Yes, the Earth is Still Warming. No, it Didn’t Stop 16 Years Ago.
February 8, 2013There are probably as many climate change myths circling around the internet as there were days of record-breaking temperatures in 2012. The latest myth (a variation on another myth) is that global warming stopped 16 years go. This is similar to other claims that say, "global warming stopped in year X."
This variation of the myth got its start after the Daily Mail (a London tabloid) reported:
"The world stopped getting warmer almost 16 years ago, according to new data released last week.
The figures, which have triggered debate among climate scientists, reveal that from the beginning of 1997 until August 2012, there was no discernible rise in aggregate global temperatures.
This means that the ‘plateau' or ‘pause' in global warming has now lasted for about the same time as the previous period when temperatures rose, 1980 to 1996. Before that, temperatures had been stable or declining for about 40 years" (Source).
As this article from Discovery shows, the Daily Mail article is filled with misrepresentations and falsehoods (not that such a fact ever stops these myths from spreading). The Daily Mail attempted to use a report from the Met Office to show that the planet hasn't been warming for the last 16 years, but as this statement from the Met Office explains, "The first decade of this century has been, by far, the warmest decade on instrumental record".
The report the Met Office did put out doesn't even make mention of the issue brought up by the Daily Mail article. In fact, the Met Office explained this to the Daily Mail in an email exchange:
Q.1 (From the Daily Mail) "First, please confirm that they do indeed reveal no warming trend since 1997."
The linear trend from August 1997 (in the middle of an exceptionally strong El Nino) to August 2012 (coming at the tail end of a double-dip La Nina) is about 0.03°C/decade, amounting to a temperature increase of 0.05°C over that period, but equally we could calculate the linear trend from 1999, during the subsequent La Nina, and show a more substantial warming.
As we've stressed before, choosing a starting or end point on short-term scales can be very misleading. Climate change can only be detected from multi-decadal timescales due to the inherent variability in the climate system. [emphasis added] If you use a longer period from HadCRUT4 the trend looks very different. For example, 1979 to 2011 shows 0.16°C/decade (or 0.15°C/decade in the NCDC dataset, 0.16°C/decade in GISS). Looking at successive decades over this period, each decade was warmer than the previous—so the 1990s were warmer than the 1980s, and the 2000s were warmer than both. Eight of the top ten warmest years have occurred in the last decade.
Over the last 140 years global surface temperatures have risen by about 0.8ºC. However, within this record there have been several periods lasting a decade or more during which temperatures have risen very slowly or cooled. The current period of reduced warming is not unprecedented and 15 year long periods are not unusual (Source).
Choosing a random starting point in order to get the data to say there is no warming is an old climate "skeptic" trick. The last part of that message is important so I'll restate it: "However, within this record there have been several periods lasting a decade or more during which temperatures have risen very slowly or cooled." Global warming isn't about temperatures rising year-by-year in a straight line. Variation is expected (a point I touched on in my previous post).
So what else do we know? Well, the last 35 years have shown an increase in global temperatures. But the warming has varied from year to year. Various weather events, such as El Nino, along with volcanic activity have an impact on this year-to-year variation. The upward trend is driven by greenhouse warming from human-created emissions. If you watch this video, you'll see that even after those natural causes are taken out we still see an upward trend in temperatures over the last 16-years.
And let's not forget that 2012 was the hottest year on record in the US (Source).
It's as simple as that really. This myth is, well, a myth. The planet is warming, and humans are the cause.