Judy: As we reported, California
is still struggling to deal with
record heat, and the electrical
operator warning that there
could be outages tonight.
The heat is particularly
challenging right now.
But the drought and the high
temperatures could be putting
California at higher risk for
flooding and other complications
from superstorms down the line.
A recent study suggests the
golden state must also prepare
for a large flood event.
For more on this, here's
Stephanie sy.
Stephanie: Scientists call it a
mega flood or mega storm, 30
days of continuous moderate to
severe rain and snow covering
wide swaths of land.
They haven't had one of these in
California since 1862.
But a new study says climate
change is increasing the
likelihood of another one
hitting the state.
The study authors say
californians could expect a
month long series of storms that
could flood parts of the state
with more than 100 inches of
precipitation.
Daniel swain is a co-author of
the study and a climate
scientist at UCLA and joins us
now.
Daniel, thank you so much for
joining us.
Just paint a picture for us of
what this would look like in
different parts of California if
this kind of mega storm were to
strike today.
What kind of havoc are we
talking about?
Daniel: Thank you for having me.
As you mentioned the last time,
California saw a weeks long
storm sequence of this magnitude
way back in the 1860s.
So back then California was home
to fewer than half a million
people as opposed to nearly 40
million people today.
So it's a very different
landscape in which this sort of
event would be unfolding.
A lot more people and
infrastructure potentially in
harm's way.
And so this would likely be very
disruptive and destructive
statewide event, affecting
multiple major urban areas and
most of California's major
economic sectors simultaneously.
Stephanie: You know, Daniel, I
grew up in California, we've
been preparing for the so called
big one, referring to
earthquakes, since I was a kid.
Put into context how much
californians should worry about
this and prepare for it?
Daniel: Well, coincidentally
enough, one of the terms from
-- terms for modern mega
flooding California is
California's other big one.
Literally the other kind of
major disaster that would cause
potentially immense destruction
and harm for millions of
californians.
And I think that, you know, a
lot of folks in California are
focused today on drought and
water scarcity and things that
stem from that like wildfires.
And for understandable reasons.
We've seen a lot more of that
than water over flooding in
recent years.
But the reality is, this is a
part of the world that is still
intrinsically susceptible to
systems is that the most
extremely large events
periodically and climate change
is raising the odds.
Even though they've been rising
somewhat quietly, and lately in
the background is dealing with
all of this water scarcity, we
would ignore increasing flood
risk at our peril.
Stephanie: And according to your
study, Daniel, climate change by
your estimates, increases the
likelihood of a mega flood and
by twice is as high of a
likelihood.
Daniel: Indeed, we did find that
climate change has actually
already increased the likelihood
of an extreme storm sequence
creating widespread flooding in
California.
So that's something that's
essentially already happened
with the warming that has
already occurred.
Further warming is going to
increase that risk even more
potentially resulting in a
tripling or even quadrupling of
that risk relative to what it
would have been about a century
ago.
So that's a pretty large
increase in the odds and it
means that over the next 30 or
40 years, an extreme storm
sequence like the one in our
study, is more likely than not
to occur in California.
And so this is not something
that is in the far tail of
unlikely probability.
This is something that is very
plausible and very what could
happen sooner rather than later.
So really we need to be thinking
about this over the next few
decades.
Stephanie: And beyond
California, what should other
western states expect?
Do they face a similar
possibility?
Daniel: Yes, I think it's quite
likely that the risk of very
large flood, extreme
participation in flood events is
increasing broadly, even in
places that are currently
experiencing a lot of drought
and water scarcity.
In fact, we even see hints of
this this past summer, the
desert southwest currently
facing the multi decadal mega
drought, as it has been termed,
where they've seen extreme flash
flooding on a localized basis
during summer monsoon.
So they're still in a very
severe long term drought, but
the short term, individual
places have experienced very
dangerous and destructive flash
flooding right in the middle of
that.
So of course, that's on a
smaller spatial scale than the
mega flood that we're talking
about in our own work.
But it does indicate just how
much this this risk is
potentially widespread across
the western U.S.
In this study, we're focused on
California, but the risks are
very broadly spread across the
west, not just along the pacific
coast, but also in the interior
places that are typically
, thought of as being drier
places.
Stephanie: Is California and
other western states prepared
for this?
Daniel: I think that's the
billion and perhaps even
trillion dollar question.
Because the last time that there
was an economic analysis done or
-- done for a flood of this
magnitude, it was estimated that
it could approach a trillion
dollar disaster in California.
So this is a really important
question.
Not just in the context of short
term disaster response, making
sure fewer people are harmed by
this event when it inevitably
does occur, but also from an
economic perspective, this would
be a hugely disruptive event.
And I think there is, you know,
this is something we're working
to assess for the state of
California and other regional
and federal agencies, where the
weak points might be.
That's one of the purposes of
the research.
That is just one component, we
really want to do is be able to
figure out where those weak
points are, and hopefully
address as many of them as
possible before this event
actually occurs in the modern
world.
So hopefully, California and
other regions with similar risk
will be more prepared, and not
be caught by surprise when these
sorts of extreme flood events do
eventually arrive at our
doorstep.
Stephanie: Daniel swain, a
climate scientist at UCLA.
Daniel, thank you for joining
us.
Daniel: Thanks again.