大象传媒

We've had plenty in the past, we'll certainly have more in the future: large international summits designed to rally global support for environmental action. This time it's Japan and a conference aimed at tackling the rapid loss of biodiversity the world is currently experiencing. Many blame us - humans - for the extinctions, and are urging quick action to better manage our resources. On this week's One Planet, we speak to the man at the centre of the action in Japan, Achim Steiner, the UN's environmental chief.

Mr Steiner tells Mike why biodiversity matters, and why no species - even those that appear to offer little direct benefit to humans - must be preserved. But he stresses that these conferences are never a finishing line, and we must be realistic about what can be achieved.

Also in the programme, Mike looks away from the rainforests and oceans to consider biodiversity in our cities. Over half the world's population now lives in urban areas - and that figure will continue to rise. We visit Professor Nobert Muller in the German city of Erfurt to ask him why city wildlife may hold the key to better preserving all of the world's biodiversity.

In a packed show, we also ask how long it takes for a species to evolve - can some animals and plants adapt quickly enough to the rapidly changing environment? And we have a poem extolling the virtues of city wildlife. As ever, tune in, have a listen and then let us know what you think. Contact the team on oneplanet@bbc.com, or do join us on our Facebook page, the link's below. You'll usually find us reading through your comments on Facebook. See you there.