Earth & Sky

Transcript of interview with Joanie Kleypas:

Joanie Kleypas, I’m a Scientist I at the National Center for Atmospheric Research.

JK: There were several talks in this session that had to do with coral reefs and global change in general. And that includes other pressures, including overfishing, direct impacts like that. The particular talk that I gave dealt with climate change issues. And that includes two main aspects of climate change – increasing temperature on coral reefs, and also the effects of changing water chemistry on coral reefs. The first one, people are familiar with. The second one, people aren’t that familiar with. But they’re both consequences of climate change and they’re both not beneficial to coral reefs, unfortunately.

JK: When the issues of global warming first came up 20 years ago, most scientists, I’d say, thought that it would be good for coral reefs. Coral reefs are tropical ecosystems; they like warm water. And, that attitude changed over the last two decades, when we had very dramatic increases in coral bleaching. Coral bleaching is basically the loss of algae, which live, in coral tissue. These algae are photosynthetic.

Coral are actually two organisms – at least those corals that build coral reefs are two organisms. They are anemone-like animals that house small, microscopic, unicellular plants in their tissues. And the plants carry out photosynthesis, and the animal benefits from having the plant live right there in their tissue. There’s this nice exchange between the two. The little algae that live in the tissue that do photosynthesis can supply the coral animal with sugars and carbohydrates and other things that it needs to live off of, but in turn, it’s thought that the zooxanthellae benefit from the byproduct from the corals, that would be the nitrates and the other recycled types of nutrients. So it’s this really nice symbiotic relationship between the plant and the animal. When the corals bleach, these conditions cause stress in the organism, and it’s through that that the animal itself gets rid of the algae. So there’s a breakdown in the symbiotic relationship. And, because the algae are what give the coral their color, they become transparent. And you can see this white, calcium carbonate skeleton underneath. And they turn white – that’s why we call it bleaching.

In the last two decades, bleachings have become much more common, and they’re almost always associated with increases in temperature. So, we’ve had some reefs where almost 100% of the corals have died through this process. They don’t always die, but when they do, the complete loss of these corals on the reef and the whole composition of the reef changes. And, it takes a long time for those reefs to come back to their pre-bleached state. This is a big change that we’re seeing in coral reefs, and I don’t think you can find many scientists who would say that global warming is good for coral reefs.

So what we once thought was that global warming would allow reefs to expand up the coast, so that we’d have reefs going up to Georgia and towards the Carolinas, because those temperatures would warm up and we’d have an expansion of reefs. What we’re really finding is that a lot of reefs are being killed off by increases in sea surface temperature. And that’s been pretty alarming. There’s some thought that corals would be able to adapt to higher temperatures, and we think that because we have corals in the Red Sea and the Persian Gulf which tolerate very high temperatures – up to 34 degrees Centigrade. But it depends on what that particular coral is used to. It’s kind of like humans. If you’re used to living in the tropics, and hot weather doesn’t bother you very much. If you’re used to living in colder climates, and you’re exposed to hot weather, you can die of heatstroke. So, there’s an ability for corals to adapt to warmer temperatures, but the problem is that the increases in sea surface temperature that we’re seeing are faster than the rate at which coral can adapt. And that’s a problem. And that’s why it’s hard to predict what’s going to happen to corals in the future. It all depends on how fast the temperatures rise.

JK: We didn’t come out with any real predictions of what percentage of reefs are going to bleach in the future. Some people have tried to do that. I did it in the talk. If you look at the rate of temperature change, and you put on top of that the rate at which we can get the coral to adapt to that temperature change, already, because we’re having these global scale mass coral bleaching events, it’s pretty strong evidence that they’re not adapting fast enough right now. And, that’s the scary part. Given the current predictions of climate change, we see most of the scenarios, mostly the warming associated with most of these scenarios is probably too fast for some of these coral species. It doesn’t matter what scenario we follow at this point, we’re probably going to see some species either eliminated or drastically reduced. Those would be the species that are most sensitive to increases in water temperature. Other species are more robust and they’re likely to weather through some of these scenarios. So the net result is that we would have coral communities with lower diversity because some of the more sensitive corals would be eliminated, and some other types of corals would survive. So there would be a change of community structure of the coral reefs. That’s the very likely scenario. Now, how many corals are going to be drastically reduced, that’s a tougher question. Typically the branching corals are the ones that are more sensitive than the table corals. The ones that we actually think about the most when we about coral reefs, those are the one that already show high sensitivity to increases in temperature. The big head corals, the ones that can live 300 years old or more, those are more robust against rising temperatures. And most people think those are more likely to survive coral bleaching events.

The numbers that predict how much warming there will be by the year 2050, I think it’s between about 1-2 1/2 degrees Centigrade by the middle of this century. We want to shoot for the lowest number. We didn’t make any predictions, we just said these are the increases in temperature. We already see that the average increase in temperature in the tropics has only been about 2/10 of a degree centigrade over the last couple of decades. So it hasn’t been really hot. Most of the bleaching is associated with localized areas where the temperature actually went up above 1-2 degrees Centigrade. That’s where you get your bleaching events. The corals are used to this maximum thermocline temperature, and it varies a little bit. And in the last ten years, those temperatures have been exceeded by 1-2 degrees Centigrade for a week or more. And in those cases that’s when the coral’s get stressed and then bleach. So, if you try to talk about local changes in temperature, and global changes in temperature, in the averages, there’s a very big difference in the numbers. So when we talk about a one-degree centigrade difference in the temperature in the tropics, that doesn’t mean this sort of nice, gradual, change in sea surface temperature everywhere. It means that some of these areas are going to have much greater increases in temperature, from much lower increases in temperature. And the average amount is one degree centigrade. What we’re worried about is all the areas where the temperatures spike up well above what the corals are used to. And that is actually what we’re seeing in these mass coral bleaching events. In the Indian Ocean, in 1998, there was warming associated with El Nino. I think that over half the reefs suffered major mortality in the Indian Ocean. So that was a very severe bleaching event. And that’s because the temperatures went up a lot in that particular region. Whereas in the same year, in another ocean, you have areas where there was no temperature increase, and no bleaching at all.

Coral bleaching is a phenomenon that scientists have known about for a long time. And it’s always those coral bleaching events where local events, it may be due to sudden changes in temperature, sudden changes in salinity, a storm that suddenly drops a lot of freshwater on to the reefs – those kind of issues that enter smaller, local scales. Then in the 1980s, 1982-83 there was a mass coral bleaching event that Peter Glynn documented beautifully for the Galapagos. That is when almost every coral in the Galapagos died because sea surface temperatures went up so high and all of the corals bleached. Since then, we’ve seen more and more of these events, and the major events in the early 90s, and this whopping event in 1997-98. Every year, we’ve been seeing more and more increases in these large scale-bleaching events, where entire reefs are affected by sea surface temperatures. For example, the Great Barrier Reef usually extends 2000 km or more. In several of these episodes now, there’s been bleaching up and down the reef. So even though no other coral is affected, almost all the region of that reef was affected. So the scale of these events is getting a lot bigger. That’s been really weighing to scientists who study these things. Often there’s mortality associated with coral bleaching, or the organisms are weakened. So, even though they may recover and not die, the reefs have been hit pretty hard. It’s like getting hit by some illness and trying to recover, and in that period while you recover you’re really vulnerable to all kinds of things like disease. So this whole attitude toward coral bleaching has changed from one where we though it was an isolated event, to now where we understand that these events are getting more extensive. They’re occurring in all oceans, and they’re having higher mortalities associated with them. And that’s where we are in terms of watching this develop over the last two decades. We also realize now that almost all of these events are associated with temperature. That’s the main culprit. So there’s no doubt in scientists minds that these mass coral bleaching events are associated with increasing temperature. It’s a no-brainer.

JK: Well that’s a really interesting question, because you’d like to say that one area is more vulnerable to bleaching than another area. We know that some reefs, like those in the Galapagos, are more vulnerable to bleaching than other areas because they’re in this environment that’s so strongly affected by warming events and the big changes in temperatures that are associated with that. There are other reefs, at higher latitudes that exist at relatively constant temperature conditions. I think we have this false sense of security that these reefs will be left largely unaffected by temperature. But as each year passes, and more of these bleaching events occur, we’re starting to see that even some of those reefs that we thought were safe from bleaching are actually experiencing coral bleaching. That’s a little bit alarming. I think one thing we need to look at more closely that hasn’t been looked at quite enough yet is to look to those areas that are already pretty warm, because it’s quite likely that they’re a thermostat to how hot the oceans can get. And maybe I wouldn’t want you to put this out on the news yet, because I haven’t published it, but I think what scientists are seeing now is that it doesn’t look like any of these reefs are protected from increases in sea surface temperatures. It’s truly a global phenomenon. That includes bleaching occurring in Hawaii, which is a fairly high latitude reef, bleaching occurring in Bermuda, which is a very high latitude reef. So it affects reefs everywhere. And that’s a tough one to plan for.

JK: Okay, the ocean chemistry issue is a very tough one to understand. It’s very counterintuitive. What happens is that as you increase concentration of carbon dioxide in the atmosphere, you’re increasing the pressure of that carbon dioxide in the atmosphere. And more of it is driven into the ocean, in particular, right there at the interface between the atmosphere and the ocean. When you drive more CO2 into seawater, it forms carbonic acid. Acid lowers the pH of the water. This affects coral reefs because those organisms secrete calcium carbonate. Under acidic conditions, those organisms secrete less calcium carbonate. And a good analogy is osteoporosis. If you secrete less bone material, you’re bones get a little bit more thinner, and you get more fragile. That’s what we think will happen to some of these coral organisms. So they’re secreting less calcium carbonate. Two things can actually happen when they do this. One, they’ll grow more slowly. And when a coral grow more slowly, that makes it less competitive for space on a coral reef. Or it makes them more fragile. And that makes them more susceptible to breakage and to erosion. And then a third issue is – the reef itself is filled up by these organisms. So if you decrease the amount of calcium carbonate that’s being secreted, you’re also going to decrease the ability of that entire reef to grow. And so there’s several consequences of changing the acidity of the ocean, just because it changes the whole calcium carbonate budget that we know about in the ocean.

JK: What one of the aspects of increasing atmospheric carbon dioxide is not only global warming, is it’s effect on sea water chemistry. And, if you think about this over geologic time, there’s strong evidence that the current levels of atmospheric carbon dioxide that we have today is quite a bit higher than what we’ve experienced over the past 400,000 years. And so these organisms have been growing in this environment where this sea water chemistry has not changed over that period by much at all. So what’s happening now is that seawater chemistry is changing at a fairly rapid rate. And seawater chemistry is changing because we’re driving more carbon dioxide into the ocean. So these fossil fuels we’re burning are adding more carbon dioxide into the atmosphere. The oceans actually sequester, or absorb, about 1/3 of those fossil fuel emissions right into the ocean. And it doesn’t do that without any kind of chemical change. It causes a decrease in the pH. If you think about a soft drink, for example. Soft drinks are produced by driving CO2 into the drink itself. And then capping it into a can or a bottle. If you measured the pH of a soft drink, the soft drink would have a pH that’s pretty darn low. I think often they’re about a pH of about 5 – that’s a fairly acidic drink. We’re doing something similar in the oceans. We’re actually driving more CO2 into the oceans, and also driving the pH down. This causes all kinds of chemical changes in sea water, so that organisms that secrete calcium carbonate to form their skeletons, and that includes corals, secrete less of that calcium carbonate. And so, that’s a very important part of that organism, and it allows them to grow upward to collect light, it’s analogous to the way a tree grows upward, or grows over the ground. If you change the growth rate of that tree, you change the way it functions in that community, and it’s the same way with corals. So we think that some of these corals are going to grow more slowly, on the surface of the reefs. If they grow more slowly, that makes them less able to compete for space. And they’re competing for space with all kinds of other organisms, and particularly with fleshy, macro algae. The second thing that can happen is that their skeletons are less robust. Their skeletons will be more fragile, will be more susceptible to breakage or to erosion. And then the third, bigger picture thing, is the fact that coral reefs themselves are built up of the skeletons of these organisms. And so if you reduce the production of calcium carbonate of these organisms, you reduce the capacity for that reef to grow and actually build a reef. In some cases we think that if you decrease the pH of the oceans, then those reefs will quit growing completely, and some of them might disappear. That’s important, because those reefs are important structures off of coastal zones. They do a lot for protecting coastal zone environments, or creating environments for other important ecosystems like mangroves. There’s two different ways to look at this. And that is, the coral is going to be affected. And also, the reefs are going to be affected.

JK: Well, we know the case for putting carbon dioxide into the oceans is not good for the calcium carbonate secreting organisms. There’s also evidence that it’s not good for very many organisms at all. And that’s because you are going to be changing the pH. So if you think about deep sea organisms in particular, which are used to very constant environments, once these fossil fuels that are absorbed into the ocean are transferred to deeper ocean depths, how will it affect the biology of those organisms? It’s a big question. But it’s one of these quiet aspects of climate change that doesn’t get discussed very much. We don’t see it – we tend to treat the oceans like carpets where we can sweep fossil fuels under them. But I think it’s important that we understand what the consequences are. The ocean doesn’t just take up this carbon dioxide benignly – there are definitely changes in the chemistry, and that chemistry in turn will change the biology. I don’t want to be dire about this. If people hear some of these things, they might get scared (laughs).

JK: Predicting what will happen is a really tough one. We’re only scratching the surface in this area, in terms of how ocean chemistry is going to change the biology of the oceans. It’s just like temperature. Some organisms are going to be more sensitive than others. Some of those organisms could be affected in very bad ways, and driven to extinction. We just don’t know. It’s possible that some organisms will actually benefit from increased acidity. But we don’t know that either.

If you just think about your own blood chemistry. if you change the pH of your blood, you would expect something to happen. You would expect some changes in the way your body functions. So if we use a human being as sort of an analogy to what’s going on in the oceans. We can expect certain biological systems to function differently. And that might mean changes in which organisms do well in the oceans and which organisms do poorly… I think we’re already measuring those changes.

JK: Let’s contrast the effects of temperature with the effects of chemistry on coral reefs. So temperature causes some of these episodic events like mass coral bleaching. They’re very visible – they’re very scary. They make us worry about temperature change a lot. In the background, occurring constantly, at a very constant rate, is this change in seawater chemistry. We can’t see it. It’s acting at a very slow rate – to where we can’t actually see coral on a reef dissolving for instance. It’s a lot tougher to measure. But it is the “tortoise” in this race. We’ve got this slow moving process of seawater chemistry change, which is sort of creeping along in concert with changes in atmospheric CO2 concentration. Whereas you’ve got these temperature changes which have tended to be episodic, so we have these more rapid changes in temperature, which have caused this mass, visible, coral bleaching. Both of them are operating. One is visible, one is not. One we know kills coral, the other one doesn’t outright kill the coral. It just affects the way they function. So those two things are happening in parallel die to the same problem, which is increasing atmospheric carbon dioxide. We don’t know what the long-term changes are – I mean either one of those. We can only go by IPCC types of predictions, and we can use what we know already about these ecosystems to make predictions. The problem here is, we’re trying to predict these changes about this ecosystem in an environment where we have no data to show how they’ve operated in the past. So the first thing you want to do when you want to predict what happens to these ecosystems is you go back and you say, when did they have these conditions before, and how did they operate under those conditions. So, when was the last time we had really high CO2 and low pH in the ocean? When was the last time we had really high temperatures? We go back and you can’t find those periods. You have to go back millions of years to find those periods. If you go back that long ago, evolution has taken place. It’s very hard to say that the coral that lived under high CO2 conditions, millions of years ago, is going to behave the same under these conditions now. So there’s some really tough obstacles to making predictions about how any ecosystem on the planet is going to respond to future conditions, because these future conditions that we’re moving into are like nothing we’ve seen in at least the last 1/2 million years, and probably many millions of years.

JK: I think that’s a point that a lot of people don’t realize – is that this new planet, this new atmosphere that we’re creating, is unlike any atmosphere we’ve had in a long, long time. So it’s very tough to make predictions because we have no analog to fall back on.

JK: I’d say that yes, most scientists that look at ocean chemistry agree that the ocean chemistry is changing in response to increases in atmospheric carbon dioxide. And, over the last twenty years, they’ve measured these changes, and yet, the surface ocean, the ocean that’s in contact with the atmosphere is becoming more acidic. And, in terms of the deep ocean, which is not in contact with the atmosphere, those changes take a lot longer to occur. So to transfer carbon dioxide from the atmosphere to the deep ocean involves these slow ocean currents, the slow overturning of the ocean conveyer belt, which brings atmospheric CO2 from the surface ocean down into the deeper parts of the ocean. But already, at depths of 50-100-500 meters, the ocean has detectable amounts of this anthropgenic carbon dioxide. And, associated with that, a detectable drop in ocean pH. So, unequivocally, there is a change in ocean chemistry already. And it’s very predictable – more predictable than temperature, for example, that the ocean will become more acidic as we increase atmospheric carbon dioxide concentrations even further.

JK: Coral reefs – I think most people in the United States aren’t aware of their importance. For most people they’re basically tourist destinations. Now they’re tourist destinations because they’re very beautiful, they have really high biodiversity, the aesthetic value of actually getting in the water, and looking at these beautiful communities – they’re called rainforests of the ocean, and that’s for very good reasons. They’re extremely beautiful ecosystems that I encourage anyone and everyone to have a look at these ecosystems for yourself. They’re really captivating. That alone, I think is probably it’s primary value of coral reef ecosystem, they really, by their own rights these really biodiverse communities, can support a lot of different types of organisms. And that, by itself, is a very important basic concept of nature, and a very attractive thing to humans. You know, biodiversity is this sort of a naturally attractive aspect of ecosystems.

But if you want to get on the more practical side, coral reefs support, because of their biodiversity, they support a lot in the way of fish communities, and that in turn supports a lot of people that rely on them. I think there’s something like 1/3 of the world’s population lives within 100 km of the coastline. And a lot of that is in the tropical coastline. And that’s where coral reefs occur. So these reefs support a lot of these people that live in the tropics. That includes tourism, that includes fishing, collection of other organisms for things like the aquarium industry, shells, those sort of things. And reefs themselves protect the coastlines. They protect the coastlines and they allow for other ecosystems to develop, which are also important, and that would be mangroves. There’s a paper that just came out by Peter Mendowitz a few weeks ago that showed that the diversity of fishes on reefs is greatly enhanced by the presence of mangrove. So that these two ecosystems together depend on each other. So the coral reef creates the environment where the mangrove can grow, and the mangrove creates the environment for the fish of that coral reef. So there are interconnections that are subtle but extremely important to supporting the biology of the ocean. The biodiversity of coral reefs is the highest of any marine ecosystem. It may be the highest of any ecosystem on the planet. We haven’t a clue to how many species occur on reefs yet. It’s really tough to go out there and account for all of the species because they’re underwater.

What I think is interesting is that coral reef scientists – and I think probably a lot of people who work on ecosystems, we’re forced into this mold over the last few decades to justify the existence of these ecosystems. And usually that meant justifying it economically. If you go to our politicians and say, oh, this ecosystem is disappearing. We need to protect it. Well, why do we need to protect it? Does it support us economically? This question has come up over and over again. This is one value of the ecosystem. And people have tried to say, “well, reefs are important because they do a lot of recycling of nutrients. They’re very good for keeping our water clean, protecting coastlines. If you had to replace a reef with a manmade barrier, it would cost millions of dollars to do that in a lot of places. So there’s this sort of “valuing” that we had to go through to justify, basically, the existence of the reef. I’m seeing over the last few years, the reef scientists are saying, “regardless at what you consider the economic value of the reefs – and the values range in magnitude when you actually go through that exercise.” They range from, a million dollar for a reef up to 10 million dollars for a reef – that kind of issue. Well, if you really think about it, a lot of the aesthetic value that’s there has a really high value and it’s priceless. I’d like to see one of these “priceless commercials” come out . Biodiversity of the reefs – priceless. They’re just amazing ecosystems that have evolved over millions of years – why should we have to justify them economically when it’s hard to find a person on the street who doesn’t appreciate their value intrinsically.

JK: We want to know, for political reasons, if you put in this amount of money and this amount of effort, to, say create a marine park to protect this reef, is that economically justified? In other words, are we going to get more money off of this reef or more services from this reef because we protect it, or not? That’s one reason people want to do it. The other one is that we sort of feel justified to say that these things are worth something. When you see them being removed or being killed off, (we think), “oh, I’m sure that this ecosystem has a lot of value, and we’re destroying it.” And so we try in many different ways to put some sort of value, some sort of quantitative measure of the value of these reefs. It’s not easy. It’s not as easy as saying, if this pasture land supports 100 head of cattle, vs. this rainforest which supports 100,000 species of diversity, it’s apples and oranges – you can’t do it. It’s the same way for coral reefs. How many fish are supported by this reef, how many tourists come to this reef? We have all different ways to value reefs. They’re free ecosystems. They provide a lot of services that no one pays for – but when we destroy them, we all pay for them. So that’s sort of the bottom-line. So if you remove all of your reef ecosystems, you’re going to lose some of your protection of your coastlines, you’re going to lose your fisheries – it’s kind of a no-brainer. You’re going to lose your tourism industry.

JK: There were three of us that pulled this report together, Bob Buddemeier, myself, and Rich Aronson. And we did this for the Pew Center for Climate Change. It took us about a year to pull this report together. And what we tried to do, in the most unbiased way as possible, was to pull together all of the literature that tackled the issue of how climate change would affect coral reefs in the future. And we tried to put in the context, as closely as possibly, in terms of future predictions based on the IPCC. So, it was a summary of all of the existing literature. One of the main things we tried to do in this report is not to just look at climate change, but to look at climate change in the context of all of the other stresses, which were affecting coral reefs right now. So instead of just addressing things like temperature, and chemistry changes, potential changes in precipitation – those sorts of issues – what does it mean for a reef that’s already under stress from overfishing? Or what does it mean on a reef that’s already under stress from siltation from deforestation practices. So we tried to keep this in the context of say, there are multiple pressures on coral reefs, how does climate change play into that. And that’s sort of the history of the report. We did a painstaking job of trying to make sure that all of the information that we had in here is accurate and well represented here in the report. In it we also tried to write it so that it’s readable by the general public. We’ve gotten rid of a lot of the technical jargon that turns people away. So we tried to make it into a report that people can sit down and actually read and find out for themselves, what’s going on with coral reefs.

JK: I can’t remember the date of the earliest data that we pulled in together, but it’s all the way up through the early part of 2004 – we included information that’s as up to date as possible. And, sometimes we go back perhaps to the middle part of this century just to establish the possibly some historical facts. But mostly, because this report is on global climate change, and because global climate change has not been considered to be a huge problem on reefs until about two decades ago, most of the information was 20 years, the oldest information in the report is probably about 20 years ago. We addressed the paleontological aspect, – are you talking about the literature or the information? We do address the geological aspects of reefs – reefs have been around for many millions of years – all the way up to what’s happening with them today.

JK: The sources of the information – most of them are very recent, we try to get the most up to date information. Some of the information goes back about 20 years. Most of its scientific literature – peer reviewed scientific literature.

JK: There are ultimately about over a quarter of coral reefs have been destroyed or nearly destroyed. And that 15% of all coral reefs were destroyed in the 1998 coral-bleaching event. You see in all of these statistics, it’s really hard to get that information. For example for the rainforest destruction, we can use satellite data to try to quantify that. In the oceans, you have to have people in the water, making those estimates of how many corals are gone, basically. It’s a really tough exercise to do. There’s something called the global coral reef monitoring network, which has really undertaken that task. And they get as much information as possible from these underwater surveys and from scientific observations to try to pull together a global picture of what’s happening to reefs on a unit by unit basis. And that’s where we get a lot of our information. The way people get information in the Caribbean, for example. The Caribbean has shown a tremendous loss in what we call percent coral cover, it’s a measure of how reefs are doing – it’s just one measure. But it’s probably the most commonly used one. People go underwater. They do transects. They take a quantitative measure of what percent of that reef is covered by live coral. Then they come back with that figure. Using data that has been taken in that same way over the last few decades, we definitely see that that measure – percent coral cover – that’s declining.

JK: Okay, let’s say you’re swimming out on a reef and you look straight down on a reef, and you try and estimate what percent, in your field of view, what percent of that bottom on the reef, on the surface of the reef, is actually covered by living coral. If you look on a reef, you can actually see that on some parts of the reef are actually patches of sediment. Other parts of the reef are covered by soft coral, this sort of fleshy algae which grows. And then there’s other parts of the reef which are just dead surface – where nothing is going on. So we looked at it and tried to make an estimate of what percentage of that reef that you’re looking at, at that very moment, is covered by live coral. And that’s your estimate. Some people use real strict, quadrat (rectangular sampling unit) style measurements, and some people use tape measures, some people use video surveys for photographic for photographic surveys of the surface of the surface, to get those estimates. And that’s how it’s done. Lots of water time.

JK: Yeah, what can the man on the street do about this, right? I’ll give you another analogy that I think is useful. We have lots of different impacts on coral reefs. Some of them are direct impacts like I mentioned before, overfishing, siltation through deforestation practices, too much nutrient runoff, those kinds of things. Those are things we can control. The global climate change issues are things that are much tougher to control. Those require policy change, political actions – it requires public opinion about that sort of thing. I think public opinion can change. The way we think about fossil fuel emission. I think that the more we back legislation to try to cut fossil fuel emission, the better off we’ll be. We really want to shoot for the lowest amount of fossil fuel emissions that we can. And that way we’re going to limit all these future changes in climate and the future changes in temperature and changes in seawater chemistry. In the meantime, what you want to do is try to remove all of those direct impacts on reefs. These are things we can do right now. We can change fishing practices, we can change land use practices, those things we can do right now, and we can remove those kinds of pressures on coral reefs. And when you do that, they have a better chance of weathering through any of the future climate changes. And a good analogy is a person in a doctor’s office. Suppose you’re going to the doctor’s office and he tells you, “you have a chronic illness, and it’s going to get worse.” If you can’t treat the chronic illness, what does he tell you to do? He says, get rid off all those other stresses that you might be doing. Stop your smoking, stop drinking, and try to get some light exercise, give your body a chance to handle this light illness. And those are things that we want to do for coral reefs. Until we can try and get a handle on global climate change, and try to slow down – in the meantime what we really need to support is protecting coral ree ecosystems, either in marine parks, or some kind of marine protected area, and to remove all of those smaller stresses like overfishing and bad land-use practices, and given them chance, until we can figure out what to do about climate change.

JK: One thing that you might want to link to is that new IMAX movie that’s out on coral reefs. A lot of people have really been stricken by the beauty of the photography – it also has a strong message in it as well.

The following person was interviewed for today’s program. Our thanks to:

Joan Kleypas
Scientist
Environmental and Societal Impacts Group
National Center for Atmospheric Research
Boulder, CO