Meta: I honestly didn't read the plan in full the first two times I posted. Instead I went to Wikipedia and looked up global catastrophic risk. Then once I had an understanding of what the definition of global catastrophic risk is; I thought up solutions (How would I best solve X) and checked if they were on the map.

The reason why I share this is because the first several things I thought of were not on the map. And it seems like several other answers are limited to "whats outside the box" (Think outside the box is a silly concept because it often involves people telling you exactly where the box is and where to think outside of) and indicated by things near the existing map. I am not sure that you are getting great improvements to the map from the way you have set the problem.

New idea: If I were hosting the map there would be a selection of known x-risk problems.
Something like:

AI:

• paperclippers
• UFAI
• Oppressive AI (modifies our quality of life)
• trickster AI (AI built with limits, i.e. human happiness - redefines its own reference term for human and happiness and kills all old humans that are not happy)

Nanotechnology:

• 2nd gen Molecular assembly that escapes containment (on purpose or by accident)
• Race to profit includes a game of chicken to take the highest risk.

Biotechnology:

• new disease with no known relationship to existing diseases and high virulence (difficult to cure)
• new strain of old disease (known effect and a race to fight it off)

Nuclear:

• catastrophic death of all life by nuclear war and ongoing radiation
• reduction of lifespan due to radioactivity induced cancer. (possibly reducing us back to pre-colonial civilisation)
• concerning speed of mutation due to nuclear particles (either in humans or in things that harm us or ensure our wellbeing, i.e. viruses, food supplies)

Global climate:

• planet becomes uninhabitable to humans
• planet becomes less habitable to humans - slows down growth of science/technology
• humans are forced underground limiting the progress of scientific research or our ability to sustain food produce.
• humans are cut off from each other and forced to live in small colonies

And what each of the solutions on the solution map might help solve.

Edits: formatting. I still can't get the hang of formatting after this long!

Edit: it looks like you are working on other maps at http://immortality-roadmap.com/.