The science behind a climate headline Rachel Pike

I’d like to talk to you today about the

scale of the scientific effort that goes

into making the headlines you see in the

paper headlines that look like this when

they have to do with climate change and

headlines that look like this when they

have to do with air quality or smog

they’re both two branches of the same

field of atmospheric science recently

the headlines looked like this when the

Intergovernmental Panel on Climate

Change or IPCC put out their report on

the state of understanding of the

atmospheric system that report was

written by 620 scientists from 40

countries they wrote almost a thousand

pages on the topic and all of those

pages were reviewed by another 400 plus

scientists and reviewers from 113

countries it’s a big community it’s such

a big community in fact that our annual

gathering is the largest scientific

meeting in the world over 15,000

scientists go to San Francisco every

year for that and every one of those

scientists is in a research group and

every research group studies a wide

variety of topics for us at Cambridge

it’s as varied as the El Nino

oscillation which affects weather and

climate to the assimilation of satellite

data to emissions from crops that

produce biofuels which is what I happen

to study and in each one of these

research areas of which there are even

more there are PhD students like me and

we study incredibly narrow topics things

as narrow as a few processes or a few

molecules and one of the molecules I

study is called isoprene which is here

the small organic molecule probably

never heard of it the weight of a

paperclip is approximately equal to 900

Zeta iliyan 10 to the 21st molecules of

isoprene but despite its very small

weight enough of it is emitted into the

atmosphere every year to equal the

weight of all the people on the planet

it’s a huge amount of stuff it’s equal

to the weight of methane and because

it’s so much stuff it’s really important

for the atmospheric system because it’s

important for the atmospheric system we

go to all lengths to study this thing we

blow it up and look at the pieces this

is the U for smog chamber in Spain

atmospheric explosions or full

combustion takes about 15,000 times

longer than what happens in your car but

still we look at the pieces we run

enormous models on supercomputers this

is what I happen to do our models have

hundreds of thousands of grid boxes

calculating hundreds of variables each

on minut timescales and it takes weeks

to perform our integrations and we

perform dozens of integrations in order

to understand what’s happening we also

fly all over the world looking for this

thing

recently joined a field campaign in

Malaysia there are others we found a

global atmospheric watchtower there in

the middle of the rainforest

and hung hundreds of thousands of

dollars worth of scientific equipment

office tower to look for isoprene and of

course other things while we were there

this is the tower in the middle of

rainforest from above and this is the

tower from below and on part of that

field campaign we even brought an

aircraft with us and this play in the

model ba one four six which is run by

Pham normally flies 120 to 130 people so

maybe you took a similar aircraft to get

here today but we didn’t just fly it we

were flying at 100 meters above the top

of the canopy to measure this molecule

incredibly dangerous stuff we have to

fly in a special incline in order to

make the measurements we hire military

and test pilots to do the maneuvering we

have to get special flight clearance and

as you come around the banks in these

valleys the forces can get up to 2 GS

and the scientists have to be completely

harnessing in order to make measurements

while they’re on board so as you can

imagine the inside of this aircraft

doesn’t look like any plane you would

take on vacation it’s a flying

laboratory that we took to make

measurements in the region of this

molecule we do all of this to understand

the chemistry of one molecule and when

one student like me has some sort of

inclination or understanding about that

molecule they write one scientific paper

on the subject and out of that field

campaign will probably get a few dozen

papers on a few dozen processes or

molecules and as a body of knowledge

builds up it will form one subsection or

one sub subsection of an assessment like

the IPCC although we have others and

each one of the eleven chapters of the

IPCC has six to ten subsections you can

imagine the scale of the effort in each

one of those assessments that we write

we always tag on a summary and the

summary is written for a non-scientific

audience and we hand that summary to

journalists and policy makers in order

to make headlines like these thank you

very much

you