Kind: captions
Language: en
this week began with tropical storm
nicholas reaching category 1 hurricane
force right before making landfall along
the texas gulf coast
and last week hurricane larry reached
category 3 and then weakened but not
before causing power outages as a
category 1 in newfoundland canada
the atlantic hurricane season runs from
june 1st through november 30th and this
year's already been record setting
hurricane henry alone produced the
rainiest hour on record in new york city
a record that was broken again less than
two weeks later by hurricane ida
here are just a few of the recent
headlines ida made landfall off the
coast of louisiana packing winds of up
to 150 miles per hour an extremely
dangerous cat 4 storm unleashing
damaging winds torrential rains and a
life-threatening storm surge the
remnants of hurricane ida delivering a
historic soaking in the northeast elsa's
potential wrath is bringing up the issue
of climate change and its effect on
hurricanes
so here's what i'm wondering about are
hurricanes getting more frequent
stronger more destructive and is any of
this connected to climate change this is
nova now where we look for the answers
behind the stormy headlines i'm alok
patel
[Music]
ah
all right sorry i guess we lost
communications
but we are looking at imminent landfall
of this storm
if you're watching the news on august
29th you might have seen al roker
getting soaked by hurricane ida as it
barreled through new orleans
winds of 150 miles per hour
our our lights are right now forecast
storm surges upwards of 15 to 16 feet 20
inches of rain or more with this system
ida is the latest storm to the u.s as a
category 4 hurricane
but even after it was downgraded to a
tropical storm it wasn't finished what
people didn't expect
was that as it kept on going it stayed
strong enough and it swept up enough
water vapor to dump record amounts of
rain
in the new york area in some places the
highest one hour rainfall total ever
recorded catherine hey ho is an
atmospheric scientist and the chief
scientist for the nature conservancy
she's also the author of saving us a
climate scientist case for hope and
healing in a divided world in the states
dozens died in ida's wake it goes
without saying that hurricanes are some
of the most powerful natural phenomena
on our planet
floods and rip currents can result from
a hurricane strong winds heavy rainfall
and storm surge which is when coastal
waters rise to abnormally high levels
heiho is convinced that the data shows
that hurricanes are getting stronger
and that it's because of climate change
here's the thinking
climate scientists estimate that 93 of
the excess heat trapped in the
atmosphere by greenhouse gases finds its
way into the ocean
and warm water is hurricane fuel
what we are seeing is when they form
because there's so much more energy
available to them
more of them are stronger they're slower
so they move slower and they dump more
rain on us and it's for a very simple
reason
that as you warm the air it's capacity
to hold water vapor goes up goes up
quite fast seven percent for one degree
celsius increase in air temperature
carrie emanuel is a professor of
atmospheric science at the massachusetts
institute of technology and this means
that extreme rainstorms not just
hurricanes but any kind of like strong
thunderstorm or other kinds of storms
that rain will generally rain more
so as these storms move along there's
more water vapor for them to sweep up
and dump on us for example with
hurricane harvey that hit the city of
houston back in august 2017 we know that
it had about 40 percent more rain than
it would have if the same hurricane had
happened 100 years ago
also the warmer ocean water evaporates
quicker and that makes more water vapor
so there's this whole feedback effect
going on where the warmer it gets the
stronger and more damaging the
hurricanes get and then there's also the
fact that warmer water takes up more
space
so sea levels rising for two reasons
reason number one is because land-based
ice and greenland in antarctica is
melting and that water is going into the
ocean but the second reason is simply
because as the ocean gets warmer it
actually literally takes up more space
so when a hurricane comes along a lot of
the damage is due to hurricanes along
the coast are because of storm surges
well as sea level rises those surges can
reach further and further inland
flooding more and more areas that
wouldn't ordinarily be flooded
and as we destroy our coastal wetlands
and as we build more and more valuable
infrastructure right along the coast
we're putting ourselves even more at
risk it's a lose-lose lose
you may think hey hurricanes mainly
affect coastal areas but that's not as
true as it once was
when hurricanes move over land you know
they weaken pretty quickly right you're
unplugging them from the ocean so
they're not plugged into their energy
source anymore but
because there's warmer air and more
water vapor in the air and because
they're getting stronger to begin with
we're also seeing that hurricanes are
lasting longer at higher intensities
over land than they used to
and catherine hayjo says hurricanes and
tropical storms are moving farther north
before they dissipate
and that's because warmer water is
spreading further forward and so they
can maintain their hurricane status
further northward than they used to
so it isn't like hurricanes have never
made it to canada before well now though
hurricanes are moving up the coast and
along halifax and even newfoundland
they're getting storms that are still at
hurricane strength because the warm
ocean water is warm enough to keep them
going further north warmer conditions
also can cause wind speeds to go up as
you add greenhouse gases to the
atmosphere
you increase the upper limit of wind
speed that you can have
thermodynamically in a hurricane
now
a very tiny percentage of actual storms
reach this speed limit
but a few do and it's very important to
recognize that that goes up so that in
the future we expect to see and we're
beginning to see
records being broken
on
wind speed and hurricanes
climate scientists can model our
atmosphere and oceans over vast scales
dial different factors up or down on the
computer model and a bunch of
consequences fall out and they see all
of this as temperatures get warmer the
models don't necessarily show hurricanes
getting more frequent at least not in
the north atlantic but they predict that
hurricanes get stronger and more intense
and extreme storms generally dump more
rain
but how accurate are these climate
models does nature actually behave the
way computers predict
what do the observations on the ground
tell us
that after the break
okay let's take a look at what these
look like on the ground when we think
about hurricanes there are a few
important features to consider their
frequency how many of them we see in a
season their track so their location and
trajectory their size the diameter of
the storm and their intensity meaning
how strong they become a hurricane is a
technically something we call a tropical
cyclone frank marks has been a research
meteorologist for 42 years at noaa the
national oceanic and atmospheric
administration
he directs the hurricane research
division for noaa's atlantic
oceanographic and meteorological
laboratory they tend to form over oceans
in the pacific and the atlantic and the
indian ocean
typically in the summer part of the year
for that hemisphere when the oceans are
the warmest
they are
relatively rare typically on the globe
any year there's between 90 and 100
tropical cyclones
that varies very little it hasn't
changed much over the time i've been
studying them and marx says that though
north atlantic hurricanes are causing
more damage than in the past
that's not necessarily because they're
more intense you know we've had
very intense tropical cyclones almost
back to our records go back to the 1850s
and so there's been immense storms doing
a lot of damage
the problem is that population has
shifted
and so our risk
of damage has gone up tremendously plus
there's been a demographic population
shift towards the coastlines
towards the warmer climates as we've
developed things like air conditioning
and got rid of malaria you know people
have migrated towards the tropics so
even though there's no noticeable change
in the actual storms
if there is that's very slight i haven't
seen it in 40 years
we have made a dramatic change in the
way we live
which has made us extremely vulnerable
you know the lifestyle we have the
amount of property we put into the
storm's potential paths
the areas of the most growth in the
united states
has been in hurricane-prone areas
there's a universal agreement because
the data is absolutely uncontroversial
that there's huge increases in hurricane
damage all around the world here again
is carrie emanuel but there's also
universal agreement that most or maybe
all of that signal is demographic it's
not meteorological or climatological
it's just that
the world's population exposed to
hurricanes has tripled since 1970 that's
not just in the us it's all around the
world so you have more people living
in places with hurricanes you're going
to get more damage but what about the
idea that climate change is making the
storms more intense and dangerous
is such a change actually showing up in
our observations of real storms over the
last few decades
carrie emanuel thinks this kind of
change could be hard to see
because compared to models real world
data are noisy the theoretical
prediction of increased intensity
is such that
we would only expect the signal to
emerge from the noise about now
you know it wouldn't have emerged 20
years ago for example
the fact that we haven't unequivocally
seen a
signal compared to the noise
is no reason to disregard the risks that
were long ago predicted and rely on very
very solid physics
most of our observations come from the
north atlantic but that only accounts
for about 12 percent of the world's
hurricanes it's not like science is
decided by a vote
but
there are some things that we feel we
know very well like hurricanes ought to
produce more rain
and other kinds of storms as the
temperature increases it's just such
simple physics it's very hard to argue
against it
um
there is a tendency
among some people dealing with this
problem to treat climate change as a
problem of signal detection and
attribution
but it isn't the whole story by any
means
i'd like to say that if we had 10 years
of climate records which would be
horrible we would still be fairly
confident
about um stating that we are
putting ourselves at risks of worse
damage from hurricanes just based on
simple theory and and models but despite
all the noise some studies are seeing a
clear signal like one published last
year based on satellite data from 1979
to 2017
it's very tricky because satellites have
improved over time as part of this study
atmospheric research scientist james p
carson along with other researchers
actually degraded the quality of the
modern satellites to match that of the
older satellites and when he looked at
that what he found specifically was that
the proportion
of hurricanes that reach high category
by staffer simpson category 345 has been
increasing over time in a statistically
significant way the skill that's
generally used to characterize hurricane
strength was developed in the 1970s by
engineer herbert stafford and
meteorologist robert simpson hence its
name the safer simpsons scale
and it is exclusively based on the
maximum sustained wind speed in a
hurricane daniel swain is a climate
scientist with the institute of the
environment and sustainability at ucla
so you get a category one two three four
or five storm based only on what the
maximum sustained wind in that
particular storm is but a hurricane
strength is more than its wind speed so
the current scale says swain isn't
perfect
okay back to carrie emanuel and that
study showing that the proportion of
hurricanes reaching high category number
on the safra simpson scale is increasing
and um
i think that's an important result the
first time we've sort of seen that
signal we didn't really expect to see it
until about now in this very noisy and
and and somewhat um deficient data
um but again it was it it is coupled
with a strong theoretical prediction
that that is what we should see and so
when you take them together it's a
pretty strong case that we have a pretty
high risk of more intense hurricanes
so the physics is pretty clear
according to everything we know about
how the atmosphere and the oceans work
as the planet's temperature rises
hurricanes are supposed to get more
intense
but when it comes to knowing exactly how
much that's already happening the
current data are messier and are telling
a less obvious story what we do know is
hurricanes are causing more damage
to us
we humans interacting with these
disasters are what caused the suffering
katherine heiho again so you know if a
hurricane never hit land would it be
disaster if we didn't live along the
coastline would a hurricane be a
disaster no we'd be like oh a hurricane
hit 100 miles over there but we live
over here
putting ourselves in harm's way is what
causes this suffering and often for many
people they don't have a choice it's not
like they can choose where they live and
whether it's in houston or miami or new
york or whether it's in mumbai or
madagascar
it's always the people who already have
the short end of the stick who are
suffering the most from these impacts
and these vulnerabilities says hey ho
will intensify with climate change we've
had hurricanes on this planet before we
had humans
so it isn't that climate change is
creating hurricanes it's taking
something that already exists and making
it a lot worse
climate change is what the us military
now calls a threat multiplier it takes
every other issue we are already
concerned about today and it makes it
worse
[Music]
what trends are you seeing
in public opinion now you know are you
finding
fewer people are receptive to scientific
evidence are you seeing the opposite is
your job getting easier or harder i want
to share my favorite cartoon with you i
know we can't see the cartoon but let me
just tell you what it says
and in the cartoon there's a set of
physicians who are saying to each other
well surely if we just tell the public
the facts about covid and vaccines
everybody will do the right thing and
then beside them you see a bunch of
climate scientists literally rolling on
the floor laughing
it's black humor because we have said
the same thing for decades if we just
tell the public their facts yes we've
checked it is not volcanoes it's not
natural cycles it absolutely is us it's
bad we need tac now everybody will just
do it
right
no wrong
catherine heyjo says people who are
dismissive of climate change get a lot
of air time
and so we tend to think the biggest
problem is that there's people who just
don't know the science
it turns out that people who are
dismissive are only seven percent of the
population
a very loud percent but 75 say yeah sure
it's i know it's real
but only 35 percent of us think it
matters
that's the biggest gap we have
and there's even a name for it it's
called psychological distance
[Music]
do you think it will affect me and
everybody just says no we don't think it
matters to us and so that's why talking
about it is so important not talking
about greenland or polar bears or
antarctica talking about what's
happening where we live how wildfires
are burning greater area how the smoke
is making our kids sick how the
hurricanes flooded our home how
extreme heat put people in the hospital
where we live
connecting the dots between what we
already care about our health number one
our kids and our families health the
safety of the place that we live the air
that we breathe the food that we eat
that is the number one thing that every
single one of us can do to help move the
needle on climate action
when i was a student i thought climate
change was an environmental issue that
environmentalists cared about and the
rest of us sort of wished them well
what i've learned is that climate change
is an everything issue
sure it's an environmental issue but
it's also a health issue it's an
economic issue it's a national security
issue it's a poverty issue and a hunger
issue a humanitarian issue a refugee
crisis issue
and so by extension to care about
climate change we don't have to be a
certain type of person we don't have to
vote a certain type of way we only have
to be one thing and that one thing is a
human who lives on this planet
[Music]
nova now is a production of gbh and prx
it's produced by teres bernardo ari
daniel jocelyn gonzalez isabel hibberd
sander lopez monsalve and rosslyn
tordesillas
julia court and chris schmidt are the
co-executive producers of nova sookie
bennett a senior digital editor
christina monan is associate researcher
robin kasmar is science editor and devin
robbins is managing producer of podcasts
at gbh
our theme music is by the dj who can
always keep the party surging dj kid
koala
i'm alok patel we'll be back in two
weeks which is more than enough time for
you to get prepared in the event of a
natural disaster
you may want to gather important phone
numbers an emergency medicine kit locate
local shelters make sure you have food
water supply power source important
documents keep gas and a first aid kit
in your car and go over an emergency
evacuation plan with your friends and
family and keep a lookout for those pets
as well stay empowered and stay safe
gbh