What does "They" refer to?

Many present efforts to guard and maintain human progress, to meet human needs, and to realize human ambitions are simply unsustainable - in both rich and poor countries. (a)They draw too heavily, too quickly, on already overdrawn environmental resouce accounts to be affordable far into the future without bankrupting those accounts. (b)They may show profit on the balance sheets of our generation, but our children will inherit the losses.

In the above, what does each "They" refer to?

(Regarding (a), is it "Many present efforts" or "both rich and poor countries"?)

Thanks a lot.