THE BIG PICTURE:
In recent years,
millions of US acres,
burned by wildfires per year,
are nowhere near a record,
in even the worst recent yerar,
of 2015.
(2017 might slightly exceed 2015).
Even in the year 2015,
acres burned,
were less than 20%,
of the 1930 record.
(1930 was the worst year on record,
followed very closely by 1931).
There was mild uptrend,
of acres burned,
since a low point 1998,
but global warming,
can't be blamed,
because acres burned,
were higher before 1950,
long before “global warming”,
started in 1975.
DETAILS:
The mild global warming,
from 1975 to 2000,
was either natural,
caused by rising CO2,
or had other cause(s).
No one knows.
The 1975 to 2000 warming,
was very similar to,
the 1910 to 1940 warming,
which is said to have,
unknown natural causes.
Please note:
Unlike the global
average temperature,
the US average temperature
is still below the 1930s peak,
at least for now,
because government bureaucrats,
keep "adjusting",
US 1930s temperatures,
to make the decade cooler.
Maximum temperatures,
for the northern
two thirds of California,
have also declined,
since the 1930s.
Historical Statistics
of the United States,
include areas burned by wildfires,
from 1926 to 1970.
The National Interagency Fire Center,
has additional data after 1970.
Every year from 1926 to 1952,
had more acres burned,
than the worst modern year of 2015.
And modern years,
don't have fewer acres burned,
because there are,
fewer forests around,
to burn, these days.
The USDA Forest Service,
says “forest area has been
relatively stable since 1910”.
The largest fire,
in Canadian history,
was the 1825 Miramichi Fire,
burning three million acres,
in New Brunswick,
and extending into Maine.
The 1871 Peshtigo, Wisconsin fire,
blackened 1.5 million acres,
and killed 1,500 to 2,500 people.
Tucson, Arizona had individual fires,
that burned over one million acres,
before 1890.
In 1910, three million acres burned,
in "The Big Blowup".
(aka The Great Fire of 1910).
During the 1930s Dust Bowl years,
20% to 35% of the USA and Mexico,
were in extreme drought.
Back in the 1880s,
California ranchers,
and timber owners,
promoted “light burning”,
to reduce fuel for larger fires,
and maintain their pastures.
Light burning,
created man made,
fuel free fire breaks,
that could stop,
a future wildfires,
from spreading.
Around the 1970s,
some US government agencies,
adopted “let it burn policies”,
if homes were not threatened,
Global warming nuts now claim,
climate change resulted in,
five times more fires,
than in the 1970s.
Of course they data mine,
to mislead us,
as usual,
by cherry-picking,
specific years,
starting with an,
unusually low acres burned year,
such as 1995,
and ending with an,
unusually high acres burned year,
such as 2006,
to present a very
misleading percentage increase.
(Compared the short-term,
blue bar chart below,
with the large long-term,
red bar chart, just below it.)
From 1957 through 1998,
total area burned, in fact,
was rarely more than 5%,
of the 1930 record.
(and the nearly as high 1931).
After 1998, annual area burned ,
did have an uptrend,
but no years reached 20%,
of the area burned,
in either 1930 and 1931.
( 2017 might reach 20% ).
There are three logical reasons,
for a mild area burned uptrend,
since 1998:
(1)
Increased fuel load:
Every decade,
the US Forest Service,
conducts an inventory,
of our public and private,
timber resources.
Today we have 57% more,
standing timber,
than in 1953,
the year I was born.
We quit harvesting timber.
on federal lands,
in the late 1970s,
but the trees continued to grow.
The number of fires,
varies a lot from year to year,
but the long-term,
area burned trend,
correlates with,
the increase in,
timber volume.
(2)
Higher Percentage of Fires
Started by Humans:
The US Forest Service reports,
90% of all wildfires,
are started by humans,
usually unintentionally,
and the estimated percentage,
has been in an uptrend.
The 2016 California fires,
were not started by,
spontaneous combustion,
as Governor Jerry Brown implies.
(3)
New Fire Suppression Policies:
A change from the old,
fire suppression policy,
is to selectively allow,
fires to burn.
Dry wood, leaves,
and other materials,
are fuels that,
build up in a forest.
When humans stop a fire,
they promote conditions,
that make future fires,
more severe,
than they would have been.
Large fires are more likely today,
because past fire suppression,
caused unnatural fuel build up.
Possible explanations
for some of the large,
year-to-year variations,
of area burned,
on the west coast:
(A)
El Ninos and La Ninas:
They are natural climate cycles,
affecting the Pacific Ocean.
El Niños induce more winter rainfall,
and more plant growth,
which serves as fuel,
for the next fire season.
There was a very strong 2016 El Nino.
Periodic La Niñas induce droughts.
Fires are obviously more likely,
during droughts.
Periodic droughts,
and the resulting high fire risks,
are part of natural climate change.
(B)
Pacific Decadal Oscillation (PDO):
The PDO is a natural climate cycle,
that results in 20 to 30-year periods,
of more frequent El Niños,
alternating with similar periods,
of more frequent La Niña’s.
La Nina-induced droughts,
increase the risk of fires,
from California,
to the Colorado Rockies.
The PDO explains,
climate swings,
along the west coast.