Seasonal vegetation response to climate change in the Northern Hemisphere (1982–2013)

Abstract

This study investigated vegetation response to climate change exhibited by temperature, soil moisture, and solar radiation at Northern Hemisphere (NH) scale during the growing season and seasonal periods by analyzing satellite observations of vegetation activity and climatic data for a period of 1982–2013. Generally, About 75.8% of NH was dominated by increasing NDVI3g during growing season in 1982–2013, and 50.7% significantly increase. Autumn NDVI3g is the main cause, with 77.7% increase (45.0% significantly increase). The increasing tendency of greenness was stalled and even shifted to vegetation browning after 1994–1997 specifically in Central Europe, Northern North America, and Central Siberia. NDVI3g increase during the growing season shifts from 0.017year−1 to 0.006year−1, which mainly due to decreased spring NDVI3g and slowdown of summer NDVI3g increase. Specifically, three time intervals were identified with relatively peak NDVI3g, i.e., 1990, 1997 and 2010, and three time intervals with trough NDVI3g, i.e., 1983, 1992–1994, 2002–2005. The factors potentially influencing vegetation growth in different parts of NH are complex and varied. Temperature is recognized as the critical factor behind vegetation greenness in high latitudes especially for spring and autumn temperature, in North America and Siberia. Soil moisture is the key factor influencing vegetation growth in central Canada, eastern USA and western Africa. And solar radiation is corresponding to vegetation trend in North part of North America, eastern China. This study helps identify key factors for vegetation changes and understand vegetation response to climate change at NH scale.