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Estimates hearings: Great Barrier Reef

Estimates & Committees
Christine Milne 12 Sep 2008

STANDING COMMITTEE ON ENVIRONMENT, COMMUNICATIONS AND THE ARTSGreat Barrier Reef Marine Park Authority Discussion Senator MILNE—I am very interested to know what the current impacts of climate change are on the reef. I would like to start with the surface temperature. Could you tell us how the water temperature has changed—if it has changed—over the last decade and what the trend line is? What is the threshold that has triggered a bleaching event in the past? Are we anywhere near that in terms of average temperatures now? Can you give us a sense of the temperature and the coral bleaching threshold? Dr Reichelt—I will try to keep that— Senator MILNE—I know you could write a thesis on it. Dr Reichelt—It is a good question and it is a difficult one to answer precisely because of the high variability from year to year in peak summer temperatures, which is the statistic that matters. Since a mass bleaching event was noticed on the Barrier Reef in 1979, I believe there have been about eight or nine recorded, with that in 1998 being the largest. They happened again in 2002 and 2004, and there is a statistical pattern of an increasing frequency of events. We are fortunate that the summer just gone was in a cooler year. The statistic you watch is the lead-up to summer. That is when there are indications. We do have some months to look ahead. If the temperature anomalies, as they are referred to—in other words, two degrees above the typical longer term averages—occur for more than six to eight weeks, then you see a bleaching and potentially mass mortality. The scale of it is something that people are not generally aware of. In 2002, I believe it was, something like 50 per cent of the entire Barrier Reef was bleached but only five per cent of it was killed. I might be mixing it up with the 1998 event actually, but it is something that in each summer is of great concern. There is a rising underlying trend of increasing temperature, but it is over the scale of 50 years that it has been rising. The forecasts are that the frequency and risk are increasing. Senator MILNE—You said that the bleaching events are becoming more frequent, so is it right to say that the recovery of the reef is therefore more problematic on each occasion? How much has it recovered, for example, since the last two major bleaching events? Dr Reichelt—I am told that the areas that showed damage in the last really significant one—which was in 1998—have been positive and good. I recently visited personally some areas out of Cairns and to me they looked like very good coral cover areas and I was told they had suffered in the 1998 event. We know from the crown-of-thorns situation that if you kill, say, 80 to 90 per cent of the coral in an area it takes between eight and 15 years to see a full regrowth. What we also suspect but do not know is that bleaching is more likely to be patchy on the Barrier Reef. It does not all heat up at once because it is such a big area. It is like the discussion on the Antarctic this morning. As to if we see more frequent events, our policy at the moment is to do whatever we can to take every other pressure off the reef—in other words, to increase its resilience to allow that recovery to occur as fast as possible. Senator MILNE—Just taking this from what you said, there is an underlying water temperature trend upwards? Dr Reichelt—Yes. Senator MILNE—And there is a temperature that has triggered bleaching events previously. What is the current underlying temperature now and how close is that to the temperature that triggers a bleaching event on the reef? Dr Reichelt—As I was saying, the curve is very spiky and variable. The underlying trend shows, I think, some three-quarters of a degree or a degree over 100 years or thereabouts. We are talking only a degree or two which makes all the difference, so we are really suggesting that within the next 20 to 40 years that frequency could be above the rate for full recovery. So we expect, unfortunately, that if that warming trend continues we will see visible effects on the coral cover of the reef. Senator MILNE—The second area I wanted to talk about was acidification. Are you doing any monitoring on the impacts of acidification and whether that is intensifying—with carbonate loss and reforming corals? Dr Reichelt—We cooperate closely with those who are doing that work—namely, the Australian Institute of Marine Science, the University of Queensland and others. Recent publications show that the effects reduce the density of skeletons. Those grown in the last 20 years are statistically showing evidence of less dense skeletons, so ostensibly there is evidence of changes in acidity. It is one of those ones for which it is harder to determine what the impacts will be. It is a slightly longer term problem than the warming problem, but ultimately over centuries it is potentially a much greater problem than warming. Senator MILNE—So given the increased underlying temperature and evidence of deterioration through acidification, are there any other major impacts directly attributable to climate change? Putting aside the resilience issues which I will come to in a moment, are they the major two that are impacting on climate change? What about sea level rise? Dr Reichelt—The other two I am aware of with the potential would be sea level rise and the increasing intensity and frequency of tropical storms. I would rate the scale of sea level rise that is being discussed and forecast, based on my knowledge of rate of reef growth and extension, as not as significant a problem as certainly the first two are. With ‘tropical storms’, I do not know of any scientific studies that have modelled that, but I would rank that well down the list after the two you have raised. The other issue that is indirectly related is changing river run-off due to climate change. As you are aware, run-off water with the sediments, nutrients and so on carried from the agricultural areas is of major concern and is something that is being worked on intensively. Senator MILNE—I am looking at this $200 million over five years for the Great Barrier Reef Rescue Plan. In fact that money cannot tackle the impacts of climate change in terms of underlying temperature, acidification or sea level rise—or can it? So what we are talking about there is giving the reef the best chance it has got by eliminating other threats to it. Is that essentially what we are talking about? Dr Reichelt—There are two parts to it. What you say is true: there is a strong focus on adaptation and building resilience. But there are other elements to it—spreading best practice and promoting best practice in mitigation and lowering the footprint of operators. In a sense, that raises the awareness of the issue nationally and internationally. There is another issue. I think you mentioned water quality and resilience. There are some things that we may be able to do in terms of a response to helping the recovery of local areas that are affected by patchy coral bleaching, such as changing the local planning regimes, and they are also being looked at. We are doing that in partnership with those in the reef tourism industry, so they are aware of the issues. It might be altering anchoring permissions and things like that to lower the pressure on the reef. Senator MILNE—What about vulnerability to invasives? Invasives are always a problem, but are you anticipating a greater threat from invasives with the increased temperature? Dr Reichelt—It is possible and there is some preliminary work happening, not so much on the traditional ballast water and shipborne ones, which are also important and being dealt with through separate means, but there is a correlation between rising temperatures and coral disease. So to the extent they are either outbreaks or invasives, people probably do not know enough about it at the moment. But if I was pointing to sleeper issues associated with climate, coral disease would be one. It is not a major problem at the moment on the Barrier Reef. Senator MILNE—Okay. So given the amount of warming already locked in because of the amount of carbon dioxide in our atmosphere now, are you of the view that we are beyond the threshold for the world’s coral reefs and that we are now managing for decline? Dr Reichelt—I am not of that view. If nothing was done now, I would be of that view. The trajectory does not look good for the world’s coral reefs. If strong action is taken globally on mitigation and on the resilience issues, then I think we are still within the window of being able to manage the reef, or help it get across what is potentially a difficult period for the next century or two. Senator MILNE—Okay. So do your scientists have a view about the point at which there is no return for the coral reefs, either in parts per million or in water temperature terms, and what are those points? Dr Reichelt—The science debate at the moment runs between 450 and 500 points where serious impacts on the reef would be expected if you cross those thresholds. Senator MILNE—And what is the ideal threshold for the reef? Below what? Dr Reichelt—We probably passed it some time ago. Senator MILNE—In terms of the building resilience side of it, how is the $200 million over five years going to be spent in this next 12 months—whatever the allocation is in the next 12 months? What sorts of programs are we talking about? Mr Borthwick—This is an issue that is best directed towards our Marine and Biodiversity Division. It is not being run by the Great Barrier Reef Marine Park Authority, although they are doing some aspects in conjunction with us. Dr Reichelt—As Mr Borthwick indicated, the bulk of those funds is directed at actions on the ground with NRM bodies and farmers and landholders. Senator MILNE—So the bulk of that $200 million is going to be for stopping run-off on land? Dr Reichelt—Yes. Senator MILNE—Essentially, and pesticides and pollutants and so on? Dr Reichelt—That is correct; $146 million of that. Senator MILNE—$146 million of the $200 million? Dr Reichelt—Yes. There are funds set aside for research and monitoring and also Indigenous engagement. The marine park authority’s areas of expertise and interest would be with Indigenous traditional use marine resource agreements, improving the engagement of traditional owners in catchments and engaging them in the issue of water quality and local management. The other area is water quality monitoring in the ocean—in the marine park. Our view, and it is reflected in the policy statements, is that you really need to have an audit or a measure of whether you are making a difference. We would see ourselves as carrying the marine monitoring side of it—the reef health and the quality of the water. Senator MILNE—So essentially, from what I can understand, with $146 million being spent on land for run- off, this is really a pollution abatement scheme rather than a climate rescue package, given that you have just said that your part of it is relatively small and most of that is engagement and some monitoring? Senator Wong—Senator, you are entitled to your opinion about what the scheme is best described as. I am not sure that is something that Dr Reichelt can comment on. Senator MILNE—No. Senator Wong—Obviously, his evidence is consistent with the government’s position. It is the case that we need a strong and effective global response to climate change. There are a whole range of consequences, as you know, to global warming. The government has put in place $200 million for the reef rescue plan and a $9 million climate change action plan for 2007 to 2012. Obviously, adaptation or building resilience broadly is something we have to address as well as the international negotiations and our domestic framework. Senator MILNE—Just to finish, in terms of GBRMPA’s performance indicators on this money reducing the impacts of climate change, what would you say your performance indicators are going to be for that $56 million over five years? Dr Reichelt—I think the portfolio budget statement—I will just find it—does record those. I am just looking for the specific ones here. Essentially, we want to understand the phenomenon more effectively. In the past the impact of climate on the reef and bleaching events and so on have been treated holistically, or how much of the reef has bleached. What we do know now—and it is quite recent information—is that different parts of the reef have different resilience. In taking your point earlier, the water debate is closely linked to the climate debate. The sorts of work we will be doing, apart from working with the tourism industry on some of those adaptation issues—accrediting best practice operators who lower their footprint and recognising and rewarding those through our high-standard operator program—we will also be looking at opportunities for understanding the finer scale risks and resilience of the reef. To give an example, if an area of the reef was naturally more resilient and it happened to be in the path of a more heavily loaded river, that would become a very high-priority area for action. So the work on climate and understanding the impacts on the reef are linked to building the resilience and it will be fed back into setting priorities for action on the land. Senator MILNE—And presumably, that could lead to changes to the zoning if parts of the reef demonstrate greater resilience or greater vulnerability, depending on which it might demonstrate? Dr Reichelt—Yes it, could. Senator MILNE—Thank you.

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