365 Days of Climate Awareness 202 – Decline of the Great Barrier Reef: Shipping and Boating Activity

Shipping is specifically relevant to global warming in terms of the amount of carbon dioxide emitted by ships which typically burn bunker fuel, a very thick, dirty, carbon-rich crude oil product. Indirectly shipping matters because it is an excellent indicator of overall global economic activity (in 2008-9, when the Great Recession was taking hold, shipping indexes worldwide collapsed, in some cases months before other indicators fell). Increased shipping means not only more direct greenhouse gas emissions, but also a growing world economy, which is anathema to limiting global warming.

Number of commercial freight ships in Australia, 1998 - 2013.

Shipping in Australia increased dramatically since 2000, and is projected to increase further, particularly with Queensland’s mining boom. The northeast coast is regulated intensely because of the Great Barrier Reef, but several threats exist even without accidents which impact it directly. Discharge of bilge water can introduce exotic, sometimes invasive species (invasive species can be indigenous, and not all exotics are invasive). Three exotic, invasive species are especially dangerous:

• The Northern Pacific seastar (Asterias amurensis) – a large starfish which eats crustaceans, native to the waters of southeast Asia
• Asian Green Mussel (Perna viridis) – outcompetes native species for food and space, native to the Asian coast
• Crown-of-thorns Starfish (Acanthaster planci)

Principal Shipping Routes, 2016. 99% of Australia's trade is by sea.

Though rare, ships do run aground on the reef (three between 2000-2010), and when they do, the damage is locally catastrophic, creating a large gash in the reef’s fabric and possibly spilling large amounts of fuel or cargo. Anti-fouling paint scraped from the hull is also toxic to reef organisms. For these reasons shipping near the Reef is sharply restricted but impacts still occur, such as on April 4, 2010, when the Chinese coaler Shen Neng 1 ran aground on Sudbury Reef, after having left a grounding scar 3 km/1.9 mi long, and spilling 800 tons of fuel oil. After nine days tugboats succeeded in pulling it off the reef and then towed it back to its home port.

How ships' ballast water brings exotic species around the world.

The Shen Neng 1 ran aground on Sudbury Reef on April 4, 2010, spilling 800 gallons of fuel.

Tomorrow: global warming and New Zealand indigenous species.

Be brave, and be well.