as for the world ending.. its always good to have some reserves in terms of essentials. 1) freeze dried food 2) water 3) guns/ammo (finite firearms) 4) compound bows/cross bow with extra stockpile of arrows 5) clothing shoes 6) antibiotics/first aid tools (iv bags and starter kits) there are a lot of exponential curves regarding modern civilization. Food production, energy extraction are some, most exponential curves eventually collapse, the primary constraint is cheap energy. Unless a phase shift occurs regarding energy, huge pains will be witnessed. It takes generally 50-75 years for another energy source utilization infrastructure to be implemented. natural gas being the cheapest. Bioengineering/biotechnology, can convert organic matter to energy. The primary organic matter is waste that humans put out. There will always be energy but the cost shifts associated can lead to disruption in civilized way of life. ie bacteria have been engineered to create fuel. http://www.gizmag.com/bacteria-sunlight-co2-renewable-petroleum/18223/