Eight worst wildfire weather years on record happened in the last decade


Date:
November 29, 2021
Source:
University of Alberta
Summary:
The world's eight most extreme wildfire weather years on record
have occurred in the last decade, according to a new study
that suggests extreme weather is being driven by a decrease in
atmospheric humidity coupled with rising temperatures.



FULL STORY ==========================================================================
The world's eight most extreme wildfire weather years have occurred in
the last decade, according to a new study that suggests extreme fire
weather is being driven by a decrease in atmospheric humidity coupled
with rising temperatures.


========================================================================== "Extreme conditions drive the world's fire activity," said former U of A wildfire expert Michael Flannigan, who conducted the research with study
lead Piyush Jain, research scientist with Natural Resources Canada,
and Sean Coogan, postdoctoral fellow Faculty of Agricultural, Life & Environmental Sciences.

"For example, in Canada, just three per cent of fires are responsible
for 97 per cent of the area burned." For the study, the team examined
extreme fire weather trends from 1979 to 2020 using common fire weather
indexes that provide estimates for fire intensity and rate of fire spread,
as well as changes in vapour pressure, or humidity.

The results link trends in rising global temperatures and decreases in
humidity to the likelihood that naturally occurring extreme fire events
will happen more often, spread to new areas and burn more intensely than
ever before in recorded history.

Decreasing relative humidity was a driver of more than three-quarters
of significant increases in intensity and fire spread, and increasing temperature was a driver for 40 per cent of significant trends.



==========================================================================
The study also found significant increases in extreme weather that can
cause major fires in close to half of the Earth's burnable land mass -- including in Northern Canada and British Columbia.

Flannigan said regions around the world have almost universally witnessed
an increase in extreme weather in the past 40 years, with marked increases
in the last two decades.

"It's not a big surprise, but with climate change, we expect warmer
conditions to continue and this trend to continue, expand and get worse."
In British Columbia, for instance, Flannigan said three of the last five
fire seasons -- 2017, 2018 and 2021 -- are the three worst on record.

Devastating BC Flooding Illustrates Further Risks of Increased Fire
Activity Living with wildfire also means living with the consequences
of fire. The recent flooding that is crippling land travel in and out
of B.C.'s lower mainland is a good example.



==========================================================================
"It is not all attributable to fires, but fires do play a role. When you
remove the vegetation, the rain is not being intercepted by the trees,
the roots aren't picking up the moisture, there is nothing to give the
soil stability - - you're much more likely to see land- and mudslides
in burnt areas.

"This has been documented in California for years." He noted even if
global warming stopped tomorrow, the wildfire threat would continue to
loom large for decades, so communities need to prepare for all wildfire eventualities.

"We're on this path of a new reality. It's not normal
because there's nothing normal about what's going on." ========================================================================== Story Source: Materials provided by University_of_Alberta. Original
written by Michael Brown.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Piyush Jain, Dante Castellanos-Acuna, Sean C. P. Coogan, John T.

Abatzoglou, Mike D. Flannigan. Observed increases in extreme fire
weather driven by atmospheric humidity and temperature. Nature
Climate Change, 2021; DOI: 10.1038/s41558-021-01224-1 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211129122718.htm

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