Along the streets and alleyways of our future eco-cities there will be borders of wild flowers buzzing with bees and butterflies. Swifts and bats will fly freely again to and from the eaves of public buildings and tower blocks. Glimpses of solar panels, wind turbines and roof gardens, reflected in self-cleaning windows, will frame the high horizon. It will take under 7minutes to walk to your nearest public transport, recycling centre and local farmer's market. A tree-lined park, river or lake will be just as close.

Does it sound romantic and as far away as the Emerald City seemed to Dorothy when she first set foot in Oz? Such improvements to the sustainability, biodiversity and natural quality of urban life are already part of the greening plans for many cities around the world. And for good reason. It's the first time in history we face a situation where half of the world's population is located in urban spaces rather than rural areas. Planning the future of our cities will make or break a green economy.

Above: Green roofs are starting to pop up all over London. Enough of them could cut down flooding risks, help cool the city, and reduce health hazards in the anticipated hot summers that climate change may bring. And make more space for nature.

In places like Curitiba, capital of Brazil's Parana State, and Sweden, to name a couple, there have been big successes in cutting pollution, fuel consumption and waste through innovative city planning. There are also more ambitious schemes for completely new developments such as Masdar City near Abu Dhabi. Masdar is being hailed as the world's first zero carbon city and a showcase for sustainable living.

And what of Britain's most energy-efficient cities? Are they doing as well as they should? Here in London, there has been much talk of the Green Olympics with sustainability embedded firmly in Olympic planning from the outset. Pictured right is the area around east London's Olympic Park site which is being transformed in line with sustainability guidelines.

The costs and benefits of making our cities and urban housing greener and the promise of the greenest-ever Olympics will no doubt be among the hot topics on the agenda of this week's Earth Debate taking place here at the Museum. Olympics sustainability head, David Stubbs, joins the panel of key speakers to discuss Green cities in a green economy.

Green cities in a green economy - how to pioneer a sustainable transition? is on Wednesday 14 March from 19.00 to 20.00 GMT in the Attenborough  Studio. Like the last two it folllows a Question Time format with an invited studio audience and four panellists.

Watch the Green cities debate live on our website or join us on our online community to have your say before, during and after the event. On the night, you can contribute questions or comments using #earthdebates on Twitter.

This is our third Earth Debate, organised jointly with our Earth Debates partner, the Stakeholder Forum for a sustainable future, in the lead-up to the UN's Earth summit in June, Rio+20.

Find out more about the Earth Debates and watch the previous debates on video

Join in the UK's Climate Week activities

As I walked through the Museum’s Earth galleries last week it made me chuckle to see a small sign posted on the What is Earth’s future? exhibit. The sign read ‘Out of Order. This exhibit is being repaired…’ The group of young lads who noticed it too were also highly amused at the irony of it.

The Museum's What is Earth's future? exhibit, recently declared 'Out of order'. Symbolic of things to come for our planet? The exhibit, located in the From the Beginning gallery in the Museum's Red Zone, has since been restored to its spinning globe with haunting moving images projected on it. Select images to enlarge them

Of late, we’ve experienced some trying times behind the scenes in the Earth galleries office block, where I work. First our staff lift ground to a halt (leaving us with a lung-busting hike up the stairs), then the water packed up - just as well since the toilets had stopped working - and to top it all off  the heating threw in the towel for a day at the height of the recent cold spell. However, we soldiered on to make the Red Zone's galleries the greatest show of Earth on Earth. And, because we care and because the Natural History Museum is an inspiring place to work, we were happy to do so (like the rest of our 'fairly happy' fellow Britons as recently observed in the much-talked-about Happiness survey.)

It strikes me that what happened in the Museum's Earth galleries is in uncanny synchronicity with the central concerns of our current series of Earth Debates, which continue here over the next three months: if we don’t do some vital repairs to our resources and society, will parts of the Earth soon be declared out of order too? What is the real impact of what we produce and consume on our surroundings? Does our quest for the greatest show, greater monetary wealth and the constant demand for more material goods come before our immediate day-to-day living needs? Are we happier and do we feel more valued if we are more affluent or is it because of what we achieve and where and who we are with?

Would you be willing to go vegetarian, or even just to switch to eating poultry, pork or pasture-fed beef rather than grain-fed beef to reduce the impact of agriculture on the environment? Big decisions are ahead at the next international Earth summit.

There is little point in me trying to explain here why the UN's earth summit in Rio de Janeiro in June is so important (aka Rio+20 as it is being held 20 years after 1992's seminal summit). It would take too long - our Earth Debates partner, the Stakeholder Forum for a sustainable future, who are coordinating and guiding key discussions in the lead-up to Rio+20, has identified 97 key issues (see the tag cloud below) - and besides our Earth Debates pages online already do a very clear job of this and will point you to all the right places for more information.

What's more vital is that the Museum needs your input now on the big issues that will be acted upon at global level in June. We need your thoughts on a sustainable green economy for the world or your local area, and all your favourite bugbears that go with it, as part of our ongoing Earth Debates.

Each of our four Earth Debates, with its four panellists and invited audience, is broadcast live from the Attenborough Studio on our website. The format of each debate is like BBC’s Question Time and you can watch it live, follow or contribute your questions or comments using #earthdebates on Twitter, or post your views to our online community before, during and after the event.

The next Earth Debate is this Wednesday 22 February from 19.00 to 20.00 GMT where the panel and studio audience will ask Beyond GDP - how can we measure progress? This debate will question the alternatives - like measuring our wellbeing and the value of the environment - to the traditional measures of economic growth and and asks what is needed for businesses and governments to invest in a green economy rather than exploit it.

Bookmark the link to the webcast and to #earthdebates on Twitter to join us on the night.

Missed the first Earth debate on 25 January about the price of nature? Watch the highlights in this short video clip which features debate chair Tim Radford, panellists Professor Sir Robert Watson, Claire Brown, Ian Dickie and Will Evison, and audience member Tony Juniper.

'Business as usual is absolutely unsustainable... but we also have to show business that there are solutions.' An extract from the closing comment of Defra's Robert Watson in January's first Earth Debate.

Watch the whole of the first debate Ecosystem economics - can we put a price on nature? (video of the 1st Earth Debate).

The third debate will tackle Green cities in a green economy - how to pioneer a sustainable transition? on 14 March 2012, followed by the fourth debate Food security - how do we feed 9 billion people in 2050? on 11 April 2012.

Find out more online about our Earth Debates and the Rio+20 Earth Summit in Rio de Janeiro

Get more information on the the Stakeholder Forum for a sustainable future and their priority concerns.

The Museum's Sensational Butterflies exhibition is definitely the fluttery flavour of the week. Not only has an incredibly rare half-female-half-male butterfly hatched in the exhibition's butterfly house very recently, Sir David Attenborough also made a very special appearance there today.

The rare dual-sex butterfly recently hatched in our Sensational Butterflies exhibition is a great mormon, Papilio memnon, from Asia. One half is female, with paler colours and blue, red and tortoiseshell flecks. The other half is male and is darker.

The discovery of this unusual dual-sex butterfly - such creatures are called gynandromorphs - caused huge excitement in the Sensational Butterflies exhibition when it was originally spotted. Gynandromorphy happens very occasionally across a range of species, from spiders to crabs. The word comes from gyn which is Greek for female and andro which is Greek for male.

Luke Brown (below right), manager of the exhibition's butterfly house says:

'Pure bilateral gynandromorphs are incredibly rare. I have only ever come across two in my whole career. So you can understand why I was bouncing off of the walls when I learned that a stunning half male, half female bilateral gynandromorph had emerged in the puparium at this year’s Sensational Butterflies exhibition. Many permanent butterfly exhibitions will go through their entire existence without ever seeing one of these rarities.’

The gynandromorph butterfly, however, may not be around for much longer. These species, sadly, only live for two to three weeks.

Read the news story and learn more about the gynandromorph discovery at Sensational Butterflies

Our other exciting and famous visitor to Sensational Butterflies today, which some lucky schoolchildren were lucky to catch a glimpse of, was Sir David Attenborough. He was here to help launch the Big Butterfly Count project organised by the Butterfly Conservation group which asks us to help record butterfly sightings from 16 to 31 July.

Children from The Russell School in Richmond with Sir David Attenborough are charmed by a swallowtail at the Big Butterfly Count launch in our butterfly house this morning.

'Butterflies are one of the stars of the British countryside. Summer just wouldn’t be summer without them' says Sir David

It's the second year running for the Big Butterfly Count and last year more than 10,000 people took part with 189,000 butterflies counted This year's results may help reveal the impact of our record-breaking spring weather.

Our Sensational Butterflies exhibition with its butterfly house full of 100s of live exotic butterflies and moths is highly recommended for a summer holiday visit. Open until 11 September 2011. Tickets £3.50.

As you approach the butterfly house marvel at the glorous outdoor garden (above) where you can learn butterfly-attracting tips for your own garden. Inside the butterfly house, who knows what else may hatch in the coming months? You might even catch sight of the extraordinary Madagascar moon moth (right). But remember when you visit, it's hot, hot, hot in the house, 'cos that's the way the butterfly beauties like it.

Find out about our Sensational Butterflies exhibition

See some exhibition highlights

Buy Sensational Butterflies tickets online

The nationwide OPAL Bugs Count also asks you to look for butterflies, in particular the small tortoiseshell butterfly. There are a humungous 380,041 bugs counted so far at the time of writing, but it grows larger every minute!

Learn more about the butterfly life cycle

More photos taken at the Sensational Butteflies exhibition this week. Select images to enlarge them

Do you know what bugs are living near you? Are some spiders more common in cities or in the countryside?

Help us find out by joining in the new nationwide Bugs Count survey launched today, 8 June, by the Museum and OPAL partnership. The scientists asking for our help want to know what bugs are out there and the differences between what we find in the cities or rural areas.

Hunt for bugs in soil, short or long grass. Search on paving and outsides of buildings and on plants and shrubs.

On your bugs hunt, keep a special eye out for six specific minibeasts, including the small tortoiseshell butterfly (right), which is in decline. Use the Species Quest bugs sheet to help in your identification.

You'll be surprised at what buggy creatures you can find in towns and the countryside.

On the recent Big Nature Count of our Wildlife Garden, we found over 60 species of bugs in a morning and the final count hasn't been done yet. As well as the unusual drab wood soldier fly, Solva marginata, discovered, there was a new Coleophora glaucicolella moth found, not recorded in the garden before. And just the other day, a Museum volunteer out on a field trip in Surrey's Bookham Common, found a population of scarlet malachite beetles, left, one of the UK's rarest insects.

Read the news story about the bug count and which six specific minibeasts you should look out for

Come along to the Museum's Attenborough Studio this Saturday, 11 June, to hear two Big City Big Hunt talks at 12.30 and 14.30 with our scientists. Afterwards, you can take part in various bug-hunting activities and pick up a Bugs Count pack in the Wildlife Garden.

What's a bug?

The term ‘bug’ is a widely used name for insects. In our Bugs Count we are including non-insect groups such as spiders, centipedes, millipedes and woodlice. These are all collectively part of the group called arthropods and are invertebrates.

True bugs are a specific group of insects that include shield bugs, water bugs, aphids, scale insects and others.

More bug information

Find out about bug identification in our Nature Online section

Join the Bug forum

Browse our Young naturalists page and enjoy the Big Nature Day video

Discover how to identify the Cockshafer May bug and watch the video

There's no doubt about it, when you join us for our Big Nature Day extravaganza this Sunday on 22 May, you'll get your hands dirty.

But that's pretty essential if you're going to help our scientists and wildlife experts in the Big Nature Count to find and identify how many different species of plant and animal there are in our Museum Wildlife Garden. It's a 24-hour census - or a bioblitz race for those familiar with the term -  to celebrate International Day for Biological Diversity and International Year of Forests, as well as the start of the UN's Decade on Biodiversity.

Can you handle it? Find out which worm charmer to be on Big Nature Day with our experts in the BBC film clip on our website

As Stuart HIne, manager of our Centre for UK Biodiversity says: 'We have many visitors to the Wildlife Garden, from our regular human ones to more unusual visitors such as honeybees, damselflies and hawkmoths. In fact, since the garden opened in 1995, we’ve recorded more than 2,000 different species and it would be great to know what's about on Sunday.'

Along with the regular Big Nature Count guided tours, worm charming (above) will be a popular highlight of the day. There are two sessions at 12.00 and 15.00. The recent rain should help lure the worms to the ground's surface. Although we're hoping that the sun will shine gloriously on the day, of course.

Spot the spots on the ladybirds you find and watch out for cockchafer May bugs on the Big Nature Count guided tours. Select images to enlarge

Other garden action includes the Bugs Count, Tree Hunt, moth trap checking, investigating pond life, and check out the Bee Tree.

Inside the Darwin Centre, head over to the Specimen Roadshow to identify your favourite specimens (or bring in a picture) and there are nature talks in the Darwin Centre's Attenborough Studio.

Look around and above, plants and trees may hide moths (like this Poplar hawkmoth, left) and butterflies. There are eight common trees in the Wildlife Garden to identify. Select images to enlarge

Take pictures on the day

Most important of all, though, bring your cameras or have your mobile phone to the ready to snap the species you do manage to spot. With these, you can help us create a spectacular Photo Wall in the Darwin Centre atrium at the Interactive Media area. You can print your pictures here for the display or upload them with your comments to our Big Nature Day guestbook on the computers available or at home afterwards.

Big Nature Day is a free, drop-in event that will appeal to all ages, but you'll need to book on the tours and worm charming sessions.

When you arrive at the Museum head for the West lawn or Darwin Centre atrium where you'll be directed to the Base Camp in the Darwin Centre Courtyard, the hub for the day's activities, and where you can see lots of special displays.

Keep up to date on our Big Nature Day website for the Big Nature Count tours schedule and latest information

Get prepared for the activities on Big Nature Day by watching some great how-to nature videos on our website

Explore the Museum's Wildlife Garden

Discover what else is on for the International Year of Biodiversity

Visit our newly-launched Decade on Biodiversity website

Yann Arthus-Bertrand film treats at the French Institute on 22 May and on the International Year of Forests website

If you want to see an amazing nature documentary by The Earth From Above photographer Yann Arthus-Bertrand, head over to the nearby French Institute for a special free screening of Home at 18.30. Our Museum botanist Sandy Knap is introducing the film. Although it's free you need to book a place on their website.

Find out about booking for the special screening of Home at the French Institute

You can also catch a glimpse of Yann's special short fiilm for the International Year of Forests on the official website

Bird cherry blossom has just started to appear in the Wildlife Garden

I popped in earlier in the week to get a breath of fresh air and chat to Caroline, the garden's manager, who took me round to point out the signs of new life.

There are pretty primroses, cowslips and wood anenomes peeping out here and there and the first few bluebells. The blackthorn, Wild cherry and Bird cherry trees are all beginning to blossom.

'Frogs arrived in the pond around the middle of March,' recalls Caroline, continuing 'and we saw the first frog spawn around the 22nd. The toad spawn came a few days later. Toads usually follow frogs.' We lean over the large freshwater pond to observe the mush of spawn clinging to the watery bank and spot a solitary moorhen on one of the islands.

It's a busy time for nesting birds, but this spring the moorhen has made her nest outside in the open in front of the nesting box provided. Caroline fears for the vulnerability of the nesting family, but won't interfere.

I learn that the first holly blue butterfly was seen in the last couple of weeks and the trees resound with the chatter of green finches and magpies.

Caroline and her team have been busy getting ready for the public opening of the garden and planning this year's seasonal garden activities and monthly family weekend events. The first weekend event, Spring Wildlife, is on 8 May, so check the website for more information and updates nearer the time.

The Wildlife Garden is not only a place for our visitors to enjoy in the spring, summer and autumn. It's also an urban habitat where we record, identify and conserve species. During the winter months, the Wildlife Garden team have been busy coppicing, pollarding, hedge-laying, weeding and planting to extend woodland areas.You'll see signs of their labours when you visit.

Find out about the Wildlife Garden on our website

Take part in our bluebell survey this year

Join our cherry tree survey

Read our latest news story about bluebells

Enjoy some recent early spring photos of the Wildlife Garden. See some of the species you might spot if you visit soon. Select images to enlarge them

Nesting moorhen... tread quietly round the pond

Common toad tadpoles will emerge in the ponds soon

Marsh marigolds by the pond

Cowslips

The first of the bluebells, these ones look like native bluebells to me...

Willow

Greater stitchwort

Primroses

The last daffodil blooms

Tomorrow, Friday 11 March, is sadly the last day that our Waterhouse Gallery will be home to the winning and commended photographs of the Veolia Environnement Wildife Photographer of the Year 2010 exhibition.

Chick delight. This photograph is jumping with the joys of Spring. Johan captured the hungry Arctic tern chicks in Látrabjarg, Iceland, Europe's most westerly point. Highly commended in the 15 - 17 years category.

I had one last dash around the gallery yesterday and, as always, was moved by certain images that I hadn’t noticed as much before, like the joyful Chick delight (above), and Laurent Geslin's romantic Paris life (below), with its furry friends enjoying a night out.

Paris life. Laurent got down on his belly for this dazzling shot of rabbits silhouetted againt the bright lights of Paris at nightfall. Highly commended in the Urban Wildlife category.

The exhibition’s design this year was particularly special because we introduced a new structural framework featuring a white woven fabric backdrop. These changes enhanced the exhibition experience and created a more intimate and inviting setting for the spectacular imagery, helping the photographs look ever-more luminous.

Over 124,000 visitors enjoyed the 2010 exhibition here and the last few months were especially popular. Every late night Friday at our monthly After Hours has been a sell-out.

But it isn’t over for the 2010 exhibition. The UK and international tour has already started and if you head west to the Bristol City Museum and Art Gallery (right), you can see the photographs there until 5 June 2011.

Find out more UK and international dates of the tour on the Wildlife Photographer of the Year website.

In the meantime, photographers have until 18 March to get in their images for the chance to be Veolia Environnement Wildlife Photographer of the Year 2011. Find out how to Enter the competition.

Who knows what incredible images and wildlife characters await us this year, but one thing’s for sure, there will be a new Young Veolia Wildlife Photographer of the Year as 18-year-old Fergus Gill who won the Young competition for 2 years running in 2009 and 2010 is now an adult! He says:

‘Now that I am 18, I must confess I’m excited about moving up the ranks into the adult competition. Whilst I have a lot of work to do if I am to win any awards when competing against such high quality entries, I’m looking forward to the new challenge and where my future work takes me.'

And his tip for being a potential winner: ‘From my experience the best chance of being successful is to get a different take on a common or overlooked species.’

If you want a commemmorative book or print of one of your favourite images, visit the online Wildlife Photographer of the Year shop

And enter our competition to win a fantastic goody bag of things inspired by the exhibition

Left: Fergus Gill receiving his award as Veolia Environnement Wildlife Young Photograher 2010 with his winning image, The frozen moment. The photograph was taken on Boxing Day, 2009 at the bottom of Fergus's garden in Perthshire.

Select the images to enlarge

Five years ago a female bottlenose whale found her way into the River Thames. At 6 metres long, the whale was unmissable and her every move was followed by the public and the media.  Sadly, despite human efforts, she died towards the end of a rescue attempt, under the gaze of the world’s media.

Last weekend, the whale's skeleton went on display at our Tring Museum in a new free exhibition, The Thames Whale Story.

I asked Alice Dowsell, the exhibition's interpretation manager, to tell us about the final installation:

'It’s been an exciting week at Tring since the enormous Thames whale skeleton was installed on 18 January. After a lot of hard work and planning in transporting the whale and its custom-built case out to Tring and into the only gallery large enough to hold it, we’ve been enjoying everyone’s reaction to the display. It seems lots of you out there have fond memories of the whale and its journey in the Thames back in January 2006 – hard to believe that was five years ago. Alongside the whale skeleton we also have other specimens carefully chosen from our 3,000-strong research collection.

'There's been fun for the younger visitors too this week who have enjoyed dressing up in lab coats to play our Prepare Yourself game. They’ve been working out just how scientists go about turning a big dead whale into a nice skeleton for our collections. We’ve also had young and old trying their hand at Body Detectives, learning that there’s a lot about an animal’s life that you can find out after it’s dead.'

Richard Sabin, the Museum's Senior Curator of Mammals, seen here preparing the skeleton, adds:

'It’s great to get the Thames Whale out on display in the Natural History Museum at Tring. The setting in gallery 5 is superb. There is still so much public and media interest in this story after five years, and the exhibition will really give us a chance to put the use of Museum research collections into context.'

Find out about visiting the Natural History Museum at Tring

Read the news story about the Thames Whale Story exhibition