No credit as oceans turn sour

NOW that Ross Garnaut’s draft report has been released, most of the climate change debate in Australia will focus on the economic effects of any emissions trading scheme.

However, there’s another carbon problem, which will profoundly affect our oceans, that has received scant attention beyond a small band of marine scientists and is largely independent of global warming.

The public, aware of the role of carbon dioxide in climate change, doesn’t know of its function in acidifying the oceans and the hundreds of years that would be required for recovery.

Ocean acidification refers to the natural process whereby carbon dioxide dissolves in the sea, forming a weak carbonic acid. The ocean is a major sink for atmospheric carbon dioxide and has absorbed about 48 per cent of the CO2 emitted by human activities since the pre-industrial age.

A recent report from the Antarctic Climate and Ecosystems Co-operative Research Centre claimed that carbon dioxide in the atmosphere is at its highest level in 650,000 years, and possibly 23 million years, and half has been dissolved in the oceans, making them more acidic.

Australia has a direct stake in the ocean acidification problem: it will affect every part of our marine environment. And our offshore estate has just become a lot bigger. Three months ago the UN Commission on the Limits of the Continental Shelf, while not accepting all bids, recognised Australia’s claim to the continental shelf where it extends beyond our exclusive 200 nautical mile economic zone. This is a vast oceanic area: 2.5 million square kilometres, or 10 times the size of New Zealand and 20 times the size of Britain.

Rising levels of acidity in the oceans surrounding Australia could have a profound impact on marine industries and dire consequences for many Pacific Island communities, presenting strategic and humanitarian challenges.

Mounting levels of CO2 in the Southern Ocean has caused deep concern among scientists studying the long-term productivity of the world’s oceans. Under conditions of increasing acidification, parts of the oceans will deteriorate and progressively become uninhabitable for certain types of plankton, central to the ocean food chain, and coral structures. The Southern Ocean is particularly important because it is very efficient at absorbing CO2 from the atmosphere: it’s here where the first effects are being felt.

Ocean acidification is likely to have a cascading effect, reaching parts of the food chain such as fish and shellfish. Marine researchers are saying that a business-as-usual scenario of CO2 production will ultimately result in destruction of marine life on an enormous scale.

Some shell-forming species will struggle to maintain or reproduce their vital shell structures and skeletons, which will have a direct effect on the ocean food web.

Some species will decline, others will be displaced or will disappear, and patterns of fisheries will change, potentially threatening the food security of millions in the Asia-Pacific and damaging Australian fisheries economically.

Another study identified ocean acidification as a primary causal factor in common reef fish getting lost at sea during a crucial stage of their development. And rising acidification could also interfere with the respiration of fish, the larval development of marine organisms and the ability of oceans to absorb nutrients and toxins.

Coral reefs such as the Great Barrier Reef, which are hot spots of biodiversity, will suffer. Acidification will weaken coral structures and stunt coral growth, leading to a significant decline by the middle of this century. This will deprive parts of the Australian coastline of a natural protective barrier against the ocean, leading to greater threats from storm activity and cyclones.

Similarly, environmental threats to nations in our region with extensive coastal exposure will increase, resulting in more demands on Australia to assist countries facing environmental disasters. For low-lying island nations such as Kiribati and Tuvalu, already facing inundation from the rising sea level, the threat could be existential.

Some researchers have proposed ocean fertilisation as a simple, environmentally friendly and effective fix: the deliberate addition of nutrients to the sea in order to stimulate phytoplankton growth in the hope that the CO2 is captured in the marine organisms and then transferred to the deep ocean, where it would be stored, possibly for centuries.

However, neither the environmental safety nor the efficacy of ocean fertilisation has been adequately assessed. It could risk side effects such as artificially induced phytoplankton blooms that degrade the maritime domain of countries that share sea borders with Australia.

In the absence of any clear preventive solutions, and with so much at stake, Australia needs to understand how best to adapt to the problem of acidic seas.

There are several initial steps we should take. We need a more collaborative national research effort to enable broad partnerships to develop across the research community with marine-focused agencies, increasing Australia’s capacity and readiness to adapt to global oceanic changes.

The present arrangement of loosely associated research institutions lacks the required funding and co-ordination to develop an accurate national assessment of the ecological impacts of the problem.

Related to this, we need to address our marine research capability. Australia has only two major research platforms, and both vessels are approaching the end of their useful lives. We have less capacity here than many of our neighbours and we are barely on par with NZ’s capability.

There are cost-effective, short-term strategies that would start to fill the information gap. There are nine moorings at shelf locations across Australia being established through the integrated marine observing system, which measures what’s driving ecosystem change in the oceans.

The federal Government could assist with enhancing the limited carbon-measurement capability of these moorings to help define the natural variability in acidification and how it’s changing. Merchant vessels could be utilised to collect water samples needed to measure the rate of change in ocean acidity: sustained observations from Australian coastal waters are required to determine how acid levels are changing and to identify and ultimately predict how ecosystems will respond to acidification.

Australia should become a lead nation in monitoring acidification levels in regional waters and raise the issue of sustaining our oceans at every opportunity in regional and international bodies concerned with global environmental change, such as the International Maritime Organisation.

Australian scientists working in the Southern Ocean and the Great Barrier Reef region have considerable expertise that could assist Indo-Pacific states whose national interests are linked to the oceans. Many of our neighbours in the Indo-Pacific region depend on coral reefs for marine-based tourism revenue and food security. Fish stocks in Southeast Asia indirectly support about 100 million people: understanding the consequences of acidification for these communities could help to prevent future calls for Australian development assistance.

And our security decision-makers need to factor in ocean acidification into longer-term national risk assessments. Talking directly to Australia’s marine science experts on the problem would be a sound place to start.

We have a larger stake in this issue than most countries. We are an oceanic superpower, with the third largest area of offshore marine estate in the world. Australian fisheries generate $2billion in revenue, and the Great Barrier Reef, the world’s largest coral reef, supports a $6.9 billion industry. And we’re close to the Southern Ocean, which is the principal means for pumping CO2 out of the atmosphere: that’s where the alarm bells are ringing.

People didn’t believe the melting icecaps idea a few years ago but it’s just been reported that for the first time in recorded history the North Pole may briefly be ice-free by September as global warming melts away Arctic Sea ice. Polar scientists believe the chances of a totally ice-free North Pole this northern summer are greater than 50-50, and a Russian parliamentary committee has just warned that the Arctic icecap may be gone by 2070.

As the debate about who wins and who loses in the future Australian emissions trading regime intensifies, we should remember that with ocean acidification there will only be losers. Discovering the ecological effects of our souring oceans requires urgent action.

Anthony Bergin and Ross Allen, The Australian, 5 July 2008. Article.

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