37 billion eggs in one basket

http://articles.news.aol.com/business/article.adp?id=20060625161409990005&ncid=NWS00010000000001

So Warren Buffet has decided to begin giving away his fortune during his lifetime contrary to previos plans of waiting till his death. Personally, I think that the projected larges charitable gift in history is fabulous but not necessarilly well planned. The way it is set up, Buffett will give a fixed amount to the Gates foundation and his children's foundations yearly. Each year however, the donation will decrease by 5%. Of course if the stocks of his company raise in value, it could offsett or surpass the 5% decrease. The foundation would then have to annually spend the dollar amount of Buffett's donation. This donation will be made every year that either Bill or Melinda Gates are active in their organiation.
I think this is amazingly generous. The man is basically giving away 95% of his fortune. I just don't think that giving that large amount of money to 5 or so organizations is really wise. For instance, the Gate's foundation focuses on stopping the spread of HIV/AIDS, teburculosis, malaria and improving the nation's libraries and High schools. Very noble enterprises. But what happens if another major crisis happens? (IE Ebola becomes airborne, a major blight strikes the US and many of our food suppliers, a major depression hits and 30% of our populatoin becomes homeless etc) Shouldn't there be some sort of saftey fund for something HUGE and urgent that couldn't otherwise be addressed? I suppose there is always the government and anything this major probably would get official attention. I guess it just makes me nervous to have so much money in one place. But Warren Buffett is the financial genious not me so he probably knows what he's doing.