I’ve been undertaking research in
Antarctica now for nearly 30 years so
I’ve seen a few changes and perhaps the
most dramatic though are the increasing
complexity of the scientific questions
being asked by the scientists themselves
and the advances in technology and skill
to answer those questions and indeed the
degree of collaboration that’s now
required to answer some of those really
complex scientific questions my own
interest in Antarctica began with a
fairly rudimentary epiphany as an
undergraduate geology major and that was
that an ice cube on the bottom of the
world was not going to be very
compatible with a warming planet it had
to melt and if it did where did all that
water go and it’s a pretty significant
Ice Cube 26 quadrillion tons that’s 26
thousand million million for those of
you who are counting the zeroes and
that’s enough to raise sea level around
the globe by as much as 60 meters so I
started looking through the geological
record for evidence of past intervals of
warmth and higher sea level the journey
took me around New Zealand to South
America and of course here in Antarctica
and turned out not to be a very quick
job so I’ve teamed up with a lot of
people along the way and we’ve unearthed
evidence from beneath Antarctica’s ice
sheets and oceans that indicate past
intervals of warmth one of the
challenges of working here in Antarctica
is that evidence is hard to find
it’s either under the ice or under the
water around Antarctica but along the
way we’ve unearthed quite a lot about
this continent it’s ice sheets have
expanded and retreated on a periodic
basis as the planet has
and warmed and the ice sheets changed
more dramatically than you might expect
just a few degrees of warming of the
planet results in loss of between two
and twenty percent of Antarctica’s ice
sheets that’s partly because warming of
the planet is not uniform the poles tend
to warm at more than double the average
rate and think on this a meter of sea
level rise comes from only two percent
change in the Antarctic ice sheet in a
meter of sea level rise displaces a
hundred million people around the planet
now when Antarctica’s ice sheets cool
and expand and retreat the ocean follows
suit that’s because Antarctica is
cooling the ocean in driving ocean
circulation and atmosphere and climate
follows as well because the temperature
gradient from the equator to the pole
causes atmosphere to reorganize it turns
out that Antarctic has this huge
flywheel that translates just small
changes in warmth of the planet into
significant global changes in
circulation sea level and climate no
matter how you look at it small changes
in Antarctica have big impact on the
rest of the planet obviously the ice
sheets have a great deal of inertia so
you might think that these changes are
slow but it turns out from the
geological evidence not to be the case
as the earth warmed out of the last
glaciation between 10,000 and 20,000
years ago it did so in a stepwise
fashion long intervals of relatively
stable or slowly changing climate and
sea level punctuated by significant
episodes of melt with sea level rising
by as much as four metres per hundred
years in some of those
intervals of melt the other thing we’ve
learned along the way is that past
levels of atmospheric carbon dioxide and
the atmosphere have a huge effect on the
planet low levels of atmospheric carbon
dioxide result in relatively stable ice
sheets high levels of atmospheric carbon
dioxide less stable ice sheets the
Antarctic ice sheets have varied between
200 and 300 parts per million the ice
sheets have grown and retreated on a
periodic basis but 400 parts per million
seems to be a critical threshold above
that the geological record reveals
significant loss in the Antarctic Ice
Sheet and sea level rise as much as 10
metres and above 500 parts per million
as much as 20 meters rise in global sea
level so as the earth passed through 400
parts per million atmospheric carbon
dioxide a year or so ago at a rate not
previously seen in the geological record
we were left wondering how long would it
take for Antarctica and its ice sheets
to catch up the risk here is not in what
we know it’s in what we don’t know the
knowledge gap leads to uncertainty and
that uncertainty makes it difficult for
us to develop plans or take action it’s
further exacerbated by the potential
enormity of Antarctic as impact on the
globe but challenges only seem enormous
when we don’t know the pathway through
mountains our unscalable until someone
works out how to get to the top so what
we’re talking about here is the unknown
pathway the geological record has a
fairly low resolution we we have a
pretty good
where the system will come into
equilibrium as the planet warms what we
don’t know is the pathway to get there
the steps the thresholds the changes in
right on our way to a warming planet
now obviously solving this problem can
be done pretty easily if we develop a
comprehensive understanding of the ocean
ice climate system here in Antarctica
but we can make significant progress
around the edges where different parts
of the system come into contact we’re
Antarctica connects with the southern
ocean where the ocean connects with the
ice and where the atmosphere connects
with the ocean and the ice at the edges
we can learn about how one part of the
system drives change in another part of
the system at the edges we can learn how
indicative change in one part of the
system might be of the system of a whole
it’s pretty easy to fall into the trap
of observable change in one part of the
system driving our whole understanding
of the whole system
take for example growing ice sea ice
around Antarctica it may well indicate a
calling continent but not if the source
of the sea ice is the melting fresh
water from beneath
Antarctica’s ice shelves I’ve undertaken
quite a lot of work in the geological
record using sediment cores and the
whole aim of that has been about trying
to understand the rates of change and
trying to bring down their resolution of
understanding of the geological record
it turns out to be a pretty complex
system but one thing I’ve learned from
my geological training and that is that
past life is indicative of ocean and
climate condition change in environment
changes the life now on long timescales
species come and go but on shorter time
scales populations move and population
health changes the life integrates
across the environment
and the life integrates through time so
life is indicative of trend rather than
variability in the system what do I mean
by trend and variability
well variability is the backwards and
forwards the natural backwards and
forwards in the system about an average
state and trend is change in that
average state if we pick up well it
takes a lot to measure the difference
between Ted trend and variability a lot
of measurements through quite a period
of time if we pick up a change in trend
then we need to be able to attribute it
to a cause that way we can work out
what’s driving the system and the change
now if we take a whole of ecosystem
approach we can do that and that’s
because species in one part of the
ecosystem respond to different parts of
the environment that way you can work
out what’s driving change in your
ecosystem now one thing I’m working on
at the moment is trying to piece
together the modern change in Antarctica
from a series of long-term ecological
research and monitoring points around
Antarctica to try and pick up that
modern change and one place we’re
interested in is Cape adir some 700
kilometers north of here that’s got base
it’s pretty close to the Southern Ocean
at the northern edge of the Ross Sea
it’s also home to the largest Adelie
penguin rookery in Antarctica somewhere
upwards of a million birds and offshore
there are kelp forests not seen further
south here in the Ross Sea and at first
glance the water column seems to be an
extension of the southern ocean on to
the Antarctic shelf so it’s a great spot
to pick up the influence of the Southern
Ocean and
Antarctica it’s also one of the few
points in mainland Antarctica that
extend into the newly agreed raw sea
marine protected area so again another
spot to get some baseline understanding
of ecosystem health it’s a difficult
place to get to no one will argue with
that
but it’s an important place to
understand the impact of warming in the
southern ocean into Antarctica another
place that’s important to look at is the
sub-antarctic islands around the
northern perimeter of the Antarctic
circumpolar current with their own
iconic species that are also responding
to environmental but change but in this
case propagating north out of Antarctica
to the rest of the world so can we
actually do anything about this
obviously we need to solve this
knowledge gap to be able to make
informed decisions and do something more
about our future but you know we can
actually act on what we already know we
know that the planet is warming year
upon year we know that atmospheric
carbon dioxide levels and other
greenhouse gases have contributed to
that warming over the past few years
atmospheric co2 is increasing it 1/2 to
1% per annum so surely it’s possible to
turn that around 1/2 to 1% and we can
all do something about that it’s going
to be made a lot easier if we understand
more about our own carbon footprint what
it is that we use what it is that we’re
buying that contributes to this increase
in carbon dioxide that’s what the carbon
trading system was all about trying to
work out the origin of our carbon and
where it ended up in the atmosphere but
the reality is we all need to do some
saving that’s what the discussion in
Paris was about so we’re talking about
it we’re just not quite doing it yet
there’s a bit of a standoff here between
governments and individuals as
individuals we kind of rely on
government to have these big questions
sorted out in a plan in hand but the
government of the day is concerned with
the issues of the individuals today
that’s why they get elected and that’s
why they stay elected so we’re waiting
for government and they’re waiting for
us
let’s break the cycle that’s what the
New Zealand enteric Research Institute
is all about brokering a public-private
partnership to undertake research on
some of these more challenging questions
that transcend geopolitical boundaries
that’s the problem with climate change
no one country is going to solve it on
its own it’s going to take each and
every one of us to make a difference
together thank you you