Climate-Driven Increases in Global Terrestrial Net Primary Production from 1982 to 1999

Abstract

Recent climatic changes have enhanced plant growth in northern mid-latitudes and high latitudes. However, a comprehensive analysis of the impact of global climatic changes on vegetation productivity has not before been expressed in the context of variable limiting factors to plant growth. We present a global investigation of vegetation responses to climatic changes by analyzing 18 years (1982 to 1999) of both climatic data and satellite observations of vegetation activity. Our results indicate that global changes in climate have eased several critical climatic constraints to plant growth, such that net primary production increased 6% (3.4 petagrams of carbon over 18 years) globally. The largest increase was in tropical ecosystems. Amazon rain forests accounted for 42% of the global increase in net primary production, owing mainly to decreased cloud cover and the resulting increase in solar radiation.

Storage and Turnover of Organic Matter in Soil

“…Most coupled climate carbon-cycle models predict that terrestrial ecosystem productivity increases in the first half of this century due to CO 2 fertilization and moderate increases in temperature, but has moderate declines after that due to more severe changes in climate (Sitch 2003;Gerten 2004;Friedlingstein 2006;Fischlin et al 2007). For example, the productivity of intact Amazonian forests has been increasing over recent decades, variously explained by episodic disturbance and recovery dynamics, changing species distribution, CO 2 fertilization, modest warming, reduced tropical cloud cover, and increased radiation (Nemani 2003;Baker 2004;Chambers and Silver 2004;Lewis 2004;Malhi and Phillips 2004;Boisvenue and Running 2006). These C gains are predicted to be transient, however, due to losses associated with escalating heating and drying trends (Malhi and Phillips 2004).…”

Temperature and Snow-Mediated Moisture Controls of Summer Photosynthetic Activity in Northern Terrestrial Ecosystems between 1982 and 2011

“…Temperature is the main climate constraint on plant growth in the cooler northern regions, whilst soil moisture becomes more important toward the forest-grassland ecotone in the southern boreal region [3]. The rapid warming during recent decades has significantly ameliorated the limitations on plant production by frozen ground and low temperatures [3,4]. This has resulted in widespread lengthening of the growing season, greater photosynthetic activity and enhanced ecosystem carbon sequestration across the northern latitudes [3,[5][6][7][8][9].…”

“…Temperature is the main climate constraint on plant growth in the cooler northern regions, whilst soil moisture becomes more important toward the forest-grassland ecotone in the southern boreal region [3]. The rapid warming during recent decades has significantly ameliorated the limitations on plant production by frozen ground and low temperatures [3,4].…”

“…Vegetation gradients and productivity patterns across the Arctic and boreal terrestrial ecosystems are interactively controlled by temperature, soil moisture, light and nutrient availability during the growing season [1][2][3]. Temperature is the main climate constraint on plant growth in the cooler northern regions, whilst soil moisture becomes more important toward the forest-grassland ecotone in the southern boreal region [3].…”

Large-scale vegetation responses to terrestrial moisture storage changes

“…In many parts of the world, such as Australia, water storage is the dominant limiting factor in vegetation growth (Donohue et al, 2008;Nemani et al, 2003). As such, changes in water storage can lead to changes in vegetation mass and greenness (Yang et al, 2014).…”