The IPCC Assessment Reports How Good Have Climate Forcasts Been

i am going to talk about some of the

things that i’ve been involved in

in terms of research i’m really happy to

be part of this countdown and in fact

i’m definitely going to tee off of

johann rockstrom’s

talk because i’m actually going to talk

about three of these tipping points that

he

mentioned and that i actually have done

research

on the question that i’m going to try to

ask today

focusing on the the ipcc assessment

reports is really

how good of a job have the climate

forecast been

um and and um therefore

um you know should we take them

seriously and should we take them

seriously going into the future

the earth is definitely undergoing a

trans transformation

um and uh some people call this

new era the anthropocene of of man-made

um change to the earth and and dr

rockstrom

definitely mentioned that um one of the

ways that we’ve been able to document

this transition

and this transformation is through the

intergovernmental panel on climate

change

this group um sponsored by the united

nations produces reports of

peer-reviewed

climate change research um and

all of the reports that they produce

are also reviewed by the governments

that sign

the climate agreements so for instance

the paris agreement that occurred a few

years ago

had to be approved by by all the

countries that were involved in those

climate negotiations which is which is

almost basically all the countries in

the world so the ipcc reports go through

stringent

not only stringent scientific review of

peer-reviewed literature that is um

science for the sake of science not not

um

reports done for industry these are

science

that are are reporting on science as

well

as as peer review through the government

that through the governments that sign

the agreements so it’s an extremely

stringent

um process and they produce every five

to six seven eight years reports and the

first one came out in 1990

well in 1990 i was just finishing up my

master’s degree

in geophysics and in 1995 when the

second report came out i was just

finishing my phd

so you can see that this time period of

these reports has really spanned my

entire career because i’m kind of an old

guy now

but these have really been the source of

of

all the information that we’ve learned

about about climate change

and how we synthesize this over time so

this is a familiar curve hopefully to

you and it shows

the increase in temperature i do want to

mention

that the 10 warmest years um eight of

them have occurred in the last decade

so you can see that this decade you know

decade by decade

since about the 1980s we have definitely

seen

warmer and warmer and warmer decades as

we’ve gone forward

the other thing i want to note is that

back in 1990 when this first report came

out

and when i was still a young man um

it wasn’t clear if you blot out all the

the temperature data um for the years

since 1990 you can see that it wasn’t

clear back then

whether or not we were facing what basic

what future we were facing

but i’ll i hope to show you today that

the ipcc reports

even back in 1990 gave us some hints at

where we were headed

and then i’m going to show you three

examples of of how

the climate system has responded to

these changes

so these are excerpts from the first

report from 1990

you know there is a natural greenhouse

effect

on earth that keeps our planet warmer

than it does otherwise would be

we didn’t have the greenhouse effect

we’d be a frozen rock

but the emissions resulting from human

activities release carbon dioxide and

other greenhouse gases into the

atmosphere

these increases will enhance the

greenhouse effect

if they’re not removed from the

atmosphere they increase the greenhouse

effect

and that’s going to result in warming so

the fact that this has occurred

is now directly attributable to those

increases in greenhouse effect

it’s not natural variability this

down here is natural variability

this what we’ve seen since the since the

1980s is no longer

uh natural um another thing is is that

they predicted that the greenland and

antarctic ice sheets may still be

responding to the last ice age

um but we’ll see that that actually is

not true and as dr

rockstrom um uh mentioned

the climate system is responding a lot

faster than we were able to then we

predicted back 30 years ago

a couple other things that the high

northern latitudes the arctic region

would be the

one of the first places where we would

see warming

we would see reduced sea ice extent and

thickness which is

which i’ll i’ll prove to you and show

you from the data that we have that

that’s true

um they forecasted little uh change in

the extent of greenland

and the antarctic ice sheets but this

has actually not happened because of new

science

that has occurred in the last 30 years

that show the effect of the warm

that the warmer oceans are having on

these ice sheets in terms of greater

discharge of icebergs from both from

both of these

ice sheets and then finally the effect

of of wildfires

um we can see that potentially serious

changes have been identified

even in 1995 in the second report

that include high temperature events so

forth

um with resulting consequences from

fires and i will mention forest fires

here in a minute

so just really quickly i’m going to go

through some data

we’re going to focus on the high

northern latitudes because this is one

of the things that i remember learning

about early on in the 90s is that the

arctic

and then and then and the that would be

the first place that we would see the

changes

and i’ll give two examples sea ice and

greenland

and then i want to bring this home to

how it is affecting

um you and and myself

and people in this region and even

locally so

to to impress upon you the fact that

even though we’re experiencing global

climate change

we in fact are beginning to see the

effects

regionally and locally even in our own

backyard

so this is a picture of the seasonal

cycle of sea ice

sea ice grows in the winter and reaches

a maximum

year after year in march it then

starts to decrease as the

arctic gets warmer and it reaches a

minimum

in september and in fact we just reached

this minimum this blue line right here

is 2020. so we’ve got a lot of curves

here that show the seasonal cycle these

are all the years that we have satellite

data from

from 79 to 2020. if i take

all the years from 81

to 2010 and i average them i get this

black line here

and the variability over that time

period is shown as these shaded colors

but what we’ve also shown here is 2012

which we where we had the minimum and

2020

where we set the second lowest arctic

extent of sea ice ever recorded

in the satellite record we can also see

that right now

this blue line appears to be crossing

this

red line which means that when it does

that we are going to have the lowest sea

ice extent of any

time in late october that we’ve ever

recorded in the last several decades

so this is what it looks like comparing

the 19 september 1980

to september 2020 you can certainly

um sail a boat right through this ocean

in in the summertime now as opposed to

uh you know

40 years ago you weren’t able to do that

so things are changing and this is a

direct consequence

of a warming planet secondly

the thing that i want to have you

concentrate on are the colors here

over here we can see a combination of

blue and red colors

on the left this is the 1970s from 72 to

again this is this record of mass

balance of how much ice is on greenland

was derived from satellites

that began in in the 70s so we can see

that

some portions of greenland back in the

70s we’re gaining mass that’s why the

the colors are blue and somewhere we’re

losing but there was a mixture

as we go forward in time across the

screen here you can see that in the

in the 2010s all of the circles are red

um the dark red is discharge is the

change in the amount of icebergs that

are coming off the

off of the greenland ice sheet and the

light colors are the amount of melting

which is something that i’ve i’ve been

interested in my own research

so it turns out that greenland is a much

more significant

the melting and discharge of ice from

greenland is a much more significant

contributor

to sea level rise than was predicted

um even in in the the first second third

reports of the

of the ipcc the final thing is this

bringing it home now regional wildfires

this is a from a report

by nasa um they they have six trends i’m

going to focus on three just real

quickly

there are more fires you can see that

this uh this line going up from uh

from the 1800s here forward

is showing um that there are more fires

going

in time and those fires are larger

they’re hotter

and larger um this all points to the

fact that wildfires are going to have a

big impact on our future especially in

the western us

and you can see the effects here um

and we know this um on

because a month ago we have this

horrendously

poor air quality in our area from fires

that were burning

in central oregon or actually in central

western oregon around

um eugene and salem and those were

generating enormous

amounts of of smoke that went

really all the way to europe and were

visible there

and so our air quality in spokane

reached

a record high of 479 the previous high

that almost

doubled the previous high that was set

in

2018 so we’re seeing historic

fires with historically bad

air quality i want to note that the aqi

the air quality index if it gets over

500 which it did

over much of the of this area that is

beyond

beyond the epa’s the epa’s scale

for health effects of smoke so it’s not

even hazard it’s

hazardous it’s beyond hazardous

so these fires are getting larger and

they’re occurring more often

and they’re affecting a larger portion

of the west and they’re creating bad air

quality which affects

human health so in conclusion global

climate change

is a lot more than just a rising

temperature

of the earth there are lots of impacts

um humans are already experiencing the

experiencing the effects both globally

and locally

the earth’s temperatures are going to

continue to rise

as long as we continue to emit

greenhouse gases into the atmosphere

and without removing them somehow

therefore we can expect the impacts to

increase and worsen

which we’re beginning to see we’re

definitely seeing the effects now

overall the ipcc predictions have been

remarkably good they’re focused on the

high latitudes the high northern

latitudes

the effect of sea ice the

as time went on we had better

predictions of what was happening with

greenland and antarctica

and our focus on climate allowed us to

learn new processes

that are accelerating as climate change

is is occurring

and are causing sea level to rise even

faster than we expected

and unfortunately a number of these

things have been underestimated

and so we um we we you know we expect to

see more of this in the future until we

deal with this problem

but getting to what dr pizki said in

closing

i don’t want you to be paralyzed i want

this to

hopefully be a wake-up call we’ve been

working on this

a long time climate science has been

producing this message it needs to be

consumed in a way that

creates action and

we must connect with each other

scientists

um need to connect with people we’ve

been trying to get our message out for

30 years

but we need to continue to do that and

we need need to do it

by reaching out and encompassing as

many people as we can into this problem

because it’s going to take a lot of us

to solve it

but it absolutely is solvable so don’t

be paralyzed

and make sure you connect with each

other even those that may not

think the same way you do thank you very

much