The Bill and Melinda Gates Foundation has been focusing on toilets for some time. The foundation believes toilets are a key to health and economic growth across the developing world. As Bill Gates said recently in a speech, "More than half the world's population doesn't have the safe sanitation they need to lead healthy and productive lives." In addition to spreading disease, he added, "Unsafe sanitation also puts a huge economic burden on countries that can least afford it. Globally, it costs an estimated $223 billion a year in the form of higher health costs and lost productivity and wages."

Back in 2012 the foundation announced four winners of a "Reinvent the Toilet Challenge," and went on to launch a second round of grants to university research departments. By 2018 new generation toilets were being rolled out across India, and last November Bill Gates opened a "Reinvented Toilet Expo" in Beijing, holding a jar of human feces as he explained the reasons toilets are fundamental for human health.

Some of the technologies? A solar-powered toilet generating hydrogen and electricity, a toilet producing biological charcoal, minerals, and clean water, and a waterless toilet with nano membranes and combustion to turn solid waste to ash, powered by the movement of closing the toilet lid. The "Tiger Toilets" popular in India take advantage of a worm that thrives on human feces and digests it into valuable garden compost.

And now researchers at Georgia Tech, with engineers from Switzerland's Helbling Technik, are working on a "Generation 2 Reinvented Toilet" challenge. This team is looking to espresso machines for inspiration, because they think there are pressure, liquid and heat lessons that could be applicable to toilets.

The challenge is to move away from the need for water and electricity inputs, find ways to turn waste into useful material, and make toilets that can be produced, installed and managed very cheaply.

And as the initial research phase continues to result in workable prototypes, the toilet business can be expected not only to save billions of people from disease and put them on the path to longer and more productive lives, it can also be a powerful engine for economic growth: billions of cheap toilets could be sold in new markets for significant profit. Bill Gates estimates that by 2030, toilets will be a $6 billion a year global business opportunity.

Our climate is changing rapidly. A quarter of the world's population is at risk of drought; the threat of Amazon deforestation has never been so critical; and Ebola is making a comeback. This is a time when it makes more sense for entrepreneurs to think about global needs and their solutions, rather than the next gadget wealthy Westerners might like to add to their already overflowing collection of comforts. In the 21st century, it's clear that we need to reduce, not increase, Western consumption if we want to respect planetary limitations. At the same time, there is a huge growth market in elevating the living standards of underserved people.

The toilet example paints this picture well.

It's a way of putting technology to use for a better world, and we should refocus all our R&D in this way. Don't we want to use technology to help feed a growing global population, in the face of potential food scarcity due to weather events? Don't we want to use it to bring electricity to those in the dark? And don't we want to envision a world where people find ways to make life more meaningful and abundant?

Let's start with toilets.