You can define anything anyway you want, but you are not going to get anywhere if you would like to create some definitions that excludes major critics of established climate science. In fact, I believe that your very use of the word "contrarian" and your proposed definition of it,
"disputing that current global warming is happening and that it results from human activity"
indicates a profound ignorance of climate science and it's constituent parts. You may have -
- scientists who think land use is underrated and CO2 overrated as factors in climate change
- scientists who thing CO2 is a minor factor and natural variations are the major factors
- scientists who believe the asian brown cloud and black soot are the looming threats, compared to which CO2 is not important
- Scientists who believe in the possiblity that man could be changing the climate, but whose work shows little actual effect
- Scientists who refute specific issues of the AGW hypotheses
- glacier retreat natural, not related to AGW
- sea level rise natural, not related to AGW
- land temperature rise based on measurement errors
- unprecedented recent global temperature rise incorrect, past variations in temperature prove that
- greenland not showing a historically unprecedented melt
- arctic ice not showing a historically unprecedented melt
- hurricanes frequency or intensity not related to AGW
- polar bears not threatened by AGW
And many other variations based on the specific subject areas the scientists are working in.