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A28 SCIENCE
Monday 6 January 2020
Q&A: How climate change, other factors stoke Australia fires

AP Science Writer power lines, Flannigan said.
Australia's unprecedented Usually discarded ciga-
wildfires are supercharged rettes don't trigger big fires,
thanks to climate change, but when conditions are so
the type of trees catching dry, they can, he said.
fire and weather, experts Q: ARE THESE FIRES TRIG-
say. GERING THUNDERSTORMS?
And these fires are so ex- A: Yes. It's an explosive
treme that they are trig- storm called pyrocumulo-
gering their own thunder- nimbus and it can inject
storms. particles as high as 10 miles
Here are a few questions into the air.
and answers about the During a fire, heat and
science behind the Aus- moisture from the plants
tralian wildfires that so far are released, even when
have burned about 5 mil- the fuel is relatively dry.
lion hectares (12.35 mil- Warm air is less dense than
lion acres), killing at least cold air so it rises, releasing
17 people and destroying the moisture and forming a
more than 1,400 homes. cloud that lifts and ends up
"They are basically just in a thunderstorm started by
a horrific convergence of fire. It happens from time to
events," said Stanford Uni- In this image released Thursday, Jan. 2, 2020, from the Department of Environment, Land, Water time in Australia and other
versity environmental stud- and Planning in Gippsland, Australia, smoke rises from wildfires burning in East Gippsland, Victoria. parts of the world, including
ies director Chris Field, who Associated Press Canada, Flannigan said.
chaired an international "These can be deadly,
scientific report on climate month hit 121.8 F (49.9 C). makes it more difficult — or tralia," said David Karoly, dangerous, erratic and un-
change and extreme "What would have been a impossible — to put out," leader of climate change predictable," he said.
events. He said this is one of bad fire season was made Flannigan said. hub at Australia's National Q: ARE THE AUSTRALIAN
the worst, if not the worst, worse by the background The heat makes the fuel Environmental science Pro- TREES PRONE TO BURNING?
climate change extreme drying/warming trend,'' drier, so they combine gram. "The normal peak fire A: Eucalyptus trees are es-
events he's seen. Andrew Watkins, head of for something called fire season is later in summer pecially flammable, "like
"There is something just in- long-range forecasts at weather. And that deter- and we are yet to have gasoline on a tree," Flan-
trinsically terrifying about Australia's Bureau of Me- mines "fuel moisture," which that." nigan said. Chemicals in
these big wildfires. They go teorology, said in an email. is crucial for fire spread. Q: IS WEATHER, NOT JUST them make them catch fire
on for so long, the sense Mike Flannigan, a fire sci- The lower the moisture, the LONG-TERM CLIMATE, A easier, spread to the tops of
of hopelessness that they entist at the University of more likely Australian fires FACTOR? trees and get more intense.
instill," Field said. "The wild- Alberta in Canada, said start and spread from light- A: Yes. In September, Ant- Eucalyptus trees were a big
fires are kind of the iconic Australia's fires are "an ex- ning and human-caused arctica's sudden strato- factor in 2017 fires in Portu-
representation of climate ample of climate change." ignition, a 2016 study found. spheric warming — sort gal that killed 66 people,
change impacts." A 2019 Australian govern- There's been a 10% long- of the southern equiva- he said.
Q: IS CLIMATE CHANGE RE- ment brief report on wild- term drying trend in Aus- lent of the polar vortex — Q: HOW CAN YOU FIGHT
ALLY A FACTOR? fires and climate change tralia's southeast and 15% changed weather condi- THESE HUGE AUSTRALIA
A: Scientists, both those said, "Human-caused cli- long-term drying trend in tions so that Australia's nor- FIRES?
who study fire and those mate change has resulted the country's southwest, mal weather systems are A: You don't. They're just go-
who study climate, say in more dangerous weath- Watkins said. When added farther north than usual, ing to burn in many places
there's no doubt man- er conditions for bushfires in to a degree of warming Watkins said. until they hit the beach,
made global warming has recent decades for many and a generally southward That means since mid-Oc- Flannigan said.
been a big part, but not regions of Australia." shift of weather systems, tober there were persistent "This level of intensity, direct
the only part, of the fires. Q: HOW DOES CLIMATE that means a generally dri- strong westerly winds bring- attack is useless," Flannigan
Last year in Australia was CHANGE MAKE THESE FIRES er landscape. ing hot dry air from the in- said. "You just have to get
the hottest and driest on WORSE? Australia's drought since terior to the coast, making out of the way... It really is
record, with the average A: The drier the fuel — trees late 2017 "has been at the fire weather even riskier spitting on a campfire. It's
annual temperature 2.7 and plants — the easier it least the equal of our worst for the coasts. not doing any good."
degrees Fahrenheit (1.5 is for fires to start and the drought in 1902," Australia's "With such a dry environ- Q: WHAT'S THE LONG-TERM
degrees Celsius) above hotter and nastier they get, Watkins said. "It has prob- ment, many fires were start- FIRE FUTURE LOOK LIKE FOR
the 1960 to 1990 average, Flannigan said. ably been driven by ocean ed by dry lightning events AUSTRALIA?
according to Australia's Bu- "It means more fuel is avail- temperature patterns in (storms that brought light- A: "The extreme fire sea-
reau of Meteorology. Tem- able to burn, which means the Indian Ocean and the ning but limited rainfall)," son in Australia in 2019 was
peratures in Australia last higher intensity fires, which long term drying trend." Watkins said. predicted," said Australian
Q: HAS AUSTRALIA'S FIRE Q: ARE PEOPLE STARTING National University climate
SEASON CHANGED? THESE FIRES? IS IT ARSON? scientist Nerilie Abram. "The
A: Yes. It's about two to four A: It's too early to tell the question that we need to
months longer, starting ear- precise cause of ignition ask is how much worse are
lier especially in the south because the fires are so we willing to let this get?
and east, Watkins said. recent and officials are This is what global warm-
"The fires over the last three spending time fighting ing of just over 1 degree
months are unprecedent- them, Flannigan said. C looks like. Do we really
ed in their timing and sever- While people are a big fac- want to see the impacts of
ity, started earlier in spring tor in causing fires in Austra- 3 degrees or more are like,
and covered a wider area lia, it's usually accidental, because that is the trajec-
across many parts of Aus- from cars and trucks and tory we are on."q