Though the science of climate change is complex, the facts are simple: our world is heading toward trouble. I saw this last year when I visited the Antarctic, where age old ice is melting much faster than we originally thought it would.
Left unaddressed, climate change could cause an unravelling of the progress that has been made toward achieving the Millennium Development Goals, and could also have serious implications for peace and security. Unless we make radical changes in the way we live, by the time the youth of 2008 reach my age, the world may well have become a rather inhospitable place.
The theme for this year's observance of International Youth Day is "Youth and climate change: time for action." Today's young people will bear the consequences of climate change, thanks to the unfortunate legacy of their elders. In many developing countries in particular, youth - especially girls and young women - are often responsible for farming, finding water and collecting fuel wood. These tasks will be rendered more difficult - and will take even more time away from education or productive activities - as climate change affects the availability of water, agricultural productivity and the survival of ecosystems.
Yet young people are also well placed to contribute to the fight even now. They are adept at spreading new habits and technologies. They are adaptable and can quickly make low-carbon lifestyles and career choices a part of their daily lives. Youth should therefore be given a chance to take an active part in the decision-making of local, national and global levels. And they can actively support initiatives that will lead to the passage of far-reaching legislation.
We will need the spirit of youth in abundance as the world seeks to embrace cleaner, more sustainable forms of energy, including renewable resources. The transition to a low-carbon economy that we hope young people will see in their lifetimes offers tremendous opportunities. Not least, economic growth that is fuelled by clean energy and technological innovation will create jobs that could help alleviate the dire global problem of youth unemployment.
On this International Youth Day, I urge young people around the world to invest their energies and bright ideas into shaping a safer, more sustainable planet.
Ban Ki-Moon is the secretary general of the UN