2018 was the fourth warmest year in the global surface temperature record, according to year end updates from NASA, NOAA and the UK MetOffice, albeit somewhat cooler than the 2016 peak. This continues a string of record or near-record annual temperatures, with the top four occurring in the past four years.
As in my previous updates (see here and here), I’ll provide some additional context, highlighting the issue of coverage bias and ongoing Arctic warming. Series that use statistical methods to account for areas with few or no observations, especially in the Arctic, continue to diverge markedly from those with little or no interpolation. Recent observations also show the emergence of a seasonal pattern in Arctic warming, an important aspect of coverage bias that has been less explored thus far. In addition, the last decade or so has seen the emergence of ship-buoy SST bias, first identified in a key 2015 paper from NOAA and confirmed in our 2016 paper.
The recent synchronized update of all four of the most closely followed temperature series (along with the buoy-based SST series from our 2016 paper, Hausfather et al) has inspired a long overdue surface temperature update. First I’ll look at the four global temperature series over the last 35 years, and then examine 2017 in the context of recently identified biases in GMST records.
Over the past few weeks, there has been much discussion of global surface temperatures, as 2016 broke the previous 2015 record in all surface temperature series. Here I will place 2016 in context, highlighting the role of rapid Arctic warming in recent surface temperature evolution as seen in a comparison of four operational data sets. The 2016 increase over 2015 was much larger in the analyses that account for missing areas, especially the Arctic, providing additional impetus to address coverage bias among research groups that still have not done so. I’ll also take a quick look at the growing effect of residual biases from ship-buoy measurement adjustments in sea surface temperature (SST) analyses in recent years, which has led to some additional divergence between the two major operational SST series underlying these four global series.
In retrospect, 2014 was an interesting year for climate watchers, and a turning point of sorts. That year, global mean surface temperature matched record highs for the instrumental period, without any assist from the El Nino weather pattern that usually accompanies such warm years. That turned out to be a prelude to a record-smashing 2015. And 2016 may well provide an unprecedented third surface temperature record in a row, as the influence of the current super El Nino will likely peak in the first half of this year.
But 2014 was also notable scientifically for the emergence of a previously under-examined scientific issue: namely coverage bias in observed surface temperature series, especially the HadCrut4 record issued by the UK Met Office.
This most widely cited temperature series does not account for missing areas, especially in high latitudes, likely leading to an underestimate of the overall rise in global temperature since the 19th century.
Not only that, but there is increasingly compelling evidence that the recent short-term slowdown in the surface temperature record was much less pronounced than previously estimated, if rapid Arctic warming is fully reflected, along with potential biases from the changing mix of sea surface temperature measurement sources in recent years. Thus the discrepancy between very short-term and multi-decadal trends in the observations appears to have been exaggerated in prior estimates, including IPCC AR5.
There has been a big change at WIREs Computation Stats.
In a stunning (but welcome) development, James Gentle of GMU and Karen Kafadar of IndianaUniversity have been named editors-in-chief, joining remaining original editor David Scott.
I last discussed WIREs Comp Stat back in July, when Edward Wegman and Yasmin Said were quietly dropped as editors. I outlined the problems that apparently led to their summary dismissal.
Yes, the Deep Climate blog is finally returning after a hiatus of several months. Over the next few months, look for at least two or three posts per month, as I gradually return to former activity levels. Thanks to everyone for their patience.
Here are some topics that could be discussed on this open thread.
1) Margaret Munro of Post Media has reported on the latest initiative to fight muzzling of Canadian scientists by the Harper government.
Federal Information Commissioner Suzanne Legault is being asked to formally investigate the way the Harper government has been “muzzling” and restricting access to federal scientists.
The request, accompanied with a report [7Mb PDF] on the government’s “systematic efforts” to obstruct access to researchers, was made jointly on Wednesday by the Environmental Law Centre at the University of Victoria and Democracy Watch, a national non-profit group.
2) The IEA Energy Technology Perspectives 2012 report has just been issued, together with a detailed online presentation. In my opinion, this is “must read” for anyone interested in climate policy, and realistic pathways to avoiding the worst effects of climate change. There is, of course, still a yawning gap between current government policies and policies required to limit global warming to about 2 deg C above pre-industrial levels.
3) Russell Seitz has started a very entertaining blog entitled VVattsUpWithThat (yes, that’s a double V!). A recent post discusses the conviction of Heartland Institute science director Jay Lehr for defrauding the EPA in the early 1980s.
The eleventh domino has fallen.
The extraordinary 2012 Arctic sea ice melt has resulted in a September average sea ice extent of 3.61 million sq km, according to the latest monthly data from the National Snow and Ice Data Center (NSIDC), smashing the previous record of 4.30 million sq km set in 2007.
Today, I’ll quickly review the last month’s progression. I’ll then examine the plausible future course of the Arctic sea ice “death spiral” that is likely to see the Arctic virtually free of sea ice by the 2030s if not sooner, culminating with a new graphic representation of the Arctic sea ice death spiral.