Eddie Mabo occupies a large place in the history of relations between indigenous and other Australians. He played that role because he was a man of exceptional capacity and tenacity and also because he was part of the minority of indigenous Australians whose original home was in the islands of the Torres Strait.
The Torres Strait and the adjacent lands of Australia, Indonesia and Papua New Guinea, and the people who live there, share many things, including exceptional vulnerability to climate change.
A few years ago, some of the common king tides - which arise regularly when the moon and sun are aligned in their gravitational pull on the seas - started to have uncommon effects. The water rose above the beaches and flooded the places of human settlement. On the Torres Strait islands, the people of Eddie Mabo's island, Mer, moved to higher ground. Villagers in the Fly River delta and some of the adjacent coasts found their gardens and watering places inundated and ruined by salt. Thousands sought sustenance in the crowded and impoverished town of Daru, which had long outgrown the demands for a livelihood that people placed on it.
This looks like human-induced - anthropogenic - climate change. Global warming will raise the sea level simply by expansion of the water as it warms. The average rate of sea level rise from 1961 to 2003 was almost 1.8 millimetres plus or minus 0.5mm annually. In the decade to 2003, it was 3.1mm plus or minus 0.7mm annually. This doesn't sound much but the accumulation of increases at a few millimetres a year, accelerating over time, soon becomes hugely disruptive for people who live so close to the water.
The Intergovernmental Panel on Climate Change Report of 2007 estimated that for business-as-usual emissions growth similar to that anticipated by the Garnaut Climate Change Review, probable sea-level rise would be 26 to 59 centimetres. Three-quarters of this was expected to come simply from thermal expansion, with a small contribution from the melting of terrestrial ice. Dynamic changes in ice flow could raise the upper limit by 10 to 20 centimetres. A key conclusion of the panel's sea-level rise projections was that larger values above the upper estimate of 79 centimetres could not be excluded.
Fifty centimetres of sea-level rise will make life vulnerable to the king tides and the storm surges in the places where most of the 8000 or so Torres Strait people now live. A metre of sea-level rise would be much worse.
For most of Mabo's Australian fellow-citizens of the Torres Strait, and the larger numbers of Papua New Guineans and Indonesians in adjacent areas, their only choice would be to seek new livelihoods in new places.
It will be easier for Torres Strait citizens of Australia, with their rights to live and work and get access to social security and services in Australia. Successful development in the Western and Gulf provinces of PNG and the Merauke and Asmat districts of Indonesian Papua would ease the strain. It is in the interests of all to assist such development where we can. But we would be optimists to think that development in these places alone could carry the resettlement load.
The more benign possibilities from a failure of effective global mitigation are likely to require the relocation a long way from their homes of hundreds of thousands living in and adjacent to Torres Strait.
And even if these relocations turn out to be possible without huge trauma, there will be a loss of human heritage. The loss would go well beyond the economic losses that I tried to measure in intricate detail in the Garnaut Climate Change Review. These are the immeasurable losses to which I referred in chapter one of the review - the loss of natural and human heritage - that we must try to bring to account outside the economic models.
Humanity is now in the process of a collective decision on whether to take great risks for the economy and the natural and human heritage of the future by failing to break the link that has been present since the Industrial Revolution between economic activity and greenhouse gas emissions.
Climate change mitigation is a conservative issue.
The central policy issue is whether and how much we are prepared to pay to conserve established patterns of human life and civilisation and to improve our chances for handing on prospects for more enriching lives from generation to generation.
Professor Ross Garnaut is the author of the Garnaut Climate Change Review. This is an edited version of his 2009 Eddie Koiki Mabo Lecture, delivered in Townsville last night.
This article was first published online on The National Times