Ecos examines the debate on sea level rise

The report indicated that, by the end of the 21st century, sea levels could rise higher than previously predicted due to accelerated melting of polar ice sheets, highlighting a critical gap in our understanding of how polar ice sheets will respond to global warming.

As a result, the IPCC has added a polar ice ‘caveat’ to its latest estimates that takes into account the wide range of possible responses of the polar ice sheets.

The Greenland ice sheet holds the equivalent of 7m sea level rise, while complete melting of the West Antarctic ice sheet would add another 5 to 6m to current levels.

Factors that could accelerate polar ice sheet melting include more rapid heat absorption as the white surface is replaced by darker wet ice, melting rates exceeding snowfalls, and direct contact of warmer seawater with the underside of ice sheets.

Some leading climate researchers including the CSIRO’s Dr John Church say that recent trends in global sea level suggest we are tracking towards the upper trajectory of the IPCC’s 2001 projections – an 88cm rise by 2100, consistent with the projected upper limit in the 2007 IPCC report.

Ecos outlines some actions being taken in Australia by federal, state and local governments to prepare for sea level rise and higher storm surges.

Damage caused by sea level rise and stronger storms is likely to impact, among other things, wetland habitat and biodiversity, coastal properties and infrastructure, tourism, traditional culture, real estate prices, insurance premiums, and emergency planning.

Ecos also reports on the need to improve the monitoring, regulation and management of Australia’s vast underground water resource.

Groundwater supplies many streams, rivers and lakes. However, large volumes of bore water are consumed without metering or charge, and its use is often unrestricted.

As a result, authorities don’t know how much is extracted by farmers, mining and industry users, households, local councils and sports facilities. 

Excessive use and pollution are leading to lower water tables, reduced flows to wetlands, groundwater salinisation and land subsidence.

Elsewhere in Ecos is a report on the plight of an internationally significant wetland – the Macquarie Marshes near Bathurst, NSW. 

The 220,000ha wetland, registered under the Ramsar Convention as a site of global ecological significance, once boasted Australia’s greatest diversity of waterbirds.

Today, much of the wetland is degraded due to the recent drought and allocation of water from the Macquarie River for irrigation.

Other stories in Ecos 137 include:

• Men of the trees: A volunteer organisation in Western Australia is helping farmers and others put 600,000 trees a year back into the landscape. Men of the Trees was inspired by Richard St Barbe Baker, an early 20th century environmentalist whose legacy lives on today.
• Whale shark conservation wins: Brad Norman, who won a Rolex Award for Enterprise for his whale shark research in 2006, is using the prize money and publicity from the awards to pursue his dream of setting up localised whale shark conservation ‘nodes’ around the world.
• Triple bottom line pays dividends: Market research shows that companies who put a value on social, environmental and community issues are registering above-average financial performance. Of the top five performing funds in Australia in 2006, three were socially responsible investment (SRI) funds.
• Indonesian marine reserve declared off West Papua: Indonesia has established a network of seven protected area off West Papua, which harbour some of the world’s most biologically diverse coral reefs, mangrove forests and other coastal ecosystems.

ECOS MAGAZINE – Issue 137 is available at major national newsagents or online at: www.publish.csiro.au/ecos

ECOS is a bimonthly colour subscriber publication covering environmental and sustainable development issues relevant to Australia and the Asia-Pacific region.