The problem is, they disagree with each other, often impolitely. Instead it spins out many futures, each assuming that folks with one particular bias make the policy and that the world actually does, or does not, behave the way their bias expects it to behave. For short I call them red, blue, and green. Reds see the world as full of risks, but none that can't be handled by informed experts and intelligent governance. Global warming is real, but it can be controlled with carbon taxes and regulations.
Population growth needs to be subdued with strong family planning programs.
Poverty, water scarcity, environmental destruction can all be solved with vigorous bureaucratic measures. Blues have a cheerier world view. Risks are small, nature is resilient, the planet is huge, humans are ingenious. All that's needed is for those overbearing reds to get out of the way and let entrepreneurs and new technologies take over. The future promises great abundance, unless we regulate everything to death.