Mankind's future will be greatly impacted by multiple global environmental changes underway and societal needs throughout the 21st Century. They must be effectively addressed and resolved for the sustainable continuation of civilization, as we know it today. The traditional major religions of the world must also change if they are going to have relevancy and provide value in the future. Such religions must realize the need to tolerantly and respectfully work together, contributing altruistically their combined efforts to meet these future humanitarian needs. Mistakes of the past can no longer be repeated, as the consequences facing all mankind and our global future are considerable. These include a 4-7 F increase in average global temperatures, severe weather and climate changes with extended durations, rising sea levels, which will impose substantial impacts and flooding on all coastal cities and seaports affecting a majority of the world's population, economies, and governments' abilities including the present UN to respond. A global population crisis, where the planet's current 6.5 billion people will double by 2050, and double again to over 25 billion people before the end of the century if current inaction on birth control continues at present annual rates (1.9%) in two-thirds of the world. These events and associated problems are all underway and presently unabated in slowing down! Throughout history religions committed many grievous errors and imposed much misery on mankind. Such blind religious belief driven destructive events must not continue. A sustainable future for all will be provided not by traditional religious beliefs of the past and present, but by the formation of anew democratic "world government," and scientific leading-edge research. They're applications and knowledge gained must serve and provide for the betterment and benefit of all mankind, while preserving the planet's critical environmental and ecological systems.