New York Times: wildfire seasons are longer

Yesterday the New York Times published an article titled, “Wildfires, Once Confined to a Season, Burn Earlier and Longer”.

Here is an excerpt:

…Fires, once largely confined to a single season, have become a continual threat in some places, burning earlier and later in the year, in the United States and abroad. They have ignited in the West during the winter and well into the fall, have arrived earlier than ever in Canada and have burned without interruption in Australia for almost 12 months.

A leading culprit is climate change. Drier winters mean less moisture on the land, and warmer springs are pulling the moisture into the air more quickly, turning shrub, brush and grass into kindling. Decades of aggressive policies that called for fires to be put out as quickly as they started have also aggravated the problem. Today’s forests are not just parched; they are overgrown.

In some areas, “we now have year-round fire seasons, and you can say it couldn’t get worse than that,” said Matt Jolly, a research ecologist for theUnited States Forest Service. “We expect from the changes that it can get worse.”…

British Columbia using assisted migration to help forests keep up with climate change

range of Western Larch
The range of Western Larch, Larix occidentalis, sometimes called Western tamarack. From Natural Resources Canada.

Warming caused by climate change is moving the suitable habitat for some plant species farther north in the northern hemisphere. A plant that was once comfortable in one location may be finding it is becoming too warm for it to thrive.

British Columbia, unlike the other Canadian provinces, has changed their rules about replanting forests, hoping to ensure that adapted tree varieties can keep up with the moving habitats. Critics say assisted migration, as it is called, has sometimes produced disastrous results in the past when species were placed in new environments.

Western larch
Western Larch, a deciduous conifer. Photo from Montana Outdoors.

Vice’s Motherboard web site has a fascinating article by Stephen Buranyi on the subject. Here is an excerpt:


“The Western Larch can live for hundreds of years and grow to over 200 feet, but the oldest Larch trees in northern British Columbia’s Bulkley Valley are only about four feet tall. In fact, the nearest full grown Western Larch is nearly 900 kilometers south by the US border, which has been the Larch’s natural range for thousands of years. These are the first trees of their kind to be planted so far north.

If the disastrous history of invasive species has taught us anything, it’s that it’s often difficult to predict the consequences of such a change. Ecologists and conservationists generally caution against moving a species outside of the areas they naturally live—a process known as assisted migration—and governments generally agree with this take. Across North America there are strict prohibitions against the large scale movement of living populations.

But for the past seven years the province of BC has allowed millions of trees to be planted toward the northernmost reaches of their natural range and beyond. The government is working with scientists who predict that our climate is changing so quickly that, 50 years from now, when the trees are fully grown, the conditions in the trees’ new homes will actually be more like their old ones.

“It restores the tree to the environment for which they are best suited,” said Greg O’Neill, an adaptation and climate change scientist with the BC government, who helped design and implement the province’s assisted migration program. But while BC scientists think that they’ve acted just in time to prepare their forests for the future, no other province appears ready to adopt assisted migration as a strategy anytime soon.

Many trees are what ecologists call foundational species—organisms whose removal would cause enormous disruption in the ecosystem. Trees are a sort of infrastructure for forests; they bind the soil, retain water, and provide food and shelter. Just like the infrastructure unpinning cities, it takes years to establish a tree population, and they are virtually impossible to move.

And yet, because BC’s northern regions are warming at nearly twice the average rate, much of the province’s 55 million hectares of forest may find that their homes have moved north without them. A 2006 paper from the University of British Columbia applied a climate based model to forest ecosystems and showed that some species ranges could shift by up to 100 kilometers each decade.

Rules in BC require that, as trees are cut down, planters use seeds from the same area to re-plant, preserving the genetic character of the forest. O’Neill and his colleagues produced a forestry report in 2008 that drew on the projected range expansions due to climate change, and their own extensive experiments testing various tree species in different climates. They suggested that the province instead expand the distance seeds could be moved uphill, to track with global warming. Later that year the Chief Forester’s Standards for Seed Use were changed for the majority of BC’s commercial tree species to reflect the suggestions in the report.

According to O’Neill, “these were the first policy changes that addressed climate change in forestry.”

Then, in 2010 the standards were changed again, to allow Western Larch to be planted hundreds of kilometres away from its current range. “That had been a long-standing paradigm that no-one dared transgress,” said O’Neill. One ecologist had even called BC’s migration plans “a little scary.”

It’s difficult to overstate how deeply rooted the aversion to moving nature is for many biologists. In 2009 assisted migration was called “planned invasion” in a report that listed our really awful, truly just stupendously bad track record with species that unexpectedly turn invasive…”

Was the 2014 wildfire season in California affected by climate change?

Happy Camp Complex, 2014
Happy Camp Complex in northern California in 2014. Photo by Kari Greer.

2014 was a busy year in California for wildland firefighters. Battles were fought over 555,044 acres of blackened ground in the state, which was the eighth largest number of acres burned in the last 28 years. So far in 2015, fires have covered 838,465 acres in California, which puts it fifth highest in 28 years.  (Stats from Cal FIRE and the NIFC National Situation Report.)

We have always been dubious of linkages between one weather event and long term climate change. When a senator brings a snowball onto the Senate floor or a governor talks about this summer’s fires to prove their cases that climate change does or does not exist, both may be over stating their “evidence”.

However, I’m not a meteorologist or climate scientist. But some of them who are, took a stab at investigating the possible attribution of extreme weather-related events in 2014 to global climate change. In their report, Explaining Extreme Events of 2014 from a Climate Perspective33 different research groups explored the causes of 29 different events that occurred that year.

The first event in the report is titled, Extreme Fire Season in California: A Glimpse Into the Future. It is debatable if the 2014 fire season in California was “extreme”, since like we wrote earlier, it had the eighth largest number of acres burned in the last 28 years according to data from the land management agencies. The authors, Jin-Ho Yoon, S.-Y. Simon Wang, Robert R. Gillies, Lawrence Hipps, Ben Kravitz, and Philip J. Rasch, reported “thousands more fires than the five-year average” between January 1 and September 20.

We don’t put very much stock in numbers of fires, since a small spot that can be stomped out by a couple of firefighters counts just as much as a 300,000-acre conflagration. Total burned acres is much more meaningful. The area burned data that the scientists studied was derived from satellite observations, which can underestimate wildfire extent due to its limit in the minimum detectable burned area, timing of the satellite overflights, light fuels cooling before being detected, and obscuration by cloud cover.

The report also examined the Keetch-Byram Drought index, and determined that “in terms of the KBDI and the extreme fire risk, 2014 ranks first in the entire state”, but it was not clear what time period they were referring to (it may have been since 1979).

The authors fall short of attributing the “extreme” 2014 fire season in California to global climate change:

Our result, based on the CESM1 outputs, indicates that man-made global warming is likely one of the causes that will exacerbate the areal extent and frequency of extreme fire risk, though the influence of internal climate variability on the 2014 and the future fire season is difficult to ascertain.

2014 climate events
Location and types of events analyzed in the publication. The image is from the study.

LA Times article about climate change and wildfires draws criticism

An article in the Los Angeles Times about climate change and wildfires that we first wrote about on October 20 is drawing criticism. Reporter Paige St. John cherry-picked quotes from several fire or climate experts that were misleading in order to advance the notion that climate change is not affecting fires, nor will it affect them in the near future in a significant way. We pointed out that Ms. St. John’s article would have been more appropriate on the Times’ Opinion page rather than the News section.

Mother Jones took issue with some of the misleading statements in the Times article:

…The Times piece is very strange. It starts by quoting Roger Pielke, the go-to guy for any reporter who wants a skeptical take on climate change. But even Pielke doesn’t actually say climate is unrelated to increased wildfire activity. Next up is a quote from a guy concerned with fire risk who naturally thinks we should focus on making homes safer, but doesn’t comment on climate science one way or the other. Next comes a scientist who has “concluded that global warming has indeed shown itself in California.” Then a Forest Service ecologist who says “California has had an average of 18 additional days per year that are conducive to fire.”

Next comes a UCI team who reported that climate change will increase fires in Southern California by 64 percent over the next few decades. But instead of simply reporting that, the piece acknowledges only that fires will “increase,” and then casts doubt on the result by noting that the UCI model has error bars which indicate that the increase could be between 12 percent and 140 percent. Then a prediction from a “UC Merced expert” who speculated about “a possible decrease of such fires as dry conditions slow vegetation growth.” Finally a National Park Service climate change scientist is quoted as saying “We are living right now with a legacy of unnatural fire suppression of approximately a century.” That’s true enough. Elsewhere, however, that same scientist has also said, “climate has dominated all factors in controlling the extent of wildfire in Western U.S. forests in the 20th century.”

In other words, virtually everyone quoted in this article either (a) says nothing about climate change or (b) says climate change is an important factor in the rise of wildfires in California and the West. And yet, somehow all of this is written in a way that makes it sound as if climate change has nothing to do with wildfires, and it’s topped by a headline that says in no uncertain terms, “Gov. Brown’s link between climate change and wildfires is unsupported, fire experts say.”

Very peculiar.

And from

The Los Angeles Times reported that “scientists who study climate change and fire behavior” dispute California Gov. Jerry Brown’s comments describing a link between the state’s recent wildfires and climate change. However, numerous scientists and major scientific reports have detailed the connection that global warming has to both recent and future wildfires in the Southwest, including the 2014 National Climate Assessment, which stated that climate change has already “increased wildfires” in the Southwest region and could lead to “up to 74% more fires in California.” Moreover, the experts cited by the Times do not contradict Brown’s statements, and the only one who directly criticized Brown was Roger Pielke; it is unclear from the article whether it quoted Roger Pielke Sr. or Roger Pielke Jr., but both father and son have made dubious climate-related claims in the past that were debunked by climate scientists…

(UPDATE October 24, 2015)

Today the LA Times published an article titled, Readers React: Don’t dismiss the link between wildfires and climate change, scientists say, which includes portions of three letters from experts that disagree with the implied premise in the original article.

LA Times refutes California Governor’s assertion that larger fires are caused by climate change

When California Governor Jerry Brown visited the site of the Rocky Fire that burned over 69,000 acres and destroyed 43 homes, he linked this summer’s large fires in his state to climate change, saying, according to the LA Times,

The fires are changing…. The way this fire performed, it’s not the way it usually has been. Going in lots of directions, moving fast, even without hot winds… It’s a new normal. California is burning.

In an article that should have been published on the Opinion page rather than in the News section, LA Times Reporter Paige St. John wrote:

Brown had political reasons for his declaration.

Ms. St. John supported her argument by listing positions the Governor has taken on climate change, implying, therefore, that the Governor’s stance on climate change is “political”. Governor Brown previously encouraged presidential candidates to state their position on climate change, supported legislation to reduce gasoline use in California, and has spoken about climate change negotiations that culminate in Paris in December.

The article also includes information from fire experts who mention other factors that affect fire behavior, such as landscapes altered by a century of fire suppression, timber cutting, and development.

Ms. St. John wrote:

But climate scientists’ computer models show only that global warming will bring consistently hotter weather in future decades. Their predictions that warming will bring more forest fires — mostly in the Rockies and at other higher elevations, while fires may actually decrease in Southern California — also are for future decades.

The NOAA chart below, from an article we published in September, 2014, displays the average temperature in California for January through August of each year, from 1900 to 2014. It shows a clear trend in California of rising temperatures. Not “in future decades”, but for the last 115 years.

California, average temperature, January through August
California, average temperature, January through August

The graphic below from the 2009 Quadrennial Fire Review written for the U.S. Forest Service by the Brookings Institution, documents the “Lengthened fire season due to climate change”.

wildfire season length climate change
The orange bars show estimates of new fire season length by region. Graphic from the Quadrennial Fire Review published in 2008, titled “The Future of Wildland Fire Management” by the Brookings Institution.

Researchers are predicting that beginning 26 years from now the number of weeks in which very large fires could occur will increase by 400 to 600 percent in portions of the northern great plains and the Northwest. Many other areas in the West will see a 50 to 400 percent increase. The portions of California that have vegetation capable of supporting large fires will see increases of 50 to 300 percent or more.

If they are correct, the effects of climate change are not generations away. Firefighters starting out today will be dealing with this on a large scale during their careers.

Future Very Large Fires wildfires
The projected percentage increase in the number of “very large fire weeks”—weeks in which conditions are favorable to the occurrence of very large fires—by mid-century (2041-2070) compared to the recent past (1971-2000). (NOAA)

It is our position that unusual weather for one day, a month, a year, or even a decade does not prove or disprove a long-term climate trend. So when a senator brings a snowball onto the Senate floor or a governor talks about this summer’s fires to prove their cases that climate change does not or does exist, both are over stating their “evidence”. (In the first example, to a ridiculous extent.)

Both gentlemen need to consider much more data, such as the average size of fires over the last few decades or the California temperatures over the last 115 years.

Average size of fires by decade, lower 49 states, 1990 - 2013

And yes, there are factors other than weather that affect the size of fires, including decades of fire suppression in some areas. But not all large fires have burned in areas that have not been visited by fire in 50+ years. A careful analysis can’t discount the effects we are experiencing now — higher temperatures and longer fire seasons.