In the midst of the catastrophic wildfires of Northern California that have claimed 41 lives and either destroyed or damaged more than 5,700 buildings, I wanted to know where the cutting edge of science on this issue is today. What made the California wildfires so strong and unusually destructive? Regardless of what started the fires, what conditions allowed the fires to spread so quickly? Did climate change have anything to do with it? What are scientists currently working on that can help communities better prepare for wildfires?
I had the good luck to work through my questions with NASA Earth scientist and fire expert, Dr. Douglas Morton. I reached Dr. Morton by phone while he was attending SilviLaser 2017 – a conference that brings together scientists who use a powerful laser technology called LIDAR (Light Detection and Ranging) to develop extremely high-resolution 3D maps of forests.
How has the amount of land burned by wildfires changed over time?
When it comes to wildfires, Dr. Morton let me know that NASA has been using satellites to measure changes in wildfire over time, globally and regionally. What they found is that globally, the amount of land burned by wildfires has declined over the past 18 years. This is because more and more land is being converted from natural landscapes, where fires naturally occur, to agriculture.
The Western U.S. is an exception to this – wildfires have increased in this region over time. In California alone, more than one million acres of land have been affected by wildfires this year, putting this year on track to be one of the most destructive on record in the state. More on what is causing those increases in wildfires later.
What made the California wildfires so strong?
When considering what fueled the California wildfires, Dr. Morton pointed to heat as a key factor, with these fires coming on the heels of an unprecedented heat wave in the region. In addition, high winds and drought conditions allowed the wildfires to strengthen and spread quickly. The hot, dry winds (known as Diablo winds) reached up to 79 mph.
Do we know whether climate change contributed to the California wildfires?
Attributing individual disasters to climate change is a complex and growing field. For an event like the wildfires of Northern California, Dr. Morton noted that what we can say at the moment is that the high temperatures in the area – one ingredient of wildfires – have been anomalous.
Beyond the Northern California wildfires, several studies show a link between the previously mentioned increase in wildfire activity in the Western United States and climate change as a result of increasingly warm and dry conditions in the region. Looking forward, climate change is likely to increase the frequency of large, intense forests fires in the West.
What ability do scientists have to predict wildfires?
NASA scientists are using their understanding of the Earth system to figure out which places are likely to have wildfires as far as 3-6 months out from an event. Dr. Morton noted that some places are more predictable than others. For example, as a result of all of the hurricanes in the North Atlantic, Dr. Morton shared that there will likely be more fire activity in the Amazon next year.
How does that work? Hurricanes are a way that the Earth transfers heat away from the Equator. Warmer ocean waters are tugging a belt of rainfall known as the “Intertropical Convergence Zone” northward. Warmer water fuels hurricanes, and these storms pull moisture with them. As a result, there is less water available to the Amazon, and these drier conditions lead to more fire activity following years with more hurricanes and tropical storms in the Atlantic.
However, not all places are conducive to such seasonal forecasts. Dr. Morton described how seasonal wildfire forecasts are currently possible in places (like the Amazon) where fire activity is affected by temperatures at the top of the ocean (also known as sea surface temperatures).
Dr. Morton explained that Northern California’s wildfire activity is not linked to such sea surface temperatures. Instead, it is a place that responds to smaller-scale and shorter-term factors. For example, a dry pocket of air might be enough to tip Northern California into a high wildfire risk situation.
What are the new frontiers for wildfire research?
When wrapping up our conversation, Dr. Morton pointed out that scientists like himself are trying to improve wildfire forecasts, and get forecasts down to shorter timescales that decision makers can use – that is where the cutting edge is right now. He noted that there is a conference at Columbia University coming down the pike where scientists will gather to share knowledge and exchange ideas on this very topic.
We may often think of NASA as the part of the government that sends rockets into space. However, NASA’s scientists and Earth observations are vital to helping make Americans safer here on Earth. Scientists like Doug Morton are pushing the envelope so that decision-makers at the federal, state, and community-level can ultimately have more accurate wildfire forecasts, more time to prepare, and a better chance of protecting lives, property, and ecosystems.
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