"Global warming or global climate change" would seem to be not
the issue. Our world is faced with climate collapse. On a global
scale. Surely IF our planet's climate collapses, arguments about
'warming' or 'change' would be irrelevant. If the "computer model"
propaganda won't fit, we will have to acquit for parts heretofore
unknown.

Climate collapse is the correct term as the earth's ecosystems relate to current life forms, including humankind. And if we fail to mitigate dramatically what is unfolding at a faster pace than previously predicted, everything else will become a moot point.

Nature and the universe will continue on according to the pretty clearly understood essential laws of nature, with or without us. Pity we aren't more committed to staying along for the ride, or at least leaving that option for our grandchildren.

The delayers and deniers desperately need to get a clue regarding the reality-based world. At least Obama, unlike his predecessor, values and has a grasp of facts, logic, and empirical reality.

'American Leadership' isn't so much the point. That's a very self flattering interpretation of something much more banal.

It is about US participation, not leadership. Without US participation international initiatives on climate change will fail. Period.

That has not so much to do with lack of US leadership but with matters or mere feasibility. In a globalised world everybody competes with everybody, including the US. Cutting carbon emissions costs money. There is no sense in implementing unilateral (say European) cuts on carbon when the biggest emitter abstains and by the way gets itself a competitive advantage of not having to pay for reduced emissions, while the others do.

In light of that it is very unpersuasive for about everybody else, especially the developing nations, to impose on themselves burdens the US shirk.

I respectfully disagree with Sigmar Gabriel. The science doesn't
support the agenda you are promoting.