Professor Nathan Bindoff is a world renown physical oceanographer at the University of Tasmania’s Institute for Marine and Antarctic Studies. His research takes him on voyages of discovery where he documented the first evidence of changes in the Indian, North Pacific, South Pacific and Southern Oceans, and the earth's hydrological cycle from ocean salinity. He predicted fire catastrophes. His most recent work is studying the decline in oxygen content of the oceans. All of these global climate changes have been attributed to human activity. Nathan Bindoff is one of the lead authors contributing to the Intergovernmental Panel on Climate Change (IPCC) reports that are informing world leaders on climate policy.

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What's your PI.

Professor Nathan Bindoff and his background in physical

oceanography is so extensive.

There is no way I can cover his massive research studies,

but we can narrow it down.

Well, Nathan is a professor of physical oceanography at the

university of Tasmania's Institute for Marine and Antarctic studies.

And my gosh, he was the coordinating lead author on the ocean's chapter in the

fourth intergovernmental panel on climate change in 2007, in which he was awarded

a certificate for his own contribution of Al Gore winning the Nobel peace prize.

That is just so amazing.

And then again, in 2014, he took a lead in the fifth assessment

climate change report.

Well professor Bindoff and his colleagues documented some of the

first evidence of the high melt rates of the Antarctic ice sheet.

His most recent work is on documenting the decline in oxygen content of the

oceans and dynamics of the Southern ocean.

When he's not on a boat doing research, he tries to be on his own boat that he built

from wood, a hobby that he so much enjoys.

And now he is here to talk about all of this and what the

future holds for our planet.

Professor Nathan Bindoff . Thank you so much for coming on the show to

share your amazing positive imprints.

00:02:50

Thank you, Catherine.

00:02:51

That's a lovely introduction.

This is so incredible to finally meet you after reading so many

articles and reading your research and hearing about you from other researchers.

There's so much to talk about and I'm going to kind of let you guide as to

what research you want to chat about.

Professor Bindoff explains who he is and how he came to be part of the

intergovernmental panel on climate change.

00:03:18

Oh, Nathan's a a practical, pragmatic

00:03:23

sort of guy that likes to, actually I, I often, draw parallels to, uh, parboil

00:03:31

detective stories where, you know, the, the, the lone detective is out there.

00:03:38

Well, private eye is out there and he's taking the clues and

00:03:42

kind of discovering something.

00:03:43

And, and that's kind of how I feel about science

00:03:46

actually.

00:03:47

You know, you, you look at observations, you discover things, you compare them,

00:03:53

you get evidence and you build a story.

00:03:55

And it's just like that parboiled detective guy, that those parboil

00:04:01

detective stories where you figure out what's going on and then you

00:04:04

write it up and turn it into a paper.

00:04:07

And the pragmatic part of me is the part that likes to, turn this sort

00:04:12

of discoveries in science, into things that are important and relevant to

00:04:18

people who think about the environment.

00:04:22

So you know, the participation in IPCC, for instance, Was sort of a

00:04:29

fluke, a wonderful fluke, by the way.

00:04:32

I was in the corridor one day and one of my ex supervisors came by and he said, oh,

00:04:41

you should, you should nominate for IPCC.

00:04:45

And that's all he said.

00:04:46

And that night I went away, uh, put in a nomination and

00:04:52

that began my career in IPCC.

00:04:54

I was invited to be a coordinating lead author in that fourth assessment

00:04:59

report, which was the one that actually led to a moment in history where

00:05:04

00:05:12

And then suddenly the stern report came out and that talked about the

00:05:17

economic consequences of climate change.

00:05:20

And Al Gore had his movie on the inconvenient truth.

00:05:25

00:05:33

2008, we had a change in our narrative around, uh, the acceptance of

00:05:39

climate change and the need to act.

00:05:42

And it was a terrific moment.

00:05:44

And then it was sort of topped off by IPCC winning with Al

00:05:50

Gore, the, Nobel peace prize.

00:05:52

And, and, and I actually liked the fact that it's not, it's not a, a

00:05:59

prize for scientific excellence.

00:06:01

It's not a prize for intellectual endeavor.

00:06:04

Actually, it's a prize for creating an opportunity if you like for peace.

00:06:11

So you can see, I, I like the observations, I like the detail,

00:06:15

like a narrative, and then actually, if it does good, if it does good,

00:06:20

then that makes me very happy.

We talked about some of his quotes and I brought up this one.

"When I commenced my career, the question of whether the ocean state

had changed was completely open.

It was a voyage of discovery."

Well, professor Bindoff has been on this voyage of discovery, bringing back his

research to share with the IPCC., the intergovernmental panel on climate change.

And I asked professor Bindoff about the history of the IPCC

and the state of the ocean.

00:06:55

So let's, let's talk IPCC for a moment.

00:06:58

IPCC was a, a vision and that vision was an understanding that the changing

00:07:07

composition of the atmosphere.

00:07:09

So this was for measurements of atmospheric CO2.

00:07:13

The changing composition of the atmosphere was going to influence the planet.

00:07:18

At that moment there was a decision and it was in the time of, Margaret

00:07:25

Thatcher and Ronald Reagan.

00:07:27

A decision was made to create a panel.

00:07:31

And that panel was a joint effort between United nations environment program and

00:07:38

the world meteorological organization.

00:07:42

And what happened was that that panel was created very perceptively it excluded

00:07:48

it's not quite true, but it is basically excluded non-governmental organizations.

00:07:53

So they made it a report to governments.

00:07:57

And because it's a United Nations process, that process demands that every country

00:08:07

has a, what they call a focal point.

00:08:10

And that focal point in each country is the avenue by

00:08:15

which the IPCC reports, , and.

00:08:20

Development and their commissioning is, created within each of

00:08:24

the countries that participate.

00:08:27

United Nations is 195 countries and almost all participate in the IPCC process.

00:08:35

So this process immediately meant that, every report is well understood.

00:08:43

at some levels of governments.

00:08:45

That's unusual relative to other kinds of reports.

00:08:49

There's a similar report around, , chlorofluorocarbons,

00:08:52

in the upper atmosphere.

00:08:54

And there's a similar process there.

00:08:57

So that's basically the process around, but, , the IPCC, it

00:09:03

00:09:08

And it came from the inspiration of Bert Bolin.

00:09:12

Bert Bolin was a, Swedish, atmospherics, scientist, famous actually.

00:09:18

And it was him plus a couple of others.

00:09:21

And the first report was quite very, very thin.

00:09:24

Actually, it didn't even say that humans were influencing climate, but

00:09:31

curiously, that report was enough to create the United Nations Framework

00:09:37

Convention on Climate Change.

00:09:39

And that's the body that runs the conference of parties every year, which

00:09:45

negotiates, , the processes around emissions and hopefully emissions

00:09:50

reductions, as we go into the future.

You've given a wonderful explanation on the IPCC.

And I appreciate that because I was unaware of some of the history,

and I was definitely unaware in how much of the partaking you have

had in this historical and most important piece that is going to take

us and is taking us into the future

with regard to legislation and changes in lifestyle.

00:10:17

Yeah.

00:10:19

So IPCC evolves actually.

00:10:22

And in the first report, there was no mention of the oceans and in

oh, there was no mention of oceans.

00:10:28

Correct.

00:10:29

And then the second assessment, there was, uh, no mention really either.

00:10:34

And then in the third assessment, they talked about sea-level and

00:10:39

then in the fourth assessment, they actually introduced an oceans chapter.

00:10:44

And, and the reason an oceans chapter was introduced was because there

00:10:50

had been a bit of a revolution going on in the oceanography community.

00:10:55

It goes to the first question you asked.

00:10:58

The oceans were considered to be static, unchanging.

00:11:01

They had so much, , inertia that they were basically unable to change.

00:11:09

They were kind of a fixed fly wheel.

00:11:12

If you like, circulating the global ocean.

00:11:16

And then increasingly oceanographers and atmospheric scientists have

00:11:21

understood that there was El Nino.

00:11:23

Then we came to understand actually the deep ocean was changing subtly as well.

00:11:29

And we found that, that there was on starting to appear on global scales.

00:11:35

So what really happened was that we understood that the oceans too were

00:11:42

responding, that they weren't static and that they were changing and that

00:11:49

knowledge and the amount of literature that was starting to accumulate at

00:11:54

that time allowed for the introduction of this chapter around oceans.

00:12:00

It's the building of the momentum around the science.

00:12:04

It was a increased realization that the oceans were important that

00:12:09

they were changing and evolving.

00:12:11

And, at that time, we believe that the ocean, uh, sea level change was through

00:12:18

primarily through, thermal expansion.

00:12:20

So that's where you warm up the ocean and it expands.

00:12:24

And that's the biggest contributor to the rising sea levels.

00:12:29

That's actually changing again, so that rising sea levels, are now

00:12:35

dominated by the melt of the ice caps, both Antarctica, Greenland, and, the

00:12:43

glaciers mountain glaciers as well.

00:12:46

So the heating of the oceans, isn't the biggest component to

00:12:51

the rising sea level anymore.

00:12:53

So that's a new level of knowledge that we've actually got.

00:12:56

So this is part of this voyage of discovery where we're actually learning

00:12:59

more progressively more about the earth's system in response to climate change

One of Nathan's earliest discoveries was that of the planet's

melting Antarctic ice shelves.

He and his colleagues made measurements, studied the data and concluded

something absolutely extraordinary.

00:13:21

With colleagues.

00:13:22

Um, so I wrote some early papers around, the melt of , the Amery ice shelf.

00:13:28

In fact, I remember a conversation.

00:13:30

I said, oh, 50% of this.

00:13:32

ice shelf is melting, from the ocean, from the underside.

00:13:36

It's a paper that's buried in the past, the glaciologists

00:13:40

telling me that was impossible.

00:13:41

Well, actually what's happened is this has become a prime research, , activity

00:13:47

here in Hobart and elsewhere in the world.

00:13:50

It was the capacity for those ice sheets to have a huge, huge impact

00:13:57

on rising sea level, is enormous.

00:14:01

I've used a lot of superlatives there, but it's true.

00:14:04

There were some papers just recently, which some people are backing away from

00:14:09

a little bit, but they were predicting 16 meters of sea projecting, 16 meters of

00:14:15

00:14:21

So think about 16 meters of sea level.

00:14:24

That's enormous.

00:14:25

These estimates, are reducing, , but they're still very large.

00:14:29

Just recently in the report that we did on oceans and cryosphere and a

00:14:34

changing climate, the governments' insisted on showing the sea level

00:14:39

00:14:43

00:14:47

but the sea level projections were showing, at the upper range, five

00:14:51

00:14:56

Now, just to give a context, I think if it's eight meters, we can

00:15:02

row in our boat to the footstep of, Capitol hill and step out.

00:15:08

Of course, in the case of the Thames parliament, uh, we

00:15:13

could step through the windows.

00:15:16

Uh, uh, you know, uh, most of Florida has disappeared, south Australia.

00:15:22

I think if it goes to eight meters, we can have a ocean in the middle of Australia.

00:15:28

So, so, you know, these are very significant, profound,

00:15:33

possibilities for, , future, sea level in an unmitigated world.

that's key.

00:15:42

that's the key.

00:15:43

And so, so it hasn't happened of course.

00:15:45

Um, it's, it's something that humans could, materially alter

00:15:51

by making certain decisions.

00:15:54

So it's sort of a value judgment.

00:15:55

We can have this hotter, higher sea level world if we choose, or we can actually

00:16:02

step back, we mitigate emissions and not have that hotter higher sea level world.

00:16:10

And there are some distinct benefits,, I think that's my value judgment, if we

00:16:16

were to reduce our emissions to zero.,

oh, I think it is a decision that we do need.

But there are people who won't change until it's legislated

00:16:26

So some of the language we might use, we

00:16:29

scientists might use is that we society needs a license to, reduce emissions.

00:16:36

Society has the license to omit them.

00:16:39

Yeah.

00:16:39

Right.

00:16:41

We now need a license to reduce them to zero.

00:16:45

And, uh, that is actually something that no individual can accomplish.

00:16:51

Right.

00:16:52

So, so therefore means that, no individual country can

00:16:59

actually accomplish it alone.

00:17:01

So it does require a genuine collaboration of all the nations to actually agree,

00:17:07

and then follow a pathway to reduced emissions, , to kind of avoid the

00:17:14

worst outcomes of climate change.

00:17:17

Some people may not realize, but we've already committed to

00:17:20

quite a bit of climate change.

00:17:22

We've already come one degree of warming since the instrumental

00:17:27

00:17:30

Now one degree of global warming means that actually over Australia,

00:17:34

it's 1.4 times that, over the, Arctic it's, uh, even more and over

00:17:41

the tropics, it's actually less.

00:17:43

It's a global average.

00:17:45

Some areas will have larger temperature changes than others.

00:17:50

We've already committed to that.

00:17:52

We can already see that, the water cycle over the planet has been altered.

00:17:58

We can already see that Greenland and Antarctica are losing increased mass.

00:18:03

That's something that's become very obvious in the last 20 years

00:18:08

on this voyage of discovery.

00:18:10

These things mean that we've already committed to those changes.

00:18:15

If we switched off our missions tomorrow, right which is, would

00:18:20

be an extraordinary thing.

00:18:21

We would still warm up by another 0.3 to 0.4 degrees.

00:18:26

if we want to avoid 0.5, we'd have very little time left

00:18:30

actually, if you think about it.

00:18:32

Cause if we've committed to a further 0.3 degrees, we've come 0.1.

00:18:36

We've only got 0.2 of headroom.

yes.

00:18:40

so say you can see that it's now

00:18:42

becoming a very urgent problem if you want to minimize the

00:18:49

consequences of climate change..

00:18:52

One of the things that became obvious was that the, interaction between the ocean

00:18:59

and the ice sheet was quite significant.

00:19:03

And so we actually did a wintertime voyage.

00:19:06

We went to Antarctica in July.

00:19:10

So that's our Southern hemisphere winter.

00:19:13

We were there against the continent in a, , ice breaker and making measurements

00:19:19

right in front of the, of a, um, it's not, not the biggest glacier.

00:19:25

Uh, they'd called the Mertz glacier.

00:19:28

It's actually that place has now broken off, but it was a source of

00:19:34

very dense what we call Antarctic bottom water, very dense waters, some

00:19:40

of the densest waters in the world.

00:19:42

And because they're dense, they'll actually flow down the

00:19:45

continental slope so they'll start off on the continental shelf

00:19:49

they'll fly down the continental slope and then they end in the abyss and

00:19:54

they actually drive a circulation that we call the overturning circulation.

00:20:02

And this overturning circulation is an important component of the

00:20:07

global thermohaline circulation or the global thermite.

00:20:11

Global thermohaline circulation in the world.

00:20:14

It's a driver of the deep ocean circulation.

00:20:20

And as a consequence, we were there exactly to study that flow.

00:20:29

Now I've talked about the deepest ocean that right there in front of the glacier,

00:20:34

you also see and toughen the case, very fresh waters that reflect the melt of

00:20:41

the bottom of the, glaciers themselves.

00:20:44

And so we estimated that melt rate and we came to understand how much was being,

00:20:50

lost by the ice sheet there in winter.

00:20:53

What's new and more important to the story of climate change is we've realized

00:20:59

that these glaciers are thinning..

00:21:03

And so they're losing, they're not in equilibrium.

00:21:06

If they're an equilibrium sea level would be unchanged, but

00:21:10

actually they're thinning.

00:21:11

And so sea level is actually going up as a consequence and the ice sheet itself

00:21:17

on average is actually losing mass.

00:21:20

So it's transferring mass that, in the Antarctic ice sheet itself into the

00:21:26

oceans and causing sea level to go up.

00:21:31

And that voyage was the first ever against the Antarctic continent in winter.

00:21:37

00:21:39

That voyage, was actually on the relatively newly commissioned

00:21:43

Aurora Australis so that was the Australian icebreaker.

00:21:48

That ship has now come to end of life.

00:21:51

And it's about to be replaced.

00:21:53

There'll be a new Australian ice breaker that will replace the Aurora Australis.

00:21:58

It was both a science ship and also a resupply, ship.

00:22:04

And the moment that we actually got that, icebreaker, the Australian Antarcitc

00:22:11

research took a quantum step upwards.

00:22:14

That vessel gave Australia new capabilities that it

00:22:18

00:22:22

, it's interesting.

00:22:23

I.

00:22:25

I was sort of, um, a little bit hesitant.

00:22:28

I have to say, there you go.

00:22:29

I was a little bit hesitant about going to, , Antarctica working at sea.

00:22:36

I've spent more than two years at sea now, uh, in my career.

00:22:40

Right?

00:22:41

So I've got over the hesitancy, but, the first trip I was, it was

00:22:47

actually a particularly rough trip.

00:22:49

I remember kind of feeling only 80,, 90%, 90% of the time.

00:22:56

Uh, and, uh, that was, that was a tough voyage actually.

00:23:00

And, and, you know, shaped my life.

00:23:05

Sea-going life is actually a very pleasant once you get into the rhythm

00:23:10

of it, it's a very simple life.

00:23:13

And in the case of, research in Antarctica itself, you

00:23:17

get the most fantastic views.

00:23:19

You know, you're privileged in a way you, you see these ice sheets, um, they're,

00:23:26

they're cliffs right there in front of the ocean and they're brilliantly white.

00:23:33

And then, , the green of the green to sort of clear blue of the ocean and

00:23:40

the contrast in color is, , striking.

00:23:44

And then sometimes you see these ice sheets, they have icebergs and

00:23:48

they're flat tabular kinds of icebergs.

00:23:52

Icebergs

00:23:54

always flattened tabula, typically in the Antarctic, quite unlike the icebergs

00:23:59

in the, from the Greenland ice sheet.

00:24:02

And, but often you see surf on the have wave cup platforms on them and

00:24:06

you can see surf there and people,

00:24:09

oh, that's cool.

00:24:10

and some people have actually surfed them.

00:24:12

So, so there are these very beautiful, there's this, sea

00:24:17

life, some extraordinary sea life.

00:24:20

The thing that's grabbed me the most actually, and what allows

00:24:23

me to keep on going back is the science that's associated with it.

00:24:30

The science in the end is the driver of this activity and, and

00:24:36

the, the, joy of seeing it all is kind of a peripheral thing.

00:24:41

Hate, hate to say it that way, but actually that's what,

00:24:44

makes it for repeat trips.

well, it certainly shows your dedication to not just the work

that you're enjoying doing, but to the future of decision-making of our planet

and populations that live on our planet.

I think that's a huge responsibility for scientists to undertake when you know,

very well that when you are doing this research and you're coming back with

the statistics and the projections, and if we keep going the way we're going

and things don't get changed, if you lose populations, animal populations,

that's a, that's a heavy emotional burden.

I think

00:25:23

You're quite right that, but I'm not

00:25:25

actually frustrated, by the world.

00:25:29

I feel personally that I've actually done the work, I've made, made with the

00:25:36

measurements, we've reported the science I've worked with IPCC with literally,

00:25:42

you know, uh, 200 to 300 scientists with the similar kind of thinking.

00:25:48

We've put these assessments together with, literally seven to 10,000

00:25:53

different papers, we've assessed it.

00:25:56

We've written the reports.

00:25:58

They're being communicated to government.

00:26:00

We have actually done our job.

00:26:03

And, and, and in that sense, , I'm not frustrated because I can see that actually

00:26:10

to make the decision and for society to agree to act on it is a big thing too.

00:26:18

And we're in that process.

00:26:20

So my task is really to continue to do that job, to communicate

00:26:26

what's going on, how things are changing, why it might be urgent.

00:26:32

Um, what are the consequences?

00:26:35

Cause that's, that's the projections part.

00:26:37

You know, we can look a bit into the future.

00:26:39

If we continue on this path, this is what it will mean.

00:26:43

And, and if we continue to do that, then hopefully the rest of society can find

00:26:51

the solutions that allows to transform to the new world where we don't have

00:26:59

emissions going into the atmosphere.

00:27:01

We limit the amount of damage caused by climate change.

00:27:05

And, we address the other problems that we need to solve.

00:27:09

And that's a deeply society related question.

00:27:14

I think scientists have done a terrific job in communicating it.

00:27:17

It's deeply political to get to perhaps, uh, where we might like

00:27:22

to be, but we're in this moment where we're trying to get there.

00:27:27

That's why we have these institutions like IPCC, United Nations, the

00:27:32

World Meteorological Organization, the United Nations Framework

00:27:36

Convention on Climate Change.

00:27:38

It's why they have a meeting every year, every year, the ministers and

00:27:43

bureaucrats of every country actually go and discuss how to make the decisions.

00:27:49

They may not succeed, but they actually do do it, every year.

00:27:53

So ya, there's a considerable effort going into the process and hopefully we'll turn

00:27:58

the corner and, uh, really have action.

00:28:01

We have had action in the past and that's why I'm not, uh, pessimistic.

00:28:05

I think it is a solvable problem.

00:28:08

There was a report just released that describes the fact that, you know, with a

00:28:13

concerted effort, we could actually limit global warming to one and a half degrees.

00:28:18

We could actually do it.

00:28:21

And there are pathways to get there.

00:28:24

Scientifically, there are pathways to get there and then sociologically

00:28:28

and decision-making, let's see if we can get to those parts.

00:28:34

So, so you can see I've stepped back from being frustrated

00:28:38

sure.

00:28:38

Sure.

00:28:39

because I feel like we've,

00:28:41

I've done as much as we can.

00:28:43

Scientists have done as much as they can.

00:28:45

And,

you've great at what you are doing.

and it's inspiring.

00:28:51

and so, well, thank you.

00:28:53

And so the other half of it is can we as society, accept that, make the

00:28:59

value decision and transform itself.

00:29:03

And the nice thing I think is that, , 20 years ago, renewables may not have

00:29:08

been so cheap and you can see the huge increase in renewables in the landscape.

00:29:13

And you can see many of the transformations of the energy business

00:29:17

that are going on, and you can see the pressure on the coal industry.

00:29:22

So you can see that there are forces and pressures trying to

00:29:28

change the pathway that we were on.

00:29:31

Emissions are still going up.

00:29:32

We haven't turned the corner, but you can see that there's action.

00:29:36

Not enough maybe.

00:29:37

Maybe it's my worldview, but that narrative I gave was

00:29:42

one, of precisely about hope.

00:29:44

It was about the hope that we could collaborate globally and actually

00:29:50

understand the innovations that we can embrace and change the course.

00:29:57

And it does require the world to do it together.

Bindoff predicted the catastrophic fires that would occur.

Right now my own state of New Mexico is experiencing horrific fires, which are

the absolute worst in recorded history.

Well, professor Bindoff wrote papers years ago on this very subject.

He wrote.

"If the temperature rose and continues to rise

sea levels could rise by three to four meters and Greenland could disappear.

There would be at least a 20% increase in fire danger and catastrophic fire

events would be more likely to occur."

00:30:35

It's uh, the fire season has been

00:30:38

an extraordinary wake up call for, Australia and the wildfires in the USA

00:30:45

, had extraordinary impacts.

00:30:48

The report that you referred to we wrote, basically pointed to the

00:30:52

fact that these extreme conditions are going to occur more frequently.

00:30:56

So we said twice as often, but they actually affect the

00:30:59

bigger area, uh, as well.

00:31:02

and then when you put those two together, they turn out to

00:31:06

be four times more workload.

00:31:08

It's like a 20% per decade, increase.

00:31:12

So these are nontrivial changes that are emerging because of that warming.

00:31:18

And it's primarily because of the warming.

00:31:20

There are other things that go into fire, but there's, that's primarily because

00:31:25

of the warming that goes, associated with increasing the fire danger.

00:31:30

So, so yes, we did talk about that years ago and I'm off to meet the Premier today.

00:31:35

And I'll probably mention it again.

Well, my goodness.

I would love to have an update on that meeting that professor

Bindoff had with the Premier.

Well today, professor Nathan Bindoff and his team are studying oxygen levels.

00:31:50

Yeah.

00:31:50

So, so oxygen, a lot of people, don't understand that the ocean is a very

00:31:59

small reservoir of oxygen, obviously critical for fish to live off and

00:32:04

much of life, within the oceans.

00:32:08

But it turns out that if you make measurements of the oxygen content

00:32:14

in the oceans, there are some areas where it's actually declining and

00:32:21

this work that we're doing is actually about documenting those declines.

00:32:26

And there are some particularly big declines in the equatorial

00:32:31

zone of the Pacific and also in the Indian and Atlantic oceans.

00:32:38

And there are declines at high latitudes as well.

00:32:42

These declines aren't so aren't so big that the fish can't, can't ac tually

00:32:48

still function but their declines are altering the distribution to some

00:32:54

extent of fish in the equatorial parts.

00:32:58

It's just reflecting the fact that we're on this voyage of discovery,

00:33:03

where the oceans are changing and oxygen is just another one

00:33:08

of those things that's changed.

00:33:10

And, you know, it's, it's not talked about a lot about, it's actually a

00:33:16

thing that's going to have influence, particularly in the equatorial

00:33:22

zone, future equatorial zone.

00:33:26

In the past records, the paleo oceanographic records we have, it's often

00:33:31

talked about, the, chain variations in oxygen in the global oceans.

00:33:36

So geologists have understood that there are, uh, changes in

00:33:40

the oceans on long time scale.

00:33:44

The difference here is that these changes that we're talking about

00:33:49

are connected to human activity.

00:33:51

So it's, uh, human induced oxygen decline, in fact, in the United States,

00:33:58

there have been some famous, uh, kills of crabs washed up on the Oregon coast.

00:34:05

And these are connected to this, changing oxygen levels, in

00:34:10

the equatorial ocean actually.

00:34:13

And at various times, those low oxygen zones catch up with the

00:34:18

crabs, which are sitting out there on the continental shelf.

00:34:22

They suddenly don't have enough oxygen.

00:34:24

So they actually, asphyxiated, I suppose and then washed up, that

00:34:30

is an example of the growth of this oxygen minimum layer in that zone.

00:34:35

So it is influencing, uh, Marine life and their distribution.

00:34:41

It's a sort of a localized catastrophe for those animals.

00:34:45

Tuna populations have tended to move a little bit in response

00:34:50

to these oxygen content changes.

00:34:53

There are other kinds of effects on Marine wildlife.

00:34:57

It's, it's always complex, but that's actually what's going on.

00:35:01

And, uh, the project that I was that, that I was referring to there is

00:35:06

about understanding how that oxygen is actually changing the global oceans.

00:35:13

And we have relatively few observations for it.

00:35:16

So it's, it's a, um, it's not as detailed or accurate picture as we

00:35:21

might have for ocean temperatures

oh, but you'll get that

00:35:26

with a few more measurements.

right?

Yeah.

And the reason I had mentioned fisheries is because that

will be an economics question.

00:35:37

Yeah.

00:35:38

So, so this is, something we've detailed in our most recent IPCC report actually.

00:35:45

There are three things going on if you like.

00:35:48

The atmosphere's warming up..

00:35:51

The surface ocean warms up at a faster rate than the deeper ocean.

00:35:57

And because the surface ocean is warming up at a faster rate,

00:36:02

um, warmer water is lighter.

00:36:05

And so, uh, the surface waters are becoming more buoyant

00:36:09

relative to the deeper waters.

00:36:12

And now oxygen mostly gets into the deeper waters because there's a,

00:36:17

what we call ventilation, literally, you know, uh, the exchange between

00:36:22

the atmosphere and the deep ocean.

00:36:24

Um, and that process is inhibited or reduced or slowed by the warming

00:36:31

up of those surface waters, because it's actually physically harder

00:36:35

to take the surface water and move it into the deeper ocean.

00:36:40

And.

00:36:41

Because it's physically harder there's less oxygen being

00:36:44

moved into the deeper ocean.

00:36:46

So when I say deeper below a hundred meters, and as a consequence of

00:36:52

biological activity in that depth range, the oxygen content is the oxygen is

00:36:57

consumed and it's, uh, becomes lower.

00:37:01

So this decline in oxygen is really caused by surface ocean warming and,

00:37:09

and a reduced rate of exchange between the atmosphere and the, and the deeper

00:37:14

ocean, below 100, 200, 300 meters.

00:37:19

Um, and, and that's what we've been documenting.

00:37:23

And we can attribute it to the human influence because we know that, in

00:37:28

following the scientific method, if you like, models that do not have

00:37:33

changing cO2 do not have warming of the surface ocean, um, will still have

00:37:40

the same equilibrium oxygen inside.

00:37:43

But when you warm the ocean progressively from rising greenhouse gases, you

00:37:49

find that the pattern of oxygen change, agrees with what's observed

00:37:53

and you can formally attribute it to that rise in, , CO2 in the atmosphere.

00:38:02

So the response looks like climate change, and that's why we say

00:38:08

it's to do with human activity.

00:38:10

, so, so Catherine, I can talk quite a lot as you might have, uh, appreciated

00:38:16

but let me say, it's been a pleasure to chat, about these bigger picture

00:38:22

issues with a little bit of extra time versus a normal media event.

00:38:29

It allows, I think a, um, kind of a nice, nice discourse about, the

00:38:35

problem that is confronting the earth..

00:38:39

I'm I'm very optimistic that we can actually solve these, this,

00:38:44

this particular problem, because I can see the innovation that we

00:38:50

acquire, the technologies we require.

00:38:53

I can see that there's a potential for the transformation transformations

00:38:58

that we acquire to occur.

00:39:00

And so I'm actually hopeful that we can accelerate the progress and actually,

00:39:07

minimize, minimize the, problem at hand.

00:39:10

And, and of course I can then just go back to doing ordinary old oceanography.

00:39:15

Don't have to, uh, work on these socially relevant problems,

00:39:20

become the academic that I was.

00:39:24

Um, you know, it's been very interesting and fascinating time

00:39:28

to be working in the oceans.

00:39:30

The oceans, unlike meteorology, the oceans, Uh, 20 years behind

00:39:35

the meteorological community.

00:39:37

And so I've actually entered this career into this career at a, at a kind of an

00:39:43

exciting moment where we've kind of become to understand much more about the oceans

00:39:49

and we've developed, tools and methods to explore and see, how it's changing and

00:39:57

how it's moving and how it's responding to, climate change, for instance.

00:40:02

I've been a participant in these things, iPCC, I feel actually that, uh, if

00:40:08

there are any budding scientists out there, if you do it right, there can be

00:40:12

a very exciting and exhilarating career..

00:40:16

Oh, I, I agree.

00:40:18

Thank you so much, Nathan.

00:40:21

You are just so good in your field and you are a very well-spoken speaker.

00:40:27

You're extremely inspiring and your positive imprints are certainly global

00:40:32

but your, your imprints are such a legacy because this research is for

00:40:39

yesterday, today and the future, and it's going to be obviously research needed.

00:40:45

I commend you for taking on the role that you are taking, not just as

00:40:50

a scientist, but as a spokesperson

00:40:53

and I appreciate that.

00:40:55

, I think that I want to end with letters to earth,

00:40:59

Nathan, I'm going to

00:41:00

share my screen with you because this letter that you wrote to earth

00:41:05

is very inspiring and it just shows your optimism and everything that you

00:41:11

believe in for the future of our earth.

00:41:13

Um, thank you Catherine.

00:41:16

From time to time.

00:41:18

I do think about the future.

00:41:20

My dream is that the picture we so frequently paint will be different.

00:41:25

Not the catastrophe that is so frequently forecast, but a world where the pressing

00:41:31

problems that cutoff circumvented with human ingenuity and self-realization

00:41:37

and mobilized by collaborative effort, a world where humans decide the future

00:41:43

to be sustainable and transformed,

00:41:46

and a transformed one that successfully reconciles climate change, our needs

00:41:51

for food, energy, and all of life.

00:41:57

That is what I imagine we can achieve.

Professor Nathan Bindoff.

thank you.

so much for your inspiration and your commitment to your science and research.

Thank you for sharing on your positive imprint.

00:42:15

thank you Catherine..

To learn more about professor Nathan Bindoff and his research go

to university of Tasmania website, UTAS.edu.au and search button for Nathan

Bindoff, N a T H a N B I N D O F F.

You can read more letters from scientists and oceanographers

from isthishowyoufeel.com?

You can also write your own letter to earth by going to letterstoearth.com.

In two weeks, join members of the Matt Palmer band as they share music and their

climate change research from England.

Your positive imprint.