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