The gamut of natural human reactions to the appalling events we witnessed on September 11th must run their course: shock, grieving, fear of what happens next, and the need to take action to prevent further, even worse, terrorist attacks. There must also be action to deal with the general situation in the Middle East, particularly the need for a just and long-term settlement of Palestinian-Israeli problems, or this region will remain a seedbed of fanaticism.
But beyond these issues, I have another sadness and even greater fear: that the world will forget the even greater threat we all face from global warming. If we do not start to face up to this threat properly, the chaos that will ensue over the next century as half the Earth tries to relocate to find food and water will make these recent events, awful as they are, pale into insignificance.