In a comment made 7:09 PM on January 5, 2012 to an article titled “Natural-gas plans threaten greenhouse-gas targets” http://www.theglobeandmail.com/news/national/british-columbia/bc-politics/natural-gas-plans-threaten-greenhouse-gas-targets/article2291990/comments/ “GlynnMhor of Skywall” claimed “All four of the major global temperature datasets show how temperature increases have stalled over the past decade, and those are actual facts … And no CO2 dataset that I am aware of fails to show the monotonic year-over-year increases at the same pace as seen during the late 20th century warming period.“
This was stated with his usual innumerate eyeballing of 4 low resolution sites, ignoring two of the most dependable – NCDC and RSS. So I have prepared a mathematical assessment. The graphs and analysis follow.
The first graph shows both the RSS (lower troposphere) and NCDC combined land and ocean temperatures since 1979, the first year for satellite data. Both graphs show monthly values, which are very noisy and subject to seasonal changes but I also included a floating 12-month average to filter out seasonal differences.
RSS and NCDC Global temperatures since 1979. Click on the image for a full-sized copy.
The second shows the “residuals”, the difference between the measured temperatures and the least-squares fitted line. They represent acceleration and deceleration in warming. Please note the acceleration between 2000 and 2008, a period which he and many others have called a cooling period. Wrong. The linear increase is continuing although subject to the usual noise experience in the past.
What should be obvious is that the period 2002 to the present is very little difference from past variability, especially that described by Swanson, Tsonis et al (see my “Cooling Myth” page under the “Editorial” section. That variability is caused by chaotic interactions among the main ocean currents, e.g., El Niňo and La Niňa. I find it very interesting that the period 2000 to 2008 did not show a cyclical drop like those seen before 1999. There have been two La Niňa since, however, bound to see a return to the usual cycles.
In addition, the recent solar cycle was slow but seems not to have had a major impact. There are studies, however, reported on my website showing that volcanic activity and aerosol production by increased burning of coal have had some cooling impact but that is transient; aerosols have a relatively short life in the atmosphere so we should probably expect a return to rapid warming. Those of you who reject the idea that CO2 is the dominant cause of warming should visit my “Greenhouse Gases” page in the “Science” section.
Another conclusion which I draw, from the second graph is the the rate of change is currently negligible and has been for decades, with trivial acceleration at the surface and similarly in the lower troposphere.
GlynnMhor has some favourite unsubstantiated theories but they remain as conjecture until we see legitimate scientific studies related to his confirmational bias. As a seismic engineer in the fossil fuel industry I have had expectations that he could do some math and statistical analysis but that remains absent from his comments. He has often refused to visit my site and continues to make claims which are refuted by evidence. Of course he won’t see these graphs or analysis unless he visits. Here are the URLs:
ClimateInsight 