Response to a Climate Science Skeptic

Climate science skeptics often post comments on Facebook pages in an effort to disseminate their skepticism.  The following post was recently made to the page of a friend. I was invited to respond to the comment. Herewith, following the post in question, is my response.

Kurt Hanke
All based on the phony notion that CO2 is driving runaway global
warming. There were several periods, thousands of years earlier in
this interglacial that we live in, where earth’s temperature was
warmer than it is today, and yet atmospheric CO2 levels were lower.
CO2 cannot possibly be a potent driver of global warming when this the
case! Think about it – if CO2 is the primary driver of global warming,
then during the Medieval period, the Roman period, and thousands of
years before that, when temperatures were warmer than today – CO2
levels should have also been higher than today, but they were not! CO2
levels back then were lower by at least 100 ppm. In addition, the
estimates for the climate sensitivity of CO2 have dropped rapidly as
alarmist climate models deviate more and more from observed data – as
the graph below shows. Therefore all the fear mongering about carbon
is the scam of the century, and they have suckered you into pushing
towards eliminating carbon-based fuels altogether, which means
significantly weakening our economy, which is a petroleum-based
economy …. and that is really the end game for these leftist freaks.
They hate the US.

These comments essentially make four claims which I will deal with in sequence:

1-There were several periods, thousands of years earlier in this interglacial that we live in, where earth’s temperature was warmer than it is today

2- Estimates for the climate sensitivity of CO2 have dropped rapidly

3 -Alarmist climate models deviate more and more from observed data

4-Climate scientists and climate activists are leftist freaks who hate the US.

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