Today (19 November) is Green Day, when Peterborough is officially launching its bid to become the UK's Environment Capital. To mark this momentous event, we asked three experts on the environment - as well as some young ecologists - to imagine what Peterborough could look like in 50 years time, if we all worked together to create an environmental heaven. But we also take a look at how things could go seriously wrong if we don't take action - green hell:

Hugh Cripps
The Peterborough of 2058 will be set within a necklace of wildlife-rich parks created after the old landfill sites were mined for their valuable 20th century "waste" materials.

It links up with the Great Fen Project, which was extended back in the '20s into the larger Peterborough and Cambridgeshire Fenland National Park, and the large John Clare Country Regional Park.

As the UK's premier centre for sustainable tourism, people from all over Europe arrive by train to visit our wonderful countryside, exploring the area by bicycle, horseback or electric bikes, stopping off at the many attractions, local markets and eating in the numerous "local food" restaurants.

In the evening, visitors will join the locals in wandering about the city centre, calling into the friendly cafés and pubs before listening to live music or taking in a play or movie.

Peterborough's reputation as the UK's Environment Capital is clearly demonstrated by its fantastic network of free electric buses which whisk you to all areas of the city, while the entire housing stock has locally manufactured state-of the-art solar roof tiles, generating all the energy needs of the homes.

As well as manufacturing the very best renewable energy equipment, Peterborough is also known for its large repair and restoration business cluster, where anything from clothing to electricals are overhauled before being returned to grateful owners.

Technology has at last delivered on the promise to reduce the working burden for mankind.

Although Peterborians now work less hours of paid work, they nearly all volunteer to help their communities.

From growing food for the elderly through to helping the local youth club, everyone has a true community spirit.

Hugh Cripps is chief executive of Peterborough Environment City Trust (PECT).

Trevor Gibson:
The Peterborough of 2058 is known internationally as the Environment Capital of the UK, where sustainability is an automatic and intrinsic part of decisions taken at all levels.

For residents and visitors alike, this Peterborough is one where everyone is proud to play their part in protecting and enhancing the local environment and passing on their enthusiasm for doing so to their children.

The city is the place of choice for seminars and workshops on sustainable growth, as people from all over Europe visit to learn from our best practice, with our internationally-renowned university at the heart of all such learning.

Our environmental credentials are evident to all such visitors. They can clearly see Peterborians moving into, and around, our exciting city centre by a range of innovative transport options including electric buses and community cycles. The vibrant river frontage even incorporates a number of landing stages for water taxis.

Visitors can also see a range of small and large shops with a clear focus on local products and locally-grown food.