What understanding of the so called science does the enviro left comprehend about global warming?

Well...polar bears are drowning, but not because of sea level rise, it's because the ice packs are shrinking rapidly...but that's neither here nor there...Science is all based on data, which can be collected, peer-reviewed, and verified...conclusions can then be drawn from that data...nobody seems to argue about the data...it's all there...temps are rising...ice is shrinking, etc, etc...one group(deniers) just happen to interpret the data in a different way, or believe that man has nothing to do with it...regardless of evidence to the contrary.