Wood Mackenzie forecasts weak global GDP growth over the next five years.Developed economies face structural headwinds such as ageing demographics while emerging markets must address reforms without the cushion of high commodity prices. On top of this cyclical factors are at play. Growth drivers especially in the developed world look unsustainable. Last year we thought these cyclical factors would come to a head in 2018. But with commodity prices worse than expected and political instability deepening it appears that cyclical slowdown has come sooner.