This article in the New Scientist entitled 'Methane controls before risky geoengineering, please' by Prof. Kirk Smith, makes the following points:

This paper argues that organic agriculture can feed the world. The authors state that the principal objections to the proposition that organic agriculture can contribute significantly to the global food supply are low yields and insufficient quantities of organically acceptable fertilizers. They evaluate the universality of both claims. 

Because food is a basic necessity, the agriculture sector is showing more resilience to the global economic crisis than other industries. But the risks could increase if the economic downturn deepens. Falls in agricultural prices and in the production and consumption of farm goods are likely to be moderate as long as the economic recovery begins within two to three years. As the downturn lowers food prices, pressure is eased on recession-hit consumers who have less money to spend, it says.

A paper published in June 2009 , asks Can organic agriculture feed the world? and argues that it cannot. (K. W. T. Goulding and A. J. Trewavas, AgBioView, June 24 2009, Rothamsted Research, Harpenden and Institute of Molecular Plant Science, University of Edinburgh). In a recent publication, Badgley et al. (2007) claimed that organic farming, if used worldwide, would provide sufficient food for a growing world population. This claim was based on a literature survey of two kinds:

The House of Commons' International Development Committee has published this report in June 2009, summary as follows: