A supermassive black hole is moving toward Earth at almost the speed of light. As it approaches our planet, its enormous gravitational forces triggers natural disasters larger than any the world has seen.
Since the Industrial Revolution, humans have released over 1.5 trillion tonnes of carbon dioxide or CO2 into the earth's atmosphere. In the year 2019 we were still pumping out around 37 billion more. That’s 50% more than the year 2000 and almost three times as much as 50 years ago. And it’s not just CO2. We’re also pumping out growing volumes of other greenhouse gases such as methane and nitrous oxide. Combining all of our greenhouse gases, we’re emitting 51 billion tonnes of carbon dioxide equivalents each year. And emissions keep rising – but they need to get down to 0!
The air around us is not just empty space; it is an integral part of the chemistry of life. Plants are made from carbon dioxide, nitrogen nourishes the soil and oxygen gives us the energy we need to keep our hearts pumping and our brains alive. But how did we come to understand what air is made of? How did we come to know that this invisible stuff around us contains anything at all?