Mood disorders and the discovery of a pain signalling organ in the skin could explain why chronic pain occurs – and how to treat it.

Trees and insects may play a significant role in the emission of methane – a potent greenhouse gas – and improving our understanding of exactly how this happens could help in targeting more effective ways to fight global warming.

In January, we examine how the cryosphere - ice sheets, glaciers, sea ice and other frozen parts of the planet - is changing and what this means for our planet. Earth’s cryosphere reflects the sun’s heat, regulating climate. But as the cryosphere melts, sea levels are rising and there are other impacts too – such as glacier collapse, which can generate massive avalanches.  We speak to glacier expert Professor Andreas Kääb about the current state of the planet’s ice and snow and how better satellite measurements can help us understand the impacts of melting. We look at Earth’s so-called 'third pole’ of the Tibetan plateau and how ice melt will affect the millions who live in the mountains and those who depend on its run-off for water. We look at a project drilling in the Antarctic for what could be the world’s oldest ice (1.5 million years old) to see what it can reveal about climate history. And we speak to sea ice scientist Polona Itkin to get a glimpse into a day in her life aboard German icebreaker Polarstern, currently carrying out the largest Arctic expedition in history.

We need to understand how glaciers are shrinking in order to better adapt to climate change impacts such as changes to water supply, landslides and avalanches, says Professor Andreas Kääb, a glacier expert from the University of Oslo in Norway. 

Declaring a global planetary emergency, improving sub-volcanic imaging to predict eruptions and developing artificial intelligence that works for humans are some of the urgent actions and research that experts in different fields want to see in 2020.

From bacterial invisibility cloaks to unexpected dinosaur colors, Horizon uncovered some fascinating facts in 2019. Here are our 12 favourites.

We need an active public debate on the ethics of gene editing technology to realise its potential and prevent it being used in nefarious ways, for example by the military and amateur scientists, and to take cultural differences into account, according to Professor Christiane Woopen, executive director of the Centre for Ethics, Rights, Economics and Social Sciences of Health (CERES) at Germany’s University of Cologne.

Breeding together corals that have naturally high heat tolerance and planting them on coral reefs could increase the reefs’ resilience to climate change and reduce the impact of bleaching events, according to Dr James Guest, a coral reef ecologist from Newcastle University, UK. He is studying this ‘assisted evolution’ approach to coral conservation and examining the risks associated with it.

Thanks to the ‘cut and paste’ gene editing technique CRISPR, scientists are homing in on a cure for sickle cell disease - a genetic blood disorder - while other research is looking at how to expand the potential of CRISPR-based treatments.

Earthquakes are sudden and their shaking can be devastating. But about 20 years ago, a new type of earthquake was discovered. We cannot feel them, and geologists still know very little about them, such as how often they occur.

Black holes in the early universe pose a bit of a problem. Based on observations from telescopes on Earth and in space, we know that some black holes grew to be a billion times the mass of the sun just one billion years after the Big Bang. Our current models of black hole growth, however, can’t explain this speed of growth. So how did these supermassive black holes come about?

Seven years after scientists successfully managed to adapt a gene editing system used by bacteria into one that can be easily used in labs to edit human genes, we take a look at some of the emerging applications and ethical issues of CRISPR-Cas9. We talk to the head of the European Group on Ethics in Science and New Technologies about whether the simplicity and low cost of CRISPR means that there is potential for misuse and what should be done about this. We find out how scientists have used CRISPR to create cows lacking two sugars that trigger the human immune system, leading to hopes of longer-lasting heart valves for transplant patients and healthier red meat. And we speak to researchers who are using CRISPR to improve other gene editing technologies.

Scientists have cloned a genetically engineered bull which they hope will help heart valve transplant patients lead better quality lives and benefit people with red meat allergies.

Europe changed dramatically during the Bronze Age, with huge population shifts generally ascribed to the rise of new metal technologies, trading and climate change. But scientists believe that there may have been another reason for this social upheaval – the plague, possibly transported by, or on the back of, newly domesticated horses.

Drugs that activate or block the body’s oxygen-sensing machinery to treat conditions such as anaemia in patients with chronic kidney disease and cancer are being made possible because we now understand the way that cells respond to oxygen deprivation, according to Sir Peter Ratcliffe, one of three winners of this year’s Nobel prize in physiology or medicine.

There are, arguably, only two interesting facts about bogs. The first is that some people have a jolly good time swimming through them, notably at the World Bog Snorkelling Championships held each year in central Wales, UK. The second is that they could help save the world.

When Timothée Boitouzet studied architecture in Japan, where buildings need to survive earthquakes, he realised the next smart material might be one that humans have used for thousands of years – wood.

It may be that life is lurking out there on other planets. But stuck here on Earth, how can we ever know for sure? A good place to start is by looking for the compounds on other worlds that are known to be the key ingredients of life as we know it.

Despite advances in both virtual and augmented reality technology in the last few years, there’s one area that remains neglected: touch. With your VR headset on, you might be able to explore the sights of a vast forest and hear birdsong all around you, but you won’t feel the dampness of the moss on a tree trunk or the squelch of leaves underfoot.

Despite advances in both virtual and augmented reality technology in the last few years, there’s one area that remains neglected: touch. With your VR headset on, you might be able to explore the sights of a vast forest and hear birdsong all around you, but you won’t feel the dampness of the moss on a tree trunk or the squelch of leaves underfoot.