Avoiding confusion for stabilization targets for climate change and ocean acidification

Long Cao and Ken Caldeira from the Carnegie Institution at Stanford have a new paper in Geophysical Research Letters on atmospheric carbon dioxide (CO2) stabilization and ocean acidification, a critical topic for current marine science and public policy. Hoegh-Guldberg et al (2007) illustrated the essential chemistry at the heart of this problem as follows:

Essentially, as CO2 dissolves into the oceans it forms an acid leading to decreased coral calcification and growth through the inhibition of aragonite formation (the principal crystalline form of calcium carbonate deposited in coral skeletons). The increased acidity caused by increasing atmospheric CO2 is known as ocean acidification and it is a separate, though inter-related, phenomenon to increased temperatures caused by CO2 acting as a greenhouse gas.

Cao and Caldeira (2008) found “that even at a CO2 stabilization level as low as 450 ppm, parts of the Southern Ocean become undersaturated with respect to aragonite [and] therefore, preservation of existing marine ecosystems could require a CO2 stabilization level that is lower than what might be chosen based on climate considerations alone.”

These results are similar to Hoegh-Gulberg et al (2007), who concluded “… contemplating policies that result in [CO2]atm above 500 ppm appears extremely risky for coral reefs and the tens of millions of people who depend on them directly, even under the most optimistic circumstances.”

Hoegh-Guldberg et al (2007) illustrated the expected the conditions of coral reefs under different levels of atmospheric carbon dioxide and temperature increases as follows:

These findings are very significant for governments around the world and other policy-makers because much of the current policy debate on climate change focuses on stabilizing greenhouse gases, including carbon dioxide, between 450-550 parts per million carbon dioxide equivalents, thereby allowing a rise in mean global temperatures of around 2-3°C (e.g. Stern 2007; Garnaut 2008; Australian Treasury 2008).

Continue reading “Avoiding confusion for stabilization targets for climate change and ocean acidification”

The missing link in the “solutions” to climate change

The recent Garnaut report states that “the solutions to the climate change challenge must be found in removing the links between economic activity and greenhouse gas emissions.” In order to successfully mitigate climate change impacts on both the environment and the economy, we need to go a step further and replace those links with avenues … Continue reading The missing link in the “solutions” to climate change

Scientists urge Prime Minister Kevin Rudd to crack down on climate change issues

The Age is reporting on an open letter to the Australian Prime Minister Keven Rudd, urging the PM to make strong cuts in Australia’s greenhouse gas emissions by 2020. The letter, written by myself and 15 other Austalian scientists who contributed to the IPCC report, was released on the eve of the final report by … Continue reading Scientists urge Prime Minister Kevin Rudd to crack down on climate change issues

“Garnaut report sparks call to arms for at-risk Barrier Reef”

ABC News, 5th July The Great Barrier Reef Marine Park Authority says it accepts the findings of the Garnaut report on the impact of climate change on the reef. The report found if carbon emissions are not reduced, the reef could die within decades. The Authority’s Russel Reichelt says governments and industry must take strong … Continue reading “Garnaut report sparks call to arms for at-risk Barrier Reef”