Actually, two charts today taken from a presentation given by Gerald Meehl on the 5th January 2015 at the American Meteorological Society’s 95th annual conference. Meehl is a senior scientist at the National Center for Atmospheric Research (NCAR). First up, a chart showing that you should think of global warming as a stepwise movement as opposed to a smooth upward curve (click for larger image):
Where climate skeptics are wrong is to say that the last decade is not substantially hotter than the previous decade. Where they are right is to say that over the course of the last decade, global surface temperatures have only warmed just a bit. But global warming doesn’t just incorporate the atmosphere, it includes the oceans as well. Global warming broadly defined to include the whole earth system has never stopped, it just shows up in different places at different times. From Meehl’s summary slide:
The mechanism behind this shift is the Interdecadal Pacific Oscillation (IPO), which at times transports heat from the Pacific Ocean’s surface to the deep ocean. Unfortunately, at other times, this process also works in reverse.
In the past, models, methodology and supercomputing power were not sufficient to capture the IPO and thus temperature hiatuses. However, Meehl believes that science has progressed and we are now in a position to model and predict both temperature pauses and accelerations. And it looks like an acceleration is just about to begin (bottom left chart, click for larger image):