Green line is Hansen’s GISStemp overlaid on Hansen’s 1988 forecasts. Scenario C assumes no CO2 emissions after the year 2000. Temperatures are lower than that scenario, which would imply that increasing CO2 has essentially no effect on the global temperature.
Richard Muller believes that Hansen’s temperature record is accurate, which would mean that the headline below is exactly wrong.
AgainstFor Global-Warming Skepticism
What about poor station quality? Again, our statistical methods allowed us to analyze the U.S. temperature record separately for stations with good or acceptable rankings, and those with poor rankings (the U.S. is the only place in the world that ranks its temperature stations). Remarkably, the poorly ranked stations showed no greater temperature increases than the better ones. The mostly likely explanation is that while low-quality stations may give incorrect absolute temperatures, they still accurately track temperature changes.
When we began our study, we felt that skeptics had raised legitimate issues, and we didn’t know what we’d find. Our results turned out to be close to those published by prior groups. We think that means that those groups had truly been very careful in their work, despite their inability to convince some skeptics of that. They managed to avoid bias in their data selection, homogenization and other corrections.
Global warming is real. Perhaps our results will help cool this portion of the climate debate. How much of the warming is due to humans and what will be the likely effects? We made no independent assessment of that.
Mr. Muller is a professor of physics at the University of California, Berkeley
hansen\s zero emissions scenarios