Why on Earth do I think that Capitalism will cause Human extinction?

From the discussion on superbanker Lietaer's video at Naked Capitalism.

A commented by the name of BT London asked me (under a previous comment by me):

Why on earth do you think ‘the system’ is going to kill ‘Humandkind’? This is ludicrous hyperbole.

There were some other answers, surely very valid, but just for the record, this was mine (after a minor typo correction):

Mostly because the ecology of planet Earth is collapsing (global warming, nuclear catastrophes, depleted oceans, deforestation madness, widespread growing pollution, Monsanto-made destruction of soils, overpopulation). It may still be soon enough to contain such collapse but I’m already despairing admittedly. 

No hyperbole here at all: either we destroy the (Capitalist) system or it will destroy us (and most other species). Earth will stay and maybe life will flourish again in due time but without us humans. 

We have most unusual capacities for an animal species but we are clearly not at the level of collective responsibility that such capacity demands. A few may be but most aren’t and certainly the powerful are against Earth in almost every single case. 

But without Earth’s life support we are nothing and there’s no colony in Mars to run away to in the foreseeable future, mind you.

Today’s alternative is Ecosocialism or extinction.