Global warming ‘pause' didn't happen, study finds Reassessment of historical data and methodology by US research body debunks ‘hiatus’ hypothesis used by sceptics to undermine climate science
The year 2014 was Earth’s warmest in 134 years of records, according to an analysis of surface temperature measurements by Nasa scientists. In a separate, independent analysis, scientists at the National Oceanic and Atmospheric Administration also found 2014 to be the warmest on record.
Global warming has not undergone a ‘pause’ or ‘hiatus’, according to US government research that undermines one of the key arguments used by sceptics to question climate science. The new study reassessed the National Oceanic and Atmospheric Administration’s (Noaa) temperature record to account for changing methods of measuring the global surface temperature over the past century.
The adjustments to the data were slight, but removed a flattening of the graph this century that has led climate sceptics to claim the rise in global temperatures had stopped. “There is no slowdown in warming, there is no hiatus,” said lead author Dr Tom Karl, who is the director of Noaa’s National Climatic Data Centre. Dr Gavin Schmidt, a climatologist and the director of Nasa’s Goddard Institute for Space Studies said: “The fact that such small changes to the analysis make the difference between a hiatus or not merely underlines how fragile a concept it was in the first place.”
The results, published on Thursday in the journal Science, showed the rate of warming over the past 15 years (0.116C per decade) was almost exactly the same, in fact slightly higher, as the past five decades (0.113C per decade). Adapted from Noaa National Centers for Environmental Information In 2013, the UN’s most comprehensive report on climate science made a tentative observation that the years since 1998 had seen a “much smaller increasing trend” than the preceding half century.
The results highlighted the inadequacy of using the global mean surface temperature as the primary yardstick for climate change. Karl said: “There’s been a lot of work done trying to understand the so-called hiatus and understand where is this missing heat.” A series of studies have since identified a number of factors, including heat transferred into deep oceans and small volcanic eruptions, that affected the temperature at the surface of the Earth. “Those studies are all quite valid and what they suggest is had those factors not occurred the warming rate would even be greater than what we report,” said Karl.
Dr Peter Stott, head of climate monitoring and attribution at the UK’s Met Office, said Noaa’s research was “robust” and mirrored an analysis the British team is conducting on its own surface temperature record. “Their work is consistent with independent work that we’ve done. It’s within our uncertainties. Part of the robustness and reliability of these records is that there are different groups around the world doing this work,” he said. But Stott argued that the term slowdown remained valid because the past 15 years might have been still hotter were it not for natural variations.
In the coming years the world is expected to move out of a period in which the gradient of warming has not slowed even though the temperature has been moderated. This means “we could have 10 or 15 years of very rapid rates of warming,” he said. “Even though the observed estimate is increased, over and above that there is plenty of evidence that the rate of warming is still being depressed,” he said. “The caution is around saying that that is our underlying warming rate, because the climate models are predicting substantially higher rates than that.”
Noaa’s historical observations were thrown out by unaccounted-for differences between the measurements taken by ships using buckets and ships using thermometers in their engine in-takes, the increased use of ocean buoys and a large increase in the number of land-based monitoring stations.
“Science can only progress based on as much information as we have and what you see today is the most comprehensive assessment we can do based on all the information that’s been collected,” said Karl. Schmidt called the new observations “state of the art” and said Nasa had been in discussions with Noaa about how to incorporate the findings into their own global temperature record.
Prof Michael Mann, whose analysis of the global temperature in the 1990s revolutionised the field, said the work underlined the conclusions of his own recent research. “They’ve sort of just confirmed what we already knew, there is no true ‘pause’ or ‘hiatus’ in warming,” he said. “To the extent that the study further drives home the fact ... that global warming continues unabated as we continue to burn fossil fuels and warm the planet, it is nonetheless a useful contribution to the literature.”
Bob Ward, policy and communications director at London’s Grantham Research Institute, said the news that warming had been greater than previously thought should cause governments currently meeting in Bonn to act with renewed urgency and lay foundations for a strong agreement at the pivotal climate conference in Paris this December. “The myth of the global warming pause has been heavily promoted by climate change sceptics seeking to undermine the case for strong and urgent cuts in greenhouse gas emissions,” said Ward.
Since scientists began to report a slower than expected rate of warming during the last decade, climate sceptics have latched on to the apparent dip in order to question the validity of climate models.
Last February, US Republican presidential candidate Ted Cruz told CNN: “The last 15 years, there has been no recorded warming. Contrary to all the theories that – that they are expounding, there should have been warming over the last 15 years. It hasn’t happened.”
Cruz’s rival for the Republican nomination, Jeb Bush, was using the pause to argue for inaction as early as 2009.
The Global Warming Policy Foundation (GWPF), the UK think tank set up by Nigel Lawson to lobby against action on climate change and which hosts a flat-lining temperature graph on the masthead of its website, was dismissive of the study.
Dr David Whitehouse, an astrophysicist and science editor for the GWPF, said: “This is a highly speculative and slight paper that produces a statistically marginal result by cherry-picking time intervals.” He claimed the temperature graph was at odds with those of the Met Office and Nasa, despite both organisations saying the new study’s results were consistent with their data.
Is There a Scientific Reason Many Conservatives Hate Science?
Last week, we went through a familiar ritual: Hand-wringing and alarm over Republican politicians denying scientific reality. This time around, the main focus was Rick Santorum, the anti-evolutionist and climate change denier who is one of the worst of the worst in this area (and who promptly obliged by making a new and fresh anti-science statement).
But hey, it's always something.
We've been repeating this pattern at least since the early George W. Bush years. A Republican makes a dubious scientific claim, a Republican officeholder or appointee suppresses a scientific report, a scientist in a Republican administration gets muzzled...the names change, but the story does not. I chronicled it all in a book that is now seven years old--The Republican War on Science--and I wasn't the first.
Nor will I be the last. The very fact that Jon Huntsman (who just nabbed third place in New Hampshire) has been able to successfully frame himself as the "pro-science" Republican candidate itself speaks to the misalignment of his competitors with reality.
Some of the conservative denial of science may well be cynical in nature. But there's no doubt from polls that large numbers of conservatives really believe this stuff--that global warming isn't real, nor is evolution. And indeed, the denial of reality extends well beyond science and into other fields likeeconomics and history.
When you have a phenomenon this recurrent, it seems to me that at some point, it is reasonable to stop and ponder deeper causes. And are there any?
Recently, I posted a list of seven recent scientific studies showing that liberals and conservatives differ in ways that go far beyond their philosophies or views on politics. We're talking about things like physiological responses when shown different kinds of words or images, and performance in neuroscience tests. Take just one recent example: Conservatives show stronger responses to negative and threatening stimuli (words like "vomit" and "disgust"). Could this also prompt more knee jerk reactions to scientific information that is perceived as threatening (or words like "evolution")?
The point is not necessarily that the answer is yes, but rather that it is reasonable to ask questions like these. The root causes of our political differences are now under intensive exploration by multiple different research groups, which are churning out quite a lot of published, peer reviewed science. And while this work is surely not complete (science never is), it is also unlikely to be just plain wrong. Indeed, after having spent the past year reading this research and interviewing the scientists producing it, I can confidently say that those seven studies are just the tip of the iceberg.
Here's the bottom line: An increasing body of science suggests that we disagree about politics not for intellectual or philosophical reasons, but because we have fundamentally different ways of responding to the basic information presented to us by the world. These are often ways of which we are not even aware--automatic, subconscious--but that color all of our perceptions, and that effectively drive us apart politically.
What's more, what is true for how we come to our opinions about politics is also, assuredly, true for how we approach "facts" that are perceived to have some bearing on the validity of our political opinions--whether those facts are scientific, economic, historical or even theological in nature.
Thus far--and not surprisingly--conservatives don't seem so fond of the emerging science of our politics. They seem to consider it demeaning--yet another slight aimed at them by "liberal" academia.
And it's partly true: the research in question is--like all scholarly work--largely conducted by scientists and academic liberals who want to achieve a better understanding of the nature of our political dysfunction, and also of why we are divided over things like scientific reality. But ironically, when considered in all of its complexity and nuance, much of the research actually makes Republicans look very good (decisive, resolute, loyal) relative to liberals or Democrats--and certainly a lot more politically effective.
Frankly, it seems to me that this approach ought to prompt more tolerance and understanding across our political divides, rather than less. After all, if we are reaching many of our political and even our factual opinions for reasons that we're not even conscious of--if we're effectively being pushed to accept some views rather than others, because they resonate at a deep psychological level and just "feel right"--then the only appropriate response, it seems to me, is a deeply liberal one: Tolerance. Understanding. Acceptance. Empathy.
In other words, the next time a Republican denies global warming, liberals ought to be better able to check the impulse to say "what an idiot!" and instead say something like, "I can understand why they have that kind of a response."
But then again, the next time a liberal or Democrat does something typically and predictably liberal, Republicans ought to do the same. And now the paradox: What if liberals are more open to (and simply curious about) the science of liberals than conservatives are regarding the science of conservatives?
If so, then we'll still probably have a factually polarized political arena--but at least we'll know a little bit more about why.