September 11 was, and remains, above all an immense human tragedy. But September 11 also posed a momentous and deliberate challenge not just to America but to the world at large. The target of the terrorists was not only New York and Washington but the very values of freedom, tolerance and decency which underpin our way of life.
Climate change is probably the greatest long-term challenge facing the human race.
Climate change is the world's greatest environmental challenge. It is now plain that the emission of greenhouse gases, associated with industrialization and economic growth...is causing global warming at a rate that is unsustainable.
Ideals survive through change. They die through inertia in the face of challenge.
When my parents were growing up the world's population was under three billion. During my children's lifetime, it is likely to exceed nine billion. You don't need to be an expert to realise that sustainable development is going to become the greatest challenge we face this century
We need to develop the new green industrial revolution that develops the new technologies that can confront and overcome the challenge of climate change; and that above all can show us not that we can avoid changing our behaviour but we can change it in a way that is environmentally sustainable.
In government you carry each hope; each disillusion. And in politics it's always about the next challenge.
But I am an optimist about Britain; and the difference between an optimist and a pessimist is not that the optimist believes the world is wonderful and the pessimist believes it's beset by challenges; the difference is the pessimist believes we will be defeated by them; the optimist thinks the challenges can be overcome.
A challenge so far-reaching in its impact and irreversible in its destructive power, that it alters radically human existence... There is no doubt that the time to act is now.
In 1997, we faced daunting challenges. Boom and bust economics..... Now, for all that remains to be done, dwell for a moment on what has been achieved.
The blunt truth about the politics of climate change is that no country will want to sacrifice its economy in order to meet this challenge.
As the world transforms, moves closer together, jobs are displaced, and the world of work completely changes the way we live, the way we think. As that revolution goes on around us, it is going to pose political challenges of which immigration is one very obvious one, which are going to be extremely difficult to deal with. But it's like free trade. You know, in the end, if we go protectionist, we'll make a mistake.
People divide into groups where they talk to each other, but don't talk across the divide. And yet most of the challenges we face in the world today are challenges that are to do with trade, with technology, with how you make sure that people are properly educated, reform your health care system.
Follow AzQuotes on Facebook, Twitter and Google+. Every day we present the best quotes! Improve yourself, find your inspiration, share with friends
or simply: