Annual (line) and decadal (box) mean sea-surface temperature anomalies for the Australian region relative to the 1961–1990 average. The average value for the most recent 10-year period (2002–2011) is shown in darker grey.
Sea-surface temperatures in the Australian region in 2010 were the highest on record, with nine of the months during 2011 ranked in the top ten warmest months on record. Sea-surface temperatures averaged over the decades since 1900 have increased for every decade. Sea-surface temperature datasets are separate to land temperature datasets, but both terrestrial and ocean surface temperatures have shown very similar warming trends over the last century, confirming that temperatures are rising.
The warm sea-surface temperatures in 2010-11 were strongly influenced by La Niña. La Niña events are typically associated with warmer-than-average ocean temperatures in the Australian region. Ocean temperatures around Australia were warmer during 2010-11 than for any previously identified La Niña event, likely due to the influence of the long-term warming trend of the past century.