Will we leave the Great Barrier Reef for our children?

Amidst the current policy debate in Australia on climate change is a surreal argument that policies that will destroy the Great Barrier Reef (GBR) are acceptable and economically rational. Ross Garnaut was alive to the damage to the GBR when saying Australia should initially aim for a global consensus to stabilise greenhouse gases in the atmosphere at 550 parts per million. Garnaut (2008a: 38) was brutally frank in his supplementary draft report:

“The 550 strategy would be expected to lead to the destruction of the Great Barrier Reef and other coral reefs.”

His final report does not shy away from this conclusion (Garnaut 2008b).

The Australian and Queensland governments have always silently avoided this point when explaining the costs and benefits of their climate policies. Neither has ever stated a stabilisation target for the rise in global temperatures or greenhouse gases. To do so would expose them to the criticism that their policies will not save the GBR or a host of other ecosystems.

Garnaut’s frank admission reflects the findings of research of the impacts of climate change to the GBR since mass coral bleaching occurred globally in 1998 and 2002. Rising sea temperatures and increasing acidity of the oceans due to our use of fossil fuels are now well-recognized as major threats to coral reefs and the marine ecosystem generally in coming decades.

 Coral bleaching and partial recovery on Pelorus Island, GBR: (a) 1998; (b) 2002; and (c) 2004. Source: Schuttenberg H and Marshall P, A Reef Manager’s Guide to Coral Bleaching (GBRMPA, Townsville, 2006), p12.

Coral bleaching and partial recovery on Pelorus Island, GBR: (a) 1998; (b) 2002; and (c) 2004. Source: Schuttenberg H and Marshall P, A Reef Manager’s Guide to Coral Bleaching (GBRMPA, Townsville, 2006), p12.

In relation to coral bleaching the IPCC (2007b: 12) found that:

“Corals are vulnerable to thermal stress and have low adaptive capacity. Increases in sea surface temperature of about 1 to 3°C are projected to result in more frequent coral bleaching events and widespread mortality, unless there is thermal adaptation or acclimatisation by corals.”

The findings of the IPCC suggest that a rise of 1°C in mean global temperatures and, correspondingly, sea surface temperatures above pre-industrial levels is the maximum that should be aimed for if the global community wishes to protect coral reefs. The range of 1-3°C is the danger zone and 2°C is not safe. Supporting this conclusion Ove Hoegh-Guldberg and his colleagues concluded in a review of the likely impacts of climate change to the GBR edited by Johnson and Marshall (2007: 295):

“Successive studies of the potential impacts of thermal stress on coral reefs have supported the notion that coral dominated reefs are likely to largely disappear with a 2°C rise in sea temperature over the next 100 years. This, coupled with the additional vulnerability of coral reefs to high levels of acidification once the atmosphere reaches 500 parts per million [CO2], suggests that coral dominated reefs will be rare or non-existent in the near future.”

The IPCC’s (2007a: 826) best estimate of climate sensitivity found that stabilising greenhouse gases and aerosols at 350 parts per million carbon dioxide equivalents (ppm CO2-eq) would be expected to lead to a rise in mean global temperatures of 1°C, stabilising at 450 ppm CO2-eq will lead to a rise of 2°C, and stabilising at 550 ppm CO2-eq will lead to a rise of 3°C.

Atmospheric concentrations of greenhouse gases and aerosols have already passed 350 ppm CO2-eq making stabilisation at that level extremely difficult if not impossible in practice, particularly in the context of current global growth and energy use patterns. Atmospheric CO2 reached 379 ppm in 2005 and was increasing by around 2 ppm per year (IPCC 2007c: 102). Including the effect of other greenhouse gases such as methane, the total concentration of atmospheric greenhouse gases was around 455 ppm CO2-eq in 2005 (IPCC 2007c: 102). However, the cooling effects of aerosols and landuse changes reduce radiative forcing so that the net forcing of human activities was about 375 ppm CO2 eq for 2005 (IPCC 2007c: 102).

Global emissions of carbon dioxide, the major anthropogenic greenhouse gas, are growing at approximately 3% per annum, which exceeds even the “worst case” IPCC projections (Raupach et al 2007). This places global greenhouse gas emissions on a trajectory to rise by 150% between 2000 and 2050 on “business as usual”.

When the conclusions of the IPCC are synthesised, it is clear that reductions of greenhouse emissions of 60% by 2050, such as proposed by the Australian Government (2008), even if they can be achieved, are not likely to prevent serious damage to the GBR and other coral reefs. A 60% reduction in global emissions by 2050 is likely to lead to a mean global temperature rise around 2.4°C (IPCC 2007d: 67), which is likely to severely degrade coral reefs globally. Stabilising greenhouse gases and aerosols around 350 ppm CO2-eq and allowing a rise in mean global temperature of 1°C appear to be the highest targets that should be set if coral reefs are to be protected from serious degradation.

Bleached coral cover and sea surface temperature on the Great Barrier Reef in 1998 and 2002. Source: Berkelmans R, De’ath G, Kininmonth S, and Skirving WJ (2004) 23 (1) Coral Reefs 74.

Bleached coral cover and sea surface temperature on the Great Barrier Reef in 1998 and 2002. Source: Berkelmans R, De’ath G, Kininmonth S, and Skirving WJ (2004) 23 (1) Coral Reefs 74.

This brings us back to the current policy debate – Garnaut’s frankness in recognizing the likely damage to the GBR from the targets he recommends is welcome but his conclusions leave us to wonder: is this the best we can do? Should we be prepared to write-off the GBR and a big chunk of the $7 billion it generates annually for the economy? Should we be prepared to write-off many of the 66,000 jobs associated with the GBR?
As a young boy growing up in the Whitsundays in the 1970s I did not dream that the GBR that I swam and fished on would be severely damaged by human activity within my own lifetime. Much less would I have dreamt that we would choose to allow these impacts to occur, as we are currently doing.
Garnaut’s targets are not ambitious enough and we should not accept them.

We should judge our climate change policies by this simple test: will we leave the GBR for our children? At present the answer we are giving to this question is “no”. We are all responsible for changing the answer to “yes”. We should demand targets based on what we as a society want to achieve. We should not accept targets that will produce unacceptable outcomes.
The current science indicates our aim should be stabilising atmospheric greenhouse gases at 350 ppm if we want to protect the GBR, but Garnaut does not even mention this as a potential target.

We do not yet know if we can stabilise atmospheric greenhouse gases as 350, 450 or 550 ppm but think of it this way: if we want to build a bridge across a river that is 1 kilometre wide we would not ask our engineers to build us a bridge that is 500 metres long. We should apply the same logic to climate change policy and set targets for our engineers and scientists to achieve that produce results that we want to achieve.

We need vision, ambition, and hard work to solve the climate crisis. Garnaut’s approach lacks the vision and ambition that is needed. We need to add these ingredients to Australia’s many hard workers to solve the climate crisis.

Dr Chris McGrath is a Brisbane barrister and researcher on laws protecting the GBR from climate change. This article is based on an article previously published in the Courier Mail newspaper and a research paper, McGrath (2008).


  • Australian Government (2008), Carbon Pollution Reduction Scheme Green Paper (Department of Climate Change), http://www.climatechange.gov.au/greenpaper/index.html.
  • Garnaut R (2008a), Garnaut Review Supplementary Draft Report: Targets and trajectories (Garnaut Review, Canberra, 5 September 2008), p 38, available at http://www.garnautreport.org.au/.
  • Garnaut R (2008b), Garnaut Climate Change Review Final Report (Cambridge University Press), http://www.garnautreview.org.au/index.htm.
  • Hoegh-Guldberg et al, “Vulnerability of reef-building corals on the Great Barrier Reef to climate change”, Ch 10 in Johnson JE and Marshall PA (eds), Climate Change and the GBR: A Vulnerability Assessment (GBRMPA, 2007), p 295, http://www.gbrmpa.gov.au/__data/assets/pdf_file/0008/22598/chapter10-reef-building-corals.pdf
  • IPCC (2007a), Climate Change 2007: The Physical Science Basis. Contribution of WGI to the AR4 (Cambridge University Press), http://www.ipcc.ch/ipccreports/ar4-wg1.htm.
  • IPCC (2007b), Climate Change 2007: Climate Change Impacts, Adaptation and Vulnerability. WGII Contribution to the IPCC AR4 (Cambridge University Press), http://www.ipcc.ch/ipccreports/ar4-wg2.htm.
  • IPCC (2007c), Climate change 2007: Mitigation. Contribution of WGIII to the AR4 (Cambridge University Press), http://www.ipcc.ch/ipccreports/ar4-wg3.htm.
  • IPCC (2007d), Climate Change 2007: Synthesis Report (IPCC), http://www.ipcc.ch/ipccreports/ar4-syr.htm
  • McGrath C (2008) “Will we leave the Great Barrier Reef for our children?” (IUCN), http://cmsdata.iucn.org/downloads/cel_op_mcgrath.pdf.
  • Raupach MR, Marland G, Ciais P, Le Quéré C, Canadell JG, Klepper G, and Field CB, (2007) “Global and regional drivers of accelerating CO2 emissions” 104(24) PNAS 10288-10293, http://www.pnas.org/cgi/content/abstract/104/24/10288.

7 thoughts on “Will we leave the Great Barrier Reef for our children?

  1. Just to follow-up and expand on the last comment:

    The Australian Treasury economic modelling of mitigation strategies was released yesterday (30 October 2008), see http://www.treasury.gov.au/lowpollutionfuture/

    Treasury modelled the economic cost of stabilisation scenarios between 450-550 ppm CO2-e and allowing a rise of 2-3°C in mean global temperatures above pre-industrial levels. It concluded (at page ix):

    “Australia and the world continue to prosper while making the emission cuts required to reduce the risks of dangerous climate change. Even ambitious goals have limited impact on national and global economic growth.”

    Read the fine print, however, and you will see that the report does not incorporate costs such as the loss of the Great Barrier Reef with 2-3°C warming. A somewhat breathtaking omission from the report, noted at page xi, is that “the modelling does not include the economic impacts of climate change itself, so does not assess the benefits of reducing climate change risks through mitigation.”

    The report refers to “other studies” for analysis of the costs of climate change on the economy such as Stern 2007 and Garnaut 2008. In working on stabilising at 2-3°C warming, it is not even mentioned that Stern (2007: 80) concluded that at 2°C warming “coral reefs are expected to bleach annually in many areas, with most never recovering, affecting tens of millions of people that rely on coral reefs for their livelihood or food supply.”

    In my view, the Treasury report is fundamentally flawed by omitting the costs of climate change on the economy. It’s conclusions on the economic benefits of the targets it recommends should not be accepted on this basis alone.

    In my view, if we are going to set stabilisation targets between 450-550 ppm CO2-e and allow a rise of 2-3°C, it needs to be acknowledged we expect to lose coral reefs such as the GBR. Silently ignoring the science does not mean the impacts are not going to happen.

  2. When speaking with scientists and government staff at conferences on climate change in recent years I have heard several say, “It’s too late to save coral reefs”. When I hear people say this I feel like grabbing them by the shoulders and yelling, “Tell me when we decided that? Tell me when we decided that it was too late to save coral reefs?”

    George Monbiot inspires me when he writes:

    “Is it too late? To say so is to make it true. To suggest that there is nothing that can now be done is to ensure that nothing is done. … Can we do it? Search me. Reviewing the new evidence, I have to admit that we might have left it too late. But there is another question I can answer more easily. Can we afford not to try? No we can’t.”

    See: http://www.monbiot.com/archives/2008/11/25/one-shot-left/#more-1155

  3. Pingback: Climate Shifts » Uncategorized » Declining calcification on the Great Barrier Reef

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  5. What impact will rising sea levels have on the reef? If, for example, some freak ice sheet collapse happened, adding a foot to global seal level, would the extra foot of water mean that reefs would suddenly be cooler? How would it affect other variables, like light, nutrients, and waves? Or would it be negligible?

  6. Rising sea levels are not seen as the major threat from climate change in comparison to extreme sea surface temperatures and ocean acidification but see the discussion at page 286 in Hoegh-Gulberg et al (2007) at http://www.gbrmpa.gov.au/__data/assets/pdf_file/0008/22598/chapter10-reef-building-corals.pdf :

    “Due to the slowing effect of other factors on growth [due to impacts of extreme temperatures and ocean acidification], there is the potential that coral populations might be left behind by rapid sea level rise. It is also important to keep in mind that these conclusions [of sea level rise not being a major challenge for coral reefs] are dependent on having a slow rise in sea level. They would be invalidated in the longer term if, for example, the Greenland Ice sheet were to melt rapidly. If this were so, then sea level rise would accelerate well above coral growth and would stabilise at 6 to 10 metres above current sea level. In this case, sea level rise would represent an extreme challenge for most marine habitats including coral reefs.”

    The range of 6-10m is very different from your scale of “adding a foot to global sea level”. A rapid rise of a foot of water would impact on factors such as light, temperatures and waves but if that were the only impacts, corals would be expected to cope. It is the larger effects of temperature rises and ocean acidification that are the bigger threats at present.

  7. hopefully they keep the Great Barrier Reef safe for people to visit in the future it would be sad to see it go. I think one way to keep the Great Barrier Reef and more is to promote safety if people are safe and respect the things around them then this world and communities in the world can be a safer place.

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