Some known problems cannot be addressed by humans on Earth, and include:

• The eventual exhaustion of hydrogen in the Sun and the star's transformation.
• A sudden appearance of a black hole that could consume our planet.
• A burst of gamma rays from a close supernova that destroys our ozone layer and expose us to ultraviolet rays from the Sun.
• A surprise asteroid strike that destroys a large part of the planet and blacks out the Sun.

We don't have implementable solutions to these problems, but we also cannot worry about everything. We can only address issues as they arise.