It seems that most indicators of
environmental degradation are monotonically rising in income though the
"income elasticity" is less than one and is not a simple function of income alone.
Time related effects reduce environmental impacts in countries at all levels of
income. However, in rapidly growing middle income countries the scale effect,
which increases pollution and other degradation, overwhelms the time effect. In
wealthy countries, growth is slower, and pollution reduction efforts can overcome
the scale effect. This is the origin of the apparent EKC effect.