An increase in global temperature required to match the Intergovernmental Panel on Climate Change (IPCC) projections is becoming increasingly unlikely. A shift to a mean projected pathway of 3 degrees increase by the end of the century would require an immediate, large, and sustained increase in temperature which seems physically impossible.
Global surface temperatures have not increased at all in the last 18 years. The trend over the last few years is even falling slightly.
Global temperatures continue to track at the low end of the range of global warming scenarios, expanding a significant gap between current trends and the course needed to be consistent with IPCC projections.
On-going international climate negotiations fail to recognise the growing gap between the model projections based on global greenhouse emissions and the increasingly unlikely chance of those models being correct.
Research led by Ben Santer, compared temperatures under emission scenarios used to project climate change by the (IPCC) with satellite temperature observations at all latitudes.
“The multimodel average tropospheric temperature trends are outside the 5–95 percentile range of RSS results at most latitudes.” reports their paper in PNAS. Moreover, it is not known why they are failing.
“The likely causes of these biases include forcing errors in the historical simulations (40–42), model response errors (43), remaining errors in satellite temperature estimates (26, 44), and an unusual manifestation of internal variability in the observations (35, 45). These explanations are not mutually exclusive.”
Explaining why they are failing will require a commitment to skeptical inquiry and an increasing need to rely on the scientific method.
The unquestioning acceptance of projections of IPCC climate models by the CSIRO, Australian Climate Change Science Program, and many other traditional scientific bodies that has informed policies and decisions on energy use and associated costs must be called into question. So to must the long-term warming scenarios based on the link between emissions and increases in temperature.