The winter issue of the Oceana newsletter is now online for your reading pleasure. One of my favorite features of this issue is an interview with renowned coral reef scientist J.E.N. Veron, who spent a career studying corals reefs as the chief scientist at the Australian Institute of Marine Science. Two years ago, he resigned in order to concentrate on the effects of climate change on coral reefs. He now devotes himself to educating the public about the coming crisis of ocean acidification. Oceana newsletter editor Suzannah Evans asked him about his new book, A Reef in Time: The Great Barrier Reef From Beginning to End.Can you explain what increased carbon dioxide does to coral reefs?When carbon dioxide dissolves in the ocean surface, it alters the ocean chemistry. In effect, it attacks the buffers that keep the oceans at a very constant alkaline condition and allow organisms such as corals to build their skeletons from calcium carbonate. When the buffers change and the oceans become ever so slightly acidified, corals can no longer build their skeletons and coral reefs become erosional: They erode rather than build, they retreat back and back until there’s no capacity for building the skeletons anymore. This has happened five times in the past, and the obvious fear is it’s going to happen in the immediate future all over again.Are we already seeing coral reefs suffering from acidification?Oh yes. Acidification is not uniform throughout the whole oceans. Where you’ve got poor water circulation, you can have quite acidified, large areas of acidified ocean. In my book I’ve actually photographed coral reefs in those conditions. They are basically covered with a bacterial slime and all their biodiversity has gone. They are just rubble with bacterial slime. We now see that in quite big areas, and that is primarily the outcome of all sorts of impacts followed up by acidified conditions.What kind of oceans would we have if we didn’t have coral reefs?If the oceans changed to the extent that coral reefs could no longer grow – and that will happen within the next twenty years, or the conditions will be upon us in the next 20 years and that will be played out later as the century progresses – coral reefs won’t develop, the plankton, which acts as a biological pump for pulling carbon dioxide out of the atmosphere, that won’t work. Krill will not develop in the Southern Ocean. Krill are the key component of just about all food chains in the Southern Ocean. And then we have the effects of acidification spreading out all through the oceans.This is ultimately a mass extinction event. It starts in the tropical ocean, impacting coral reefs most dramatically, but it will affect everything in all the oceans. That’s the great fear.Are divers able to see this happening?I think divers who have not seen coral reefs much still think there’s something really exciting and special. In some places they still are. Some areas of the Great Barrier Reef are as spectacular as they’ve ever been. But most areas are suffering now from mass bleaching events caused by higher than normal temperatures. These will be affecting, these cycles of high temperatures will be affecting the GBR more and more over the next twenty years.If we continue to emit carbon dioxide at the rate we are going, the worst year we’ve ever seen for mass bleaching will be an average year by 2030, and will be a good year by 2050. By 2030 we won’t have any reefs that an experienced diver would call a coral reef. It will be mostly rubble and what corals there are will be in deeper water.Is that the worst case scenario – or is there something even worse?The worst case scenario is when ocean acidification kicks in. There will be no refuges then, there will be nowhere that corals will be able to grow. By 2030, or even 2020, we’ll have past the point of no return, so this is incredibly serious. We are looking down the barrel of a big gun and we are seeing the end of the Great Barrier Reef.What can be done, and do you feel at all hopeful?I am hopeful because humans are very good at moving en masse when they feel motivated and when they really understand that a crisis of this proportion is upon us. The actual cure for carbon dioxide is pretty easy, we already have the technology; we can make it happen. I think it’s just a case of mass action on the part of people.Governments will follow, that’s for sure. All governments now are pretty much aware of major consequences of climate change. They’re not aware so much of acidification because it’s quite new in the scientific arena. But they are aware of the main issues. Governments will act as long as they believe the people are behind them.So I think education of the public has become the most critical thing. Once we do that, then the enormous range of technologies we now have can kick in, and we can fix it.Do you have a recommendation for what parts per million saturation of carbon dioxide we can live with?I think 450 ppm would be the never-to-exceed mark. If we get up to 450 I do think the GBR will not remain great anymore, I think it will be basically slowly degrading. So if we are going to keep coral reefs of the world in pristine condition, in good condition, return them to good condition, we mustn’t go higher than 350 ppm.After all, there are no records of higher levels of carbon dioxide in the genetic existence of modern corals. They’ve never experienced this before, so they can’t adapt to it. They don’t have time for an evolutionary change. Evolution takes hundreds of thousands to millions of years, they haven’t got that. They’ve only got this century, or just a few decades.So under a business-as-usual scenario, you say that by 2030 or even 2020 we’re already looking at severe depletion of coral reefs?By the middle of the century in a business-as-usual scenario, over the next 20 years, or if we don’t have a drastic reduction of carbon dioxide in the next 20 years, by the middle of the century, we will not have reefs developing anywhere. Ocean acidification will be preventing this from happening.I do believe the impacts are not just on coral reefs. They are on the oceans in general; This is something we have seen in the geological record. The essential part of all this is that corals do not have the evolutionary capacity to respond to ocean acidification that we are producing because they’ve never been exposed to it in their genetic history. We’re going back tens of millions of years before they’ve ever confronted the level of carbon dioxide that they are receiving now. When that gets too high, they will stop producing skeletons everywhere and this has been seen in the geological record many times. It’s all going to happen again.How long does it take for corals to recover from a mass extinction?The quickest time for corals to recover from a mass extinction is four million years. That’s the time that has been necessary to reinvent the know-how to make reefs. In other words, what has survived are organisms that do not build skeletons that can construct reefs. What corals do survive have existed probably without skeletons, which corals are capable of doing, they look like anemones. They have probably survived these high carbon dioxide intervals and they have taken a huge amount of time to reinvent all the components for reef building.It’s not just a matter of reinventing how to make skeletons themselves, it’s reinventing the entire ecology that is needed for reef buildings. So yeah, between four and twelve million years. It’s like having plants reinvent capacities to build forests.In that period while corals are regenerating, then the entire ocean is utterly changed?Utterly changed. What reefs eventually come back are very simple structures and have none of the diversity that modern reefs have. We look at multiple millions of years for the complexity, the diversity of reefs to slowly build up. But as far as humans are concerned, all this is very theoretical, humans won’t be around to witness any of this. We are looking at something that is incredibly serious even on the scale of earth’s history.I take it you’re an avid diver. Where’s your favorite place to dive?I’ve spent 7000 hours underwater. Just about a record, I’d think. It depends on what you’re after. If you want big, spectacular megafauna, the northern Great Barrier Reef. If you want biodiversity, eastern Indonesia is wonderful, the coral triangle as we call it.What’s your personal favorite site?I’m heading up to the northern GBR in a few weeks. The most interest is in eastern Indonesia, it’s the epicenter of biodiversity.What’s the most amazing thing you’ve ever seen?So many amazing things. Great big monstrous things, it would be impossible to say. Aboriginal fish trips found ten meters under the surface. Caves where aborigines once lived. Really big tiger sharks or whale sharks, whales, being sounded out by humpback whales is the most terrifying thing – the blast of sound they use to work out who the diver is is quite incredible. I’ve been diving so much and seen so many things that it’s all off the scale. It’s very sad that young people today will not see, and have no chance of seeing, what I’ve seen. It makes me enormously sad. I have two young children, they will never see what I’ve seen, no one will. That’s why I wrote a big three volume book, Corals of the World, to say, this is what we have, and of course it’s a very sad thing for me to reflect on what the future holds, it’s awful.Well, that’s a sad note to end this on.It is a sad note. But we have to keep hope going. I think indeed there is a lot of hope. It is the publications like [Oceana’s report] Acid Test, and I hope my book. My book is having an impact in Australia, it has turned the hearts and minds of a lot of people. I try to encourage people to read my book – when they do, I’ve never found a person who hasn’t changed their whole attitude to climate change. So, it works. We have to have a lot more such things and we have to have them quickly.