There have been big promises about tree-planting numbers over the last few years - but is there much point in planting more trees, if we're not looking after the ones we've already got? The Woodland Trust estimates that only 7% of the UK's native woodlands are in good ecological condition - with pests, diseases, climate change and development all threats to tree health. Meanwhile a report from Botanic Gardens Conservation International says that a third of the world's trees are at risk of extinction.

In this programme, Peter Gibbs finds out what's ailing our trees, and asks what can be done to nurse them back to health. He talks to scientists, campaigners and the government's Chief Plant Health Officer, and finds out about a project where researchers are on the hunt for trees with natural resistance to ash dieback, which may be able to re-populate the ash woodlands of the future. He also visits a 'research forest' in the Midlands, where scientists are piping extra carbon dioxide at some of their trees, to find out what the impact of rising CO2 levels is likely to be for trees in years to come.

Produced by Emma Campbell

The public wanted to name her Boaty McBoatface, but in the end she got a slightly more stately name. The UK's newest polar research vessel, the RRS Sir David Attenborough, has just set out on her maiden voyage to Antarctica, where she'll enable scientists to research climate change and its impacts on the polar regions.

Following a hundred years of polar exploration, this ship will write the next chapter in UK polar science.

In this episode, ocean physicist Helen Czerski gets aboard to poke around the new ship, and meets the crew members and scientists who will be taking her to the ends of the earth in search of the answers to some of the most pressing questions of our time. She finds out how the ship has been designed specially to encourage collaboration and bring together scientists from different fields. And she tries out the bunks and learns what life at sea will be like.

Find out why krill can fight climate change, how you cook at sea in a storm and what the massive hole in the middle of the ship is for!

Producer: Heather Simons

Britain's rivers are in crisis, with only 14% of them deemed to be in a good ecological state. Chalk streams are particularly vulnerable, as so much is taken out of them for use in our water supplies. Pollution from sewage and agricultural run-off only add to the problem. In this programme Tom Heap takes a canoe trip along a waterway he knows well, the River Cam, to see for himself what's going on. He talks to environmental groups and local people, and asks whether the rapid expansion of homes and businesses in the area can sustainably continue in such a water-stressed region. He concludes that urgent action is needed if rivers like the Cam are not to run dry.

Producer: Emma Campbell

Golf courses do not have a good reputation when it comes to the environment. Keeping the greens and fairways looking immaculate usually means using pesticide, fungicide and fertiliser - as well as large amounts of water. Wildlife such as pecking birds and digging moles, which can damage the pristine playing surfaces, are seen as a nuisance. But attitudes are starting to change in the golfing world. In this programme, Sybil Ruscoe finds out about efforts which are being made to make golf more environmentally-friendly. She visits a golf course in Bedfordshire, where the greenkeeper puts up bird boxes and encourages areas of wildflowers. During her visit, she meets a conservation advisor from the Royal Society for the Protection of Birds, whose job focusses specifically on golf courses - part of a new partnership set up last year between the RSPB and the world of golf. She talks to the sport's governing body and the golf greenkeepers association, to ask whether the game is doing enough to change its ways. She also hears from a geographer who argues that the game of golf is fundamentally environmentally unacceptable in a time of climate emergency. It all leaves Sybil, a golfer herself, wondering 'how green is my golf course?'

Producer: Emma Campbell

We are all surrounded by synthetic chemicals in our everyday lives - from pesticide residues in food to chemicals used in the manufacture of household products - but most of us are not aware that they also make their way into our bodies. In this programme, environmental journalist Anna Turns investigates her own 'chemical body burden' - the amount of persistent, synthetic pollutants that have accumulated inside her system. A blood test shows her that traces of pesticides which were banned before she was even born can still be detected in her body. Analysis of the contents of her vacuum cleaner reveals that chemicals used to make furniture and electrical goods more fire-resistant are there too. Anna goes around her house, room by room, identifying the key sources of chemicals, and asking how they've travelled from the carpets and cleaning products into her own body. She talks to chemists and environmental scientists and asks what the threat to human health may be, and whether it matters that we now all carry around our own toxic cocktail.

Produced by Emma Campbell

World leaders have offered up a suite of promises at the COP26 climate summit in Glasgow but how many of them will make a real dent in our greenhouse gas emissions? Tom Heap talks to experts in sustainable finance, methane emissions, deforestation, clean technology and energy to gauge the impact made so far. He's also joined by two veterans of many COP meetings, University of East Anglia climate scientist, Corinne Le Quéré and Bernice Lee of Chatham House. What do they make of the conference that the world is watching?

Producer: Alasdair Cross

As world leaders gather in Glasgow you can be certain of one thing - the loudest voices won't be coming from the people most impacted by climate change. Inuit hunters on melting ice and Pacific islanders losing their homelands to rising sea levels won't be flying Business Class to Glasgow - they won't have the chance to fight for their rights amongst the world powers and corporate interests. Tom Heap brings those voices to the banks of the Clyde for the first of two special editions of Costing the Earth from COP26.

He hears from the Adivasi people of India, marching to stop their land being taken for new coal mines and meets Yessie Mosby, a Torres Strait islander who believes the Australian government should do much more to prevent his islands disappear beneath the rising seas. In Glasgow he talks to Sarobidy Rakotonarivo about the tensions between conservation and livelihoods in the forests of Madagascar and hears how conflict and climate change are inextricably linked in the humanitarian crisis around Lake Chad.

Producer: Alasdair Cross

Photo: Courtesy of Vijay Ramamurthy

Abandoned by its entire population in 1930, St Kilda has been uninhabited ever since. What's it like to spend six months with the birds on one of Britain's most isolated islands?

Conor McKinney is a naturalist and broadcaster with what might be- depending on your personality- either the best job in the world or the worst. St Kilda is seriously isolated- it’s an archipelago of islands over one hundred miles west of the Scottish mainland and 40 miles of rough Atlantic waves away from the nearest pub or shop. That isolation means that it has a unique environment. It’s packed with rare and endemic wildlife and the owners of the island- the National Trust for Scotland- want to keep it that way. The Ministry of Defence has a construction project on the main island of Hirta and it’s Conor's job to make sure that the boats and builders that will be coming and going don’t bring unwanted guests with them- things like sea squirts, Japanese knotweed or- worst of all- the rats that would very quickly decimate the extraordinary seabirds of St Kilda.

Producer: Alasdair Cross

Taking inspiration from President Kennedy’s Moonshot which united people around a goal to put man on the moon and spurred the development of new technology in the 1960s, the Earthshot Prize is centred around five simple but ambitious goals for our planet. Chhavi Sachdev announces the winners of the inaugural prize and discusses how smart ideas from individual innovators and small companies can influence the upcoming climate debate at COP26 in Glasgow. Prizes like this prove that there are clever ideas being developed to ease our pressure on the environment, but how can those ideas be harnessed and scaled up to make a big difference globally? Chhavi is joined by Inger Andersen, Executive Director of the United Nations Environment Programme and by Juliet Davenport, founder of the green power company Good Energy, to discuss the best ways to make smart ideas part of the solution to the planet's biggest problems.

Producer: Alasdair Cross

Taking inspiration from President Kennedy’s Moonshot which united people around a goal to put man on the moon and spurred the development of new technology in the 1960s, the Earthshot Prize is centred around five simple but ambitious goals for our planet. Chhavi Sachdev profiles more of the prize nominees from all around the world.

This week Chhavi concentrates on the innovators working to reduce waste, provide clean water and develop clean energy solutions for communities without access to power. Japan is notoriously prone to natural disaster which makes it a perfect testing ground for disaster-management solutions. The Wota Box arose from the urgent need for clean water in locations hit by earthquakes or tsunamis. Using the latest techniques in artificial intelligence it controls a series of filters to remove pollutants and provide essential washing facilities where they're needed most. In Nigeria, Olugbenga Olubanjohas invented a portable battery which can be rented from a vending machine to power mobile phone chargers and laptops, bringing modern communication options to some of the poorest areas of Africa.

Producer: Julian Siddle