Fair point, but please let me clarify somewhat.
Dane Wigington has a consistent record of mishandling science to make his case, cherry picking information, citing it out of context, or the like.
His use of Vandana Shiva reminded me of the Arctic methane emergency topic that periodically appears on geoengineeringwatch.org. To support his point, for years Wigington has referred to research published by Natalia Shakhova.
http://www.geoengineeringwatch.org/tag/shakhova/
http://www.geoengineeringwatch.org/...geoengineering-cure-that-is-fueling-the-fire/
However, a careful read of her work does not support any of Wigington's alarming claims.
When I engage in conversations with chemtrail believers, I try to find out just how much they have actually read when citing scientific work like this. To me, it seems that the disparity between what a scientific article or paper actually says and what it is presented as on sites like geoengineeringwatch.org or naturalnews should speak for itself.
Unfortunately, I often find that they haven't read anything whatsoever. They seem satisfied that Dane Wigington, or Russ Tanner, or whomever has provided an accurate summation. Further investigation on their part is unnecessary. The conversation then tends to devolve into a Gish Gallop, with "look at the sky" as an inevitable counterargument.
The source of credibility, the real "argument from authority" is not science, but the gatekeepers within the chemtrail community. Faith in Wigington, Tanner, Mangels, etc. is adequate "evidence" for most followers. I think that might be why arguments made with hard data and rational systems of thought are so difficult to make.
I hope that I am wrong about that.