This morning in Aspen there’s a session anticipating next year’s Rio summit, which marks the 20th anniversary of the Earth Summit of 1992. I was lucky enough to be there, back in the day. Good times! Hung out with some great journalists, including P.J. O’Rourke, Marc Cooper and Gene Robinson. One vivid memory: Al Gore, drenched in sweat in the sweltering heat of a tent full of activists down by the beach, delivering a full-throated speech on the perils of global warming. Oh, and drinking beers at an outdoor bar with John Denver, who talked of his dream of becoming an astronaut. And good eatin’: At restaurants the meat kept coming, carved tableside. Strap on the feed bag. (Question: Can a consumer society create a green planet?)

Gore has been proved right: climate change is real, and has solidified as a central environmental challenge of our time, a problem that shadows any conversation about economic development in the decades ahead. The assertions of climate-change deniers (or skeptics, or whatever they want to call themselves) have been steadily and serially repudiated by scientific research and the facts on the ground, particularly in the Arctic. (Stewart Brand’s book “Whole Earth Discipline” notes that at least 65 surface ships have now visited the North Pole, so drastic has been the loss of sea ice.)

Since 1992, moderator Jacob Scherr of NRDC tells us, the Earth has added a billion people. There has been progress on some fronts: Hundreds of millions of people have emerged from poverty. They’re far more connected. A billion people use social media, and 1.7 billion are on the Internet. Cellphones are common in the developing world: There are 5 billion cellphone contracts today (!). Recall that, in 1992, we had an Internet and many of us used email, but we had no World Wide Web — not graphical interface — and no browsers. No search engines.

Did any of us, in Rio that year, grasp how radically the Internet and digital technology more generally would transform our lives? And our businesses?

What is just around the corner today that we haven’t anticipated?

What’s the next game-changer?

Cheap solar power, highly distributed, maybe? No more giant grid, no more need for coal-fired base-load generators?

When he was in Rio, Scherr said, he was amazed that he could communicate with his wife back in the States via this device known as a cellphone. I don’t remember how I filed my stories then but I’m guessing it was by laptop connected to a hotel phone line; if you weren’t in the hotel, or in a filing center with hard lines, you were unable to report on what you were seeing and hearing. We certainly didn’t live-blog anything.

On the other hand, it was easier to concentrate.

We weren’t expected to be connected 24 hours a day.

We could actually LISTEN to the people on stage rather than trying to listen and write and write an SEO headline at the same time.