NEW HAVEN: In the aftermath of the terrorist attacks of September 11, the effect of globalisation on Islam has emerged as a hotly debated topic. With twenty percent of the world's population professing Islam as their religion, it is a matter of more than academic interest. A survey of the evolution of Islam in recent decades shows that ummah - a universal community based on shared Islamic faith and implementation of its law - has indeed become a greater reality in an ever-shrinking world. At the same time, globalisation has also allowed divisive militancy to arise and flourish. In the years to come the force of globalisation may lead to the emergence of multiple centres of Islam rather than the current one based in Saudi Arabia Islamic historians have credited the concept of ummah as an important contributing factor in the rise and development of Islam and Islamic civilization. The evidence from various studies shows that although Muslims share a sense of being part of a global ummah, the intensity of this feeling varies significantly across Muslim countries.