How can it matter? really? it can matter because it will be proof of harm. Is't that your requirement?
1. nope, a hard thing to do what with tides and waves and such.
2. Easier, if there is any causality between rising CO2 levels and rising - but what will THAT matter? as with the GMO thing, the horse will be out of the barn and gone.
3. If we don't know enough to do anything but "screw it up more" in this case, how can you presume that we DO know enough not to screw up the GMO thing? the tampering is a hell of a lot more clear in that instance than with global warming.
Well. Good question and linkage in Saganism.
2 - huh? Why do anything but more bald and unbiased research?
3- we don't
So, to me this is the very weird, of Saganism. We don't know anything about climate or GMO, I will grant.
Yet, we know all too much about human nature, greed, the low bid, and atomic power, don't we? And I don't see, even a Gen-4 fission reactor, solving that. Plenty of Gen 1s, still here.
Weird monkeys are chaos. So, we agree on that I think.
But, weird monkey minds cannot suddenly have it both ways, It is not natural. We see proven global poison of the very worst kind, already here, cheered for. Oh ignore these little tipping points in the food chain and in DNA replication, and ignore horror weapons large and small. Cheer for it, as the Sagan, abides thee.
That is the one crazy way. Here is the other. Just ignore the fact that we need these yield increases, at this point of REAL, in the food staples supply of the entire flippin' world.
Just make up fear of climate and GMO tipping points, but you support the proven nightmare of actual tipping points. It is not natural fear, so it is contrived.
Don't you see?

All the rest is just hand waving if you don't acknowledge the risk you support, is much more real.