Various scientists have been challenging the theory of "global warming" / "climate change" with different views.
Here are some examples.
U.S.: Richard Lindzen, Atmospheric Scientist, MIT
U.K.: Freeman Dyson, Fellow of the Royal Society
Greece: Demetris Koutsoyiannis, National Technical University of Athens
Canada: Steve McIntyre, Geologist, founder of Climate Audit
Australia: Ian Plimer, Geologist
Ethiopia: Messele Zewdie Ejeta, Civil Engineer working in the U.S., uncovered associations between Saros cycles and hydrological conditions on earth while trying to address uncertainties in Global Circulation Model outputs.
Please add those scientists that you know of challenging the theory of climate change or trying to address its uncertainty. It may help to infer if a global bias exists in this pool of scientists?