Malthusianism is the theory that population growth is potentially exponential, according to the Malthusian growth model, while the growth of the food supply or other resources is linear, which eventually reduces living standards to the point of triggering a population decline. This event, called a Malthusian catastrophe occurs when population growth outpaces agricultural production, causing famine or war. Initially, right before the crisis, poverty and inequality will increase as the price of assets and scarce commodities goes up due to fierce competition for these dwindling resources. This increased level of poverty eventually causes depopulation by decreasing birth rates. As time goes on, and asset prices keep increasing, social unrest occurs, which ultimately causes a major war, revolution, or a famine. Societal collapse is an extreme but possible outcome from this process. Such a catastrophe inevitably has the effect of forcing the population to "correct" back to a lower, more easily sustainable level. Malthusianism has been linked to a variety of political and social movements, but almost always refers to advocates of population control.