A controversial debate between financial speculation and changes in agricultural commodity spot prices

Some research works state that speculation with agricultural commodities on the futures market has risen agricultural commodity spot prices. This research work analyzes the causal relationships between spot prices of corn, wheat, and soybean and agricultural commodity futures trading activities. These causal relationships between agricultural commodity spot prices and financial variables are tested for Granger-causality. Model results show that causal relationships have been found among changes in “volume traded” and “open positions” of futures contracts and changes in spot prices for corn. These results do not show that financial speculation might be a major driver of rising agricultural commodity prices.

Do Global CO2 Emissions from Fossil-Fuel Consumption Exhibit Long Memory? A Fractional Integration Analysis

In this article we use an autoregressive fractionally integrated moving average approach to measure the degree of fractional integration of aggregate world CO2 emissions and its five components – coal, oil, gas, cement, and gas flaring. We find that all variables are stationary and mean reverting, but exhibit long-term memory. Our results suggest that both coal and oil combustion emissions have the weakest degree of long-range dependence, while emissions from gas and gas flaring have the strongest. With evidence of long memory, we conclude that transitory policy shocks are likely to have long-lasting effects, but not permanent effects. Accordingly, permanent effects on CO2 emissions require a more permanent policy stance. In this context, if one were to rely only on testing for stationarity and non-stationarity, one would likely conclude in favour of non-stationarity, and therefore that even transitory policy shocks