Climate Fact: East Asian “Greenness” and Temperature Trends
Since 1982, spring in East Asia (defined here as the eastern third of China and the Korean Peninsula) has been warming at a rate of one degree Fahrenheit per decade. In late winter or spring, plants come out of dormancy and produce leaves when the cumulative temperature exceeds a certain threshold. Because temperatures are now warmer, plants in East Asia are beginning to produce vegetation an average of seven days earlier than they did in the late 1970′s, which has been linked to a noticeable rise in the amount of vegetation covering the landscape. This increase in vegetation means an increase in evapotranspiration, or the process through which soil moisture is turned into water vapor when it is absorbed through plant roots and transferred as vapor into the air through leaves. Despite the overall temperature increase, the increase in evapotranspiration has worked to decrease the average springtime maximum surface temperature, as energy from the sun that would otherwise be measured as sensible heat (leading to an actual temperature rise) is instead being stored as latent heat in the water vapor.
Season: Spring
Source: Jeong, SJ et al. “Increase in vegetation greenness and decrease in springtime warming over east Asia.” Geophysical Research Letters 36 (2009): L02710.)
