Frogs, toads and newts are becoming a less frequent sight in our ponds and gardens. Globally 40% of amphibians - almost 2000 species - are threatened with extinction according to the IUCN red list. Some scientists even say we're on the verge of the 6th mass extinction. Yet with things at such an alarming state Tom Heap asks what's being done to save these creatures and if it's too little too late?

Amphibians are a key part of the food chain but not only do they control less favoured bugs, they have also been described as 'hopping pharmacies' carrying important chemical compounds on their skin which have been used for medicines. If they disappear so does that link.

Tom hears about the different factors which are impacting on numbers - including habitat loss, climate change and diseases such as chytrid fungus and ranavirus. Andrew Blaustein at the University of Oregon is currently doing research to find out why some species are more vulnerable to chytrid than others but has also found parasites causing mutations in frogs nearby - including some with up to 15 limbs.

Meanwhile, of the UK's seven native amphibian species, one- the pool frog - has already died out. Tom travels to the secret location where they've been reintroduced from Sweden to find out how well they're doing and what can be learnt from this near-miss. Tom also gets his hands dirty on toad patrol, helping them cross busy roads as they come out of hibernation and return to their ponds for breeding. As he asks motorists to apply their brakes he also asks just how much this will do to halt their decline.

Producer: Anne-Marie Bullock.

Tom Heap meets the activists hoping to bring an end to illegal fishing by tackling the problem head on: by getting in the way of pirate fishermen.

The Black Fish is a relatively new NGO (Non-Governmental Organisation) who aim to stop the fishing of juvenile Bluefin Tuna in the Mediterranean and prevent to use of illegal drift nets - by cutting them. Drift nets were banned by the United Nations in 1992 but they are still used illegally around the world.

The Black Fish are soon to launch unmanned reconnaissance aircraft in the Mediterranean to monitor illegal fishing and find out exactly who is doing it and where.

Tom also meets campaigners who believe that the only way for fish stocks to recover is for a ten year moratorium to be imposed, allowing species of fish to become plentiful once more.

Presenter: Tom Heap

Russia's Lake Baikal is the oldest and deepest lake in the world, containing 20% of the world's unfrozen fresh water. Dr Anson Mackay from University College London is one of a team drilling through the bed of this extraordinary body of water. The cores of sediment that they pull up from the depths will tell us not just about the environmental history of Baikal, they'll tell us about 1000s of years of global climate change. Today the lake is threatened by pollution, rising population and Mongolian gold mining. Can the story of the lake's past help preserve it for the future?

Tom Heap tells the story of the expedition as we join Dr Mackay and his colleagues to piece together the history of Baikal and search for clues to the future of all freshwater on Earth.

Tom Heap discovers an unlikely battle in the war to protect remaining wild rhino populations being fought here in the UK. Rhino horn is now worth twice as much as gold because of its perceived value in Asian medicine. New markets in Vietnam have increased the pressure from poaching on wild populations but also on horn found in museums and zoos in the UK. Museums are now warned not to display real rhino horn and zoos like Colchester have had to increase security measures to protect their live rhino. To help prevent illegally obtained horn from leaving the country scientists in the UK are setting up a DNA database of all the horn kept here in museums, private collections and on the heads of living rhino in zoos.

Tom discovers that these highly threatened animals can be surprisingly gentle given their size and that thefts from UK museums have become increasingly common. The criminal gangs looking to profit from horn theft are highly organised and DNA forensics could be vital in achieving convictions.

It is hoped that a reduction in illegal horn feeding the market will help put an end to the demand but there are also new arguments for a legal trade using farmed rhino whose horns could be regularly shaved. The debate around legalisation remains live but many agree that a worldwide DNA database would be the only way to regulate and prevent poached rhino horn being traded. Wildlife crime officers say that DNA forensics could be vital in helping protect rhinos and many other endangered species in the future.

Alice Roberts revisits the - quite literally - ground breaking 'Incredible Edibles' concept of Todmorden and finds that their inspiration has spread across the UK.

Wasteland throughout our cities is being turned into productive agricultural land. Forget roof top gardens, green walls and window boxes, what we're talking about here is derelict, often hazardous brown field sites hidden within our urban landscapes that are now becoming a valuable link in our food chain. But that's not all, in reclaiming this land whole neighbourhoods are being regenerated. No site is too small or too large. From back-alleys on terraced streets in Middlesbrough to acres of polytunnel-lined, disused railway banks in Bristol, these once unproductive - and often hazardous - plots are now feeding their communities via vegetable boxes and even restaurant supply chains.

With a little effort, could our cities really feed themselves? Could this be the answer to both our food security and the improvement of our urban environments?

The demand for exotic and unusual pets is growing. Reptiles and amphibians , including snakes, lizards and geckos are popular pets for those looking for something alternative to cats and dogs. Some are captive bred or captive farmed and others are caught from the wild. The British Veterinary Association is re-evaluating its position on wild caught animals but the animal lobby group the Animal Protection Agency has called for a ban on the trade completely. They argue it causes suffering to the animals but also damages the environment.

Miranda Krestovnikoff looks behind the scenes at Heathrow where officers have intercepted animals being smuggled in illegally. She also speaks to Traffic, the wildlife monitoring organisation about the impact on the ecosystems when species are taken out of the wild and also asks what happens when exotic pets are released into the UK countryside.

But those involved in the pet trade in the UK say it's come a long way over the last 20 years. Miranda's invited to Exotic Pets UK which breeds some animals but also imports wild-caught species. They say they make the customers aware of where each species is sourced so they can make an informed decision but say if more people bred these animals in the UK there'd be less need to import. But Chris Newman from the Federation of British herpetologists and REPTA says the trade in species helps protect their habitat and a ban could actually threaten them.

2013 is predicted to see the biggest baby boom in 40 years. Whether it's the Royal baby or an after effect of the Olympics nobody is certain. But what does this mean for the planet? Dr Alice Roberts, who is herself expecting, finds out whether population really is the biggest threat to our environment.

Producer: Helen Lennard.

Miranda Krestovnikoff looks at new building materials for environmentally-friendly houses and asks where you should start if you want to build your own eco-home.

Costing The Earth visits Ashley Vale in Bristol: a self-built community of eco-homes to find out, ten years on, if the project has been a success.

Miranda also discovers the latest building materials and techniques available to those embarking on 'grand design' style projects and discovers how difficult and expensive it is to build your own environment-sensitive home.

Presenter: Miranda Krestovnikoff

Micro-solar lamps are now lighting parts of Africa that the grid cannot reach. Tom Heap investigates how the solar spread is emulating the wide reach of mobile phones in Africa.

There are currently over 100 million kerosene lamps across Africa that are the main source of light in parts of the continent that are either off-grid or where people cannot afford to hook-up to the electricity grid. These lights are polluting, dangerous and expensive.

Burning a kerosene light in a small room produces the same detrimental effect as smoking two packets of cigarettes. They are a fire hazard and they can cost as much as 15% of an average salary to fuel in some parts of the continent.

Tom heap sets out to discover if a small desktop solar lamp that costs a fraction of the running expenses of a kerosene lamp can improve the health of millions of people and help to lift Africa out of poverty.

This week's programme is produced in conjunction with BBC Newsnight and BBC World's 'Our World' programme. To watch the films made to accompany the programme visit the Newsnight and Our World websites.

Presenter: Tom Heap

A geothermal revolution is set to electrify Africa. Tom Heap visits the Rift Valley in Kenya, a potential source of abundant energy to find out if promises to light up even the remotest parts of the continent are going to come true.

Tom enters Hell's Gate National Park to meet the engineers harnessing the power of hot steam trapped beneath the crust, and heads north to the Menengai Crater to find geologists prospecting for power.

Back in Nairobi Tom meets businessmen and shopkeepers held back by a lack of readily available electricity and visits the poor neighbourhood of Kibera to find out how power and light can transform the lives of all Africans living with limited electricity.

This week's programme is produced in conjunction with BBC Newsnight and BBC World's 'Our World' programme. To watch the films made to accompany the programme visit the Newsnight and Our World websites.

Presenter: Tom Heap