You keep saying that, but do no explain why. I do not buy that scientist/engineers cannot quantify man's by-products?
No numbers means not objective. If Man made influences are as significant as some claim, why are they so hard to quantify. Could it be that the "noise" (non man caused factors) is so great that the "signal" (man caused factors) cannot be measured? How is it the we can "know" CO2 is a green house gas and rank it compared to other green house gases and yet cannot quantify the actual amount of green house effect?
Having followed the "debate" since the 80's. IIRC a number of issues were deemed unable to quantify have been at least partially quantified.
Lots of unknowns. Do you know how much heat an industrialized nation is putting into the atmosphere? Every industrialized nation since the onset of the IR? How about you, do you know how much you are changing the planet? How about nuclear blasts? Sure we can make guesses, form an hypothesis and that's what we do. But how do we know if the planet is heating or cooling on its own to add or subtract the effect of man's involvement? The industrial revolution is only a few hundred years old, we need more time to build our theory but that doesn't mean we aren't formulating what we see objectively.
What science does is observe facts and form an hypothesis about those facts, as new facts come in the hypothesis becomes more refined. When our hypothesis holds up for many conditions we call it a theory: The Theory of Gravity, for example.
No numbers mean no objective? Not true, we can use logic to establish an objective assessment:
Objects fall down not up, gravity must be pulling them toward the earth and not repelling them away from the earth.
That's an objective assessment not a subjective one without numbers.
Rob