What is the probability that significant global warming is occurring or will soon occur, and is primarily caused by human actions?
There’s no reason to use a vague word like “significant”. I think it would be best to use the formulations that the IPCC uses.
There are two interesting issues:
1) Do people understand the current strength of evidence for climate change?
P(Most of the observed increase in global average temperatures since the mid-20th century is due to the observed increase in anthropogenic GHG concentrations)
2) Future warming:
P(Continued GHG emissions at or above current rates would cause further warming and induce many changes in the global climate system during the 21st century that would be larger than those observed during the 20th century)
Source: http://www.ipcc.ch/publications_and_data/ar4/syr/en/spms3.html
If there’s room for a third question I would also like:
3) P(Average Northern Hemisphere temperatures during the second half of the 20th century were higher than during any other 50-year period the past 1300 years)
Using the same sentence that the IPCC uses has the advantage that we can compare the estimates of people who take the survey with the estimates of the IPCC.
Yes, but including the question that the IPCC doesn’t ask is also important.
Question 1 fails to distinguish between “Increases in GHG are not antropogenic” and “Increases in GHG are not driving the increased temperatures” and “Average global temperatures have not risen since the mid 20th century.” None of those claims lack evidence to support them, although some have less support than others.
Less useful than a more specific question’s answer might be, but not literally useless. There is always going to be a tradeoff between length and specificity, you have to choose somewhere to stop nitpicking.
There’s no reason to use a vague word like “significant”. I think it would be best to use the formulations that the IPCC uses. There are two interesting issues:
1) Do people understand the current strength of evidence for climate change?
P(Most of the observed increase in global average temperatures since the mid-20th century is due to the observed increase in anthropogenic GHG concentrations)
Source: http://www.ipcc.ch/publications_and_data/ar4/syr/en/spms2.html
2) Future warming: P(Continued GHG emissions at or above current rates would cause further warming and induce many changes in the global climate system during the 21st century that would be larger than those observed during the 20th century) Source: http://www.ipcc.ch/publications_and_data/ar4/syr/en/spms3.html
If there’s room for a third question I would also like:
3) P(Average Northern Hemisphere temperatures during the second half of the 20th century were higher than during any other 50-year period the past 1300 years)
Source: http://www.ipcc.ch/publications_and_data/ar4/syr/en/spms1.html
0) P(Most of the observed increase in GHG concentrations since the mid-20th century is anthropogenic)
Using the same sentence that the IPCC uses has the advantage that we can compare the estimates of people who take the survey with the estimates of the IPCC.
Yes, but including the question that the IPCC doesn’t ask is also important.
Question 1 fails to distinguish between “Increases in GHG are not antropogenic” and “Increases in GHG are not driving the increased temperatures” and “Average global temperatures have not risen since the mid 20th century.” None of those claims lack evidence to support them, although some have less support than others.
C’mon. Let people specify their own criteria. If we were this nitpicky about every single question, the survey would be ginormous.
If different people use different criteria to answer the question, the result is useless.
Less useful than a more specific question’s answer might be, but not literally useless. There is always going to be a tradeoff between length and specificity, you have to choose somewhere to stop nitpicking.