Scientists puzzled over the lack of sea level rise have found the answer: Australian floods.
The rains – evaporated ocean – were so heavy in Australia during 2010 and 2011 that the world’s sea levels actually dropped by 7mm. And rain in Australia is different: rather than ending up in rivers and making its way back to the sea, the rain that falls in the dry outback tends to disappear, going instead to inland waterways or sitting in shallow inland seas until it evaporates. This effect was strong enough to overcome the global trend in rising sea levels and actually lower the whole world’s sea levels temporarily.
Three climactic phenomena were responsible for the drenching of Australia during that time: La Niña, the Southern Annular Mode and the Indian Ocean Dipole coincided, resulting in 300mm more rain than the continent usually gets. This set of events, that scientists have only now pieced together, is a reminder of just what a complex climate system we inhabit.
Australia is now dealing with a drought, and sea levels are rising faster than ever, about 10mm a year.
- Climate News Network: Australia’s floods had global effects
- Geophysical Research Letters (subscription required): Australia’s unique influence on global sea level in 2010–2011