I wish they had asked these groups what percentage of global warming was caused by mankind instead of trying to manipulate this into something black & white. This gives the appearance that the "researchers" were intentionally trying to skew the result and/or have little or no knowledge of the uncertainties involved.
It's hard to think of a less biased way to ask the question than the researchers did. This survey is actually a good example of how to craft excellent questions. More people should look to it. Your quotations around "researchers" is a poor attempt to discredit them and your accusation of bias seems to have no grounding in reality.
Not only are these questions held constant over time, allowing for a longitudinal analysis, attempting to have lay people quantify a specific amount of climate change attributable to humans would 1.) not provide additional understanding of the topic and 2.) probably confuse those being surveyed. Their way was much better.
The questions asked were simple, which do you agree with:
1. Climate change is happening now, caused mainly by human activities.
2. Climate change is happening now, but caused mainly by natural forces.
3. Climate change is not happening now.
Simple, clear, and easy. That's what you want from a question.
Same goes for the status of the science:
1. Most scientists agree that climate change is happening now, caused mainly by human activities.
2. There is little agreement among scientists whether climate change is happening now, caused mainly by human activities.
If you look at the questions, they keep the wording consistent with only the decisive words being changed. This is a good example of how to make a good survey question. I'm sorry if their well made survey tells you things you don't want to hear.