What gives China more power on the Security Council than Brazil or Colombia?
China is a permanent member of the Security Council and has veto power.
G4 countries are a group of 4 countries comprising of India, Brazil, Japan and Germany who support each other's bid for UN security council seat. Currently there are only 4 permanent members of UN security council and G4 countries are bidding to expand it. Currently, there are 5 permanents members of UN security council( UK, USA, China, France and Russia), who is holding veto power.