IMHO, the toxic chemicals comparison doesn't work.
For climate change, you have alternatives to raise people's quality of life more effectively and saying that you must prioritize fighting climate change over ... better healthcare, sanitation (avoidance of toxic chemicals!*), nutrition, workforce development, etc. is not really an easy sell because the other paths yield better ROI.
*Edit*
Why? Absurd claims are absurd claims - I have zero doubts about the AGW outline and majority of case and data put forward in the IPCC papers despite never having seen the Gore film nor even living in the USofA.
That is a red flag, regarding almost anything. It's a blind spot.
How do you reconcile arguing it isn't "alarmism" and acknowledging the claims are "absurd"?
You're definitely trying to have it both ways on the issue of whether people have been guilty of promoting alarmism.
To me this is like claiming someone in 1901 was an alarmist for talking about how dumping chemicals into our waterways was destroying them and dumping chemicals out the back of plants was creating polluted toxic ground as they observe increasing numbers of dead fish. And they were right, there are endless numbers of extremely toxic superfund sites and even more that are poorly documented that we know are killing people.