Climate Scientists: Gobal Warming is Real

Those who deny the existence of global warming make much of polls which allegedly show that scientists have grave doubts that the Earth’s climate is warming. Those who tout such polls rarely mention that the scientists being polled are, by and large, not climate scientists. One might as well ask a plumber whether he thinks that mole on your shoulder could be cancerous…

What happens when climate scientists are polled? The so-called “controversy” vanishes, that’s what…

In 1991 the Gallup organization conducted a telephone survey on global climate change among 400 scientists drawn from membership lists of the American Meteorological Association and the American Geophysical Union.

We repeated several of their questions verbatim, in order to measure changes in scientific opinion over time. On a variety of questions, opinion has consistently shifted toward increased belief in and concern about global warming. Among the changes:

• In 1991 only 60% of climate scientists believed that average global temperatures were up, compared to 97% today.
• In 1991 only a minority (41%) of climate scientists agreed that then-current scientific evidence “substantiates the occurrence of human-induced warming,” compared to three out of four (74%) today.
• The proportion of those who see at least a 50-50 chance that global temperatures will rise two degrees Celsius has increased from 47% to 56% since 1991.
• The proportion of scientists who have a great deal of confidence in our understanding of the human-induced sources of global climate change rose from 22% in 1991 to 29% in 2007. Similarly, the proportion voicing confidence in our understanding of the archeological climate evidence rose from 20% to 32%.
• Despite these expressions of uncertainty, however, the proportion which rating the chances at 50-50 or better that the role of human behavior will be settled in the near future rose from 47% in 1991 to 69% in 2007. 

The moral of the story: If you want to know what the experts in a field think, ask the experts in that field... not experts in some random mish-mash of other fields.

(hat tip: Deltoid)