Climate changewhy the urgency
hello
my name is jamie and i’m a geologist
what that means is i’ve spent the better
part of my adult life
explaining to people that i don’t just
study rocks i’ve told this to my family
i’ve told this to my friends i’ve told
this to
border control agents instead i study
the earth
and there are a lot of things that
really excite me about the
earth for example in the image that you
see here
i study the interaction between the
surface waters of the ocean
and how those interact with the
atmosphere to form the sort of swirling
spheres that you see
across the tropical ocean there and
those are the storm tracks that we know
the hurricanes that bring us all sorts
of weather
i study very interesting interactions
between
life in the surface ocean with the water
and the atmosphere
i study really interesting interactions
between life on land with the soil and
extreme environments
and what that’s taught me to learn
which you can’t say it says dear
inhabitants is to understand
and listen to the earth in a way that i
think
most of us don’t really understand on a
day-to-day life
or in our day-to-day life and so
what i want to share with you today over
20
years of research that i’ve been doing
are the sort of
lessons learned so how many of you have
seen the figure over here on the left
by show of hands
just a few on the left here what we’re
looking at
is how co2 is changing in our atmosphere
so that’s carbon dioxide
so carbon dioxide as you can see since
about 1956
has been rising and we know that largely
to david keeling here who started
measuring the amount of co2 in our
atmosphere
back in 1956 and for those of you who
have a keen eye
instead of just the black line that
you’ve been seeing you can see this red
line that sort of
underlines that black line so if we look
just the past
five years this red line you can see
goes up
and it goes down and that’s happening
over an annual cycle
if you think about why that’s actually
happening it’s really fascinating
so most of the vegetation on earth is
located in the northern hemisphere
and the trees here as an example so
in at the start of spring trees start to
get their leaves they start to grow
they photosynthesize and we would start
at the top of one of these red peaks
and as those trees and plants in the
northern hemisphere photosynthesize
they breathe in and they breathe in the
carbon dioxide
there’s so many of them that we can
actually measure that in the global
atmosphere
and then during autumn and during winter
those trees they lose their leaves the
plants start to
become dormant and that co2 starts to
increase again
until spring comes again so that’s what
we’re seeing here
if that were the only thing that was
happening on earth in terms of the
carbon dioxide
the black line that you see would just
be a flat line hovering around whatever
the concentration was
in the atmosphere but instead we see
that that’s rising
and david keeling back as early as 1960
was able to tell that that was rising
and he was able to tell that that’s due
to fossil fuel burning
and how we’re changing land use
so if we look again at the record from
1956
till today being a geologist and
studying the earth
allows me to think about things in
longer time periods the earth’s been
around a lot longer than the rest of us
have been and so
often we don’t think about the very long
time scales
so we can actually extend this record
back through time
by using ice cores
that are over 3000 meters long they were
collected by scientists
and they come from antarctica and
they’re able to look at the little
bubbles within these ice cores
and measure the atmosphere in those
bubbles and that gives us a record of
how carbon dioxide
has changed through much longer time
periods
so the first one that i’m going to show
you now is we’re going back to 1700
ad so i’ve i’ve extended time in that
direction
which means the part we were looking at
before is just here all squished up to
the top so
this is the change that we were looking
at from 1956 till present
and what you can see over 300 years of
time and said
is that carbon dioxide in the atmosphere
has been rising since maybe around the
mid
1800s or so and we can see that
the change in co2 and the increase in
co2 in the atmosphere is increasing
a lot more towards the present time
which is shown by the steepness of that
line
so we can look back even further in time
we can go all the way to 10
000 years ago and when we look across
this time frame
carbon dioxide has been relatively
stable over that time period in the
global sense and we can start to see
that
the changes that we’re seeing today
are a lot more obvious and they’re a lot
more different from what we saw
previously and even though co2 is quite
stable during this time period
there are periods in time when there
have been major cultural
and land changes so if you were to time
travel
back 8 000 years ago and you were going
to go to the african sahel
you would look around you and you would
describe the landscape as green
wet lush rivers whereas today
even though there were not huge global
changes that happened at
over the course of time today it would
be a very arid landscape and if you were
trying to make your living here it’d be
quite difficult
another example is the mayan
civilization
which around 1300 years ago
collapsed and the collapse of the mayan
civilization civilization
is attributed to the droughts that they
experienced along with social pressures
but you can see in this global record of
carbon dioxide
very little was happening globally at
the time
although locally there were very severe
droughts that occurred
so this is the furthest back in time
we can extend our record from the vostok
ice core this is 800 000 years ago
and you can see today is all the way up
here
one of the things that you might see in
the record is we’re seeing sort of
cycles similar to what we saw on an
annual basis
from the trees breathing in and
breathing out and what this is actually
showing us
is what the earth is doing over very
long time scales almost as a built-in
thermostat so you can see that
these periods of time where there’s
rises
happen really quickly and those are
warming periods going into interglacials
similar to where we are today and
the long long cooling trends that we see
going down
these are glacial periods these are
periods where a large part of the
northern hemisphere is actually
covered in miles of ice it’s a very
thick ice
and it’s what we can see is
and what we know is is that these high
co2
fast co2 events correspond with very
quick
warming temperatures there’s feedbacks
in the sim
system that amplify those but
the main processes earth has
for this cooling is to
dissolve mountains and dissolve rocks so
rain water dissolving granite so if you
drip drain water
on your kitchen counter made of granite
until it dissolved those are the sort of
time scales it takes
for the earth naturally to take carbon
dioxide out of the atmosphere
so if we look at the kind of changes
that are happening today
scientists have been able to do a lot of
clever things to understand what’s
happening
and one of the ones that concerns me
that i want to share with you
is about ocean heat content so they’ve
been able to go back to
very early measurements of ocean
temperatures
this is the challenger this is an
expedition that went out in the late
1800s
and they’re able to combine the
measurements from these shipboard
measurements
with more recent um high-tech kind of
measurements and what you can see here
is back from those original measurements
um on the challenger how ocean heat
content has changed
so in the light blue here if you can
make it out that’s the surface ocean
in the medium blue that’s kind of the
middle ocean and
in the dark blue here what you’re seeing
is we’re making measurable changes
to the heat content of the ocean down
below two kilometers
so a very large volume of water
and the thing that concerns me is
that in the first 132 years of the
record
there’s been a hundred and fifty
zeddjoules of energy absorbed and it
doesn’t concern me because i know what
azettagil is because i don’t
um but it concerns me because if you
look from 1997
to 2015 in the record the same amount
of heat energy has been absorbed as it
took 132 years to absorb previously
in terms of a zetta jewel one
joule is the amount of energy it would
take to lift an
apple so you can’t see it here because
of the lights
but one zetta jewel is 10 to the 21
joules so 10 to the 21 apples you’d have
to be able to carry to equal a zededual
and the authors explain that as being
if you dropped an atomic bomb the size
of hiroshima
every second for a year that would be
two zeddy jewels
and so what we’re talking about within
those 18
years that we’ve put 150 zetta jules in
that would be the equivalent
of basically exploding a hiroshima bomb
every second for 75 years which is
a humanly inconceivable amount of energy
that we’re storing in the oceans
what do we know about what happens with
the energy in the oceans
we know the ocean heat content drives
things like storms and storm tracks
and the intensity of storm trucks um
and although that was a tropical one
that we just looked at
some of my research is looking at what
happens this is showing the atmosphere
how the jet stream moves from north
america
across the atlantic ocean towards the uk
towards europe and i study places both
in the uk
and in europe and unfortunately the
projection
for the uk is that we’re going to get
wetter
so we’re going to be kind of stuck in
this phase where
a lot of water gets delivered to us but
you’ll notice down here
in spain while these sort of
images might be more common here
in spain where i do research aridity is
continuing to happen
so i study some of these environments
that are very high in elevation
and it’s because they’re very sensitive
to climate and they kind of give us a
forewarning of what’s happening
in these sites that i study so this is
one of the lakes that i study down here
la mosca this catchment has lost all of
its glaciers and in fact the sierra
nevada in southern
spain is the first mountain range to
lose all of its glaciers
and it lost them back in 1920.
this here similar to the ice cores are
the kind of records that i work with
this is mud from the bottom of the lake
that i had just shown you a picture of
and what we know from investigating this
lake mud and the things that it contains
is that these sites have already warmed
over two degrees in terms of summer
temperatures
and we know that the warming that’s
happening in these high elevation
sites is higher than anything we’ve seen
in the last 2000 years
and so these are the things that sort of
concern me and i think that other people
need to hear about
if you’ve paid attention to the
intergovernmental panel on climate
change
they’ve had a report that came out in
2018
and what they suggested that there’s
major consequences
for us overshooting that 1.5 degree
target
if we if we overshoot it by even half of
a degree
some of the things that they talk about
are the insects will be
twice as likely to lose half of their
habitat
99 of corals will go extinct
rather than in the current scenarios
under 1.5 degrees
they have a 10 chance of surviving
and then we know too that as as we just
looked at heat content as you warm water
it expands in addition to melting ice
sheets
sea level rise if we hit that 2 degree
mark would affect 10 million more people
than it’s predicted to hit at the moment
so sorry this hasn’t come up quite right
but this is the reason why
many people such as jim hansen
who used to be the director of nasa
goddard
who makes all the climate models
prominent
environmental attorneys and concerned
citizens are getting together
and they’re trying to get the message
out
that climate change is happening
in terms of it being an emergency it’s
something that the scientific community
has felt
all the way back since the 70s jim
henson was testifying in front of
congress in the u.s
and i think if the earth were to speak
to us today
it would ask us to give the earth a
voice
and basically say that it’s not too late
but we need to act collaboratively
and we need to act now so thank you