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SELECT COMMITTEE ON CLIMATE POLICY
23/04/2009
Emissions trading and reducing carbon pollution

CHAIR —We welcome Dr Risbey. I invite you to make a short opening statement before we go to questions.

Dr Risbey —I am a research scientist with the Centre for Australian Weather and Climate Research and CSIRO Marine and Atmospheric Research. It is very important that I stress to you that I am not speaking to you in connection to either of those organisations, I am speaking to you in my own private capacity and these are my own private opinions.

I will attempt to speak to the bigger picture in terms of what is at stake with the climate system. In that regard, I commend you on your choice of venue here today. This hotel is the very hotel where Roald Amundsen stayed when he returned from his trip to the South Pole on top of the ice sheet and announced to the world that he had made it to the South Pole.

My comments today, as per my submission, will only address term of reference C, which is regarding whether the CPRS emissions targets are sufficient to avoid dangerous climate change. Of course, that question in turn, if they are not sufficient, has corollary questions in what sorts of emission targets would be safer in this regard and, in turn, what might such targets imply for carbon policy.

In short, the CPRS targets of five per cent reduction by 2020 and 60 per cent reduction by 2050 are not sufficiently stringent to avoid dangerous climate change. The reason I form that conclusion, as others have, is that if you take these targets globally this emission path implies a CO2 equivalent concentration somewhere above 450 parts per million. At 450 parts per million there is a 50 to 90 per cent chance of exceeding the dangerous threshold of two degrees Celsius. In other words, it implies a temperature change greater than two degrees Celsius. In practice, the CPRS targets actually imply a larger temperature change than this because that level of concentration assumes that everybody follows the same path to reach those targets, whereas in practice the developed nations will have to cut more strongly than the developing nations in order to reach those targets.

What are the consequences of exceeding 450 parts per million or two degrees Celsius? If I were to answer this question 10 years ago or if we were doing this 10 years ago, a lot of us would not have terribly strong opinions about that, but the science has come a long way in the last 10 years and unfortunately, in most cases, the science has progressed so that we have a greater understanding, in some sense, of the sensitivity of the system and our exposure to the kind of feedbacks that make the problem worse and make us much more worried than we were 10 years ago. If you ask the question today, you will find that many of us feel that 450 parts per million is too high, that that does expose us to dangerous climate change. Essentially, it sets us up for a different climate system well outside the climate system that we adapted to as a civilisation. We lived through the Holocene through about 280 parts per million, so at 450 we are talking about a concentration well above that.

As to the consequences of that, you have already heard today some of our colleagues speak about the risk to the ice sheets, particularly Greenland and the West Antarctic ice sheets. At 450 parts per million we have reached the level of warming of two or three degrees, where if we look back to previous times in earth’s history, we see the ice sheets in Greenland and West Antarctic would break down or start to break down. The worry is that we get to a point where that breakdown is irreversible; we cannot go backwards. Again, that is something that this morning’s speakers also spoke about. The rates at which that breakdown would occur have consequences for sea level rise. It is very hard to categorise precisely how fast the sea will rise but again, as a rough guide, we look to the rates that sea level rose during past transitions out of interglacial periods. That means coming out of past cold periods, moving into glacials and into interglacials, how fast the sea rose. There are periods when for multi centuries, 400 years at a time, sea level rose at five metres a century.

There is some debate about how applicable those sorts of rates are to our current system. There are two key differences. One is that in our current system we do not have the additional ice sheets on North America which are responsible for some of that high rate of rise of sea level, but on the other hand we are forcing the system much harder. The way in which we are forcing the system through increased greenhouse concentrations is much harder than the forcing through the orbital variations.

Just to give you a bit more context on that from the paleo climate records. The last time the temperature was two degrees Celsius warmer than at present, or one to two degrees Celsius warmer, was about 130,000 years ago. That was in the peak of the last major interglacial period. At that time sea level was about five metres higher than present levels. The last time temperature was three degrees warmer than the present temperature was about three million years ago, in the Pliocene where sea level was about 25 metres higher than at present. Just to put that in some perspective, we are sitting here, again in this historic place, the Hadley Hotel, at about 16 metres above sea level, so we are looking at another nine metres on top of where we are sitting right now.

The risk of warming at 450 gives a 50 to 90 per cent chance of exceeding two degrees, but also gives us about a 10 to 25 per cent probability of exceeding three degrees, so it exposes us to a significant risk of putting us into that climate regime as well.

Some of the other consequences of 450 parts per million relate to ocean acidification. Essentially research indicates that this level of carbon dioxide dissolved into the ocean interferes with the ability of calcifying marine organisms to form shells. My colleague, Dr Matear, will speak to that in more detail. It also increases the risk of releasing methane clathrates and carbon from the natural biosphere. The problem that exposes us to is that can potentially provide a large positive feedback to the warming, which would take the emission concentrations out of our control, as it were.

Another significant issue is the breakdown of high mountain snow packs. Again, at 450 or at about a two degrees Celsius warming, the hydrological systems of all the big mountains—the Himalayas, the Rockies and the Andes—work essentially by taking rainfall which has a strong seasonal cycle falling in one part of the year, storing it as snow and then releasing it gradually through the rest of the year, through the drier seasons. Agricultural systems for hundreds of millions of people are based around these particular snow pack based hydrological systems, so at 450 parts per million we would see a breakdown of those snow packs and radical changes in the regime. Essentially, what happens is that the precipitation that used to fall as snow falls as rain and that which does fall as snow melts earlier so it floods earlier in the season and you do not retain the water during the dry season.

As to other consequences more locally, at a regional level we expect an intensification and perhaps a poleward extension of the subtropical ridge. What is that? That is just the high pressure system that dominates the areas immediately outside the tropical belt. The Australian continent, for example, sits underneath the subtropical ridge. All the world’s major desert regions, looking around the globe, sit underneath the subtropical ridge, so that is why we have deserts in our interior, and we are looking at an intensification of that, with consequences for our rainfall systems.

I stress at this point that the major uncertainties related to these different issues that I have spoken of relate more to their timing and rates, not to the actual consequences. These kinds of consequences will eventually occur; it is just a matter of when, not if, should we push the system too hard. Although there are uncertainties, the things that I am talking about here do not depend on results of particular climate models, they come from an understanding of the physics of the system and looking at the past earth history.

What would be a safer target? Again, deferring to my colleagues this morning, there is really no such thing as a safe target, but a safer target would be something that would be closer to 350 parts per million, because that would reduce the risk of exceeding two degrees Celsius to more moderate levels, so back down to the 10 or 20 per cent levels rather than the 50 to 90 per cent levels. That raises the question which has been discussed to some extent, in this committee, which is whether it is possible to attain 350 parts per million. I am guided here, in particular, by the work of NASA GISS scientist, James Hansen, who has done analysis to show that stabilisation at around 350 parts per million is possible, but what is required to stabilise at that level is essentially a phase-out of coal. The reason for that is clear. If you look at the figure in the handout that I have passed around, figure A shows the reserves of carbon from oil, gas, coal and land-use changes. By far the largest reserves of carbon stores are in coal, and if we are to try to keep CO2 stabilisation at the 350 level then it is imperative that we begin phasing out coal now. Unfortunately, we no longer have the luxury of delaying the time at which we begin the phase-out of coal. The reason for that is that as we keep emitting we push the system into a point where we cannot get it back down beneath 350 again.

For illustration, I refer you to figure B, which is a figure from James Hansen that shows in the initial part the concentration of carbon dioxide up to the present time and then he has scenarios going forward to achieve a reduction to 350 parts per million, and the upper red curve is based on high estimates of reserves in oil and gas. In the scenario that Hansen has outlined, essentially in order to attain 350 we build no new coal plants and we phase out existing coal plants by 2030. Then, to get below 350 there needs to be an end to deforestation within the next five or six years and use reforestation agriculture to draw down the concentrations below 350. That is technically possible, but it would require targets much more stringent than those in the CPRS. The targets for 2020, instead of being in the five to 15 mark, would be nearer the 40 per cent mark, and for 2050 it means essentially 100 per cent reductions, so we need to be more or less carbon neutral in order to attain these targets with more moderate risks.

CHAIR —Thank you.

Senator MILNE —Thank you for coming today to appear and having the courage to speak out as an individual. I would make a comment that I am sorry the science institutions do not have the same courage. I would like to go to your graph on the second page. I would like you to comment. There is the question of urgency. We are hearing a lot of people saying that we need to get to these figures over time, but it would be too dislocating to do it too quickly. I would like you to comment on why the urgency.

Secondly, you have here the role of forestry and soil as being critical if we are to get to 350 and we stop releasing the carbon from coal, so we leave that sequestered as it is, and your view about deforestation and reafforestation. I take it from what you are saying that we should immediately stop the release of carbon from any of the existing carbon stores, that is the native forests and native vegetation, and then maximise the soil and reforestation potential where we can have it. In the Tasmanian context, that would mean stopping the logging and clearance of native vegetation, and in Gippsland, New South Wales, south-west Western Australia and so on.

Dr Risbey —In broad terms, yes. The assumptions underlying Hansen’s figure here is that as deforestation is wound down and we cease deforesting the world’s forests by 2015, from thereabouts forestry is used as a sink. Yes, if deforestation continues, you can see the draw down from forestry and agriculture is about 60 parts per million in this figure, so the final concentration, instead of bringing down below 350, we end up above that. In this scenario there is no way to attain that without ending deforestation.

Senator MILNE —It is a really critical component of getting to the target. Dr Matear, will you speak on ocean acidification?

Dr Matear —Yes. I am happy to comment now. I am here to support Mr Risbey’s submission. I am here to talk about specifically this idea of ocean acidification. I am here to emphasise the seriousness and the urgency of dealing with this issue. The story I have is that atmospheric CO2 levels are rising. We know what is causing that. It is human activity that is causing the rise in carbon dioxide in the atmosphere. That carbon dioxide is going into the ocean. It is changing the chemistry of the ocean. Again, that is well known. That is not uncertain. The big chemical change that we know of is the change in the ability of organisms to calcify. Why do we care about that? Key organisms, like corals, calcify. They are going to be impacted by these rising CO2 levels. The message I really want to leave you is that if you look, particularly at the Southern Ocean, for example, in the next 100 years we will put enough carbon dioxide in the atmosphere that will dramatically change the chemistry of the surface water of the southern ocean. It will be so dramatic that organisms that currently are forming calcium carbonate will be in such an acidic environment that calcium carbonate will dissolve. I can show you from my research that roughly at about 450 ppm a large tract of the Southern Ocean will become so corrosive to calcium carbonate that organisms that form calcium carbonate will not be able to survive. By not acting on this issue you are condemning some ecosystems in the Southern Ocean to disappear. Cold water corals that have been found along the continent of Antarctica will not exist if we go beyond 450 ppm. I want you to be aware of that.

Senator MILNE —Why does that matter?

Dr Matear —We think of the ecosystem, the Southern Ocean, this iconic marine ecosystem, and I leave it to you: is that going to be our legacy, that we are going to dramatically change that ecosystem? It gets a little bit worse than that. I have focused on the Southern Ocean, but this impact is relevant to the whole of Australia. Let us look at the Great Barrier Reef. The Great Barrier Reef is based on corals. Corals calcify. Corals will be impacted by ocean acidification. Again, there have been some studies that suggest that 450 ppm in the atmosphere is kind of a threshold where we might move from corals growing at the moment to not being able to grow as effectively into the future and a demise of that potential ecosystem. We can all think about what the potential consequences would be on the economy of Australia if we lost something like the Great Barrier Reef and the tourism associated with that. I really want to leave you with the message that 450 ppm is a nice threshold to think about in terms of avoiding some of the really serious consequences of carbon dioxide in the atmosphere.

Senator MILNE —With that question of 450 parts per million, can you tell me about the marine food chain? It is not just the Southern Ocean cold water corals. What does it mean for the whole marine food chain?

Senator ABETZ —The krill.

Senator MILNE —Yes.

Dr Matear —There are many organisms in the ocean that calcify. Krill may not be as impacted because they do not form calcium carbonate. There are, for example, fundamental parts of the food chain, like phytoplankton. A large number of phytoplankton species calcify. Coccolithophorids may be one that you have come across. They are the foundation of the food web. Unfortunately, I cannot tell you what the consequences of changes to the food web will be. I can confidently say that there will be consequences. How the current food web works and how it will work under 450 parts per million atmospheric CO2 will be different.

I feel like we could go around Australia and pick on different organisms. There are corals. We could pick on organisms that we find in the Great Australian Bight. Bryozoans are another calcifier, another organism that plays an important foundation to the marine ecosystems. It will suffer under rising CO2 levels. I have not quite answered your question in some ways, but I am trying to give you a picture to show that there will be big pictures because these organisms play an important role in the marine ecosystems.

Senator CAMERON —Could you give me some idea of the nearer term consequences for Tasmania if no abatement program is put in place, either here or globally?

Dr Risbey —What do you mean by ‘nearer term’?

Senator CAMERON —Over the next 10 to 20 years.

Dr Risbey —It is much harder to characterise the nearer term consequences because we have to try to separate out what is climate signal and climate change from the noise of natural variability. For example, we are in the middle of a substantial decadal drought here in eastern Tasmania, which has had fairly significant impacts on the agricultural economy and it is also a major concern to the hydroelectricity corporation. The extent to which that drought is a consequence of climate change and natural variability, we cannot tell you. As I mentioned earlier, we expect an intensification of the subtropical ridge, which we now start to see in our observations. We expect a drying of the Australian continent, particularly the southern half of the continent, which would include eastern Tasmania. The sorts of things that we are seeing in rainfall are consistent with what we would expect from climate change, but we cannot, and will not be able to, give you a rigorous answer to that question for some decades, post fact.

Senator CAMERON —The Department of Climate Change has indicated that they believe that there will be a massive lessening of agricultural land available across the country. Does that include Tasmania?

Dr Risbey —I am not sure to where they refer. We have very different climate regimes in Tasmania. The west is a mountain based rainfall regime and the eastern half of the state is a regime more typical of the other parts of south-eastern Australia, so has more in common with Victorian and South Australian climate than it does with western Tasmanian climate. We can lump eastern Tasmania in with that and say we expect the drying in the east. What really matters is essentially the prevalence of westerly flow over the mountains, because that is what generates the rain in the west. We hope that is much more robust and much less likely to be disrupted than other parts of south-eastern Australia because its mechanism for rainfall is different.

Dr Matear —The drying that we are seeing in south-east Australia also applies to Tasmania as well, as Mr Risbey has pointed out. Dams are at extremely low levels. Rainfall has been extremely poor in the midlands part of Tasmania. Based on that, you might get the feeling that there might be some consistency between what happens in south-east Australia, in general, and Tasmania in particular.

Dr Risbey —The other factor in response to your question is that temperatures have risen across Australia consistent with the rise in temperatures globally. Those rising temperatures are having impacts on our ecosystems and on the species mix in our ecosystems. We are also seeing rising temperatures in the oceans in the areas around the Australian continent, and that is also having an identifiable impact on the species mix and the distribution of species in those waters. Species that used to exist further around mainland Australia are now prevalent around the Tasmanian coast. We are seeing temperature based responses already.

Senator CAMERON —One group of scientists, based around geologists, have come up with a different view. In fact, we had evidence to say that climate change was rubbish. That is what one scientist put. That is exactly what was put.

Dr Risbey —Can you tell us on what basis he said it was rubbish?

Senator CAMERON —Based on his research work.

Dr Risbey —There must be an argument somewhere.

Senator CAMERON —The point I want to make is that would be a minority view among scientists now, would it not?

Dr Risbey —Yes, that is a minority view. Most climatologists are of the view that it is a serious issue. People who say that it is rubbish tend not to be published in the climatological research community or tend not to be climatologists. The reasons climatologists think that the issue is serious is that the basic physics underlying the greenhouse effect, the radiative properties of carbon dioxide and the other trace gasses in the atmosphere, is very well understood. As to the implications of that in terms of how it plays out on the planet, we have a lot of framework to guide us on the basis of past changes in trace gas concentrations and orbital parameters for the planets, so there is a large body of evidence over really the last century when CO2 was first identified as an issue, but accelerated since about 1980. There is an enormous body of research that supports this.

Contrary to the view that is often put forward that the foundation of our views is the numerical climate models and it hinges on that, what the numerical climate models do is help give us a bit of guidance about what some of the regional impacts might be, but they are not the reason why climatologists, in the main, believe this is a series issue.

Dr Matear —This ocean acidification issue is independent of how the climate system will respond. It is simply rising carbon dioxide levels in the atmosphere getting into the ocean and changing the chemistry. Unless you do something about carbon dioxide levels in the atmosphere, this affect will happen. It is even simpler than that. I go on and say that there is even evidence that is happening now. There are observations done in the Southern Ocean that show biology is responding to the chemical changes we have impacted on the system over roughly the last 150 years.

Senator CAMERON —Thank you.

Senator CASH —In your article in Global Environmental Change titled ‘The new climate discourse: alarmist or alarming?’, on the final page you have a number of dot points. One of the dot points is:

Because of the inertia in the energy system and built infrastructure the transition to more energy efficient infrastructure and the phase-out of carbon sources must begin very soon to achieve the required stabilisation of CO2.

Yesterday we had evidence from two experts from within the building infrastructure area that the built environment can play a role in contributing to overall emission reduction targets from complementary measures. I would like your thoughts on how you see the role of the built environment in contributing to a reduction in the CO2 emission levels?

Dr Risbey —The built environment has an essential role to play in this. Given that we need to draw down carbon dioxide concentrations and do it rapidly, and given that the only way to do that is to phase out coal and to start phasing out coal now, we have to find alternatives to coal through renewable and alternative sources of generation, but you also need to use less energy.

In Australia in some sense we are fortunate in both those regards in that we have fairly abundant sources of solar and geothermal energy, so in terms of alternative generation we are in a good position. Also, we happen to be a very urbanised population so most of our population is in cities. That makes it, in some ways, easier to draw down the required use of energy. If you look to places like Melbourne and Sydney, for example, they have drawn up vision plans—Melbourne 2020 and Sydney 2020 plans. A key element of those plans is changes in buildings, so making all new buildings very high star rating in terms of their energy efficiency, but also changes in urban form. A key element in terms of both our water and our energy use is the spread of suburbanisation of the cities, so we need to essentially redesign our cities so that we concentrate around urban hubs, if you will, which makes building more efficient and transportation more effective for people. That, in turn, will reduce the need to generate excess power.

Senator CASH —Would you agree with the statement that we need a suite of measures to ensure that we have actions in place to reduce our CO2 emissions?

Dr Risbey —That always sounds like a good thing.

Dr Matear —It is a huge job to transition from where we are at the moment in terms of carbon emissions to where we want to be in 20 or 50 years. It is a huge transition. We are talking about reducing emissions, not by 20 per cent or five per cent, we are talking about reducing emissions by 80 or maybe 90 per cent. To limit yourself to one sector of the economy is not possible. We do need a whole range of initiatives to get us there.

Senator CASH —Another issue raised yesterday was that we need an effective policy framework in order to get the reductions in the built environment. Does the CPRS, as it stands, provide that effective policy framework or do we need to do more?

Dr Risbey —I cannot speak to the CPRS’s incentive structure more generally.

Senator CASH —That is fine. If you cannot, that is not a problem at all. Thank you.

Dr Matear —I would emphasise that five per cent is not going to be enough. That is how I would feel. I cannot speak to the actual policy.

CHAIR —I have indicated to other colleagues that we would have one question from each side so that we can keep to our program. I am happy to take questions on notice to the witnesses because then I want to close. We are struggling for time for this afternoon’s program.

Senator IAN MACDONALD —I would like to put a question on notice.

CHAIR —That is fine.

Senator IAN MACDONALD —I am one of those that do not really understand, but go along with the majority of the scientists. I do not really have a question directly germane, but while we have experts here, on notice, could you explain to me the difference between what is happening now with the melting of the ice and what happened millions of years ago when we lost the ice cap from this planet? Can you give us a simple explanation?

CHAIR —I would like you to take that on notice. I apologise, but we really do not have time to go into answers. We have a tight program this afternoon.

Senator IAN MACDONALD —Keep it simple.

CHAIR —Senator Milne has a question on notice as well.

Senator MILNE —I did ask earlier about urgency. The question that I would ask regards the difference of opinion that if we went to five to 15 per cent now and then after 2020 we ratcheted it up and after that we ratcheted it up more, do we have the time to start with five to 15?

CHAIR —Thank you, colleagues. I appreciate your forbearance on that.

Senator BOSWELL —When we come back we will be pushing for time. I wonder if I can read into the Hansard now; if you rule that I cannot, then I accept that.

CHAIR —Do it now, quickly.

Senator BOSWELL —I wish to correct my statement made in committee in relation to the Waxman bill—the draft bill released by the US House of Representatives Energy and Commerce Committee on 31 March 2009 proposing a framework for a cap and trade scheme. The statement I made was made in relation to the debate on the commitment of the US to get on board and forge an international climate change agreement the likes of which would draw together coordinated and significant global undertaking on climate change. I incorrectly attributed the clause in the Waxman bill, saying that the scheme proposed in the bill was bound by a condition that it would not increase ‘the overall burden on consumers’. The clause is, in fact, contained in an amendment to a US Senate budget bill debated on 1 April 2009 that allows Senate committees to design a cap and trade system.

I read into that the Boxer amendment. Mrs Boxer proposed an amendment to the concurrent resolution S Con Res 13 setting forth the congressional budget for the United States government for the financial year 2010 revising appropriate budgetary levels for the year 2009 and setting forth the appropriate budgetary levels for financial years 2011 through to 2014. It reads on page 33, line 21, after the economy insert:

… without increasing electricity or gasoline prices or increasing the overall burden on consumers through the use of revenues and policies provided in such legislation.

That should now be called the magic pudding amendment. I quoted from the 4 April edition of the Australian newspaper.

Lost in the Greens’ and the environment lobby’s enthusiasm in Australia over the Waxman bill was an indicative vote in the US Senate earlier this week to give Senate committees the flexibility to design a cap and trade carbon system.

The vote was made as non-controversial as possible by adding the clause that it would be a system that did not increase “the overall burden on consumers”. But not one Republican supported the innocuous amendment that was attached to a budget bill.

The article also reported:

While Australian Greens senator Christine Milne characterised the Waxman bill this week as a sign the US had seized the leadership role and was surpassing countries such as Australia, the reality is very different in the US capital.

That is a direct quote. These are my assumptions.

Senator MILNE —This is your assumptions.

Senator BOSWELL —No, these are the assumptions of the journalist.

Senator MILNE —It is in the Australian, that scientific journal!

Senator BOSWELL —I am just reading what was in the paper.

CHAIR —We need to adjourn.

Senator IAN MACDONALD —He would be finished now if he had not been interrupted.

Senator BOSWELL —I have been challenged by Senator Milne.

CHAIR —Please finish the statement.

Senator BOSWELL —The article continues:

At least three Republicans would be needed in any future vote on climate change to get a bill passed in the US Senate.

The vote was carried. The yes vote was 52 Democrat, two Independent; the no vote was two Independent and 41 Democrat. Two people did not vote. That is my statement. I thank the committee for allowing me to correct something that I said.

Senator CAMERON —I would like to make a statement on this after lunch, if you do not mind, because I think it has totally confused the committee.

CHAIR —I will consider that. Thank you, Dr Risbey and Dr Matear.

Proceedings suspended from 1.19 pm to 1.50 pm