National Oceanic and Atmospheric Administration scientists have found a solution to the 15-year “pause” in global warming: They “adjusted” the hiatus in warming out of the temperature record.
New climate data by NOAA scientists doubles the warming trend since the late 1990s by adjusting pre-hiatus temperatures downward and inflating temperatures in more recent years.
“Newly corrected and updated global surface temperature data from NOAA’s [National Centers for Environmental Information] do not support the notion of a global warming ‘hiatus,'” wrote NOAA scientists in their study presenting newly adjusted climate data.
To increase the rate in warming, NOAA scientists put more weight on certain ocean buoy arrays, adjusted ship-based temperature readings upward, and slightly raised land-based temperatures as well. Scientists said adjusted ship-based temperature data “had the largest impact on trends for the 2000-2014 time period, accounting for 0.030¬∞C of the 0.064¬∞C trend difference.” They added that the “buoy offset correction contributed 0.014¬∞C… to the difference, and the additional weight given to the buoys because of their greater accuracy contributed 0.012¬∞C.”
NOAA says for the years 1998 to 2012, the “new analysis exhibits more than twice as much warming as the old analysis at the global scale,” at 0.086 degrees Celsius per decade compared to 0.039 degrees per decade.
“This is clearly attributable to the new [Sea Surface Temperature] analysis, which itself has much higher trends,” scientists noted in their study. “In contrast, trends in the new [land surface temperature] analysis are only slightly higher.”
Global surface temperature data shows a lack of statistically significant warming over the last 15 years — a development that has baffled climate scientists. Dozens of explanations have been offered to explain the hiatus in warming, but those theories may be rendered moot by NOOA’s new study.
NOAA’s study, however, notes the overall warming trend since 1880 has not been significantly changed. What’s increased is the warming trend in recent decades.
“Our new analysis now shows the trend over the period 1950-1999, a time widely agreed as having significant anthropogenic global warming, is 0.113 [degrees Celsius per decade], which is virtually indistinguishable with the trend over the period 2000-2014‚Ä≥ of 0.116 degrees per decade, according to the study.
The U.N.’s Intergovernmental Panel on Climate Change’s “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,” the study claims.
But that’s not all NOAA did to increase the warming trend in recent decades. Climate expert Bob Tisdale and meteorologist Anthony Watts noted that to “manufacture warming during the hiatus, NOAA adjusted the pre-hiatus data downward.”
“If we subtract the [old] data from the [new] data… we can see that that is exactly what NOAA did,” Tisdale and Watts wrote on the science blog Watts Up With That.
“It’s the same story all over again; the adjustments go towards cooling the past and thus increasing the slope of temperature rise,” Tisdale and Watts added. “Their intent and methods are so obvious they’re laughable.”
NOAA’s updated data was also criticized by climate scientists with the libertarian Cato Institute. Scientists Richard Lindzen, Patrick Michaels and Chip Knappenberger argue the adjustments made by NOAA were “guaranteed to put a warming trend in recent data.”
Cato scientists also argued that NOAA’s new data is an outlier compared to other global temperature records, which overwhelmingly show a hiatus in warming.
It “would seem more logical to seriously question the [NOAA] result in light of the fact that, compared to those bulk temperatures, it is an outlier, showing a recent warming trend that is not in these other global records,” the three scientists wrote.
“Adjusting good data upwards to match bad data seems questionable, and the fact that the buoy network becomes increasingly dense in the last two decades means that this adjustment must put a warming trend in the data,” wrote Michaels, Knappenberger and Lindzen, who is a top climatologist from the Massachusetts Institute of Technology.
Scientists and climate experts skeptical of man-made global warming have become increasingly critical of temperature adjustments made by government climate agencies like NASA and NOAA. Skeptics charge that agencies like NOAA have been tampering with past temperatures to make the warming trend look much more severe than is shown in the raw data.
“It is important to recognize that the central issue of human-caused climate change is not a question of whether it is warming or not, but rather a question of how much,” they wrote. “And to this relevant question, the answer has been, and remains, that the warming is taking place at a much slower rate than is being projected.”
Georgia Tech climate scientist Judith Curry also chimed in, arguing that NOAA excluded extremely accurate sea buoy data in order to erase the hiatus in warming. Curry wrote that it “seems rather ironic, since this is the period where there is the greatest coverage of data with the highest quality of measurements — ARGO buoys and satellites don’t show a warming trend.”
“Nevertheless, the NOAA team finds a substantial increase in the ocean surface temperature anomaly trend since 1998,” she wrote. “This short paper in Science is not adequate to explain and explore the very large changes that have been made to the NOAA data set. The global surface temperature datasets are clearly a moving target. So while I’m sure this latest analysis from NOAA will be regarded as politically useful for the Obama administration, I don’t regard it as a particularly useful contribution to our scientific understanding of what is going on.”