The policies or “smart contracts” currently under development are based on blockchain, the distributed ledger technology that underpins cryptocurrencies like bitcoin. This avoids the need for paperwork and means payouts can be triggered automatically when certain conditions are met, such as a specific number of days of drought. The system uses high-resolution satellite images to detect rainfall and plant growth data.Conventional crop insurance is too expensive for more than 500m small farmers worldwide, says Christopher Sheehan, founder and chief executive of US-based WorldCover, which developed the system. “But with machine learning and blockchain technology, we can process these data very cheaply to produce a really simple crop insurance product with premiums of $20 to $50 for a farmer who might only be earning $3,000 a year.” Payments can be made using mobile money transfer services such as M-Pesa.