the wilderness area, away from people, and they allow these things to burn for months and months and months to try to allow that lighting fire to begin to shape the landscape again like it did 100 or 200 yrs ago. Those types of events probably increased the resiliency of the forest to deal with climate change and other impacts.”

The article is published in the current issue (10/27) of the International Journal of Wildland Fire.

KQED’s Central Valley Bureau Chief, Sasha Khokha, contributed to this post, as well as to the radio report.

Smoke fans out from L.A. fires this week. Clickable image: NASA

My colleague Dan Brekke, an ardent watcher of elemental stuff like water and fire, featured a map of the spreading haze in his personal blog.

By Wednesday evening Brekke relayed that flames had consumed an area about the size of Chicago (and no, he couldn’t resist the low-hanging Mrs. O’Leary reference). With less than 30% containment, smoke had spread over about three-quarters of the state. Beyond California, NOAA had tracked the plumes “northward and eastward…across southern Nevada, Utah, Colorado, and Kansas.”

Front page of Wednesday's Denver Post

From The Denver Post:

“Joe Ramey, a meteorologist with the National Weather Service in Grand Junction, said that a high-pressure system is continuing to pump smoke from several California fires and 17 fires currently burning in Utah into the state. He said a fire near Nucla in south-central Colorado also may be contributing to the haze…Most of the smoke, however, is being generated by the 190-square-mile fire burning near Los Angeles, he said.”

While the current pall is not entirely California-born, it does make the point that large wildfires cast a surprisingly long shadow.

Atmospheric scientists classify smoke as an “aerosol” (any airborne particulate matter), which has a complicated set of feedbacks on the climate. For instance, aerosols encourage cloud formation and clouds have both positive and negative feedback effects on global warming. But it’s clear that smoke plumes generate greenhouse gases and also carry toxic air pollutants such as carbon monoxide.

Briefing journalists last month at the National Center for Atmospheric Research (NCAR)–in Boulder, no less–atmospheric chemist Gabriele Pfister said that wildfires have multiple effects on the atmosphere. They “disturb the carbon cycle,” interfering with energy exchanges and generating greenhouse gases. Itinerant smoke can generate ozone pollution far from the initial fires. This presents a challenge for local regulation of “ground-level” ozone, since it’s often likely an import from distant fires.

Firefighters at the Martin Fire in the Santa Cruz mountains near Bonny Doon, CA in June, 2008. Photos by Tim Walton.

Tonight, on KQED Public Television, Quest: California at the Tipping Point explores some of the ways in which climate change will likely affect our state, including an increased risk of wildfire.

Last year, California’s fire season got off to an early and catastrophic start–and this year, generous spring rains could not cover the shortfall from two previous years of scarce precipitation. The late rains might forestall fire conditions for a while but more fires are inevitable.

Last June, more than 1,000 wildfires started in one weekend.  Throughout the course of the season, thousands more fires burned and hundreds of homes were damaged.  But if you’re among those who live in the “urban-wildland interface,” there are steps you can take to lower your home’s vulnerability to wildfire.

In the video clip below, a CalFire official tells Vicki Liviakis, who lost her home in the 1991 Oakland Hills firestorm, how vegetation around the house can feed a wildfire, and explains how Californians can create landscapes that reduce fire risk.  (You can watch the full 28-minute video, co-hosted by Liviakis and Climate Watch Sr. Editor Craig Miller, on YouTube.)

CalFire maintains this map, which tracks current fire incidents in California.  You can check this throughout the fire season for an overview of the state’s burns.

On tonight’s Quest program, Climate Watch Sr. Editor Craig Miller talks with CalFire’s Chief Deputy Director Crawford Tuttle about the increasing fire risk California faces due to rising temperatures and changing precipitation patterns.

Below are the latest maps from CalFire depicting California’s regions and communities most at risk.

CalFire's map of statewide fire threat

CalFire's map of California communities at risk

The study, which focused on California’s wildfires September and October of last year, found that the fires repeatedly boosted ozone to unhealthy levels – levels that exceed U.S. health standards — across much of California and Nevada.

While ozone in the upper atmosphere where it blocks ultraviolet radiation from the sun is a good thing for life on Earth, it’s a bad thing down here at the surface where ozone can cause breathing difficulty and aggravate respiratory problems like asthma and emphysema in humans and it can harm agricultural crops.  The EPA’s brochure on “good” and “bad” ozone identifies ozone as the main component of urban smog.

Many climate scientists are predicting hotter and drier weather for the American West, likely increasing the frequency and duration of wildfires.  “Bad” ozone might be something we’ll be getting used to.

Here’s a July article from the San Francisco Chronicle with an overview of California’s fires for the first half of 2008.