ISTANBUL The World Day to Combat Desertification and Drought is being marked on Tuesday with a grim reminder that 1 million square kilometers of productive land become degraded due to desertification every year and nearly 40% of the Earth’s land surface is classified as degraded. Observed annually with a different theme, the UN officially designated June 17 as “Desertification and Drought Day” in 1994 to raise awareness and mobilize action to combat desertification, land degradation, and