Global metal prices are expected to rise 9% this year on a pickup in demand and supply constraints, the World Bank said in an update. Accelerating global growth and rising demand are important factors behind broad-based price increases for most commodities and the forecast of higher commodities prices ahead says the bank. Upside risks to the metal price forecast include more robust global demand than expected. Supply could be held back by slow incorporation of new capacity, trade sanctions against metals exporters, and policy actions in China. Downside risks include slower-than-expected growth in major emerging markets, the restart of idle capacity, and an easing of pollution-related policies in China.