Ove Hoegh-Guldberg discusses coral reefs, global warming, jobs and phasing out coal!

Mass coral bleaching on the Australian Great Barrier Reef began as atmospheric carbon dioxide concentrations began to rise noticeably. When water temperatures rise, coral bleaching can occur causing many reef species, and tourists, to depart!

Atmospheric carbon dioxide will need to be reduced to around 320 parts per million to keep coral reefs healthy and to save the Great Barrier Reef's tourist industry which employs 62,000 people and earns $AUS6 billion per annum.

Beyond Zero talks to Ove Hoegh-Guldberg about the Great Barrier Reef

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Scott Bilby:This morning on Beyond Zero we’re speaking with Ove Hoegh-Guldberg. He’s the Foundation Professor and Director of the Centre for Marine Studies at the University of Queensland. Ove also heads the coral reef eco-system lab that focuses on how global warming and ocean acidification are affecting and will affect coral reefs. He’s held a range of academic positions, both in Australia and overseas. He’s published heaps of refereed publications and book chapters on subjects including climate change and is a regular contributor to the media. Good morning Ove, and thanks for joining us from Queensland.

Ove Hoegh-Guldberg: Good morning Scott.

Scott Bilby: And, great to have you on the show this morning. We’re very pleased.

Ove Hoegh-Guldberg: Great to be here.

Scott Bilby: Now, I’d just like to start off quickly by asking you how you got into marine biology and what was it that got you interested about the environment?

Ove Hoegh-Guldberg: Well, I think it all started when I was a kid and I lived on the edge of the bush in Sydney. And I spent most of my waking hours wandering through the bush looking at creatures and catching lizards, and so on. And I also had a grandfather who was a butterfly collector. And he used to take me on these trips to Queensland and I think - just sort of started. Next thing I know, I was a biology nerd [laughs].

Scott Bilby: [Laughs].

Matthew Wright: Just happens like that.

Scott Bilby: [Laughs]

Ove Hoegh-Guldberg: It does. Yep - sneaks up on you.

Scott Bilby: Oh well, you know. It seems to have taken you on a very interesting career path. Now, being a marine biologist, you know, being quite a world expert in this area – and we’ve heard a lot about your views on the Great Barrier Reef and the position coral reefs are in around the world in general. Can we just start off by – ‘cause we want to really talk about ocean acidification – but what is….

Matthew Wright: ….how about we just ask Ove a bit about – we’ve heard about the butterfly….

Scott Bilby:  ….exactly.

Matthew Wright: ….but a bit about the actual….

Scott Bilby: What is a coral? What is a coral? <

Matthew Wright: Well we’ll start there. OK.

Scott Bilby: And what is a polyp? Like I’ve been reading these things. They kind of – these things they look like trees – you know, as far as I’m concerned, coral under the ocean. They look, you know, they’re all nice and colourful, but what actually are they? Just in simple terms.

Ove Hoegh-Guldberg: OK. Well, coral is usually a colony of polyps, right? And those little polyps are related to sea anemones. So, they’re very simple animals. They’re in fact the simplest multi-cellular animals on the planet.

But what's special about them is that they create this mutualistic symbiosis which means that there’s two creatures that live together for mutual advantage. And the creature they live with is a tiny plant-like organism. You can't actually see them. There’s millions of them. They turn the coral brown and they're called zooxanthellae.

Now, they’re plant-like, they live inside the cells of coral, and they trap sunlight. And so the beautiful thing about this is that the coral gives them nutrients from the same metabolism and the zooxanthellae trap the sun. And as a result corals end up with huge amounts of energy, which they’re able to then use to lay down calcium carbonate. And that’s a rock-like substance which over time, over hundreds of years this stuff builds up to form reefs like the Great Barrier Reef. You know, which is something – which is fairly magnificent when you think about it. It’s 2000 kilometres long. A big blob of the exoskeletons of these tiny animals. And you can see it from space.

So it’s pretty amazing. And the other thing about coral reefs you need to know is that they are the most diverse eco-systems in the ocean. So, you look at animals in the ocean – one in every four lives on a coral reef – I mean that’s from polar to tropic. So these things are pretty amazing - millions of species living together in this one beautiful relationship.

Scott Bilby: OK. And so – it is extraordinary. But, you have a question Matthew?

Matthew Wright: Yeah, I do. So is it a bit like how – this might be simplifying it way too much – but how a tree fern sort of grows on the top of the old bit of the tree fern. So is that how the coral polyp lives on top of the reef and on top of….

Ove Hoegh-Guldberg: ….yeah.

Matthew Wright: ….the exoskeleton?

Ove Hoegh-Guldberg: Yeah. It’s a bit like that. It’s a bit like, you know, the accumulation of past organisms over time builds up the habitat. But it is like a forest. In fact, coral reefs are often referred to as the rainforests of the sea because their counterparts on land – same thing – these old growth forests build up over time – and they provide habitats for an extraordinary number of species as well. So, yeah, it is a bit like the underwater rainforest.

Scott Bilby: And so Ove, we’re going to talk about the ocean acidification issue now. And is that, the coral bleaching, is that when zooxanthellae, is that when they’re expelled from the coral? Is that the whole coral bleaching thing? Can you kind of explain that?

Ove Hoegh-Guldberg: Yeah, well, what we’ve been seeing since 1979, and significantly we haven’t seen it before then – are these things called mass bleaching events. And what happens is that you get periods where you’ve got water that’s warmer than, you know, it should be, just for brief periods of time. And it’s enough to stress the coral out to the point where the symbiosis falls apart. And so the coral and this tiny plant-like organism, the zooxanthellae, go their separate ways. And of course that’s all and good, except that’s the energy source of the coral. And so what happens after bleaching events, and this has been happening more and more as sea temperatures have been rising, you’re seeing a lot more death and disease on coral reefs.

And so, just as an example in that incredibly warm year of 1998, which of course we’re heading for very soon. The atmospheric systems tell us that we’re going to see many more of those sort of temperatures in the future. We lost 16 per cent of the corals across the planet. So coral bleaching and thermal stress on itself is enough of a problem.

Now, enter the problem of ocean acidification, and this was something which interestingly was sort of touted in the late 90s, but it was a theoretical thing, you know. And it’s based on the following problem: as CO2 is rising in the atmosphere, more and more has been going into the ocean, and when CO2 goes into the ocean it reacts with water to form an acid. And this acid has two effects. It has a primary effect on organisms just generally, because changing the acidity of water can change the way fish breathe and all sorts of things. But the major effect it has is that it starts to corrode and interact with the carbonate ions that you find in seawater, and those things are what corals need to build their skeletons.

So what we know now is that, as we’ve been rising in CO2, the Great Barrier Reef has started to slow its calcification and earlier this year two groups of scientists, one in Australia and one in Thailand, have now shown that coral reefs are calcifying now 50 per cent slower than they did prior to 1990. And there’s no similar drop-off, things have been pretty constant for the 400 years of records they looked at. So we’re in unusual times, we’re starting to see the effect of this, and of course if we go forward in time, the experimental evidence tells us that we can’t go beyond 450(ppm CO2). If we actually get to 450, coral reefs like the Great Barrier Reef will be in negative carbonate balance, actually they’ll be starting to crumble and dissolve.

Scott Bilby: And so you’ve said recently that we deduce from the history of coral bleaching that the safe level for coral reefs is probably about 320 to 325 parts per million of CO2?

Ove Hoegh-Guldberg: Yes. And now this comes from very simple logic, right? So, if you want something safe for coral reefs, you’ve got to say, well, ‘when did the problems start occurring?’ And of course they occurred in 1979. You look at the gas concentrations at that point. You build in a short lag between gas concentrations and the subsequent temperature rise, all very conservative calculations, and you find out that, well, the trigger for mass coral bleaching on a global scale and the beginning of the problem comes up at 325 parts per million (of carbon dioxide in the atmosphere by volume).

Now, you say that to any policy maker, and I’ve said this a number of times, you see they get quite alarmed. You say well, we can’t get there. But I think we’ve got to face up to this scientific reality. I mean the other part of that perspective is that CO2 concentrations have not been above 300 parts per million for possibly as long as several million, if not 20 million years, some of the experts think. We know this from the ice core records where you can go in and get the gas concentration of past atmospheres trapped in snow that’s layered up over time, and you can calculate what that concentration was and what we find is it’s never been as high as it is today.We’re already about 100 parts per million more than any other time in a million years, at least.

So, those bits of information show us that CO2 has an enormous influence, not only on the physical properties of climate – you know, weather and temperature and so on, it also has a fundamental impact on the chemistry of the ocean and that has impacts on the biology.

Now it’s not only coral reefs in this case. If you go to the polar oceans you’ve got huge amounts of productivity that’s been, sunlight has been trapped by tiny organisms called coccolithophores and these also are now struggling because they can’t make their skeletons with the water being so acidic.

So this is sort of a double whammy for coral reefs. You know, if we get to 450, the temperatures get too hot and also the chemistry of the ocean becomes hostile to the formation and maintenance of limestone skeletons.

Scott Bilby: Now, we’re speaking to Ove Hoegh-Guldberg. He’s the Foundation Professor and Director of the Centre for Marine Studies at the University of Queensland.

Ove, some guys they say well, you know, ‘What does it matter if temperatures increase by one or two degrees in the Great Barrier Reef. Well, if you compare the Great Barrier Reef corals to, say, Papua New Guinea or somewhere in the oceans round about there, the corals up there are existing in temperatures that are two degrees hotter’.

Ove Hoegh-Guldberg: Yeah, look that problem of – you can go around the planet and you can find – for example, at the northern end of the Great Barrier Reef waters are about two to three degrees warmer than they are in summer on the southern end of the Great Barrier Reef. And the corals up there are living quite happy at those higher temperatures, whereas they fall apart at the bottom end of the Great Barrier Reef. And this is showing us that there has been local evolutionary adaptation to the local temperatures.

The problem is the amount of time it takes for that adaptation to occur. And so what we know from corals is that they take a long time, you know, hundreds, if not thousands of years, to shift their thermal optima to those new temperature conditions. The coral population growing in the northern end of the Great Barrier Reef is adapting to those local temperatures. That takes hundreds of thousands of years.

Now, the problem is that we’re shifting the conditions in the ocean at a hundred to possibly a thousand times faster than we’ve seen in any other period, except for the Younger Dryas event which was a very odd geological burp in the planetary record, a hundred to a thousand times faster than any other time in recent history. So, this is outstripping the rate at which evolution can occur.

So even though we’ve got these coral species in place at those different temperature optimums, we’re not giving corals on the southern end, for example, time to adapt to those new temperatures. So, that’s the problem.

Scott Bilby: Yeah, OK.

Ove Hoegh-Guldberg: Evolution just can’t go that fast.

Scott Bilby: OK, and, yeah, that’s what’s I was going to say. We’ve spoken to so many climate scientists who have said it’s the rate of temperature change that’s a real problem, and the rate of increase of concentration of gases.

Ove Hoegh-Guldberg: Yes, and it’s really amazing, I don’t think people quite realise how fast we’re doing things. And it’s actually inherent in any, look at the future projections, you just realise that we are operating at very high rates.

But during the Ice Age transitions which occurred because of the Milankovitch cycle, which is where the tilt of the Earth changes on a regular basis over tens of thousands of years, those changes were a hundred times slower than what we’ve done in the last 150 years. And of course when you look to the ever accelerating rate at which we’re pumping in CO2 and changing planetary temperatures, you know, we could be looking at maybe a thousandfold faster than an Ice Age transition. You’ve only got to think what happened to species through Europe and so on when those changes occurred. And they’re massive, even at that speed they challenge biology.

Matthew Wright: Now, another way of looking at that - so you can’t take coral polyps from the south of the reef and move them up to the north of the reef, like, they wouldn’t grow in those conditions. Is that sort of what you’re saying?

Ove Hoegh-Guldberg: That’s right. And in fact, the experiment has been done by several researchers at the Great Barrier Reef Marine Park Authority where they moved some corals up. And they saw exactly that – and in fact they did the reverse, which was where they took some warm adapted corals from the northern end and put it at the southern end. And then they had a bleaching event and they could see that the northern end guys survived while the locals didn’t – because the northern guys were used to hotter water, and when the hot water turned up, they were OK.

And that may suggest that planting corals from one end of the Great Barrier Reef to another might be a possible sort of fix to some of these problems. And of course I always say to those people, well you just imagine this is a huge reef – I mean it’s 375,000 square kilometres of territory, probably 40,000 kilometres squared of coral. You’re not going to be able to have a planting program that will keep up with the rate of climate change. [Laughs]

Matthew Wright: But also, they’re basically different organisms aren’t they?

Ove Hoegh-Guldberg: Well they are. And you’ve got all the problems of introducing pest species or diseases and all of that. There maybe, and this is worth probably looking at, there may be some possibility that within species you’ve got different adapted populations. And those you might move around, because it is the same species. But in the end you’re not going to be able to have a program where you could move, you know, a million species from one part to another, and that’s, unfortunately, reality.

I mean, at the end of the day, we need to address the core issue here, which is to get rid of greenhouse gas emissions as much as we can from our energy systems, the way we live our lives and so on. Because trying to fix them, or adapt to the problems, is almost impossible. I’d say it would be impossible.

Scott Bilby: Now Ove, I was reading a little bit from, well an article about a paper that has just been released recently about fish species, I think it was on the Great Barrier Reef. It’s a paper by McCormick, and it’s, I’ll just quote this line, it says “Juvenile damsel fish tended to remain where they settled, even if healthier coral was only a short distance away’.

So, it was kind of interesting to hear that even if a species has a habitable area to move to, even if that’s very close in fact, it may in fact not do so. Can you just give us your thoughts on that?

Ove Hoegh-Guldberg: Yeah, well that’s just showing how everything is so tightly connected within a system like the coral reef. Fish biologists have also shown that when you remove coral from an area, and a big team went around the Indian and Pacific oceans looking at this, when you remove coral at least 50 per cent of the fishes disappear instantly because they’re connected, like those damsel fish, to specific habitats.

For example in Acropora coral, (Acropora cervicornis) which is a staghorn coral, there are whole – hundreds of species – which need the coral to settle in. They need it to hide in, and they need it to feed on. And if you take coral away, the fish just go. And then you’ve got this problem that Mark sort of identified which is that then there are all these entrained behaviours. Again, adapting, changing those behaviours takes time, it takes decades, hundreds of years of adaptation. And fish they settle on a piece of coral where there used to be living coral and it’s not the same habitat. They don’t actually have the ecological smarts, if you like, to then move to the right habitat.

So this adds again to the problem of the speed of change. You’re just pulling the carpet out from underneath a whole bunch of species.

Scott Bilby: And that speed of change is, obviously it’s complicated further, things are made a lot more difficult by the fact that you’ve got many other threats to the coral reefs, such as flooding coming in from the land, of lots of fresh water, or overfishing, and stuff like that?

Ove Hoegh-Guldberg: Absolutely. And this is where the two-pronged approach has to be I think pursued. We’ve got the emissions issue, and it’s got to be probably a step-change in our behaviour. It can’t be business as usual. But at the same time, we know that if we aggravate the situation from local stressors like overfishing and too much sediment and nutrients onto a coral reef will hasten their exit even faster. So we can buy enormous amounts of time - you know, decades of time – if we can back off those other stressors like overfishing and sediment and pollution.

So along the Queensland coastline, for example, it’s really important that we deal with the issues of degrading land along the coast which is leading to this flood of nutrients and sediments, and that’s going to take reform of agricultural practices like sugar cane farming.

The cattle industry’s got to look at this because they’re a big contributor of sediment coming out of the rivers just through the fact that cattle walk around these watersheds and so on. There’s a whole range of things we can do there which will buy us important time when it comes to the climate issue.

The thing about overfishing is really interesting because we’ve done pretty good in some respects. We’ve had very proactive management of the zoning of the Great Barrier Reef. In fact we get a big tick there because we’ve got a third of it in total protection. Many parts of the world you’ve got situations where coral reefs are basically being fished to the point where there are no more fish on it. And so no more gardeners, no more pest control officers, if you look at the different roles those species play. And so what happens is the ecosystem shifts from coral dominated to seaweed dominated, because essentially the weeds get out of control, because you don’t have the fish that eat the seaweeds and so on.

Scott Bilby: Now Ove, you know, tell me if I’m kind of coming in too far from left field here but, we had these massive dust storms in Australia just about a month ago and millions of tonnes of soil poured – well, was blown – across the continent and into, kind of across the east coast into the oceans. Did this have any effect on the Great Barrier Reef at all? Did it get up that far?

Ove Hoegh-Guldberg: Well as far as I know, that was sort of in the south-eastern side of things. I’m not an expert on it. I had some oceanographers in my group have a look at it.

Scott Bilby: Yes.

Ove Hoegh-Guldberg: They were quite interested in just the impact of all the nutrients that would then be thrown into the ocean. And you get then a bloom of algae and a whole bunch of other phenomenon, way out to sea I should say. As far as I understand it wasn’t a big impact on the reef because it was sort of really concentrated down in the….

Scott Bilby: OK.

Ove Hoegh-Guldberg: ….southern portion.

Scott Bilby: OK. That’s fair enough. And what of the fisheries and other marine industries in the area? Are they facing up to this threat to the reef? Especially the big one from global warming, heating, ocean acidification. Are they lobbying the Queensland State Government and the Federal Government to do something about this, about global warming?

Ove Hoegh-Guldberg: Well I think there’s increasing voices from all of the industries that benefit from the reef. We’ve got to realise that, you know, it’s not about a diving spot for, you know, locals, this is a major industry along our east coast. The Great Barrier Reef, for example, brings in over 6 billion (Australian) dollars each year in tourist revenue, and it’s the second largest industry that Queensland has, employing 62,000 people and creating an entire vibrant economy along the coast. And of course if the reef falls over and we lose the reputation for having the best coral reef in the world, then we’re going to lose that tourist industry. That’s just very clear and that’s been the subject of several economic studies to look at that.

The tour operators, Daniel Gschwind and others, have been regular visitors to Canberra to make the point that this is an economic issue. It’s very serious for fishing and tourism on the reef. If you degrade coral reef habitat you will affect the fish that live around them and so on, and you’ll change the system in unpredictable ways. So we’re seeing an increasing number of people going to Canberra, going to Brisbane, to sort of make their voices heard because they understand the problem. It’s in their face.

And I think, all of these solutions, and this goes to Copenhagen and so on, it’s got to be a whole of society approach. We can’t turn around and blame one or the other sectors of our society and then walk away. We’ve got to actually engage as industry, people, politicians and so on until we get a whole of society outcome.

And that whole of society outcome will have to stare in the face things like coal. If we do not reduce the emissions of coal or have technologies in place for that to occur within ten years, then we have to phase out the use of coal in energy supplies, and that’s a tough decision. And that’s got to be a decision that includes the workers, you know, Latrobe Valley, or wherever you are. That’s got to include those people as part of the solution. That is, we don’t just leave them high and dry and say no more coal. We transition those industries into the new industries, the low carbon energy systems or whatever. We help those communities go, and if we do that I think we can do this as a world. I mean, we’re seeing this with China and the US, forming alliances here, which will be very powerful….

Scott Bilby: Exactly.

Ove Hoegh-Guldberg: … once they get going.

Scott Bilby: Exactly. And that brings me to a great quote. I’ll say who it is after I’ve said the quote.

Ove Hoegh-Guldberg: OK.

Scott Bilby: We have our common enemy, the Lavoisier Group, the coal-loving, industry-funded group who are denying global warming, and someone once said of them, “They are devoted to the proposition that the basic principles of physics cease to apply when they come into conflict with the interests of the Australian coal industry."

Ove Hoegh-Guldberg: [Laughs]

Scott Bilby: And the person who said that was John Quiggin.

Ove Hoegh-Guldberg: Yes.

Scott Bilby: Now, both you and John Quiggin are going to be speaking at the Universitas 21 Graduate Research Conference coming up, aren’t you?

Ove Hoegh-Guldberg: That’s right. Absolutely.

Scott Bilby: That’s in Melbourne?

Ove Hoegh-Guldberg: Yep. John’s – he has the ability to distill things down to the simple truth of the matter, and I think that is a very good one. I mean – what’s been happening – and this is happening also in Canberra at the moment with the opposition, the Coalition. You’ve got members there, they have seen the science, they know it’s correct, but this political skullduggery is selling essentially the Australian people down the creek - to say that the science isn’t right. And it is defying physics, like saying, ‘Oh well, I don’t believe in peer reviewed science any more’. Well, you’d have to ask Nick Minchin why he gets on a plane.

Scott Bilby: [Laughs] Yeah.

Ove Hoegh-Guldberg: You know, that’s all built with the same science, reviewed science and so on.

Scott Bilby: [Laughs]

Ove Hoegh-Guldberg: So to me, and I’ve actually said this to someone, I said, “Look you’d better get off the chair because that’s been made with technology with peer reviewed science”.

Scott Bilby: [Laughs].

Ove Hoegh-Guldberg: If you’re going to act medievally, then you can’t trust that technology any more. So to me - so that’s a very good point from John.

Scott Bilby: Ove, we’d like to say thank you for joining us this morning. Unfortunately we’ve run out of time.

Ove Hoegh-Guldberg: That’s unfortunate isn’t it? It was just getting going. [Laughs].

Scott Bilby: [Laughs].

Ove Hoegh-Guldberg: Alright, thank you very much for this. It’s been fun.

Matthew Wright: And all we’ve got to do is make the Great Barrier Reef bigger than the coal industry.

Scott Bilby: Yes.

Ove Hoegh-Guldberg: Well that’s right. And there was a point just recently where, because of the GFC (global financial crisis), the Great Barrier Reef was the biggest earner in the neighbourhood. [Laughs]

Scott Bilby: Oh, great. OK. That’s an interesting note to end on. Thank you very much Ove.

Ove Hoegh-Guldberg: OK. Thank you.

Scott Bilby: Cheers.

Ove Hoegh-Guldberg: Bye.

Scott Bilby: We’ve just been speaking to Ove Hoegh-Guldberg. He’s the Foundation Professor and Director of the Centre for Marine Studies at the University of Queensland. And so, we’re going to have to say goodbye now, but if you want to hear more about – do you want to end the show there Matthew?

Matthew Wright: More about climate change? About solutions to climate change, obviously log onto the Beyond Zero Emissions website at beyondzeroemissions.org, and all our past podcasts and radio interviews and media releases are up on the website. Thank you.

Transcript by Jenny Gibson

Related links:

Climate Shifts Ove's blog

Coral Reef Ecosystems Laboratory Centre for Marine Studies, University of Queensland