seeing what sticks

The purpose of these sites is to convince people and sway opinion. People who may have heard of the concept of climate change/global warming will search the internet in an effort to inform themselves. In doing so they may stumble upon either of these websites and be treated to a framing of the truth. Anthropogenic Climate Change is an idea so massive in scale and scope that it is to be expected the issue would be debated. And because the data records and computer models show that the waste products of our civilization are altering the very climate, major political and socioeconomic decisions will have to be made. Originally, back in the 1970s, the scientific debate was raging on whether humans were altering the climate and if that was caused by the “greenhouse gases.” This debate meant more research was conducted, then new issues were raised so more research was done (such is the probing nature of science). This continued until about the late 80s early 90s when there was a basic scientific consensus. Of course more specific research continues, just like every other scientific discipline. There is still disagreement about ancillary causes/effects, but just as scientists agree in the premise of relativity or evolution there is still disagreement over the details of anthropogenic climate change.
The best way to evaluate the scientific claims of these sites is to read their references. Many times in “junk science” claims a clever argument-builder will purposefully misrepresent a source in order to build credibility. It takes careful study and a mastery of chemical and physical jargon to properly understand papers on climatology, and while I have been studying these things for my whole undergraduate career, I don’t understand the majority of papers.
I think the Grist site is more convincing because it is much longer, has more citations from more recognizable sources, and does not make purely counter-factual claims without explaining them. It is also hard to find what kind of skepticism the Friends of Science practice, but it seems to be natural variation of the sun coupled with CO2 not being a serious greenhouse gas. The most “credible” skeptics are those that have a set angle and do not throw up every last criticism (even if the criticisms contradict) and see what sticks in the public discourse.