I'm surprised that France is above us, but Brazil is simple maths. A large population with high levels of unexploited natural resources means they'll sky rocket. We'll be overtaken by India within a few decades too.
GDP figures are misleading - they don't reflect standards of living or wealth distribution at all. In those terms, countries like China and Brazil are far behind us, but we rank even farther down those lists - behind many other European countries. As Eric hinted at, each one of these lists is almost meaningless when viewed alone. Take a look at these:
List_of_countries_by_GDP_per_capita
List_of_countries_by_GNI per_capita
And even then; wealth share is skewed within a populous.