A new Met Office report: Big changes underway in the climate system? released this week, is a textbook example of poor science communication.
The report is described as new research. It isn’t. It pretends to be an even-handed assessment of current science, but in reality ties itself up in contradictions whilst trying to imply it knows more than it actually does. It presents a patina of confidence in its ability to advise on what may happen in the future, but can’t bring itself to state clearly the obvious conclusion of the science it surveys. That is, no one knows what will happen to global temperatures in the near future.
The background to the report is that this year is bound to be the warmest year of the instrumental record as far as global annual average surface temperature goes. The main reason why it has poked its head above over 15 previous years of little change – the so-called “hiatus” – is not due to a resurgence of anthropogenic global warming but due to two events, particularly the El Nino that tried to start last year, faltered and is underway right now, coupled with a hot spot – the so-called “Pacific blob.” 2015 will be warm and probably 2016 will be as well. Afterwards it is quite possible that a La Nina will cool the globe, as usually happens after an El Nino.
The “new research” turns out to be a literature survey along with a commentary. The literature included is selective, the commentary contradictory. The Met Office says a better understanding of the slowdown is needed in order to “confidently predict its end.”
There are over 30 explanations for the slowdown or “hiatus.” The report, however, focuses on the decadal changes in the Pacific and Atlantic as key players. We know very little about these important oceanic cycles, but a little more than we did a decade ago. This makes looking back at earlier predictions by the Met Office, especially those confidently made, a humbling experience.
The report’s habit of thought is established early. It says that oceanic cycles can counter or exacerbate global warming, but not, it seems, account on their own for the warming seen in the 1990s even though it could be within their ability. The Met Office also says solar activity and volcanic aerosols could “potentially reconcile” the difference between observations and model simulations during the slowdown. I wouldn’t bet on it.
Key to the uncertainty that prevents decadal predictions is the inability to distinguish between rare natural events and a greenhouse gas forced component of the climate system. No one knows if the so-called Pacific blob, or the increased trade winds in the Pacific, are natural or have an anthropogenic influence. But the approach is to treat them as though they might even though there is no real evidence more substantial than a hunch. The phrase used but not regarded is, “not fully understood.”
“Temperatures are rising rapidly”The report was presented to the media by Dame Julia Slingo.
She was appointed chief scientist to the Met Office in February 2009. Her role involves representing the Met Office across government, speaking publicly and overseeing the service’s scientific and technical strategy.
Commenting on the warmth of 2015 and its possible continuation into 2016 due to the El Nino (which the report says is a “temporary natural warming”) she said the global temperatures were, “absolutely in line with what we predicted at the end of last year that this year could well be if not the warmest then one of the very warmest.”
Let’s look at that 2014 prediction. It was that the global temperature anomaly for 2015 would be between 0.52 – 0.76°C. This means that the Met Office prediction would have been proven correct if 2015 had been cooler than 2014, 2010, 2005 and 1998, or 0.19°C warmer than 2014. Currently 2015 is about 0.12 C warmer than 2014 so the prediction is spot on! It could hardly have been otherwise.
Dame Julia said, “they are consistent with a return to rapid warming in the future.” No they are not. Remember the report said it needed to understand the slowdown (which it doesn’t) to “confidently” predict its end, which it can’t. She also added, “Big changes are underway in the climate system…We’re warming again, very much so.” To Sky News she claimed, “global mean temperatures are rising quite rapidly. However these claims do not match the data. One or two year’s numbers, linked by the Met Office too “temporary natural warming,” cannot be reconciled with such misleading statements.
What are the public and the politicians to make of the report and such remarks? I expect they will come away with the impression that the pause has ended and surface global warming is now accelerating again. This is a failure of science communication which could backfire soon. Sometimes the only thing to say, and say so clearly, is “we don’t know.”
Dr David Whitehouse is the Science Editor at the UK based Global Warming Policy Fourm to www.thegwpf.com.