QuickTake Bloomberg

The future of money is in your pocket — the one you keep your phone in, not your wallet. A growing portion of the world’s population is making phone-assisted transactions. They’re using a variety of technologies, from the text-message system popular in Kenya to the seamless credit card-and-app arrangements that move money for every Lyft and Uber ride. It’s a revolution that’s lagged in the U.S., despite offerings from Apple Inc. and a range of big retailers. In addition to providing convenience and sometimes lower fees than credit cards, these mobile-payment systems are connecting millions of previously unbanked people: In China, some beggars hold out bar codes instead of tin cups. In places such as Sweden where the apps are especially popular, cash is starting to disappear. And beyond the cash register, it’s clear that a good chunk of the traditional consumer-banking business stands to be upended.

When factories belch smoke, everybody pays. Shouldn’t polluters be the ones to feel the sting instead? That’s the big idea behind carbon pricing: Add a levy so that emissions of greenhouse gases have a cost in line with their environmental damage. Using market forces should be the most efficient way to get companies to change their ways and to fight climate change. More countries are warming to the concept, but policy makers can’t agree on the best way to do it. Europe, parts of the U.S. and China use exchanges where companies buy and sell permits to pollute. There's vigorous debate about whether those markets work better than a simple carbon tax.

Call anything a Category 5 storm, disaster or crisis and immediately it sounds awful. The label owes much of its weight to the Saffir-Simpson Hurricane Wind Scale, which is cited routinely (if rarely by its full name) this time of year during the Atlantic hurricane season. But destructive storms like Hurricane Florence underscore the inherent weaknesses in the scale, and efforts continue to try to replace it with something more useful.

When it comes to saving the world’s rainforests, governments can make a big difference, and fast. Take Indonesia, which in 2012 surpassed Brazil as the world’s leader in tropical rainforest destruction. In 2017, it engineered a 60 percent drop in tree loss from the previous year by strictly enforcing protections in vulnerable regions. On the other hand, governments can reverse course just as swiftly. Take Brazil, where a decade-long trend of improving forest protections has now gone into reverse. It’s a concern both in and beyond the tropics, with multinational companies coming under increasing pressure to stop doing business with suppliers that ravage the environment. Rainforests host half the species on Earth, help regulate global weather patterns and produce much of the planet’s oxygen. Their disappearance, through burning or felling, creates about 10 percent of the greenhouse gases the world produces in a given year that drive climate change. By one estimate, more tropical tree cover was lost globally in 2016 and 2017 than in any other years this century.

Not so long ago, homebuyers, entrepreneurs and investors went hat-in-hand to the bank to apply for a mortgage, small-business credit line or brokerage account. Financial technology, or fintech, is rapidly changing all that by making it easier to save, borrow and invest online or with a mobile device, without ever dealing with a traditional bank. For old-fashioned banks and money managers, fintech is causing dramatic upheaval, possibly the most since mainframe computers first whirred to life on Wall Street in the 1960s. It’s caught the attention of regulators, consumer advocates and industry veterans. Will a digitized financial-services industry mean lower costs, more innovation and greater access for all? Or will the dominant players ultimately stay on top, with their hefty fees, commissions and compensation, largely intact?

A surge in mobile-data demand worldwide has more and more people asking when they’ll get that speedy next-generation 5G mobile service. Companies are wondering, too, since 5G has the potential to revolutionize everything from self-driving cars to robotic surgery. Mobile providers are racing to patent technologies that will form the industry standards and build working networks. Yet not all nations are embracing the push with equal vigor. And concerns about China’s ability to use 5G equipment to spy on other nations may limit its manufacturers’ ability to profit from the world’s next mobile upgrade.