The World's oceans have warmed 50 per cent faster over the last 40 years than previously thought due to climate change,Australian and US climate researchers have reported Higher ocean temperatures expand the volume of water, contributing to a rise in sea levels that is submerging small island nations and threatening to wreak havoc in low-lying, densely-populated delta regions around the globe. The study, published in the British journal Nature, adds to a growing scientific chorus of warnings about the pace and consequences rising oceans.