Truth vs post-truth: What’s causing our record-shattering global temperatures?

The Oxford Dictionaries declared “post-truth” the word of the year for 2016, because we seem to be entering a period in which peoples’ opinions are shaped more by appeals to emotion than by facts. The word was frequently used in reference to Brexit and the US presidential election, but it’s also been long applied to the subject of climate change. Last week, a perfect example of a post-truth climate story made headlines on the alt-right Internet platform Breitbart.com and then was Tweeted by the House Science, Space, and Technology Committee.

It all started in the Daily Mail when David Rose penned an article  inaccurately suggesting that the record-breaking global temperatures of the past several years were caused by El Niño, purportedly evidenced by a “plummet” in global temperatures over land. The argument was picked up by Ross Clark in The Spectator and James Delingpole for Breitbart, the latter of which was Tweeted by the US House Science Committee.

The argument is a perfect example of one of the five characteristics of science denial: cherry picking. Rather than considering direct measurements of global average surface temperatures, Rose and company only looked at satellite estimates of the temperature of the atmosphere above the portions of the Earth’s surface covered by land masses. Even though the satellite record extends back to 1979, and the surface temperature record to 1880, they only showed the data since 1997. They also primarily focused on the single month of October 2016 because it happened to be relatively cool—in the lower atmosphere, above the portions of the Earth covered by land, according to these particular satellite estimates.

As any climate scientist will gladly explain, it’s true that El Niño events cause temperatures at the Earth’s surface and especially in its lower atmosphere to warm in the short-term, while La Niña events have a temporary cooling influence. However, it’s folly to blame the past three years of record-shatteringly hot global temperatures exclusively on El Niño, as David Rose and company have done.

It’s quite simple to demonstrate why this is true. While we saw a strong El Niño event in 2015–2016, there was an equally strong event in 1997–1998. The two events had very similar short-term warming influences on global surface temperatures, but according to NASA, 2016 will be about 0.35°C hotter than 1998. That difference is due to the long-term, human-caused global warming trend. Short-term fluctuations are just noise superimposed on that long-term trend. It’s also worth noting that in NASA’s global surface temperature data, there was no precipitous drop in October 2016. That argument only works when cherry picking the most convenient set of data, over just a portion of the Earth, in the atmosphere above its surface. They’ve picked cherries upon cherries upon cherries.

The news outlets that ran this cherry-picked story all share a conservative worldview, as does the US House Science Committee that Tweeted the Breitbart piece about it. Unfortunately, these sorts of science-denying post-truth articles and arguments tend to originate from sources with such ideological biases, because people have become incredibly polarized on the subject of climate change. The problem is, we all live on the same planet with the same climate operating under the same laws of physics. When it comes to science, we don’t get to choose our own truths.