Another aspect we need to get to grips with in analysing trade is the trade cycle. When
we discussed shipping cycles in Chapters 3 and 4, we saw that part of the cyclical effect
filters through from the demand side of the shipping model. Trade is subject to cycles
at three levels: seasonal cycles which occur regularly at particular times of the year;
short-term cycles which accompany the international business cycle; and long-term
waves arising from structural developments in the international economies.