I’ve had a daydream since I was young: if I suddenly became fabulously rich, what would I spend my money on? And while most of us will never have the opportunity to indulge on a massive scale, there is a lot of money out there, sloshing around in the world economy. A lot of it doesn’t seem to be doing much good – but what if we could get hold of some of it?

I turned my daydream into a thought experiment in my new book, How to Spend a Trillion Dollars. It imagines we have control of one per cent of world gross domestic product, which comes to about $1 trillion. By comparison, the richest 1% of people in the world own about $162 trillion in assets. I set some rules: no spending on military projects, and no spending on media or politics. You have to spend a trillion dollars on projects to improve human health and welfare, advance scientific knowledge, or protect and save the environment. I came up with ten megaprojects. From solving world poverty, to searching for alien life in solar system and beyond. I look at spending money aimed at curing all diseases and extending human lifespan, and at establishing a lasting human settlement on the Moon. There is an incredible amount of things we could do, for what in the grand scheme of things is not that much money.

The world faces many problems. The most pressing are the problems of climate change and the collapse of biodiversity. These are huge issues, and frankly some scenarios we could see in the coming years and decades are quite terrifying. But what I found in my book is that we already have the means to solve these problems. It will take political will, society will need to change, and our consumption will need to become sustainable, but the solutions are there and investment in the right areas can really do good – it could, in fact, save the world.

This decade is one of the most consequential in the history of the world. What we do now, in the next few years, will shape the planet for centuries to come. I’ve outlined the ways we can do this. From speeding the transition of our energy use away from fossil fuels, to restoring and protecting vast areas of land and sea in order to drawdown carbon dioxide from the atmosphere and to tackle the extinction crisis. We don’t have the trillion dollars, but the more we understand that the world’s problems can be solved, the more optimism and momentum we can build, and the more pressure and influence we can put on the rich and powerful people in the world. 

We can do this. Indeed, we must do this. How would YOU spend the money?