From the OP:
Sidbrown, Calliso, and others have debunked the idea in the OP that the petition signers are “experts who have studies” the science of climate change.
Another idea in the OP, that a collection of 30,000 signatures somehow discredits “claims that there is a so-called world wide consensus on the climate issue…”, also needs to be scrutinized.
The National Science Foundation (
nsf.gov) has been tracking, for many decades, the number of degrees granted in science and engineering in the US. From their data, one can conservatively infer that this group of 30,000 represent less than 0.5% of those qualified to sign the petition.
To some, 30,000 may seem like an awesome number, but it is a * tiny* minority of those eligible to sign the petition. Even without taking into account the lack of expertise among the petition signers, one must realize that their number is so small that it provides no basis whatsoever for refuting the idea that there is consensus within this scientific community.