Sachs suggests that with improved seeds, irrigation and fertilizer, the crop yields in Africa and other places with subsistence farming can be increased from 1 ton per hectare to 3 to 5 tons per hectare. He reasons that increased harvests would significantly increase the income of subsistence farmers, thereby reducing poverty. Sachs does not believe that increased aid is the only solution. He also supports establishing credit and microloan programs which are often lacking in impoverished areas. Sachs advocates the distribution of free insecticide-treated bed nets to combat malaria. The economic impact of malaria has been estimated to cost Africa $12 billion per year. Sachs estimates that malaria can be controlled for $3 billion per year, therefore suggesting that anti-malaria projects would be an economically justified investment.