 My name is Ofer Gulberg and I'm a professor of marine science. I'm also director of the Global Change Institute at the University of Queensland. I've spent my career looking at marine ecosystems and the influence of factors such as climate change. I've done that for the last 30 years and I suspect I'll be doing it until the day I retire. So, Ofer, could you tell me how did you get into this line of research? I came up to the reef when I was, well, early teens and I saw this wonderful thing called the Great Barrier Reef and then I found out that actually you could do research on it and of course I watched the required Cousteau movies and so on. But, you know, I just wanted to work on it and understand it so it was literally all about, you know, the reef. It wasn't about climate change or the environmental changes affecting the reef, it was just that I loved the reef. But the more I got into it, of course, and when I started my PhD, what I started to work on was really some of the changes that were occurring. So I still remember in the early 80s, for example, when the lab that I was in at UCLA in California, in Los Angeles, the first bleach samples coming out of the Caribbean and being sent to my professor and people going, we don't know why this has happened but large amounts of coral have gone white. We're calling it bleaching. From there we start to ask questions about why it was happening. We got, you know, the insight that it was only happening during very warm periods, you know, when the sea was flat and lots of sunlight and so on. And eventually over that time I started to work on, you know, how you stressed corals and how you got the bleaching effect and so on. And it came down to temperature, a little bit of an influence of light. But the major thing was that when corals get too warm they start to break down and the essential bit of information here is that the symbiotic dinoflagellates, these are tiny plants that live inside the cells of corals and they make them brown but they also create this situation where they can capture sunlight using these tiny plants and actually exist without feeding. Now corals do feed as well to get other compounds but this symbiosis is crucial to the biology of corals and it's a reason why we can see these very high rates of calcification on reefs like this one here on Heron Island. We start to then think well in the 90s, the early 90s it became apparent that maybe there was a big sort of temperature signal going through the oceans and of course the evidence of global climate change was increasing and then we linked it to that. And along in the short of it is that I went from being someone fascinated by the beauty of coral reefs to doing research on climate change and its impact on biological systems. And yeah, it's quite a new piece of progression but it's hard now to do much biology without considering the issue of global change at that level. So I guess that leads to my next question. You once talked about ocean acidification combined with climate change. It's like a one-two punch. What do you mean by that? Well as we sort of understood changes in terms of climate change it was mainly focused on temperature when you look at the early literature but in 1999 there was a paper by Joni Kleepass and a series of authors many from France, some from Australia that started to ask the question about what were the implications of a changing ocean chemistry when it came to CO2. And what they were showing was that since the Industrial Revolution the chemistry of the ocean should have changed quite dramatically. When I say should have it was a lot of, it was theoretical calculations and so on. But it's set in motion a very interesting set of research and questions because we had on one hand these sort of temperature extremes that were becoming more and more common in these systems we had bleaching and so on and now we had another thing lurking which as we've done about a decade of research now we know that it has some very serious effects on a range of organisms including corals. So the one-two punch thing is the fact that we've not only stressed these systems from a temperature point of view we've also imposed a rapidly changing chemistry. And that chemistry is, well I think it's fundamental to their biology of most organisms. And the way it goes is simply that as we've pumped more CO2 into the atmosphere from the burning of fossil fuels about 30% of it has actually been absorbed by the ocean. Now in one sense that's been quite good because we've had less greenhouse gases so less of a warming effect but that CO2 going to the ocean has had its own chemical impact on the ocean. And so if you can imagine a molecule of CO2 coming down into the ocean goes into the ocean and reacts with water to create a dilute acid and the effect of that acid is that as it dissociates you get a proton those protons like to attack or to combine with carbonate ions and turn them into bicarbonate. And so what's happened is as we've added CO2 to the ocean it's become slightly more acidic but we've had quite a serious drop in the amount of carbonate ions in solution. These are the ions that organisms make their skeletons with, their shells and so on. And so if you think about it all the sand here is a consequence of these organisms being able to precipitate large amounts of calcium carbonate. Turns out that since the pre-industrial period we've had a drop of around about 26% in terms of the carbonate ion concentration. Now the last thing I'll say is that those two variables temperature and pH and water chemistry are two really fundamental variables. They change everything. And that's I think what we're dealing with now is that almost every couple of weeks we're getting a new paper on another surprise, the effect of temperature and chemistry on these systems. And that's making I think it pretty hard to imagine how we're going to manage ecosystems for resilience into the future with these surprises. So I guess how do these changes ripple through the ocean and through the different whole ecosystem in the ocean and then eventually affecting humans? Can you describe that progression? Well it's interesting and it does come down to the fact that these are fundamental variables. You know we know that for example that some invertebrates, the larvae are affected more than others. And so one of those impacts very simply has been that some aquaculture industries like oysters have now been have trouble raising the larvae for their stock. Now that's sort of a simple linear, you know you change the chemistry you affect the growth of the larvae and then of course you have an impact on you know whether you can grow oysters or not. But there is a whole series of interactive effects ripple effects that you're changing one thing which might be the food of something else that then changes the biology of that organism. And there are very complex things and when they interact with temperature and then local factors because of course we're doing much more than simply changing the climate, we're changing the coastal ecosystems and the water quality just from local effects. You put all those things together and you start to get a very unpredictable system and that I think is going to be quite difficult to handle as we go forward. I mean in the latest IPCC there are a couple of really interesting consensus items that came out of it and one of them is that about 80% of the studies that are long enough to study the relocation of species are reporting changes that are consistent with ocean warming. And of course when you've got a moving ecosystem so some things like phytoplankton which are at the heart of the ocean are travelling at something like 30 to 40 kilometers per year. So that food source is going that way but the fish that often are the benefits of that type of system are travelling at much slower rates about 5 to 10 kilometers per year. So you can see you're getting a mismatch with food. You're getting things like the potential for invasive species have gone up in regions because the temperature and chemistry have become more amelial to one species over another and so we started to see those sort of effects happen as well. So going back to the one-two punch or the evil twin really got to consider the two together in trying to understand how the future might unfold and what the consequences are of not acting on fossil fuels. Scientists have been talking about the negative impacts of acidification and warming on coral reefs but one argument trying to downplay these risks is that corals can adapt to it or can recover to it. What's the situation there? Well yes people do sort of talk about this idea that if you take the behavior of organisms today and you impose future conditions on them well we're seeing an effect but what if those organisms were able to adapt from an evolutionary point of view and keep pace with those changes and of course what you'd expect to see then is that things wouldn't change because they'd be adapting to the circumstances and of course the paper that was put out very rigorous paper by D'Athe and co-authors from the Australian Institute of Marine Sciences has shown that coral cover on the Great Barrier Reef has dropped by about a half since the early 1980s so in a way that's really like demonstrating that adaptation isn't effective enough to drop that decline. I also like to point out that we're really in the early stages of changes that are probably happening well they are according to the IPCC at a rate that's the highest in 65 million years and so much slower and less significant changes have had huge impacts on life and ecosystems so there's not much evidence I think out there in nature that evolution is keeping up but then from a theoretical point of view when you consider that most corals for example have generation times of three to maybe a century this is not bacteria so you can't grow them and have them reproduce in 20 minutes and have the evolutionary process on steroids this is a really slow process for these types of organisms so I think while I think we need to do research on these topics I think at this point it would be hard to say that there's any significant evidence that this is going to change the interpretation of what we're seeing at the moment which is that the environment is outstripping the ability of biology and ecosystems to keep up with climate change throughout Earth's history there's been periods where corals have experienced mass extinctions does that tell us anything about today's situation and going into the future well the mass extinction events I think show us what's possible with actually a lot slower change which is pretty frightening I think about the rates of change we're seeing apart from the Cretaceous boundary event when you had an asteroid hit the Gulf of Mexico or made the Gulf of Mexico it's hard to think that a lot of these other ones happened over thousands of years yet we're doing equivalent changes over a few decades so I suppose these mass extinction events tell us that we can have some major effects a lot lower rates of change the other thing they tell us of course is that once you've done this it takes millions of years for these ecosystems to come back and of course sometimes you hear people say oh well you know they did come back eventually so maybe we shouldn't worry well try telling a tour operator who's got to fill his boat to take the tourists out that the reef has gone for about 10 million years and we'll be back, don't worry about it I mean these sometimes you hear these arguments and actually those ones about mass extinction events are not particularly credible if you come to the Malenkovich cycle with the Ice Age transitions again they're much slower than the rate of change that we are currently forcing on Earth's biological systems and then you had major changes so I suppose we have to say that these past events should really give us a worked example of what we could do to the planet if we don't make some deep cuts in our greenhouse gas emissions What would you say are the most interesting scientific questions in your field at the moment? I suppose the sorts of questions that biologists are asking now is what will the world be like when we do take action we know what will happen if we go down the RCP 8.5 pathway The business as usual the one we're on right now we have a very solid base for saying that reefs will be transformed most ecosystem on the planets will be transformed and the risk of really major disruptions will have gone up significantly so I think the types of questions we're asking now is okay if we were to have a rapid urbanization of our societies and we were to take the sorts of action to solve those problems and stabilize conditions on the planet what would ecosystems be like and what would we do to make sure that we then have a reflourishing of those ecosystems and this I think is where there is some optimism here and that is that I think we're going to deal with the problem because there is no other way to respond to the choice if this planet gets too hot too dry, too violent for us there is no place to go so let's assume we get to RCP 2.6 that means this rapid decarbonization over the next 30 years it means a stabilisation of global temperature by the mid to late part of the century we're going to have a sort of more acidified ocean that's going to take 10,000 years to recover from but we'll have conditions where we need to now know who's left standing and how do we best sort of manage those ecosystems so that they reflourish to obviously a different end point but to a point where they start to provide the goods and services that they used to provide for the planet and for people that to me is a really interesting area right now do you have any advice for scientists and science communicators on how best to communicate the realities of climate change to the public I think over my career as a scientist I've gone from believing that scientific publication was all to the idea that we need to publish science of course in peer reviewed journals but we then need to communicate it and it's to a much broader audience than the one that we have traditionally been so this is where I've developed a deep respect for documentary makers and that's where it's it's about the mind I mean it's got to be credible but it's about the heart and soul that's so important and I think that's the sort of thing that we have to do here is to get people to understand that this is more than just a decline of an ecosystem it's the well-being of humans the people that we love and I think that's where we've got to go it's an essence of the mind the heart and the soul we have to really try and wake people up to realise that this is happening it's very very serious but we can solve it and we have to do so not because it's going to cut the economy but because it's the planet we live on and it's the people that we love that are going to be affected and so for me that I think more and more I've really come to see that as what we have to do in science Could you give a short statement about how humans are affecting climate change from the point of view of your research Well if you go back to the pre-industrial period we have this world in which you had healthy ecosystems we also had lower numbers of people but we hadn't started to change things at a scale that we are today and so if you fast forward to the 80's, 90's and the last decade we're starting to see this confluence of factors that humans are now studying change and it's really remarkable when you think of the hairless ape out of Africa which might have numbered in 10,000 at one point in its history that now has started to has begun to change a planet's atmosphere and its biological cycle changed the weather and of course this has huge implications for ecosystems biology and so on and that's where I think it's influenced my work and as I said I started off as someone who literally just wanted to study life it was beautiful it was compelling to really looking at some of the biggest challenges that humanity has ever faced in the effect of one's career and I think there are now thousands of scientists who have the same not conversion but same sort of track where they've started all studying some part of the world and then realise that it's now changing fundamentally and very rapidly so it's sort of interesting from that point of view but at the end of the day I am an optimist I think we are this thrilling species that has pushed us right to the brink with these huge looming problems but at the same time we're in a position where we have the capability to make the greatest changes the very fact that 2 billion people are linked up on smartphone technology that are now communicating ideas is something that's never happened before in the history of humanity and so I think that's why we've seen this rapid escalation of technologies that everything's almost a surprise every couple of years about what they've done and so that gives me hope that we will with the appropriate stimuli go right, let's fix the problem let's decarbonise, let's get those new fuel sources going, let's redesign cities let's solve these problems because we can but I tell you what it's a thrilling journey right on that knife edge and I somewhere I wish we weren't quite on the knife edge but again I think we're going to survive and I think we'll solve this problem but we have to wake up now and get on with solutions