reliable resources  like LPG gas,CNG gas,Petroleum,.. etc Fossil fuels,Nuclear power..Now all these process emits energy by which we can light up our home, make food travel by car etc. etc. But by these process co2 and co gases gets produces which are effecting our atmospheric temperature ozone layer etc.So according to your question Exothermic effect of These natural resources are in actually harming us and our world.