Sentences with phrase «observational evidence yet»

However, recently published scientific papers contravene this approach and indicate that (a) we just don't have substantial observational evidence yet to attribute cause to a the rise in methane, (b) methane emissions may not have increased recently after all, and (c) human activity (fossil fuel consumption) has not been the «dominant factor» driving the (assumed) increase in methane.

But now one of the teams involved in the debate has produced the best observational evidence yet that there is more to red shifts than meets the eye.

Not exact matches

Although no observational evidence has yet been found for such structures, this remains an active area of research, in which interest has revived since it was discovered that very similar objects would be predicted by many cosmological scenarios based on fundamental string theory.

Scientists have hypothesized for decades that these collisions could serve as a primary source for these heavy elements, yet the idea had lacked solid observational evidence.

I don't think there is any robust observational evidence of a strong positive cloud feedack, either, yet all the models cited by IPCC assumed a strong positive feedback despite this.