Here's an uncharitable thought - if the money was stopped to these third world countries, there would probably quite quickly, be mass starvation, followed soon after by (un)civil war/mass murder/genocide.
As unpleasant as these things would be, it would be beneficial to the countries involved, and to the world, once things had calmed down. This would be due to reduced population, therefore reduced demands on the resources available, reduced industry (therefore reduction in pollution/global warming).
It would also inevitably create wealth for quite a few morally bankrupt individuals and businesses who would no doubt send arms tl these warring factions.
It can be argued that sending money to these countries is preventing war, famine and pestilence, which is good.
Personally, I think our government would be better served by getting its own house (country) in order first, before it tries sorting everyone else out.