Representative Lamar Smith of Texas U. S.
In truth, both articles find that warming has continued during this period, contrary to Rep. Smith’s characterization of this period as a “halt” in global warming. The new article finds that the warming during this period is a “slowdown” (compared to predictions from climate models), but not a “halt”, and thoroughly analyzes the reasons for the slowdown. An important contribution comes from the decades-long cyclical operation of the Interdecadal Pacific Oscillation.
Representative Smith is wrong in saying that global warming has halted. The newest global annual average temperatures for 2014 and 2015 have resumed increasing; that for 2015 is a pronounced record high. Warming continues unabated, even if Representative Smith won’t admit to this reality.
In a speech on the floor of the U. S. House of Representatives on March 21, 2016, Representative Lamar Smith of Texas stated “Americans deserve all the facts that surround climate change, not just those that fit the view the national liberal media wants to promote.” He disparaged the media for covering a scientific study by the National Oceanic and Atmospheric Administration (NOAA) last year (which he did not identify further) that refutes earlier work characterizing a recent decade-long period as showing what he called a “halt in global warming”. Rep. Smith then cited a new “study published in the journal Nature [that] confirms the halt in global warming” (again not identified by author or title). He stated “[a]ccording to one of the study’s lead authors it ‘essentially refutes NOAA’s study’”, and called out the media for not covering this new result.
This writer presumes that Rep. Smith was referring first to the publication by Thomas Karland coworkers at NOAA and other research institutions, published in the peer-reviewed journal Science in June 2015. Contrary to Rep. Smith’s claim that the “scientists altered global surface temperature data to try and refute the two decade halt in global warming” (emphases added), Karl and coworkers carried out a rigorous reanalysis of existing, freely available, temperature records going back to 1880, and included new data from 2012 to 2014 that had not been previously analyzed. They concluded “based on our new analysis, the IPCC’s [Intergovernmental Panel on Climate Change] … statement of two years ago – that the global surface temperature ‘has shown a much smaller increasing linear trend over the past 15 years than over the past 30 to 60 years’ – is no longer valid.” Rather, they found that the rate of warming of the world's atmosphere during 1998 to 2014 has continued unabated compared to the warming experienced in earlier decades.
It is important to note that Karl and coworkers did not “alter” temperature data in their reanalysis, but rather applied corrections to account for earlier systematic errors in certain of the datasets used. Further, they were not trying to “refute the [so-called] halt in global warming”, contrary to the accusation of Rep. Smith.
Rep. Smith states that a new study published in Nature refutes the earlier NOAA findings. This writer presumes he was referring to the publication by Fyfe and coworkers (Nature Climate Change 6, 224–228 (2016); doi:10.1038/nclimate2938; Published online 24 February 2016). Contrary to Rep. Smith’s assertion, Fyfe and coworkers do not “confirm the [so-called] halt in global warming”, nor do they “refute” Karl and coworkers. Fyfe and coworkers not only reexamined the global mean surface temperature records available, they also examined potential drivers of the observed trends.
- They found that the data analysis carried out by Karl and coworkers, as well as by other groups, showed that a “warming slowdown is thus clear in observations; it is also clear that it has been a ‘slowdown’, not a ‘stop’.” (Emphases added) That is, contrary to Rep. Smith, this new work does not “confirm the halt in global warming.” (Emphasis added)
- Referring to the work of Karl and coworkers, Fyfe and coworkers write “[r]ecent research that has identified and corrected the errors and inhomogeneities in the surface air temperature record is of high scientific value.” This appreciation of the work of Karl and coworkers contradicts Rep. Smith when he dismisses the validity of their work.
- Fyfe and coworkers write that the issue of “[h]ow unusual a period of reduced warming is, depends strongly on its length.” The actual rates of warming are highly sensitive to the choices made for the length of time considered, and for the starting points and end points of the warming interval.
- Fyfe and coworkers call the recent period, 2001-2014, a “slowdown” largely because the observed temperature trends for this period fall below modeled predictions for the period made by extending assumptions made for earlier decades into the recent period.
- The authors point out that man-made contributions to warming did not cease during the slowdown. Rather they ascribe the slowdown largely to internal variations in factors that affect climate, including the large contribution arising from the operation of the cyclical decades-long Interdecadal Pacific Oscillation (IPO) (as well as certain other variations). The IPO was in its thermally negative phase during the slowdown period. This was sufficient to counterbalance part of the man-made warming always present. Being cyclical, when the IPO reenters its positive phase, warming from the IPO will supplement man-made warming, leading to stronger increases in global average surface temperatures once again.
It is concluded that Rep. Smith’s characterization of the last 15 years of global temperature data as one in which global temperature increases have “halted” is oversimplified and mistaken. We agree that, in his words, “Americans deserve all the facts that surround climate change.”
The global average atmospheric temperature continues to increase, reaching record levels. The U. S. National Aeronautics and Space Administration reports that 2015 was the hottest year on record covering the 135 years from 1880. The land-ocean average was 0.87ºC (1.57ºF) above an average baseline for about 1950 to 1975. For 2014 that value was 0.74ºC (1.33ºF) above the average.
The Climate Research Unit of the University of East Anglia UK
NOAA also reports that 2015 was the warmest year on record, advancing 0.16ºC (0.29ºF) from the previous year, which itself was a record. NOAA’s graph of annual temperature differences from the 20th century average is shown here
Land and ocean average annual temperature deviations, for 1880 to 2015, from the reference, the average for the 20th century,. Left vertical axis in ºC; right vertical axis in ºF. Blue, annual temperature is below the reference average; red, annual temperature is above the reference average.
The image above shows that the land and ocean annual average temperature has been increasing consistently and dramatically since about 1950. There clearly is no “halt in global warming”, contrary to the floor speech given by Rep. Smith. Indeed, the rise from 2014 to 2015 is remarkably large.
Conclusion
Rep. Lamar Smith of Texas
The increased atmospheric burden of carbon dioxide is critical, because once this gas enters the atmosphere it remains resident for centuries or longer (about one-third is absorbed by the waters of the oceans). Although humanity strives to reduce the annual rate of further emissions of GHGs, such efforts cannot reduce the total amount of GHGs already present. This means that the extent of warming we are already experiencing cannot be reversed. The average global temperature will continue increasing until annual emission rates approach zero. The efforts of those who seek to lull us into a false sense of climate security are for naught; the scientific truths embedded in the global warming issue cannot be reversed simply by willing them so.
© 2016 Henry Auer
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