2312 by Kim Stanley Robinson.
This was another nominee for the best novel Hugo award.
300 years in the future, humanity has colonized Mercury, Venus, the moon, Mars, Jupiter's moons, and Saturn's moons. Neptune's moons are the next target. There are traveling space colony-ships where various biomes have been recreated, like forests with wolves and deer.
Earth itself is largely fucked. Sea levels have risen a lot (11 meters? enough to completely submerge Florida and make Manhattan into a sort of Venice, where hamster tubes connect fourth-story windows), and the permafrost is melting.
Swan's grandmother, the head of Mercury's government, has died, leaving Swan to sort out the problems she was dealing with when she died. She goes on a lot of travels and meets a lot of people, including Wahram, an ambassador from Titan (Saturn's moon) and a trusted confidant of Swan's grandmother.
The science behind having a colony on Mercury is pretty cool: there's a rolling dome on a track, and the track expands at just the rate to keep the dome rolling forward just beyond the sun. Robinson explains it in rather much detail. There is similarly explained science behind the colonies on the gas giants' moons.
Quantum computers are a thing, and people carry qubes. Swan has one implanted in her head.
There is a lot going on in the novel, and it goes on very slowly. Robinson's world building is exquisitely detailed, and he spends a lot of time introducing the reader to the world he invented, pacing be damned. It took me a long time to get interested in the book, but a hint of anti-capitalism/post-capitalism piqued my interest, so I stuck it out.
One conceit woven into the book, which is hinted at throughout but hammered a bit toward the end, is the notion that Swan, from Mercury, is mercurial, and Wahram, from Saturn, is saturnine. I suspect this play on words was a large part of the impetus behind writing this novel. That part didn't work for me.
As a whole, the book became eventually interesting enough for me to finish, but it didn't start to grip me until I was about 85% through and all the things started to happen at once. Readers who like reading detailed explanations of how space elevators or rolling dome cities work, who want to read a tour book where there are incidentally a couple people meeting and falling (somehow) in love, may not be put off by this.
I thought it was an interesting hard SF thought experiment with very detailed world building and plausible, if still very hand-wavey on some things, explanations of how things reach the point in the novel. If you're into that sort of thing, this book is for you.