By Todd Wilkinson, 1-05-07
El Nino has returned and weather forecasters believe that means another mild winter for the high plains of the U.S. West. While any claims linking the recurrence of El Nino—a cyclical warming of the Pacific Ocean—to human-caused climate change is still, at this moment, unproved, what isn't speculation is that the temperature last year went up in central and eastern Montana.Todd: The Casper Star has a nice story this morning on water worries in Wyoming: http://www.casperstartribune.com/articles/2007/01/05/news/top_story/965ec673999c977b8725725a00093d0c.txt
Comment By Matthew Koehler, 1-07-07I've always found it rather strange that every year about this time some people start predicating what type of fire season we will have during the upcoming summer. Weather is hard enough to predict day to day, much less predicting what will happen 8 months from now. I mean, how many times have you awoke in the morning - profoundly disappointed - to see bare ground when the weather forecast called for heavy snow?
When we have a dry and mild winter people start predicting "We're sure gonna have a 'bad 'fire season." Then again, when we have a wet winter and a wet spring people start predicting, "We're sure growin' a lot of fine fuels and grasses out there. We're sure gonna have a 'bad' fire season."
The fact of the matter is that in the Northern Rockies almost every single year is dry enough to have large fires. This has been true since shortly after the last Ice Age and it sure isn't going to change in the foreseeable future.
After all, normal annual precipitation amounts for places like Missoula hover around 14". By any measure that's not a lot of precipitation. Since the year 2000 we've been in a prolonged drought in the Northern Rockies; however, not every year has seen 'bad' fire seasons. To be sure, it's been dry enough every July and August but only 2000, 2003 and 2006 would qualify as 'bad' fire seasons.
The reason is that it takes more than dry conditions to start forest and grassland fires. The most important ingredient to starting a fire is an ignition source. If you don't believe me, next time your camping take a bunch of newspaper and really dry, nicely split kindling and put it in the campfire ring and wait for it to ignite all by itself.
Some summers we get a lot of dry lighting storms, while some summers we get hardly any. Some summers we get a bunch of careless campers and even some summers we get arsonists out in the woods. Again, my point is that every single summer in the Northern Rockies is dry enough to have the potential to be a 'bad' fire season.
Of course, I've been putting 'bad' fire season in quotes to highlight the subjective nature of characterizing natural and essential processes as 'bad.' As a society we need to accept fires important role in our forests and grasslands and learn to live with it.
Matthew: Good points. Language is important in how the media writes about wildfire. Going back to the summers before the Yellowstone fires of 1988 and then, during them, the ecological role of fires became apparent to me on the ground for the first time, despite a political and social atmosphere that portrayed the flame only as being "bad." Many members of the media still don't get it and ascribe value-laden words to their coverage, as if they were reporting on a blaze in a high rise apartment complex in a city. You bring up an important point too about speculation of what is yet to come. We live in an arid region. Wildfires are inevitable, though "weather" and "climate" are intermeshed. The 1988 fire season in the West was preceded by a balmy and dry winter. Lorna Thackeray's story in the Billings Gazette did a good job of laying out what weather officials believe the El Nino-related precipitation levels will be going into the summer. We need to remember that whether we're talking about climate orwildfire that weather forecasters look into the future based upon information they have now; climatologists look into the future by tracking deeper trends leading up from the past to the present. Weather is more highly speculative. The record of climate is created by its own history. Using technology, the science of both is getting better all the time.
Comment By Lance Olsen, 1-08-07As Matt Koehler correctly reminds us, many variables determine whether fire in the forest will be frequent or extensive. I suspect that Matt would go on to say that this does not diminish the importance of any of them, including heat.
As our region gets hotter, fire risk will certainly rise from that variable alone. And the prospects of rising heat are not exactly a gray area anymore. The constant political pressure to improve climate models has led to models that confirm earlier, cruder models' indication of rising heat.
Less clear is the prospect for drought, which is another pivotal variable in this subject. But we also know that dry conditions make it much more likely for forest fire, whether that fire is started by lightning or arson. And there has been steadily mounting evidence that the western United States has been set up for drying.
To understand and anticipate this drying realistically, we landlubber types need to learn to look offshore. For example, Science and Nature and other respected journals have published reports of reasonably good evidence that sea surface temperatures play a potent determing role in terrestrial drought; e.g., one Science article was titled "A Perfect Ocean for Drought."
Although the evidence for rising temperatures may be clearer than the evidence for deepening drought, the risk of drought shouldn't be taken lightly. In fact, one recent analysis produced indications that, worldwide, the extent of extreme drought will expand from today's 1 percent of earth surface to 30 percent of Earth 's surface. If that projection or anything near it bears out, fire will be more easily started across truly vast areas that, together, would make western US fires a subset of a much larger trend.
None of which means Matt errs by questioning predictions made for any single year, or for any season that is just a few months down the road. Chaos theory still holds, or, alternatively stated, there is still enough "noise" in the global climate system that climate scientists know very well that there are surprises in store for them and all the rest of us.
But set aside the clear uncertainties in short-term analyses, and there is considerably less question about the long term trend. And the natural world is sending us warnings galore. As one research team pointed out in a Nature article of March 23, 2002, "Although we are only at an early stage in the projected trends of global warming, ecological responses are already clearly visible."