In 2017, Watch for the Cries of “Global Cooling!”
In the decade after 1998, deniers of global warming loved to use the phrases “no global warming since 1998” or “global cooling since 1998.” I’m not kidding: a search for the former phrase on a search engine leads to 3,910 results; a search for the latter phrase leads to 1,870 results. Look at this image of global temperature trends using NASA data to figure out why:
The year 1998 is very important. Notice the gigantic, unusual spike in that year? If you only look at trends starting in 1998 and ignore the years before, the subsequent decade looks like a cooling decade. If you look at the broader trend and accept that of course there is natural variability for any particular year, the temperature trend is undeniable, and not just from the 1880s to the 2010s: if you look at the 1990s, it’s clear the 2000s were warmer than them, and it’s clear that the 2010s have been warmer still.
The warmest year yet for the globe is the current year, 2016, and as you can see it’s warmer by a big margin compared to just a few years back. Natural variability ensures that one of these years, we’ll have a year a bit cooler than the previous one. Maybe that’ll happen in 2017. At that point, I can guarantee you that global warming deniers will roll the “global cooling!” phrase out again. Whenever and wherever you see that phrase, ask yourself why the author chose a particular year. Then look at the broader trend to for better context. As soon as you do this, the supposed short-term “global cooling” trend will be swamped by the overall trend of global warming.