▁Energy ▁intensity ▁Environment al ▁econom ics ▁Energy ▁Account ing ▁ ▁E cod ynam ics ▁E colog ical ▁Econom ics ▁Indust rial ▁e col ogy ▁Population ▁dynamics ▁Resource ▁product ivity ▁ ▁S ust ain ability ▁account ing ▁S ust ain able ▁development ▁Systems ▁e col ogy ▁Th erm oe conom ics ▁ ▁References ▁ ▁Category : S ust ain ability ▁metrics ▁and ▁indices ▁Category : N atural ▁resource ▁management ▁Category : Resource ▁econom ics ▁Category : Th erm od ynam ics ▁Category : E ner gy ▁econom ics <0x0A> </s> ▁Dark ▁Age ▁is ▁a ▁ 2 0 1 9 ▁science ▁fiction ▁novel ▁by ▁American ▁author ▁Pier ce ▁Brown , ▁the ▁second ▁book ▁of ▁a ▁tr il ogy ▁which ▁continues ▁the ▁story ▁of ▁his ▁Red ▁R ising ▁tr il ogy ▁( 2 0 1 4 – 2 0 1 6 ). ▁Dark ▁Age ▁takes ▁place ▁immediately ▁after ▁the ▁events ▁of ▁Iron ▁Gold ▁( 2 0 1 8 ), ▁as ▁the ▁remaining ▁Society ▁forces ▁aim ▁to ▁take ▁back ▁Mercur y ▁from ▁the ▁Sol ar ▁Republic . ▁ ▁Public ation ▁Brown ▁announced ▁a ▁sequ el ▁tr il ogy ▁to ▁Red ▁R ising ▁in ▁February ▁ 2 0 1 6 . ▁The ▁title ▁of ▁the ▁second ▁install ment , ▁Dark ▁Age , ▁was ▁announced ▁in ▁February ▁ 2 0 1 8 ▁soon ▁after ▁the ▁release ▁of ▁Iron ▁Gold . ▁Dark ▁Age ▁was ▁released ▁on ▁July ▁ 3 0 , ▁ 2 0 1 9 , ▁and ▁deb uted ▁at ▁# 4 ▁on ▁The ▁New ▁York ▁Times ▁Best ▁S