Now, it's one thing what happens in the controlled environment in the laboratory and what happens in the far more complicated natural environment. There are a lot of competing factors and you have use statistical models and see which best fit the data. This involves an inevitable degree of uncertainty, which you might exploit to cast doubt on the explanation that climate change is man made.
Thus, the question is: Should we continue to increase the carbon imprint because we are not 100% sure that it does have an impact? Based on the lack of 100% uncertainty, should we DENY that there is an impact?
Tell me, why is it that insurance companies are so extremely concerned about climate change?