Bill Gates thinks the world needs an "energy miracle" to tackle climate change, and he's optimistic about our chances. The Microsoft co-founder and his wife, Melinda Gates, laid out their vision for the future today in an annual letter published by their eponymous philanthropic organization. Unlike previous letters, this year's version is geared toward teenagers, and is centered around a very childlike question: "If you could have one superpower, what would it be?" For Bill, the answer is energy; for Melinda, it's time.

In his half of the letter, Gates succinctly outlines the environmental and economic quandary that the world faces: a growing population, growing demand for services, and increased energy use. Each of these factors contributes to rising carbon dioxide emissions, a major driver behind climate change, and there's no sign that their upward trends will reverse. But Gates argues that we could still avert environmental disaster by focusing on the carbon dioxide produced by energy — specifically, by reducing it to zero.

In short, we need an energy miracle.

When I say 'miracle,' I don’t mean something that’s impossible. I’ve seen miracles happen before. The personal computer. The Internet. The polio vaccine. None of them happened by chance. They are the result of research and development and the human capacity to innovate.

In this case, however, time is not on our side. Every day we are releasing more and more CO2 into our atmosphere and making our climate change problem even worse. We need a massive amount of research into thousands of new ideas—even ones that might sound a little crazy—if we want to get to zero emissions by the end of this century.

Gates elaborated on his argument in an interview with Bloomberg Business, noting that traditional venture capitalist systems will likely not apply to something as complex as the energy crisis. "There is a $3 trillion market per year for buying energy that is bigger than any prize anyone can come up with," Gates said. "But the time it takes to develop this technology means you need slightly more patient capital. The normal venture capitalist model that has worked for biotech and worked for software is not quite right here." He cited the Breakthrough Energy Coalition — a fund he launched late last year with Facebook CEO Mark Zuckerberg — as a promising new model.

In her half of the letter, Melinda Gates focused on gender equality, and the fact that women across the globe still do far more unpaid work than men. Much of that discrepancy can be attributed to outdated societal norms, she argues, and although rich countries have made progress in reducing the time needed to do basic household chores, those tasks are far more difficult — and economically costly — in poorer countries. Changing that, Gates writes, will require both innovation — "clean energy, better roads, and running water" — as well as a broader challenge to gender-defined roles.

"I know from listening to my kids and their friends—and from looking at polling data about how teenagers see the future—that most girls don’t think they will be stuck with the same rules that kept their grandmothers in the home," she writes. And most boys agree with them."

"I’m sorry to say this, but if you think that, you’re wrong. Unless things change, girls today will spend hundreds of thousands more hours than boys doing unpaid work simply because society assumes it’s their responsibility."

You can read Bill and Melinda Gates' full letter here.