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