As humans emit more greenhouse gases like carbon dioxide into the atmosphere, the Earth continues to warm. When I use the term “warm”, I mean there is an increase in thermal energy (heat) contained in the oceans and atmosphere of this planet.
We can measure warming by measuring temperatures; however, obtaining an accurate reading of the Earth’s temperature is complicated. Temperatures change with seasons, with locations, and there are natural long term variations that move heat around. So, we don’t expect temperatures just to continue increasing at all locations and at all times. We do expect the long term trend to be upwards, however, and that is what we’ve observed.
But if you follow the conversation about global warming, and particularly if you listen to cable news or online bloggers, you might have heard that there has been a hiatus or a halt to global warming. I’ve written before on this site that there is no halt, there never has been one. However there has been a vigorous debate about whether the increase in lower atmosphere temperatures has slowed down.
A new paper, “Possible artifacts of data biases in the recent global surface warming hiatus” just published today in Science deals with this issue. In particular, the lead researcher Dr. Thomas Karl and his colleagues investigate the quality of the near-surface temperature records and ask whether they really show a slowdown.