Dimming sunlight may harm crop yields

OSLO: Spraying a veil of sun-dimming chemicals high above the Earth to slow global warming could harm crop yields in an unintended side-effect of turning down the heat, US scientists said. Some researchers say a man-made sunshade, perhaps sulphur dioxide released high in the atmosphere, could limit rising temperatures and the after-effects like the wildfires that have ravaged California and Greece. But a scientific team found that big volcanic eruptions, such as Mount Pinatubo in the Philippines in 1991 and El Chichon in Mexico in 1982, cut yields of wheat, soy and rice after spewing sun-blocking ash that blew worldwide. Pinatubo’s eruption reduced sunlight by 2.5pc, cooled the planet by about 0.5 degree Celsius, and disrupted rainfall patterns.