About the domes in 1999 AD

[Beach Bum]

Lately I've been wondering about the domes in 1999 AD. Did they make them just because it's futuristic looking, or is there some sort of ecological advantage to it?

[loserone]

I dont think so.
See the house in Anime Dragon Ball.
Cause the designer Akira Toriyama, the house like that (a dome).
Btw some of CT Characters have a similarity with Characters in Dragon Ball.

[Magus22]

They are definitely futuristic looking, and I am sure there are ecological advantages too.

With cities contained in these dome-like structures, the population is protected by weather-related elements, so it may be safe to say that they have advanced environmental controls, and ways of producing food by artificial and natural means, to name a few.

[Acacia Sgt]

Makes me wonder what'd happen with population increase though. On the other hand, there are other structures than the domed cities, though probably are of the same lot, just on a smaller scale.

[Dyxo Xinoro]

Y'know I always had a headcanon that the domes couldn't hold everyone so they started drilling into the earth to make more room without having to leave their domed cities, and in some way that either pissed off Lavos or threatened him.

[Xenterex]

http://en.wikipedia.org/wiki/Monolithic_dome
http://en.wikipedia.org/wiki/Geodesic_dome

there might be some other links that can explain a bit more regarding domes, but as a quick synthesis of my prior understanding and a skim on the articles, there are some advantages to domes and some reasoning for why they seem 'futurey'

Some of the concepts on the structures are several decades old, but structurally, a well-made dome can be deemed very resilient to natural hazards (tornados, earthquakes, etc) and there are some energy efficiency perks as well. 
Most of the concerns from dome construction (and why they're not more popular now) are mostly related to costs because they're unpopular and they're unpopular cuz they're different and somwhat unsettling (esp when considered in a large-community setting where there would be neighborhoods of several domes)

In in the 90's, if not some of the 80's, iirc domes had a bit of a visual surge because they were both 'superior' (in a way) but also very different, which coupled together functions very well for giving a future-projection type of flavor.  A variety of games and other media have experimented with how they project domes and either try to utilize their odd appearance, or try to taper-off some of that uncanny sensation by limiting the quantity and instead projecting a much larger scale (such as a single all within a single dome instead of lots of smaller domes)