Many of us depend on coffee to fuel our early morning meetings, mid-afternoon slumps or all-night study sessions. These days, the words “coffee” and “fuel” are half-jokingly synonymous. More than 9m tonnes of the bean are produced annually around the world and, once we brew it, an awful lot of waste is created. The vast majority ends up in landfill.

Carbon Monoxide is a much-publicised invisible killer. But there’s another little-known gas that kills 27 times more people, causing the deaths of 1,100 people a year in the UK alone. Worse still, it could be seeping into your home.

Anyone who’s watched a cat throwing up after munching on grass knows that our feline friends aren’t natural plant eaters. So you might be surprised to discover that these carnivorous animals share some important genes that are more typically associated with herbivores. And this might help explain why cats aren’t always easy to please when it comes to food.

The ice sheets and glaciers that extend over roughly 11% of the Earth’s land mass are home to a surprisingly abundant source of life. Sections of liquid water beneath and inside the ice provide a habitat for a genetically diverse variety of microbes. And studying these organisms gives us some clue what life may have looked like if there were indeed periods of the planet’s history when the land was entirely covered in ice for millions of years.

It’s the second most abundant substance in the universe. It dissolves more materials than any other solvent. It stores incredible amounts of energy. Life as we know it would not be possible without it. And although it covers more than 70% of the Earth’s surface, many parts of the world are in dire straits for lack of it. What is it?