The world had endured a "terrible and gruelling" past decade, the Archbishop of Canterbury said in a New Year message Friday that called for cooperation to tackle issues like extremism and global warming.

Dr Rowan Williams, leader of the world's 77 million Anglicans, added though that people should not give up on the "hope for change" or "shrug our shoulders and lower our expectations".

It had been a "terrible and gruelling 10 years in all kinds of ways", he said, stressing the global nature of many of today's concerns.

"The truth is that there are fewer and fewer problems in our world that are just local.

"Suffering and risk spread across boundaries, even that biggest of all boundaries between the rich and the poor. Crises don't stop at national frontiers.

"It's one thing that terrorism and environmental challenge and epidemic disease have taught us."

Dr Williams urged people to push their governments to change the world for the better, for example by tackling poverty.

"We've seen some signs of change; we can make more, by supporting efforts to help children out of poverty across the world -- and locally as well -- by campaigns to protect our environment, by keeping up pressure on our governments," he said.

"We share the risks. The big question is, can we share the hopes and create the possibilities? Because it's when we do share the hopes that we really see what it is to belong together as human beings."

Dr Williams's New Year message was pre-recorded and broadcast on the BBC on New Year's Day.