Growing demand for biofuels, extreme weather and climate change, and increased financial activity through commodity futures markets are the main causes of high and volatile food prices, according to the 2011 Global Hunger Index report, The Challenge of Hunger: Taming Price Spikes and Excessive Food Price Volatility. These challenges are exacerbated by historically low levels of grain reserves, export markets for staple commodities that are highly concentrated in a few countries, and lack of timely, accurate information on food production, stock levels, and price forecasting, which can lead to overreaction by policymakers and soaring prices.