More than any other continent on earth, Africa is blessed with abundant natural water resources. Our continent is home to the world’s longest river, large fresh-water lakes and countless rivers, tributaries and streams.However, our unique natural inheritance is under threat.

Across Africa, one can see threats to water supplies and cases of severe environmental degradation. Lake Chad, which supports the livelihood of 30 million people across four countries, may no longer feature on maps of West Africa in just 40 years time.

Lake Haramaya in Ethiopia is not alone in having disappeared altogether.Most alarmingly, these changes are taking place before the full impact of climate change is being felt.

Despite being the least responsible for causing it, Africans now are on the front line of climate change, with sub-Saharan Africa being more vulnerable than any other region in the world.  

As President of Mozambique, I witnessed first-hand the devastating impact of severe flooding in 2000 and 2001 when I led the emergency response to the crisis.

Tragically this is unlikely to be the last occurrence of flooding in Africa.

A recent report launched by Kofi Annan shows that there is a significantly increased risk of natural disasters due to climate change.

For African policy-makers, the environment must now be at the very top of the policy agenda, with water sustainability being accorded the highest priority in the management of the continent’s resources.

A number of countries are toughening environmental protections and developing adaptation programmes, but more needs to be done.

As African leaders prepare for the Copenhagen summit later this year, there is a new urgency for all countries to develop effective environmental policies at home and to secure a fair and ambitious climate change deal abroad. Nothing else is more pressing.

It is all the more important when considering the imperative for Africa to sharply and sustainably increase its agricultural productivity.

No country in the world has managed to develop its economy and increase standards of living for its people without first significantly increasing agricultural productivity.

About 80 percent of Africans depend on agriculture in one way or another for their livelihood.

Yet Africa’s yield per hectare for food crops is less than half the level in developing countries, less than 10 percent of its arable land is irrigated, and fertilizer remains scarce - only 8kg per hectare as compared to a global average of 100kg per hectare. Fertilizer use actually declined in one half of all African countries in the 1990s.

For African governments, this means not only putting in place the right environmental policies, but also putting money behind the rhetoric of creating a green revolution in Africa.

So far, only eight countries have met the Maputo target of allocating 10 percent of public expenditure to agricultural and rural sectors. At the same time, governments should work to harness the support of the international community.

The US$20 billion agreement to provide support for the world’s poorest farmers, reached at the G8 Summit last month, is a welcome move in the right direction, as is the World Bank’s commitment to increase substantially its support to African agriculture from US$250 million to US$400 million.

Above all, African policy-makers must embrace technology and develop their own technological solutions.

African research institutions are pioneering new forms of irrigation that could transform the way staple foods are cultivated, fertilizers are available that can feed nutrient deficient soils, modern crop varieties can dramatically increase yields and new farming techniques can make processes significantly more efficient.

Not only can it be done, but it has been done. In less than six years, the production of maize in Malawi has increased from under two million tons to well over 3.5 million tons, allowing the country to become an exporter of the crop to neighboring countries.

It is why, despite all the obstacles we face, I remain such an optimist when it comes to Africa’s agricultural development. Our continent has twelve times the land area of India, with only half the population to feed.

With few exceptions, the distribution of cultivable land in sub-Saharan Africa is equitable compared to many other regions of the world.

Moreover, the technology already exists, demonstrated through the success of improved varieties of cassava, rice and maize.

I believe that with the right commitment, policies and technologies, Africa will better the Asian agricultural miracle of the 1970s and 80s - doing so in an environmentally sustainable way.

This week the Pan-Africa Chemistry Network is convening a conference to assess the challenge of water sustainability.

It will bring together scientists from across the continent, convening  the best African minds to look at issues around water sustainability and what can be done to secure and harness water supplies.

The conference will produce a report for World Water Day next year outlining a programme for action.

I do not doubt that we face unprecedented challenges on our continent, but what I do know is that we have twenty-first century expertise with which to overcome them, and the African talent with which to apply them.

President Chissano is a former President of Mozambique