The Australian Government has set a 2020 target of reducing direct national greenhouse gas emissions by between 5 to 15% and thereby aiming at a global scenario that would stabilise global atmospheric greenhouse gases at around 510 to 550 parts per million carbon dioxide equivalents (ppm CO2-e) by the end of the century.
Heogh-Guldberg et al (2007) illustrated what these targets mean for the Great Barrier Reef and much of the marine ecosystem in the following series of pictures. Picture A on the left represents current conditions for corals across much of the GBR. Picture C on the right represents the conditions under the atmosphere being aimed for by the Australian Government.
The Carbon Pollution Reduction Scheme White Paper, released on 15 December 2008, does not acknowledge the expected impacts on the Great Barrier Reef if its global stabilisation targets are achieved but draws heavily on the economic analysis of Professor Ross Garnaut.
Garnaut (2008a: 38) was brutally frank in his supplementary draft report: “The [strategy of stabilising at 550 ppm CO2-e] 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: 127) concluded that stabilisation at 550 ppm CO2-e will result in:
“Disappearance of reef as we know it, with high impact to reef-based tourism. Three-dimensional structure of the corals largely gone and system dominated by fleshy seaweed and soft corals.”
“A carbon dioxide concentration of 500 ppm or beyond, and likely associated temperature change, would be catastrophic for the majority of coral reefs across the planet. Under these conditions the three-dimensional structure of the Great Barrier Reef would be expected to deteriorate and would no longer be dominated by corals or many of the organisms that we recognise today.”
The White Paper all but dismisses “stabilising concentrations of greenhouse gases at around 450 parts per million or lower” because “achieving global commitment to emissions reductions of this order appears unlikely in the next commitment period [after the commitment period for the Kyoto Protocol ends in 2012].”
Note, there are significant differences in targets based on stabilising atmospheric carbon dioxide at 500 ppm (which picture C above depicts) and stabilising total radiative forcing of greenhouse gases and aerosols at 500 ppm CO2-e (see Avoiding confusion on stabilization targets for climate change and ocean acidification).
However, the White Paper appears to assume total radiative forcing will continue to roughly equal atmospheric carbon dioxide levels. Therefore, by aiming to stabilise atmospheric greenhouse gases at around 510 to 550 ppm CO2-e, the White Paper appears to be aiming to stabilise atmospheric carbon dioxide (currently around 385 ppm) at these levels.
This should sound alarm bells for anyone following the scientific literature on ocean acidification, which has found serious impacts occur to coral reefs and much of the marine ecosystem above 450-500 ppm carbon dioxide in the atmosphere (Hoegh-Guldberg et al 2007; Cao and Caldeira 2008).
The public debate in Australia has largely ignored these impacts and it remains to be seen whether there will be any real challenge to the current approach being taken by the Australian Government.
The government has been less than frank on the implications of the targets it has chosen. There is no acknowledgment of the expected impacts to the Great Barrier Reef of stabilising at 510 – 550 ppm carbon dioxide or CO2-e and the choice of stabilising in this range is obscurely buried in the body of this 800 page report.
The White Paper refers repeatedly to 2020 targets of 5-15% reductions. It also refers repeatedly to stabilising at or below 450 ppm, with Garnaut’s pessimistic conclusion that “achieving global commitment to emissions reductions of this order appears unlikely”. But a reader must connect the 5-15% reductions to one of six scenarios set out on page 4-11 of the White Paper to uncover the overall stabilisation goals.
The White Paper relies heavily on Garnaut’s findings but a reader must also connect the obscurely buried stabilisation range of 510-550 ppm in the White Paper to Garnaut’s findings in his 600 page final report.
The government appears to be silently ignoring the expected impacts to the Great Barrier Reef and seeking to avoid confrontation on these implications in selling its climate change policies to the public. Tony Jones repeatedly asked Climate Minister Penny Wong of the implications for the Great Barrier Reef of stabilising at 550 ppm in an interview on ABC Lateline on (30 November 2008). She obviously knew the answer but danced around the questions to avoid stating that the government’s targets would mean the destruction of the Great Barrier Reef.
Perhaps it is too late to save the Great Barrier Reef but silently ignoring the expected impacts when setting climate change targets is disingenuous and does not advance the public debate. We need to fully acknowledge what the science is telling us. Choosing not to listen to weather forecasts does not stop it raining.
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.
- Australian Government (2008), Carbon Pollution Reduction Scheme – Australia’s Low Pollution Future – White Paper (Department of Climate Change, Canberra, 2008), available at http://www.climatechange.gov.au/whitepaper/index.html
- Cao L and Caldeira K (2008) “Atmospheric CO2 stabilization and ocean acidification” Geophys. Res. Lett., 35, L19609, doi:10.1029/2008GL035072.
- Garnaut R (2008a), Garnaut Review Supplementary Draft Report: Targets and trajectories (Garnaut Review, Canberra, 5 September 2008), p 38, available at http://www.garnautreview.org.au/CA25734E0016A131/pages/all-reports–resources.
- Garnaut R (2008b), Garnaut Climate Change Review Final Report (Cambridge University Press), http://www.garnautreview.org.au/index.htm.
- Hoegh-Guldberg O, et al (2007) “Coral Reefs Under Rapid Climate Change and Ocean Acidification” Science 318, 1737, DOI: 10.1126/science.1152509
- Lateline (30 November 2008), available at http://www.abc.net.au/lateline/content/2008/s2406044.htm