What Global Warming Hiatus? Year 5775 Was Hot

Happy New Year! Or as those who are celebrating

This claim of a pause or “hiatus” in global warming has been refuted by scientists and skeptics time and again, but one of the most widely used talking points by deniers is that “it hasn’t warmed since 1998″ (now apparently updated to “it hasn’t warmed by more than the margin of error”). Nineteen ninety-eight was a particularly hot year during its decade, but the same temperature is now normal, with four years out of the last ten exceeding it. The objective (mathematically-defined) long term trend over a period centered on 1998 is still obviously upward at 3.6 degrees per century. Only a fool would bet that climatological temperature won’t continue to rise (and notably, the Heartland Institute did not accept such a challenge by skeptics despite what their bloggers claim to believe).

My second graph shows the same data, but using July-June “fiscal year” (and like a fiscal year, I call the one that just ended “2015” even though it started in the middle of calendar 2014). What a difference! 1998 was still the hottest year of its decade, but was rapidly superseded by a long series of even hotter years: 12 out of the last 14! If a different arbitrary new year’s date had been used, deniers would never have been able to make the “global warming stopped in 1998″ argument at all. But the long-term trend, calculated rigorously as before, is exactly the same.

Just for fun, I also created a bar chart showing the number of years since 1998 that have been warmer, using 12 different starting months to define the relevant year.


In geek-speak, the records and rankings that are endlessly discussed on —> Read More