so we all know that sea level is rising at least most of due or belief they do
at least most of due or belief they do
at least most of due or belief they do hundreds of millions of people are
hundreds of millions of people are
hundreds of millions of people are living very close to sea level I come
living very close to sea level I come
living very close to sea level I come from the Netherlands I actually lived
from the Netherlands I actually lived
from the Netherlands I actually lived more than half my life below sea level
more than half my life below sea level
more than half my life below sea level in Manhattan alone
in Manhattan alone
in Manhattan alone billions of dollars of infrastructure is
billions of dollars of infrastructure is
billions of dollars of infrastructure is built as meters from sea level so we
built as meters from sea level so we
built as meters from sea level so we have reason to worry about sea level
have reason to worry about sea level
have reason to worry about sea level rise but how do we know that sea level
rise but how do we know that sea level
rise but how do we know that sea level rise is real well you can start we had
rise is real well you can start we had
rise is real well you can start we had this before sorry this is my fault
this before sorry this is my fault
this before sorry this is my fault you can start building a tide gauge near
you can start building a tide gauge near
you can start building a tide gauge near the shoreline normally it consists of a
the shoreline normally it consists of a
the shoreline normally it consists of a float attached to a wire attached to a
float attached to a wire attached to a
float attached to a wire attached to a recording device when the extent of the
recording device when the extent of the
recording device when the extent of the wire gets less sea level goes up of
wire gets less sea level goes up of
wire gets less sea level goes up of course such a tide gate sees a lot of
course such a tide gate sees a lot of
course such a tide gate sees a lot of tidal variation ocean tides but that we
tidal variation ocean tides but that we
tidal variation ocean tides but that we can take out what is left might indicate
can take out what is left might indicate
can take out what is left might indicate that sea levels rising but how do we
that sea levels rising but how do we
that sea levels rising but how do we know for sure that sea levels actually
know for sure that sea levels actually
know for sure that sea levels actually going up and it’s not the tide gauge
going up and it’s not the tide gauge
going up and it’s not the tide gauge that is sinking because that can happen
that is sinking because that can happen
that is sinking because that can happen if we extract water drinking water
if we extract water drinking water
if we extract water drinking water ground water from underneath the tide
ground water from underneath the tide
ground water from underneath the tide gauge it will start sinking and so it
gauge it will start sinking and so it
gauge it will start sinking and so it does when you extract gas or oil in
does when you extract gas or oil in
does when you extract gas or oil in Scandinavia the opposite is happening
Scandinavia the opposite is happening
Scandinavia the opposite is happening the land is actually lifting making it
the land is actually lifting making it
the land is actually lifting making it look like sea levels going down that
look like sea levels going down that
look like sea levels going down that lifting is because the earth is relaxing
lifting is because the earth is relaxing
lifting is because the earth is relaxing from the ice load in the last glacial
from the ice load in the last glacial
from the ice load in the last glacial period so in order to know exactly if we
period so in order to know exactly if we
period so in order to know exactly if we measure sea level change we need to
measure sea level change we need to
measure sea level change we need to monitor the vertical motion of this tide
monitor the vertical motion of this tide
monitor the vertical motion of this tide gauge and this we can do by putting on a
gauge and this we can do by putting on a
gauge and this we can do by putting on a tie gauge
tie gauge
tie gauge a GPS receiver the GPS receiver can tell
a GPS receiver the GPS receiver can tell
a GPS receiver the GPS receiver can tell you where you’re going in your car it
you where you’re going in your car it
you where you’re going in your car it can also tell you where the tide gauge
can also tell you where the tide gauge
can also tell you where the tide gauge is going even when the motion of the
is going even when the motion of the
is going even when the motion of the tide gauge is ever so slow so with this
tide gauge is ever so slow so with this
tide gauge is ever so slow so with this method we can tell what Silla was doing
method we can tell what Silla was doing
method we can tell what Silla was doing locally but if you have one tide gauge
locally but if you have one tide gauge
locally but if you have one tide gauge it tells you only what happens near you
it tells you only what happens near you
it tells you only what happens near you it doesn’t tell you what happens
it doesn’t tell you what happens
it doesn’t tell you what happens globally it doesn’t even tell you where
globally it doesn’t even tell you where
globally it doesn’t even tell you where it comes from so what we need to do is
it comes from so what we need to do is
it comes from so what we need to do is install many of these tide gauges this
install many of these tide gauges this
install many of these tide gauges this is a set of tide gauges from an
is a set of tide gauges from an
is a set of tide gauges from an international database you see there are
international database you see there are
international database you see there are many of them but aren’t each tide gauge
many of them but aren’t each tide gauge
many of them but aren’t each tide gauge is controlled for vertical and motion
is controlled for vertical and motion
is controlled for vertical and motion well then let’s look if they have tide
well then let’s look if they have tide
well then let’s look if they have tide gauges miss a GPS receiver if you don’t
gauges miss a GPS receiver if you don’t
gauges miss a GPS receiver if you don’t have a GPS receiver nearby we take them
have a GPS receiver nearby we take them
have a GPS receiver nearby we take them away now we also need to know if they
away now we also need to know if they
away now we also need to know if they have a long enough time record because
have a long enough time record because
have a long enough time record because we want to separate the climate signal
we want to separate the climate signal
we want to separate the climate signal which is long term from shorter signals
which is long term from shorter signals
which is long term from shorter signals like a Nino so let’s take away the ones
like a Nino so let’s take away the ones
like a Nino so let’s take away the ones that have a record of less than let’s
that have a record of less than let’s
that have a record of less than let’s say 15 years now we have very few tide
say 15 years now we have very few tide
say 15 years now we have very few tide gauges left to tell us if sea level is
gauges left to tell us if sea level is
gauges left to tell us if sea level is rising
rising
rising some of the coasts are not covered at
some of the coasts are not covered at
some of the coasts are not covered at all and in the middle of the ocean there
all and in the middle of the ocean there
all and in the middle of the ocean there are very few only add some islands so we
are very few only add some islands so we
are very few only add some islands so we still don’t know if sea level rise is a
still don’t know if sea level rise is a
still don’t know if sea level rise is a global phenomenon so how can we solve
global phenomenon so how can we solve
global phenomenon so how can we solve this the solution is simple if not
this the solution is simple if not
this the solution is simple if not elegant we simply put the tide gauge on
elegant we simply put the tide gauge on
elegant we simply put the tide gauge on a satellite and replace the wire with a
a satellite and replace the wire with a
a satellite and replace the wire with a radar post as the radar pulse travels
radar post as the radar pulse travels
radar post as the radar pulse travels through space and through atmosphere to
through space and through atmosphere to
through space and through atmosphere to the sea surface and goes back time is
the sea surface and goes back time is
the sea surface and goes back time is ticking and this travel time tells us
ticking and this travel time tells us
ticking and this travel time tells us exactly how high the satellite is above
exactly how high the satellite is above
exactly how high the satellite is above the sea sir
the sea sir
the sea sir we also put on this satellite another
we also put on this satellite another
we also put on this satellite another GPS receiver this tells us independently
GPS receiver this tells us independently
GPS receiver this tells us independently how high the satellite is above some
how high the satellite is above some
how high the satellite is above some reference service the difference between
reference service the difference between
reference service the difference between those two heights is sea level now we
those two heights is sea level now we
those two heights is sea level now we have a satellite radar altimeter and we
have a satellite radar altimeter and we
have a satellite radar altimeter and we can start measuring sea level everywhere
can start measuring sea level everywhere
can start measuring sea level everywhere in the globe at least where the
in the globe at least where the
in the globe at least where the satellite is flying we take a
satellite is flying we take a
satellite is flying we take a measurement every second to a position
measurement every second to a position
measurement every second to a position of 3 centimeters the errors come from
of 3 centimeters the errors come from
of 3 centimeters the errors come from limitations of the instrumentation
limitations of the instrumentation
limitations of the instrumentation for my knowledge of the position of the
for my knowledge of the position of the
for my knowledge of the position of the satellite as well as that we have to
satellite as well as that we have to
satellite as well as that we have to take into account delays in the
take into account delays in the
take into account delays in the atmosphere which you don’t know exactly
atmosphere which you don’t know exactly
atmosphere which you don’t know exactly this satellite is going around and after
this satellite is going around and after
this satellite is going around and after 10 days it will cover the globe entirely
10 days it will cover the globe entirely
10 days it will cover the globe entirely with measurements of 3 centimeters of
with measurements of 3 centimeters of
with measurements of 3 centimeters of height accuracy measuring 3 centimeters
height accuracy measuring 3 centimeters
height accuracy measuring 3 centimeters from an elevation of 100 1,300
from an elevation of 100 1,300
from an elevation of 100 1,300 kilometers that’s like measuring the
kilometers that’s like measuring the
kilometers that’s like measuring the span of the Golden Gate Bridge sorry
span of the Golden Gate Bridge sorry
span of the Golden Gate Bridge sorry that yes the span of the Golden Gate
that yes the span of the Golden Gate
that yes the span of the Golden Gate Bridge
Bridge
Bridge losing the thickness of a human hair now
losing the thickness of a human hair now
losing the thickness of a human hair now we have 10 days of these Infirmary
we have 10 days of these Infirmary
we have 10 days of these Infirmary disinformation and if we average all
disinformation and if we average all
disinformation and if we average all these measurements over 10 days we get
these measurements over 10 days we get
these measurements over 10 days we get global mean sea level over that 10 days
global mean sea level over that 10 days
global mean sea level over that 10 days we do that another 10 days and surely
we do that another 10 days and surely
we do that another 10 days and surely but surely we build up a time series of
but surely we build up a time series of
but surely we build up a time series of global mean sea level but with one
global mean sea level but with one
global mean sea level but with one satellite at some point the satellite
satellite at some point the satellite
satellite at some point the satellite runs out it is a limited time span
runs out it is a limited time span
runs out it is a limited time span before that happens we need to launch
before that happens we need to launch
before that happens we need to launch another satellite and we have to make
another satellite and we have to make
another satellite and we have to make sure that while they are flying
sure that while they are flying
sure that while they are flying simultaneously that they are measuring
simultaneously that they are measuring
simultaneously that they are measuring this
this
this thing so here in this plot do you see
thing so here in this plot do you see
thing so here in this plot do you see various satellites measuring the same
various satellites measuring the same
various satellites measuring the same thing while they’re flying together and
thing while they’re flying together and
thing while they’re flying together and the picture becomes clear sea level is
the picture becomes clear sea level is
the picture becomes clear sea level is rising and it’s rising at the rate of
rising and it’s rising at the rate of
rising and it’s rising at the rate of three millimeters pa over the last 25
three millimeters pa over the last 25
three millimeters pa over the last 25 years but how do we know for sure that
years but how do we know for sure that
years but how do we know for sure that these satellites that we call the
these satellites that we call the
these satellites that we call the reference mission are not measuring some
reference mission are not measuring some
reference mission are not measuring some fake trend because there is something in
fake trend because there is something in
fake trend because there is something in their instrumentation well that’s why
their instrumentation well that’s why
their instrumentation well that’s why are not just looking at these
are not just looking at these
are not just looking at these measurements scientists all throughout
measurements scientists all throughout
measurements scientists all throughout the world are looking painstakingly at
the world are looking painstakingly at
the world are looking painstakingly at the data of many altimeter satellites
the data of many altimeter satellites
the data of many altimeter satellites that have been operated since 99 to 1 by
that have been operated since 99 to 1 by
that have been operated since 99 to 1 by several of the vs. space agencies humans
several of the vs. space agencies humans
several of the vs. space agencies humans at at this moment is operating two of
at at this moment is operating two of
at at this moment is operating two of them jason-3
them jason-3
them jason-3 and Sentinel 3 both under the Copernicus
and Sentinel 3 both under the Copernicus
and Sentinel 3 both under the Copernicus program of the European Commission and
program of the European Commission and
program of the European Commission and the picture is clear all of them show
the picture is clear all of them show
the picture is clear all of them show the same thing the sea level is rising
the same thing the sea level is rising
the same thing the sea level is rising by 3 millimeters per year and we even
by 3 millimeters per year and we even
by 3 millimeters per year and we even start to see an S eration but where is
start to see an S eration but where is
start to see an S eration but where is all this water coming from for one thing
all this water coming from for one thing
all this water coming from for one thing we are melting land ice glaciers are
we are melting land ice glaciers are
we are melting land ice glaciers are retreating everywhere around the globe
retreating everywhere around the globe
retreating everywhere around the globe the edges of Greenland are rapidly
the edges of Greenland are rapidly
the edges of Greenland are rapidly melting in Western Antarctica the ice
melting in Western Antarctica the ice
melting in Western Antarctica the ice sheet is thinning
sheet is thinning
sheet is thinning this moves mass from the land into the
this moves mass from the land into the
this moves mass from the land into the ocean it is changing the gravity field
ocean it is changing the gravity field
ocean it is changing the gravity field of the earth and there are two
of the earth and there are two
of the earth and there are two satellites that measure exactly that the
satellites that measure exactly that the
satellites that measure exactly that the changes in the gravity field it can tell
changes in the gravity field it can tell
changes in the gravity field it can tell us how much of the mass is taken away
us how much of the mass is taken away
us how much of the mass is taken away from the land and dumped into the ocean
and that can tell us how much sea level
and that can tell us how much sea level has written just by melting the ice you
has written just by melting the ice you
has written just by melting the ice you see that in this plot and again you see
see that in this plot and again you see
see that in this plot and again you see a rising trend another reason why sea
a rising trend another reason why sea
a rising trend another reason why sea level is rising is because we are
level is rising is because we are
level is rising is because we are heating the oceans
heating the oceans
heating the oceans greenhouse gases trap heat in the
greenhouse gases trap heat in the
greenhouse gases trap heat in the atmosphere and ninety-three percent of
atmosphere and ninety-three percent of
atmosphere and ninety-three percent of that heat and ZAPPIN Yoshii when water
that heat and ZAPPIN Yoshii when water
that heat and ZAPPIN Yoshii when water is heated is expands so that too will
is heated is expands so that too will
is heated is expands so that too will cause sea levels rise we have hundreds
cause sea levels rise we have hundreds
cause sea levels rise we have hundreds of these floats called Argo floods
of these floats called Argo floods
of these floats called Argo floods drifting around the ocean regularly they
drifting around the ocean regularly they
drifting around the ocean regularly they plunge down to one thousand two thousand
plunge down to one thousand two thousand
plunge down to one thousand two thousand meter deep measuring along its path
meter deep measuring along its path
meter deep measuring along its path temperature and salt content then it
temperature and salt content then it
temperature and salt content then it comes up and sends their measurements to
comes up and sends their measurements to
comes up and sends their measurements to a satellite and then to a ground station
collecting all this information we can
collecting all this information we can tell how much the oceans are heating and
tell how much the oceans are heating and
tell how much the oceans are heating and how much they will be expanding that
how much they will be expanding that
how much they will be expanding that creates another plot this red line and
creates another plot this red line and
creates another plot this red line and again we see a rise about one millimeter
again we see a rise about one millimeter
again we see a rise about one millimeter per year sea levels rising dust by
per year sea levels rising dust by
per year sea levels rising dust by heating the red line about two
heating the red line about two
heating the red line about two millimeters per year the sea level is
millimeters per year the sea level is
millimeters per year the sea level is rising as a result of adding mass into
rising as a result of adding mass into
rising as a result of adding mass into the ocean because we are melting the
the ocean because we are melting the
the ocean because we are melting the earth the lab ties together that gives
earth the lab ties together that gives
earth the lab ties together that gives three millimeters per year the purple
three millimeters per year the purple
three millimeters per year the purple line now remember that independently we
line now remember that independently we
line now remember that independently we had also been measuring sea level from
had also been measuring sea level from
had also been measuring sea level from satellite altimeters that’s this white
satellite altimeters that’s this white
satellite altimeters that’s this white line and we see a striking resemblance
line and we see a striking resemblance
line and we see a striking resemblance not only gives you exactly the same
not only gives you exactly the same
not only gives you exactly the same three millimeters per year but even on
three millimeters per year but even on
three millimeters per year but even on shorter time scales we see the same
shorter time scales we see the same
shorter time scales we see the same thing this gives us an enormous
thing this gives us an enormous
thing this gives us an enormous confidence in our measurement two
confidence in our measurement two
confidence in our measurement two completely different ways of measuring
completely different ways of measuring
completely different ways of measuring the same thing we are measuring sea
the same thing we are measuring sea
the same thing we are measuring sea level rise or three minutes per years of
level rise or three minutes per years of
level rise or three minutes per years of the last
the last
the last 95 years but it is sea-level rising
95 years but it is sea-level rising
95 years but it is sea-level rising everywhere the same and that’s shown in
everywhere the same and that’s shown in
everywhere the same and that’s shown in this plot remember I told you that these
this plot remember I told you that these
this plot remember I told you that these satellites the satellite altimeters are
satellites the satellite altimeters are
satellites the satellite altimeters are coming back every 10 days in the same
coming back every 10 days in the same
coming back every 10 days in the same spot so at the same point every 10 days
spot so at the same point every 10 days
spot so at the same point every 10 days can make a trend at that location
can make a trend at that location
can make a trend at that location the yellow colors here so and the red
the yellow colors here so and the red
the yellow colors here so and the red colors show where sea levels rising
colors show where sea levels rising
colors show where sea levels rising that’s almost everywhere in the western
that’s almost everywhere in the western
that’s almost everywhere in the western Pacific it’s even more than 3 mini
Pacific it’s even more than 3 mini
Pacific it’s even more than 3 mini meters video goes up to about 10 million
meters video goes up to about 10 million
meters video goes up to about 10 million meters per year and we think that is
meters per year and we think that is
meters per year and we think that is because of strengthening of the El Nino
because of strengthening of the El Nino
because of strengthening of the El Nino currents strengthening of the process
currents strengthening of the process
currents strengthening of the process that spans oceans and atmosphere there
that spans oceans and atmosphere there
that spans oceans and atmosphere there are some spots where you see some light
are some spots where you see some light
are some spots where you see some light blue some drop near of ocean currents we
blue some drop near of ocean currents we
blue some drop near of ocean currents we think that is due to freshening of water
think that is due to freshening of water
think that is due to freshening of water we all studied as precisely and figure
we all studied as precisely and figure
we all studied as precisely and figure out what is actually going on but these
out what is actually going on but these
out what is actually going on but these kind of information will tell us more
kind of information will tell us more
kind of information will tell us more about sea level rise now where is the
about sea level rise now where is the
about sea level rise now where is the impact of Silla override the largest
impact of Silla override the largest
impact of Silla override the largest well of course it’s very large in
well of course it’s very large in
well of course it’s very large in coastal areas with a dense population in
coastal areas with a dense population in
coastal areas with a dense population in estuaries like in Bangladesh or Islands
estuaries like in Bangladesh or Islands
estuaries like in Bangladesh or Islands low-lying islands where people have
low-lying islands where people have
low-lying islands where people have nowhere else to go like some of the
nowhere else to go like some of the
nowhere else to go like some of the islands in the Maldives also coral reefs
islands in the Maldives also coral reefs
islands in the Maldives also coral reefs are inundating with a rising sea level
are inundating with a rising sea level
are inundating with a rising sea level that is eroding the coral reefs the
that is eroding the coral reefs the
that is eroding the coral reefs the coral reefs are already struggling from
coral reefs are already struggling from
coral reefs are already struggling from the heating ocean and then the
the heating ocean and then the
the heating ocean and then the acidification so what have we learned
acidification so what have we learned
acidification so what have we learned here sea level is rising sea levels
here sea level is rising sea levels
here sea level is rising sea levels rising by about 3 metres per year over
rising by about 3 metres per year over
rising by about 3 metres per year over the last 25 years we know there are two
the last 25 years we know there are two
the last 25 years we know there are two causes melting of the land ice water
causes melting of the land ice water
causes melting of the land ice water ending up in the ocean the second is
ending up in the ocean the second is
ending up in the ocean the second is that the oceans are heating and thus
that the oceans are heating and thus
that the oceans are heating and thus expanding and those of these things we
expanding and those of these things we
expanding and those of these things we can measure very well by
can measure very well by
can measure very well by satellites by GPS with Grace with
satellites by GPS with Grace with
satellites by GPS with Grace with satellite radar altimeters that we
satellite radar altimeters that we
satellite radar altimeters that we process here Jim Assad and the
process here Jim Assad and the
process here Jim Assad and the communication satellites that bring the
communication satellites that bring the
communication satellites that bring the satellite information around and all of
satellite information around and all of
satellite information around and all of this shows a continuous sea level rise
this shows a continuous sea level rise
this shows a continuous sea level rise it’s undeniable it’s relentless it is
it’s undeniable it’s relentless it is
it’s undeniable it’s relentless it is irrevocable
irrevocable
irrevocable as long as we are keep on heating our
as long as we are keep on heating our
as long as we are keep on heating our planet and our ocean and our player blue
planet and our ocean and our player blue
planet and our ocean and our player blue dot thank you
”
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