In the IPAT expression propounded by Prof. Ehrlich
1
I ⇒ Impact, P ⇒ Population, A ⇒ Asset, T ⇒ Technology
2
I ⇒ Investment, P ⇒ Price, A ⇒ Asset, T⇒ Technology
3
I ⇒ Impact, P ⇒ Population, A ⇒ Affluence, T⇒ Technology
4
I ⇒ Impact, P ⇒ Population, A ⇒ Asset, T ⇒ Trade