How would it affect the geography, environment, and gravity of the planet?

Geography: There would be loads of mountains. Mountains are part of geography. Source.

Environment: See above. More mountains.

Gravity: Depends only on the total size of the planet. Mountains don't make much of a difference.

How would it affect the geography, environment, and gravity of the planet?

Geography: There would be loads of mountains. Mountains are part of geography. Source.

Environment: See above. More mountains.

Gravity: Depends only on the total size of the planet. Mountains don't make much of a difference. Source.