From the Global Warming Information Center
"The oceans of the world have gotten warmer since the 1940s. Furthermore, it has done so from the surface down towards the bottom of the three oceans, introducing the dimension of depth, something that was not previously actively considered when measuring ocean temperatures.
Now the larger driver of the new climate oscillation is the heat we put into the oceans of the world. The world’s increasing ocean temperatures have spawned ever-stronger ocean waves over the past 40 years. This energy increases as the ocean’s temperature rises, so the energy content of the tsunamis, hurricanes and typhoons also rises,"said Sinyan Shen, Director of the GWIC in the U.S.