Climate change is finally getting some media attention in California. That is the good news.
The bad news is that the warming climate has been attracting attention though a series of unseasonable wildfires this winter and spring. The wildfires continue, though the national PL number (“Preparedness Level,” a measure of how much of the total US firefighting capability is needed) is lower now than it was a few weeks ago. There have already been injuries and property destruction this spring, and some of the fires have been incredibly intense.
As usual, “is this event due to climate change” is the wrong question, because climate change is a trend and is, by definition, only discernible across multiple events. However, the persistent drought in California that is causing that state’s terrible fire season is part of a larger long-term weather pattern related to the melting of the polar ice cap and the warming of the ice cap. So, yes, as much as any one event can be, these fires are, in part, climate change. And, overall, the trend of global warming includes more fires, and more severe fires, in muh of the Northern Hemisphere.
Climate Change increases fire activity in a number of ways. Most directly, warmer air can hold more water, so fuels dry out faster. Also a longer growing season and, in some places, more rain at some times of the year, means more plants can grow, which means more fuels later during dry periods. Earlier snowmelt and winter rain both also leave the land drier earlier in the spring than it used to be.
Currently, fire danger in parts of California, Arizona, and Alaska is above normal for June, based on the amount of fuel on the ground, its type, and how dry it is, as well as what the current and long-range weather forecasts are. This is a bit scary as June is fire season in Arizona, anyway. Depending on specific area, the reason is some combination of low snowpack over the winter, an early spring, and drought (remember that the Western US had a warm, dry winter rather than the cold, snowy conditions in the East that kept making the news).
High fire danger itself is not that unusual,of course, especially as it is balanced by unusually low danger in other places. However, what’s going on in California is extremely unusual. And, although areas of greater and lesser fire danger are expected to move and change over the summer, California is predicted to remain under threat.
Wildfires have gotten worse over the past few decades. The Western fire season has grown by about three months since the early nineteen eighties and the number of acres burned per wildfire has also increased. Fires were also increasing prior to the nineteen eighties, but that could have been caused by a buildup of fuels due to a policy of fire suppression. In recent decades, climate change has clearly become the dominant cause. The trend is expected to continue going forward–and how bad it gets depends on whether we do something and stop causing global warming.
Wildfires themselves are not bad, of course. Many ecosystems are actually fire-dependent, although very hot, very large fires can be genuinely destructive. But we don’t want our own structures and infrastructure to burn, and that means controlling how quickly fires spread. Increasing fire danger is a problem for people whose homes and businesses lie in combustible areas and it is a problem for public finances because fighting fire costs a lot of money. What we don’t often hear about in the news is how global warming makes things worse for firefighters.
More fires means more risk for firefighters simply because more of them are exposed to danger; if twice as many firefighters have to go out, you’ll see twice as many injuries and fatalities, everything else being equal. Similarly, if more fires are large and intense, the risk goes up because the number of people exposed to danger goes up.
More fire itself does not necessarily increase the danger for individual firefighters, except in that they are more likely to be called in to work. The National Interagency Fire Center and its associates have very strict rules for keeping its people safe. A very bad fire season could exhaust the system as a whole, but individuals will still be sent home before they can get personally exhausted. When conditions are particularly dangerous, firefighters back off. When people die fighting wildfires, it is almost always because someone didn’t follow the rules and climate change cannot change those rules, even if it does change fires.
That being said, there are important exceptions to this principle.
One is that extreme weather events, which increase infrequency and severity with global warming, cause fires to change their behavior suddenly. A front coming through can, quite literally, cause a previously stable fire to explode. With good weather forecasting, firefighters can get out of the way, but if a ground crew does not get the message or responds improperly to the warning, people die. This is what killed 19 people in Arizona last year.
The other issue is that global warming means warmer weather and, particularly, warmer weather at night (daytime temperatures are largely governed by the heat of the sun, which is not changing. It is the cooling quality of the night that the greenhouse effect inhibits). Firefighters wear a lot of protective gear and carry a lot of protective equipment and they have to work very hard, physically. All this makes heat stroke a very real concern.
To escape the heat, firefighters sometimes work at night. At night, cooler moister conditions also make fires lie down a bit, safer to work around. Warmer nights rob people of this respite. Hot weather also makes it harder to sleep, increasing the risk of accident and injury.
All this is not an academic concern to me. My husband is a wildlands firefighter (and has contributed some information for this article). He will probably go out on a fire this summer, probably to California.