from New York Times opinion this is the

Ezra client show

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hey it is Ezra I am on book leave but

this week taking a turn at the mic is

David Wallace Wells he is a times

opinion writer he's the author of the

uninhabitable earth life after warming

and I just think that over the past

couple of years not just his work on on

climate change and biodiversity loss but

also has worked particularly on covid

has been absolutely fantastic so I asked

him to come on and do a couple shows

around these themes I hope you enjoy

from the perspective of the climate it's

been a hellish and disorienting summer

this June was the hottest June on record

July was the hottest July on record in

Phoenix all but one day in July crossed

110 degrees Fahrenheit

the city's burn units were filling up

with people who'd fainted on the street

and been burned by the asphalt which

measured as hot as 180 degrees

of course

is not all bad news there is genuinely a

Green Revolution underway and it's

moving much faster than what many

believe possible just a few years ago

emissions haven't yet begun to decline

but Renewables are being rolled out at

such a pace and at such a low cost

that many analysts believe will hit a

carbon Peak sometime this decade

conventional modeling suggests that in

just five years we may have cut our

expected warming for this Century almost

in half

but that doesn't mean we can declare

victory

over the last decade there's also been a

flurry of new science showing that

climate risks we once expected in some

worst case scenarios

May instead arrive with much less

warming and while all of those

projections come wrapped in uncertainty

one worrying possibility is that for all

that rapid decarbonization we may not

end up on net in a much better place

which is all to say that thinking

clearly about the state of climate

change requires now holding two pretty

contradictory seeming ideas in your head

at once we're finally taking action and

quite rapidly

but the planet is changing too perhaps

even more rapidly

to help talk me through where we are

today and where we're heading

there's no one I'd want to speak to more

than Dr Kate Marvel the senior climate

scientist at project drawdown she's just

about the best person I know at holding

those two different ideas in perspective

at once

as always you can email the show with

your thoughts and guest recommendations

at Ezra client show at nytimes.com

okay Marvel welcome to the podcast thank

you so much for having me so we're

talking in early August which means a

lot of the official July temperatures

have just sort of come in and it looks

like it was a really hot month and I

think the data I was looking at this

morning said that we broke the previous

record for the hottest month ever by

0.33 C which means

we didn't just nudge the record up we

broke it by like a quarter of all of the

warming we've ever done in human history

just this summer so I think in a certain

way it looks like a kind of a summer of

climate Reckoning or climate Awakening

on the other hand it seems like we sort

of do this every summer last year we had

extreme heat that killed 61 000

Europeans we had these dried riverbeds

and for all across Europe in the US too

in China but somehow this summer has

felt to me at least a little bit

different how has the summer look to you

I mean the first thing that comes to

mind when I think about this summer is

how unsurprised I am and how climate

scientists were at least mentally

prepared for extremely hot temperatures

this summer and that is because of two

things that's because of climate change

and that's because of the El Nino

conditions in the tropical Pacific El

Nino is a completely natural climate

phenomenon that after the seasonal cycle

is the primary source of variability in

the climate it's basically where you get

warmer than average temperatures off the

coast of Peru in the equatorial Pacific

and because the entire Earth system is

connected those have reverberations

across the globe so we've got this El

Nino condition but it's nowhere near as

strong as the strongest El ninos on

record in 1998 and 2016. which means we

think it's contributing less warming at

this point than previous ones yes and

the Really significant thing that it's

overlaid on top of is climate change

just to pull back for a minute I wanted

to ask you a really big picture question

which is

is warming speeding up this summer as

we've been going through all of these

sort of unusual events and trying to

make sense of them there have also been

a couple of Assessments suggesting that

over the last decade maybe the rate of

warming is moving up a little but then

there are other people looking at the

data and saying it's quite a linear

Trend how do you assess the state of

warming and what you think we might

expect over the next decade which is

likely to be defined not by dramatic

emissions increases not by dramatic

emissions decreases but probably

something like a plateau what are we

looking at you know are things getting

warmer faster or are we basically moving

forward at the same rate we were before

the short answer is I don't know

the longer answer is

probably 10 years ago you would probably

have been asking me is warming slowing

down and that's because following the

massive El Nino event of 1998 you could

if you kind of squinted draw a line

across global average temperatures that

didn't look like it was Rising very much

you can reassess the data and it looks

like it's rising a little bit but this

led to a lot of discourse about the

so-called Hiatus in warming you even had

people on the floor of the Senate saying

there hasn't been any global warming for

10 years where is your science now

and the reason for that is that there

was a small slowdown in the warming

these decades can happen we can have

Hiatus decades we can have surge decades

which is just a reminder that these

processes that we're talking about

tend to play out over very long periods

of time and because we are humans with

the lifespans that we have and because

the story of the emissions perturbation

is the story that we have which is

depending on how you want to count a

century and a half or maybe even just a

few decades old we want to tell stories

in really short time frames but the

climate system doesn't exactly cooperate

exactly and so there's the role of

internal variability where sometimes you

know in the Hiatus decades so following

you know the big El Nino of 1998 we seem

to have experienced cooler than average

conditions in the equatorial Pacific for

an extended period of time kind of a

protracted opposite of El Nino a la

nina-like state that gave rise to large

cloud cover over those regions and that

was a stabilizing feedback that

prevented lots of warming those

conditions are now gone and so there is

an explanation where that is just

internal variability sometimes this

happens sometimes the reverse happens

what for me is a much more interesting

question is the different things that

were we call it forcing the climate

system the different external influences

that are at play in the climate system

so there was a pronounced slowdown in

warming between about

1940 to about 1980. a large contributor

of that is what we call aerosols so

pollutants what sort of normal people

think of as pollution particulate matter

that comes off of burning coal plants

burning oil

that was a seriously huge problem in

North America and in Western Europe

and that not only showed up in Health

Data and the daily lives of people in

those regions I also showed up in the

global average temperature because

aerosols reflect sunlight which means

that when there are a lot of them out

there less sunlight is cutting to Earth

and therefore the warming effect is

limited not just reflecting sunlight so

aerosols are also extremely effective at

seeding clouds so there was that direct

effect of aerosols or gas and dust that

is blocking this on but they are also

making clouds which themselves block the

Sun and so we have pretty good reason to

believe that aerosol emissions were

masking the warming it would have been

warmer had those aerosol emissions not

been there now right now the world is

not emitting zero aerosols even though

after clean air legislation in the U.S

and Western Europe

the aerosol emissions from those regions

have substantially Fallen but they've

grown elsewhere

globally aerosol burden has declined but

the burden of aerosols has largely

shifted so we're looking at emissions

from South and East Asia right now

and we expect in the future that those

aerosols are going to be cleaned up we

have already seen Air Pollution Control

happening in China in particular but as

populations notice this they they do not

necessarily normalize it they demand

changes they demand action

and so in industrializing countries the

pattern tends to be that air pollution

gets really really really bad as the

country is industrialize and then people

get really really angry about it and

something is done about it

so it is an unalloyed good thing that

air pollution is projected to fall in

the future but in terms of the climate

impact we're going to see less of that

masking we're going to see less stuff in

the atmosphere that's reflecting the Sun

and so that is a really really important

problem in the future that even if we

got rid of all fossil fuel

infrastructure tomorrow

in the short term we would see a spike

in temperature because of that air

pollution which is killing us but also

blocking the Sun and the size of that

spike is there's a lot of uncertainty

around it even more than some of the

other forcings but my understanding is

that the sort of median estimate is that

it's offering about a half a degree

celsius of cooling and that some

estimates get quite close to a full

degree of Celsius of cooling which we're

not going to be cutting that pollution

tomorrow instantaneously but in a sort

of a imaginary model world where you did

do that you could be dealing with a

quite dramatic Spike not just the

equivalent of this July but something

like a much larger and more pronounced

effect and maybe even over the next few

decades seeing as much warming from

aerosol reduction is from additional

carbon emissions yeah I do want to be

very clear that that is not a reason not

to cut aerosol emissions but it is

something that we have to be aware of

there is a big difference though between

aerosols and greenhouse gases in how

they get into the atmosphere and what

they do once they're there so all of the

greenhouse gases we're talking about are

well mixed in the atmosphere so that

means it doesn't matter who emits them

somebody in America it's them somebody

in China miss them somebody in Australia

doesn't matter every molecule of

greenhouse gas put in the atmosphere has

the same warming effect no matter where

it comes from aerosols are far more

localized their impact depends on

prevailing winds their impact depends on

where they are emitted and they don't

live very long in the atmosphere after

they're put there

foreign

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the way I read a lot of the sort of

real-time scientific analysis says that

a lot of these anomalies that we've seen

this year are within the range of what

was possible so in that sense as you say

it sort of confirms some of the

predictions and models that we've made

but they're also on the high end and I

wonder exactly how you think we should

think about that pair of facts that it's

not that these events are showing us

that our science is off but it is

showing us that we may be at least in

particular areas on particular points

skiing along the high end of what we

thought was possible at this level of

warming there are ways of interpreting

that as a comforting set of facts and

their ways of interpreting it as a

discomforting set of facts so how do you

think about it

from my perspective as a physical

scientist which I do not expect to be

the same perspective as you know a

normal person but for me when there is a

discontinuity or a disconnect between

what the models say and what is actually

happening my first question is why

is it just because while weird stuff

happens sometimes and you know this just

happens to be an event that is is

unusual or is it some fundamental

process that we're missing is there

something we don't understand about the

science

and in some cases we have identified

things that we don't understand about

the science and there are a whole bunch

of excited scientists trying to work on

those problems to try to figure out the

thing that we don't know

I think it is unnecessarily fatalistic

to say oh is the science right or is it

wrong I think for me the important

question is what do we understand and

what don't we understand and why I think

that kind of gets us into a broader

question about what climate models are

supposed to do

a climate model is supposed to be one

not in which the world as we know it

actually happens but it's something in

which the world we know it is possible

and what I mean by that is a climate

model is not designed to capture what we

call the internal variability of the

climate system the natural random slosh

back and forth of air and water that

kind of determines day-to-day weather

and even seasonal conditions like an El

Nino a climate model is not designed to

say in 1998 there was an El Nino and

this year there is an El Nino and in

three years there's going to be a la

nina a climate model instead you can run

it over and over and over again and

every time you run it the conditions are

going to be slightly different the slosh

of air and water are going to be in a

slightly different position and so a

climate model is not a weather model

it's not designed to sort of predict

short-term conditions or even

medium-term conditions what they should

do is they should reproduce the

statistics of these events they should

get the statistics correct and that

brings us into kind of a weird place

because when we're talking about the

statistics of extreme events

when we call them extreme events we're

kind of acknowledging that these things

are historically really rare it's really

hard to get those statistics and so we

are really reliant on the models to kind

of tell us like is this expected or not

how far out of the normal is this is

there going to be a normal anymore what

is that new normal going to look like

and I think the question of is it worse

than we expected that's often quite

oversold I think in the discussion like

my question to that is well did you

check because a lot of these you know

record-shattering events no climate

model was able to exactly predict in

2021 in the Pacific Northwest there is

going to be a devastating Heat Wave but

if you look at the emergence of these

record-shattering conditions climate

models pretty much say that they should

be happening you shouldn't just expect

records to be broken you should expect

them to be shattered

yeah I mean one thing that calls to my

mind and I'm reading this literature a

little bit more of a distance than you

are is just it's just striking to me

that we're talking about this summer

using all these variables which are much

more prominent in the discourse than

they were a few years ago and that's

just like we are still figuring things

out we are still learning and as a

result it makes me feel like as we're

entering into this time of real

transformation climate transformation

we're also being confronted with this

huge amount of uncertainty around

everything we know we have models that

they have confidence intervals but like

living that confidence interval means

actually living under a lot of

uncertainty because are you going to

land at the fifth percentile outcome

you're gonna land at the 95th percentile

outcome those are huge differences and

mentally we sort of calibrate our

expectations on the median projections

but like the world is telling us that

like climate and climate change is

actually quite a bit messier than taking

a median projection to the bank

absolutely for a long time I personally

have been really reluctant to talk about

on certainty because it is so easily

weaponized by bad faith actors so I want

to be really clear we don't know

everything but we don't know nothing

there are certain things that we are

very very very confident in carbon

dioxide methane nitrous oxide these are

greenhouse gases they make the Earth

warmer you put more of them in the

atmosphere you are going to see warming

that's not something that really any

serious scientist disputes that's just

very very basic physics then when it

comes to well what does that actually

mean what does it mean to live in a

world that's getting warmer again there

are some things that we are incredibly

confident in because they're just basic

physics warmer air is thirstier air you

are getting more evaporation from the

surface of the Earth

that water has to go somewhere and so on

average precipitation rates increase as

well at the same time we know that warm

air can hold more water vapor so the

carrying capacity of air for water vapor

increases by about seven percent for

every degree celsius we warm and what

that means is that when we do have these

heavy downpours there is more water to

dump on us that's something that we

understand really really well but then

what does that mean for rainfall in a

particular town a particular area that's

where we start really running into the

limitations of our knowledge the

limitations of of models in general

and that's because the Earth is an

incredibly complex interconnected system

and that complexity can make it really

really difficult to make solid firm

projections

a lot of times uncertainty is seized

upon because people think oh it's

uncertain well it could be terrible but

it could also be great and so it'll

probably be fine and I think it's really

important to be clear that we have ruled

out fine it's not going to be fine

warming is going to have consequences

and uncertainty is not our friend

because if we had that degree of

certainty if we knew sea levels will

rise exactly this amount and then they

will stop and warming will stabilize at

exactly this amount and it will stop we

would be able to make rational

adaptation decisions they would be

difficult they would be costly but we

would be able to make those decisions

because because there is that

fundamental uncertainty in the system

that's impeding our ability to make

decisions and to adapt to what's coming

and what's already here

one thing I think about is science

always has uncertainty built into it but

it's also just this crazy uncertainty

experiment that we're running by moving

the planet's climate into a new climate

system in which they're going to be a

lot of similarities and continuities but

they're going to be some things that are

really different and so there's beyond

the sort of basic scientific humility of

like acknowledging uncertainty there's

also just you know we're running this

experiment for the first time and we

have very good educated guesses about

where it will lead us but it's the risk

of running an experiment like this at

all is that they're going to be some

things that surprise us when you and I

last spoke it was about a year ago and

it was for a piece I was doing about

kind of the narrowing window of climate

future so a lot of apocalyptic things a

lot of apocalyptic future seemed you

know relatively speaking less likely

although we couldn't rule them out

entirely and as you just said a minute

ago a lot of the everything's going to

be fine soft Landing Futures where we're

also looking

pretty unlikely if not impossible one of

the other people I spoke to for that

piece was Catherine hayo and she said

something to me that I've been thinking

about a lot this summer which was you

know we've definitely done a lot in

decarbonization to reduce the upper

limit of our expected warming we're

thinking we're going to see less warming

than we thought was likely five years

ago that's great but we're also learning

a lot about when climate extremes arise

when really big impacts might hit us

hard and mostly we're learning that

those are happening sooner and faster

than we might have thought five or ten

years ago and you see a sort of similar

story unfolding in the Tipping points

discourse where the people who have been

most worried about tipping points used

to talk about them as risks at higher

levels of warming and are now talking

about them as risks at lower levels of

warming maybe even at levels of warming

like the one we're at right now and I

wonder if that is how you see the really

big picture here that even as we're

doing quite a lot to take control of

global temperature rise through

decarbonization not enough but a lot

we're also learning about how messy and

risky life at even lower temperatures

would be

I agree I think a lot of times people

are tempted to see a Paris agreement

warming Target like two degrees Celsius

or 1.5 degrees which is the high

ambition warming Target which a lot of

people are really focused on right now

those targets are not very meaningful

scientifically the Earth doesn't really

know the difference between 1.5 and 1.6

so a lot of times people think well

tipping points will definitely be

triggered if we cross a particular

threshold and that goes back to the

question of uncertainty I don't have

enough certainty I don't have enough

science nobody does to be able to say we

are safe if we limit warming to a

particular level

the flip side is also true we are not

doomed if we exceed 1.5 we are not

doomed if we exceed two if we blow past

a particular Target I think the UN

messaging is correct that it's every

tenth of a degree that matters

but going back to your question of when

might we expect these tipping points to

be breached that's something that keeps

a lot of scientists up at night so the

scientific definition of a Tipping Point

is

something that you cross that you can't

get back within time scales relevant to

human lives or human civilizations so

some of the Tipping points that we're

really worried about have to do with the

circulation of the atmosphere or the

ocean that's something that is very very

worrisome well talk us through a little

bit maybe about each of those and what

it would look like to cross those

thresholds and be on the other side of a

Tipping Point sure so let's talk a

little bit about what the ocean actually

does for us the ocean is incredibly

important in the climate system it's

obviously a near Infinite Source of

water that's where water gets evaporated

from that then gets turned into clouds

and rain and goes back

it also is really really effective at

taking up both carbon and heat so the

ocean's taking up about 25 percent of

anthropogenic carbon dioxide emissions

that's not for free a lot of that is

going into acidifying the ocean

the ocean is also very effective at

taking up heat it's absorbing the

equivalent of five nuclear bombs a

second of kind of anthropogenically

added heat heat that humans have put in

the atmosphere and another way of just

thinking about that first just to jump

in for a second is it's something like

90 of the extra heat the global warming

is produced goes into the ocean which

means they're getting nine times as much

of an impact as we're getting on lands

the oceans that's right the ocean does a

lot um the ocean also moves quite a lot

of heat around in the climate system the

currents that have names the currents

that we think about are generally

surface currents things like the Gulf

Stream those are driven by the winds and

the rotation of the earth and the Gulf

Stream and other surface currents will

exist no matter what we do they will

exist as long as the Earth is round and

rotating but those surface current

systems are superposed on a deeper

longer term circulation which we call

the thermohaliens circulation and that

is really driven by not wind but density

so what happens when water flows north

to the Arctic for example in the

Atlantic eventually a lot of it forms

sea ice the Left Behind water that

doesn't form the sea ice is saltier it's

cold it's dense and that makes it sink

so at the bottom of the ocean we have

this sort of river of failed ice that is

flowing and it's flowing Southward

eventually that water upwells it comes

to the surface again and it closes that

Loop so we have this density driven

ocean conveyor belt that moves over

hundreds of thousands of years water

around the Earth's oceans and when the

circulation of that gets messed up we

could expect to see large disruptions to

things like precipitation patterns we

have really good evidence that in the

70s and 80s pollution particulate matter

what we call aerosols from Western

Europe and North America actually cooled

the North Atlantic and there is a lot of

evidence that links that to a migration

of the rain band especially over the

Sahel and Africa so that is just kind of

an example of how again interconnected

everything is other things scientists

are thinking about are disruptions to

the arrivals of the seasonal monsoons

much like the rainfall in the Sahel that

I discussed

the monsoons are are very seasonal and

enormous walls of the world population

is dependent on Monsoon rain fed

agriculture so any disruption we have to

the monsoon could have massive massive

humanitarian consequences and that's

only the circulation category of tipping

points we might see

and those are systems that if they move

into a new phase we would expect to not

recover on the time scale of of

centuries right it would take longer

than that yes so then how does that

change the way that you think about the

broader Story I mean one thing I've as

I've been Reckoning with a lot of this

material that's occurred to me is that

we have so much science and so much

science communication about climate

change impacts this Century but thinking

about tipping points really does sort of

pull your mind a little bit further into

the future and force you to think about

climate change as a millennial kind of

event how do you balance those two

perspectives in your mind like because

there are plenty of things that like

you know may result in relatively

manageable climate Futures over the

course of the next 50 years but over the

course of the next five centuries or 10

centuries we'll be much more disruptive

I mean sea level rise is probably the

most obvious of those but how do you

balance those two different time scale

perspectives living living in the

present where we're making decisions

living a little bit in the medium-term

future where we think about the sort of

consequences of those decisions for our

children and their grandchildren and

then in the much deeper future where

we're like thinking about a world that's

probably in ways totally independent of

climate very transformed from the one

that we know today

you can ask a question what is the

warming commitment that we've already

locked in even if we zeroed out

emissions tomorrow

if we zeroed out emissions tomorrow the

consensus among most of the models is

that warming would stop

you would have a balance between two

effects so the ocean would continue to

warm up but at the same time the natural

carbon cycle would start to slowly

remove some of that carbon that's

accumulated in the atmosphere and the

net effect of those is essentially no

more warming and this is one of the

reasons why getting to Net Zero is so

important it's not just because it

actually allows us to stop warming it

could over the course of a century or so

would allow us to undo some of it too in

theory net negative would probably undo

it because again at Net Zero you've got

this you know natural drawdown of some

of the CO2 in the atmosphere but at the

same time you've got the ocean still

responding and so the compensation of

those is not that warming decreases but

warming stops in order to get warming to

decrease you generally need to do

something extra to take CO2 out of the

air whether those are enhancing land or

ocean natural sinks or engineering a

sink so you know sucking CO2 out of the

air somehow

but then the question is okay well if

warming stops whenever we stop emitting

does that mean climate change stops and

the answer is no because we are still

not finished responding to the warming

that has already occurred so even if we

did zero out emissions tomorrow and even

if we froze the temperature at 1.2

degrees Celsius above pre-industrial

temperatures

the Earth system is not done responding

to that and so we expect to see some

amount of sea level rise into the Far

Far Future as a result of that

so that's kind of one way of answering

your question we are not committed to

further warming we can stop anytime we

want to but we are not yet done

responding to the warming that's

occurred already

I've seen estimates for the amount of

additional warming that would be

required to keep carbon concentration

stable which is to say to prevent the

carbon cycle to draw down that carbon

and keep warming going as opposed to

even stopping it at something like one

to two gigatons a year and maybe that's

not precisely right there's uncertainty

around that but you know it just is

really striking to me that the Canadian

wildfires we've seen this year have

already emitted more than a gigaton of

carbon and we're not expecting those to

happen every single year but the idea

that we can be sure that if we manage

our emissions as aggressively as we can

that there aren't going to be some

surprises like those Canadian fires that

are contributing additional carbon and

preventing us from drawing down what's

in the atmosphere already that seems

quite scary that brings up another

potentially scary thing which is the

idea of a carbon cycle feedback so as

you pointed out things that live on the

surface of the planet either in the

ocean or on the land take carbon dioxide

out of the atmosphere by photosynthesis

to make themselves grow

you know a forest takes carbon dioxide

out of the atmosphere not because it

loves us not because it wants to absolve

humans of what we do but because it

needs the carbon dioxide to grow like

trees exist to exist and when they are

done existing they are done sequestering

that carbon dioxide and if we Bank on

trees to take the carbon dioxide out of

the atmosphere for us what happens when

we make it too hot for certain types of

trees to survive

there's a lot of worry speaking of

tipping points that the Amazon

rainforest and other tropical

rainforests could switch from being a

net sink of carbon dioxide removing it

from the air to a net source of carbon

dioxide and so these carbon cycle

feedbacks how are living things on the

planet going to respond to increased

warming those are big wild cards the

uncertainties are large it's almost

never a good story none of the models

are projecting a significant uptick in

the ability of the biosphere to remove

carbon in the future

so that kind of gets back to should we

do that experiment and I think no I

don't want to know what the carbon cycle

feedbacks are I don't want to know how

sensitive the Earth is to doubled carbon

dioxide I don't want to know the answer

to any of these research questions that

I'm interested in I don't think we

should do that experiment

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one of the things that has always struck

me about your writing and you're

thinking that not just your scientific

work but in your sort of more essayistic

work is how much you do Center the sort

of the human elements there's these

climate dynamics that are going on some

of them we understand quite well others

a little bit less well but we have a

pretty good sense of you know the broad

trajectory of climate change we may even

have a relatively good sense of where

the energy transition is going but all

of that is like interacting and

interfacing with the world that we have

built socially politically economically

through culture through infrastructure

and in addition to the climate

experiment we're running we're also

running this other quite messy

experiment which is like how does a

planet warmed by say two degrees or two

and a half degrees interact with the

civilization that we built under

conditions of zero degrees of warming

and even putting aside like whether the

infrastructure works or doesn't how does

it interact with our politics and our

economics to be

responding to and adjusting to a world

that's as distorted or contorted as a

world of two or two and a half degrees

would be I wonder if you could talk a

little bit about that about the human

element how you think we're doing on

that front you know politically

culturally psychologically are we making

the right sense of the changes that

we're seeing out in the world are we

confused about it like are there things

that you think the public should better

understand or you wish the public would

better understand about

what is being asked of us as people in

addition to what we're doing to the

planet itself

I think I am probably the worst person

in the world to ask that question no

because I am a physicist right like it

is my job to understand how air and

water move around in the system and air

does exactly what physics tells it to do

it's really easy to understand it always

does the same thing it fits inside an

equation really well there are

uncertainties that come from the fact

that there's a lot of air there's a lot

of water there's a lot of land it's all

interacting but fundamentally those

things do what you tell them to do

because they are obeying the laws of

physics people do not do what you tell

them to do that's why I find them

fascinating but that's also why I don't

understand them and I don't make any

pretense to having any sort of special

Insight or moral superiority to tell

people what to do

I do find people very interesting though

and I do find past examples of how

people have reacted to past climate

change to be completely fascinating so

in between you know the 1300s 1400s to

about the 1700s in the northern

hemisphere we seem to have experienced

relatively cool conditions something

that's sometimes called the little Ice

Age the best attribution Science Now

sort of thinks that was due to a mixture

of some circulation changes in the North

Atlantic and primarily a series of

really powerful volcanic explosions

which blocked the sun cooled down the

planet at least partially

and if you look at the history

especially in Europe of the little Ice

Age things start getting real weird you

start seeing an increase in religious

conflict you also start seeing an

increase in witch burnings and a lot of

times the witches that are getting

burned are getting burned or hung or

executed or accused because of something

they have done to the weather they have

raised the storm they have killed the

crops they have made the winds blow they

have done something

and it's really fascinating to look at

the linkages between the weather getting

weird and these cultural impacts that

come out of it now do I think that

climate change is going to lead to an

increase in witch burning no but it does

show how climate change happens in the

world that we've built for it and that's

something that is impossible to fit in

an equation it's impossible to have a

model that's at all meaningful that says

that well as carbon dioxide

concentrations increase the number of

old women who are going to be accused of

Witchcraft is also going to increase

that's not something that makes any

sense but that really does show the

fundamental unpredictability of human

beings and human civilizations in the

face of adversity sometimes there is

conflict you know people fight each

other

sometimes there is collaboration which

one of those is more likely to happen

well I think both are going to happen in

the future and I think it's really

impossible to have a grand unified

theory of a species that's so deeply

weird as we are

yeah I want to talk a little bit in a

minute about the suitability of the

world as we have built it for the

climate that we are entering into but

before we get to that I just wanted to

pick up on a couple threads from that

last answer I was just reading an

article in The Economist about the heat

waves and in it they drew on this work

by Marshall Burke and Sal Shang and

Edward Miguel about the relationship

between climate and conflict which

suggested that as temperatures global

average temperatures got hotter we might

see some significant additional conflict

mostly at the interstate and Civil War

kind of level and The Economist was

saying just looking at the anomalous

temperatures in July we might see like

50 more conflict than we would see

otherwise without that warming and I

emailed Marshall and said well I know

your data was like based on long-term

average trends like is this a fair

leap to make and he said well we're

actually updating it for monthly

averages and the numbers aren't very

different so I wouldn't be surprised if

that was actually how it netted out and

that is absolutely astonishing to think

about even in the range of possibilities

here but it also brings to mind all of

these other questions about how we talk

about the attribution of really

complicated events and episodes to

climate change or not how do you think

about

how to talk about that complicated web

of causality and how do you think the

world as a whole is doing and

understanding just how complicated those

Dynamics really are I think we need to

acknowledge that we're not going to get

the comfort of this false binary we're

not going to be able to say climate was

the only Factor but that doesn't mean

it's not a factor take for example

wildfires wildfires are dependent on

many different things they're dependent

on the weather hot dry conditions

they're dependent on the amount of fuel

they're dependent on ignition so either

lightning or Human Action and they're

dependent on suppression the damage they

do really depends who's Living In Harm's

Way

and not all of those things are amenable

to description by physics I focus a lot

on the physical causes because that's my

job that's my expertise but when we talk

about wildfires let's take for example

even though we're here on the East Coast

we've had impacts from Eastern Canadian

wildfires let's talk about wildfires in

the west because the science is much

more robust when we talk about wildfires

in Western North America

we do know that the hot dry conditions

that are more conducive to fire fire

weather those are getting much more

likely we also have reason to believe

that we're going to see much like a

swingier precipitation really really wet

wet Seasons really really hot and dry

dry seasons that has implications for

fuel right if you have a really really

wet winter you could have a lot of

vegetation growing and that vegetation

is going to dry out in the summer and

burn so those things are kind of

amenable to description via equations we

can say this is our knowledge of physics

this is how it's changing but what does

that mean in terms of the ability or the

desire of humans to venture into forests

and build campfires or have gender

reveal parties or whatever you know you

are looking at the culmination of not

just current policy choices but a long

history of policy choices who gets to

live on that land who gets driven off

that land who gets to make these

decisions and again I can't put it in a

climate model but it doesn't mean that

it's not vitally crucially important

yeah I mean Wildfire I think is a really

powerful example for a number of reasons

but one of the things that I always find

myself thinking about is you know

hearing occasionally from people who say

we shouldn't worry all that much about

the trends in Wildfire because fires

used to be much more pervasive in the

American West 500 years ago 200 years

ago and that's true there was more

burning in those forests in the past but

also there were not 40 million people

living in California there were probably

less than one million and the way that

we think about those risks has a huge

amount to do with those 40 million

people not just the fires themselves and

whether 2020 was merely the worst season

in 130 years or whether it was the worst

season in 500 years

and

even in a relatively steady climate

trajectory where things are getting kind

of predictably worse our experience of

that climate may still involve quite a

lot of shock moments because the world

that we've built

out in you know the infrastructural

world but also our political systems our

emotional infrastructure all of that is

calibrated to climate conditions we've

already left behind and as a result

there's going to be some episodes in

which we can tolerate some amount of

additional warming and some higher

impacts and risks but then at a certain

point that gets broken you know if you

think about sea level rise and floods

and a small flood wall can protect some

high days of flooding then you've got to

really you know even just the last foot

can have a completely devastating impact

on the city I wonder how you think about

that set of questions like the degree to

which we are all of us living on

assumptions from an earlier climate era

how much we have to do to navigate the

new world full of more climate risks and

how far along in that process we are at

a policy level but also at a you know

emotional sort of intellectual level so

first of all no adaptation is not really

an option anymore we have no choice but

to adapt to the changing climate because

climate change is already here I was

watching a documentary the other day and

it was kind of old it was about 15 years

old and I was so struck by the fact that

they were using polar bears to

illustrate climate change and I was

thinking nobody really does that anymore

because it's so obvious that this is not

a problem that just affects polar bears

this is a problem that is affecting us

and it's something that we are going to

have to prepare for at the same time you

sometimes hear this very glib like oh

we're rich we'll just adapt especially

in wealthy countries and there is no

just to the adaptation because first of

all if you don't reach Net Zero if you

don't stop climate change it's a

constant moving Target adapt to what on

the other hand adaptation means

something really really drastic it means

relocation of communities it means maybe

abandoning really beloved areas

it is an extraordinary undertaking that

doesn't mean that it's not necessary

that doesn't mean that it's not possible

but I don't think we should be glib

about it at all

along the way there there's also the

risk I think that as we see more and

more intense impacts start to adapt to

some degree we also adapt by normalizing

and by acclimatizing to things that we

would have considered unworkable and

unlivable conditions not that long ago

and I think that you know our experience

with Wildfire smoke here is pretty

Illuminating which is to say like there

were people who worried about smoke

impacts from fires five years ago in

California but most people worried about

property damage and lives lost and towns

being destroyed then starting in 2020

when we had these really eerie images

from San Francisco really bad toxic air

days I think the public started to worry

a bit more about smoke and and public

health impacts but those of us living in

the east coast were like well that's

crazy Californians they're dealing with

that that's well beyond what I could

tolerate in my own life and then we had

a few days depending on how you want to

count a few days or a few weeks of

really bad air here and

almost like by the second or third day

the emotional calibration at least of

people I knew was like well I guess this

is going to be a thing now

it wasn't to treat this impact which

five years ago we would have thought of

as totally intolerable as still

intolerable it was to incorporate that

into our understanding of the next 10 or

15 years of our lives and there's a way

in which that's quite healthy because

probably it is going to be a feature of

at least our worries if not coming every

summer but it also tells us something

about how quickly we're redefining our

standards for a comfortable climate

capable of sustaining human flourishing

and how differently we're defining those

terms in order to allow ourselves some

safe operating space emotionally for

living in that world I'm actually going

to disagree with you because what what

is a podcast without a good fight so I

actually think we cannot normalize this

and we have to push back really really

hard when you say cannot you mean that

it's beyond our capacity or do you mean

that we have to resist it we have to

resist it yeah we have to resist it and

I think there has been a strain in

climate storytelling of fatalism and

sometimes that fatalism is coupled with

while humans are bad and terrible and

this is our divine judgment our

punishment sometimes it's scolding like

you are terrible and this is your

punishment I have to live within I hate

you and sometimes it's just very sort of

fatalistic there's nothing we can do

about climate change we're just going to

have to live like this for the rest of

our lives

when the Cuyahoga River caught on fire

the air quality was terrible in New York

but that would have been kind of a

moderately bad day not that much

different than normal you know in my

parents Lifetime and that was normalized

for a long time until it wasn't until it

became clear that there were Solutions

now I don't want to say that any

particular single piece of legislation

can ever solve all of the problems but

the Clean Air Act of 1970 which was not

passed by a wonderful loving Man Who

Loved Humanity in the environment that's

not how you described Richard Nixon no

it's not but you know there was a

Confluence of factors there was

increased scientific understanding of

where this problem was coming from and

what we could do about it there was

popular pressure the first Earth day was

1970 lots of people out on the streets

marching School groups Church groups and

there was a president who saw an opening

not because he was a lovely warm fuzzy

wonderful person but because the

conditions made this possible and I

think there are a lot of stories of

environmental success in the record none

of them are perfect analogies for where

we are that's what it means to be living

in the future we are not living in a

story that has ever happened before I'm

sorry that's just what it means to be

alive but I think we cannot normalize

this we cannot say the climate is just

going to change and we're going to blow

past all of these targets and it's just

going to get worse and worse and worse

like I think we have to demand this is

we don't like this we don't

want to live like this instead of

accepting it well I think as a sort of

political goal and value said that's

totally admirable but when I think about

for instance the way that people in

Florida or California are responding to

the end of insurance for their homes

we're not seeing a mass Exodus in fact

we're still seeing to some degree in

some parts of those States real

population growth we're seeing tons of

people flooding to the parts of the US

where climate impacts are expected to be

most intense and maybe that's a sign of

optimism about our ability to redesign

our future to allow us to live in those

conditions but it also seems like not

necessarily the most rational response

to a climate we know is changing and

suggests that on the whole at a

population level even as we're

endeavoring to limit warming and

endeavoring to make a future that's more

livable we're also coming to accept

climate outcomes that a decade or a

generation ago would have seemed quite

horrifying to many of us I mean I think

we have no choice but you know you say

accept I say continue to live through

yeah you know like I don't know

precisely what the boundary between

acceptance and and merely continuing to

exist is yes these are conditions that

are happening the skies in New York were

orange earlier this summer in Phoenix

it's been over 100 degrees for however

long these are conditions that are

happening I think that it is completely

appropriate to demand that they not

happen you know we can't demand no

global warming we're already at 1.11.2

degrees above pre-industrial

temperatures we can't put that cap back

in the back we can't say we want no

global warming but we can say we want to

limit global warming and we want

sensible adaptation measures and both of

those things are incredibly tall orders

but that's what politics is for right

like we want to live in a society we

want there to be buildings built we want

there to be roads we want there to be

Subways and all of those things are way

way bigger than any one person can

deliver but we want them so we have them

and I think we need to say this is not

acceptable this is not normal and things

have to change

and when you take off your physicist hat

and put on like your politics hat like

how do you assess the state of climate

politics in the U.S and more generally

around the world I mean obviously

we're moving faster than used to be the

case there's more General consensus

about the fact of the problem the

necessity of taking some action in

response to it than even just five years

ago you know across the world but we're

still falling short of the goals and

targets that we sort of collectively set

for ourselves even as some of those

targets start to seem less safe than

they might have seen five or ten years

ago so how do you think about the state

of Politics as it relates to this

challenge like how do you calibrate your

own sense of of where we are and where

we're headed I have scrupulously avoided

having a politics hat I don't want one

what I can say from my personal

experience is I have noticed a sea

change

5 10 15 years ago there was only one

story that ever got told about climate

change and it was is it happening let's

get all of these scientists who say it

is and like this one guy says it's not

all right let's have them fight and I

understand where that came from the urge

to sort of inject conflict and drama

into what's fundamentally a really

really difficult thing to wrap your mind

around

sometimes it would be scientists

fighting with guy in a suit sometimes it

would be like look at this sad polar

bear it's gonna die and it's all your

fault because you're a bad person but

those were really the only stories that

ever got told and in I want to say 2018

because that was the release of the un's

1.5 degree Special Report which Maya

culpa I was grouchy about I thought it

was fan fiction I thought well there's

no way we're going to limit warming to

1.5 degrees why are you doing this and

you know like oh boy what the world

needs is another report great let's do

that again and for reasons that I don't

understand I was so wrong I was so wrong

about how that was going to be received

I was so wrong about how that would land

and it started something

um now the same year that Greta started

striking the foundation of XR yeah the

the synonym of uh Sunrise Sunrise talk

about tipping points that's not

something that I was able to anticipate

and now I almost never get asked is it

real I almost never get asked well what

does climate change mean and why should

I care instead I get asked the really

good questions about uncertainty about

what's happening about how we can

prepare about what we can do

and for me personally the fact that we

are talking about what we can do is

really exciting because all I ever

wanted to be in the climate debate and

climate politics was irrelevant

and I am really really rapidly as a

scientist approaching that point where I

am not the first point of contact if

you're writing a climate story you don't

necessarily go and talk to a scientist

and say oh hey is this real is this

really happening you're gonna go and

you're going to talk to somebody who

works in renewable energy you're going

to talk to an electrician you're going

to talk to somebody trying to craft

climate policy

you're going to talk to an entrepreneur

and now there are so many more stories

to be told about climate and that's

something that is a massive massive sea

change for me yeah I mean I I think

you're being too modest about being

irrelevant even speaking on behalf of

climate science because I do think that

there are these really important

questions about exactly what it means

the difference between two and two and a

half degrees particular impacts in local

plan like there's a huge amount for

science to tell us I do think we're

living in a different world now where we

do see the Machinery of decarbonization

actually finally getting going we're

starting to see that show up in our

understanding of and our projections for

the future all of that's extremely

exciting but I worry a little bit that

the story of progress and

decarbonization is crowding out some of

these other challenges and these other

difficulties that we are excited to be

on the march to net zero even if it's

going to be in 2070 as opposed to 2050

and we're excited to be you know making

impossible the scariest climate Futures

that some of us worried a lot about a

few years ago but that doesn't mean that

the challenges aren't real and real

right in front of us and may even prove

quite catastrophic when all is said and

done and I wonder how you think about

those questions as a sort of

Storytelling level which is we obviously

need to be talking about both of these

things at once the things that the

climate is telling us about how

different and likely how how much harder

life will be because of climate changes

but also

everything we're doing to take control

of those challenges both for limiting

warming and through adapting but finding

that balance feels to me like pretty

hard and maybe it feels hard to me

because I'm just on a roller coaster

about it in one month I feel one way and

one month I feel the next way about it

how do you think about it yeah again as

a kind of a storytelling level I think

all I can do is answer from myself so I

don't feel one particular way about

climate change I feel many different

ways about climate change some days I'm

very excited I'm very kind of Joyful by

looking at all of the work that's being

done sometimes I'm really afraid

sometimes I'm really really angry and I

think that's completely appropriate and

normal and natural to hold all of these

things in my head going back to your

question before about the time scales I

want to kind of invert that question

because that's the way that I think

about this a lot so there's a really

negative story you could tell where even

if we get everything right even if if we

reached Net Zero and 2050 like we're

supposed to and all of these amazing

Technologies come online and we rebuild

our entire Energy System our

transportation system we really

transform our farm system we do

everything right

we're not really going to be able to

tell climate wise for decades the best

case scenario from a climate perspective

is just less bad than it would be

otherwise and that's because it takes a

really really long time for these

changes to kind of percolate through the

system for you to distinguish the signal

from the noise so it's going to take

decades to say oh we're in the good

place as opposed to the bad place or not

the good place the less bad place

but if you

if he got the near-term benefits you get

rid of a coal-fired power plant and

immediately the next time it rains that

washes out all of the gross particulate

matter pollution the black coal plant

put in the atmosphere so you get cleaner

air almost immediately

that starts to show up in mortality

morbidity statistics really really

really quickly and just to put a pin on

it for the listeners like those numbers

are horrifyingly large you know some

estimates in the millions annually dying

from the pollution from fossil fuel

burning the estimates that I've seen say

air pollution is a factor in 11 of

deaths worldwide we're talking millions

and millions and millions of preventable

deaths so air pollution is a killer air

pollution is disgusting and air

pollution is not something that we have

to live with you know if I wanted to use

the linga I'd say that is a co-benefit

of climate Solutions but that is a

massive near-term benefit and there is a

large research literature that says that

we're going to see less infant mortality

we're going to see if we do this we're

going to see less mortality morbidity

we're going to see people living longer

healthier lives we're also going to see

increases in things like labor

productivity

now if we adopt various other climate

Solutions we get co-benefits in terms of

better biodiversity not cutting down

forests is a climate solution and that's

going to have co-benefits that show up

much much much quicker than any climate

benefit and so if you invert that and I

think about this a lot so in the ipcc

report there is a a figure of a child

born in various years and the climate

that they will experience as they grow

older I want to take that figure and I

want to kind of invert it and think

about if we take these climate actions

what are the positive benefits that can

accrue and when do they start accruing

so if we limit warming to 1.5 C our

great-grandchildren are going to thank

us for avoiding more catastrophic sea

level rise but if we do that we

ourselves not our children not even

ourselves in 10 years we are going to

experience those benefits of cleaner air

immediately there's going to be more

people alive now and I think that's

something that's really worth doing

personally

well I think that's a really great place

to end and you know since you've a

repeat guest you would know that as you

come on the show you're supposed to come

with three book recommendations um for

the audience what what are your books

my first book recommendation is actually

not a book it is a short story in fact

it's such a short story that it's about

a paragraph long and it's called on

exactitude in science by Jorge Luis

Borges and it is the perfect

distillation of the process of modeling

of trying to represent Nature by

something smaller and more tractable my

second book recommendation is kind of a

off the wall one we talked about the

little ice age and we talked about witch

burning in the little ice age

turns out that British monarch James the

first published a paper on how to

identify and deal with witches because

he was really obsessed with witches

being the king in the middle of the

little ice age

and he was previously the King of

Scotland he was brought down when

Elizabeth the first died and so if you

are a playwright and you want to appeal

to this kind of Scottish weirdo who's in

charge who's really obsessed with

witches what are you going to write and

so that's where Macbeth comes from and

I've been re-reading that in preparation

for some things that I'm writing about

the little ice age and I'm just really

struck by these themes of guilt and also

really struck by the extent to which the

witches and Macbeth are manipulating the

weather and so I think that is a really

interesting view into a world in a

different climate than the one we are in

right now

and my third book is not out yet but

it's available for pre-order in order to

preface this I have a lot of problems

with climate fiction I find a lot of it

to be kind of unnecessarily apocalyptic

or very preachy and it's just not

something that I like to consume off

hours and so there's a book which I've

been fortunate enough to read a

preliminary draft of it's called

Troubled Waters it's a novel by Mary

Anna is hegler and it's just a warm and

beautiful and complex story about a

southern black family wrestling with the

climate crisis

kid Marvel thanks for coming on the

program thank you so much for having me

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