In earlier work the effects of light intensity over the range 31 to 250 J cm⁻² day⁻¹ and carbon dioxide concentration from 325 to 900 ppm with 8-h days at 18-3 °C and 16-h nights at 15-6 °C were ...

The average level of carbon dioxide in the atmosphere across the globe passed 400 parts per million (ppm) last year, a symbolic and worrying milestone in growth of manmade climate change, the World ...