Monday10th March is Commonwealth Day. For two billion Commonwealth citizens, it is a day to share and a day to celebrate.

Yet to share is not always to celebrate. Our theme this year, The Environment ...– Our Future, reminds us that we have a responsibility to share all that is good about the environment today with the generations of tomorrow. If we forget about future generations today, they will never be able to forget - or to forgive - what we did to them, tomorrow. To bequeath a barren and polluted landscape is to disinherit.

The science is clear: our current exploitation of this planet's environment is unsustainable. We can...’t move away from the problems we have created, or wish them away. To carry on unchanged is not an option. More than 50 years ago, Mahatma Gandhi said, "There is a sufficiency in the world for man...’s need, but not for man...’s greed". Today, we cannot be certain that there will after all be a sufficiency for humankind's basic development needs, unless there is fundamental change by all.

Long before it was fashionable last century, the Commonwealth had already entered the debate about a world that was changing before our eyes. A far-reaching Commonwealth report in the 1980s led to the 1989 Langkawi Declaration on the environment, in which our Heads of Government said that 'any delay in taking action to halt this progressive deterioration will

result in permanent and irreversible damage'. It was also in the 1980s that The Maldives used the Commonwealth to raise the alarm that it was disappearing underwater.

Since then, while the world has struggled to agree international action plans, Commonwealth environmental challenges have got greater. We see them in shrinking rainforests, made worse by unsustainable logging practices in Asia and the Pacific; in dwindling fish stocks in the Atlantic and other oceans; in a thawing of the tundra in northern Canada; in encroaching desert in northern Nigeria; in flooded lowlands in Bangladesh; and in rising sea levels around Tuvalu.

We also see the environmental challenges of the future, caused by rapid urbanisation and the growth of the slums which are now home to 300 million Commonwealth citizens.

The bill for industrialization in the developed countries is only now arriving, and it...’s bigger than we could ever have expected.

An even bigger bill will come if other countries follow, and so we must find alternative paths to prosperity. Real development lies in the best use of our natural as well as our human resources: it is Development without Damage.

How is the Commonwealth to react ? We must respond in word and deed. We must do so through using our coalitions of governments; of civil society organisations; of businesses; of professional associations like the Commonwealth geographers, foresters, statisticians and meteorologists; of families and individuals.

Our Environment Ministers have agreed a new Commonwealth - wide strategy to fight climate change. Our Finance Ministers have agreed on the need to bring climate considerations into every aspect of government policy and financing, including putting a greater focus on the economics and the financial implications of climate change, and on richer countries' obligations to help poorer ones, both financially and technologically.

On the shores of Lake Victoria last November, our Heads of Government agreed the Commonwealth Action Plan on Climate Change: a serious political commitment supported by practical actions to tackle the impact of climate change. We are already active - helping to manage fish stocks in the Pacific Ocean, for instance, and supporting sustainable tourism in West Africa and the Caribbean. Our advisers are developing marine and coastal resources in Guyana, Mozambique and Papua New Guinea; meteorological data services in Botswana; and flood and coastal management plans in Seychelles. The work will go on.

Commonwealth citizens can play their own part: reducing, repairing, re-using and recycling. Businesses can help us to improve energy conservation and efficiency in manufacturing, transport systems, buildings and homes. We can act collectively, and across borders, to protect forests, have clean water, and manage pollutants and other wastes.

As 53 countries, we can build the national and international institutions involved in our environmental protection, and strengthen the laws and the education programmes which help us to take action.

It is perfectly possible to change the way we behave, in order to share our resources and live within our means. We have already learned a great deal on how to transform our economies to a low - carbon future, and there is more to be done. We must be consistent across the globe, involving everyone in the process while being sensitive to local needs and capacity, just as the environment itself adapts to local conditions.

On Commonwealth Day, let...’s sow the seeds of good environmental stewardship. The environment is our inheritance to cherish

- it is our past and our present. And it is, more than anything else, our future. Let us ensure through our actions that future generations have an even better environmental inheritance - to share, and to celebrate. Commonwealth, 10/03/08.