Farmers know that sunlight makes crops grow. Now, many are discovering that it is also vital for providing another key agricultural input: fresh water. Irrigation using decentralized renewable energy is witnessing rapid adoption. At the end of 2015, Bangladesh announced targets to support 1,250 solar water pumps by 2018, in a bid to reduce the $900 million spent per year for 1 million tons of diesel fuel to power its irrigation systems. Algeria now has 300MW of solar water pumping capacity and solar irrigation is helping farmers in Syria combat the electricity shortages from the devastating civil conflict. Irrigation is vital for development. Around the world there are 500 million one-acre farmers for whom a good supply of water is critical, not least this year as the drought from El Niño is already threatening 100 million people in Africa, Asia and South America.