A change has come to the world. Barack Obama's inauguration as the 44th president of the United States has ushered in a new age. Exactly what this means is difficult to define and where we are headed is uncertain. What is clear is that a seismic shift in history is under way and riding on it are our highest hopes. Driving our expectations are a series of global crises, foremost among them the financial meltdown, climate change and terrorism. Mr Obama is taking office promising to deal with each. He has no top-level leadership experience and we have nothing but his rhetoric and high-profile cabinet choices to assure us. But there is no getting away from it - he is a breath of fresh air. None of his predecessors in the past few decades has taken office amid so much hoopla. Some 79 per cent of respondents to a recent New York Times/CBS News poll were optimistic about the Obama presidency; 2 million people turned out in Washington to celebrate his swearing in. Never before has that happened. There is good reason for the euphoria. Mr Obama, his wife, Michelle, and their two young daughters are the first African-American family to occupy the White House. Racial barriers have come down, although they have not been shattered. Nonetheless, for minorities in the traditionally Anglo-Saxon United States, there is now renewed belief in the tired old cliche about the American dream - that anything is possible. The world over, people of minority ethnic, religious and social groups sense change. The dawning of the Obama era is a turning point for us all. There are echoes of Bill Clinton in him, but he is even more charismatic. Those old enough recall John F. Kennedy, with whom he shares the same grace and sense of humour, and a bearing that borders on that of a movie star. He has the oratorical skills of civil rights leader Martin Luther King and the intelligence of Theodore Roosevelt. His speeches and writings - two autobiographies chief among them - are compared to those penned by Abraham Lincoln. Not since the Kennedys has there been so young a family in the White House. But it is his background that is the most compelling reason why we should put our faith in him. His upbringing is full of tragedy - hurdles that should have kept him down, mired in poverty. He overcame each hurdle and bounded ahead; he is now the most powerful person in the world. There is no certainty that Mr Obama will be a great president. Global hostilities, racial, cultural and religious divisions and economic problems will not end or disappear simply because of who he is or what he says and does. His pledges may turn out to be nothing more than rhetoric. But with his inauguration, the US and the world have a chance for a new beginning. Given the challenges, this is an opportunity we should embrace.