Fossil fuels sources are depleted. Without fossil fuels there's no agriculture as they are used to produce fertilizers, also tractors, harvesters, etc work on fossil fuels.
It's possible to go back to the technologies of 17th-18th century (wind energy, etc), but these technologies are unable to support the current population of Earth and current lifestyle. Population would have to shrink to the size of the world population from 17th century also. Also, no cheap plastic toys everywhere. No huge suburbs with huge houses and cars with 4-6 liters of displacement to move from home to work.
From reading news it looks like there're no serious science and technology advances. All the advances are concentrated on how to brainwash world population more effectively and extract the money and attention by providing spiffy useless toys like cooler smartphones.