Changing snow cover in tundra ecosystems tips the Arctic carbon balance

Abstract:

The Arctic environment has witnessed important changes due to global warming, resulting in increased surface air temperatures and rain events which both exacerbate snow cover deterioration (Semmens et al, 2013; Rennert et al, 2009; White et al, 2007; Min et al, 2008; Sharp et al, 2013; Schaeffer et al, 2013). Snow cover duration is declining by almost 20% per decade, a far higher rate than model estimates (Derksen and Brown, 2012). Concomitant with increasing temperatures and decreasing snow cover duration, the length of the arctic growing season is reported to have increased by 1.1 – 4.9 days per decade since 1951 (Menzel et al, 2006), and, plant productivity and CO₂ uptake from arctic vegetation are strongly influenced by changes in growing season length (Myneni et al., 1997; Schaefer et al., 2005; Euskirchen et al., 2006). Based on more than a decade of eddy flux measurements in Arctic tundra ecosystems across the North slope of Alaska, and remotely sensed snow cover data, we show that earlier snow melt in the spring increase C uptake while an extended snow free period in autumn is associated with a higher C loss. Here we present the impacts of changes in snow cover dynamics between spring and autumn in arctic tundra ecosystems on the carbon dynamics and net C balance of the Alaskan Arctic.

References

Derksen, C., Brown R. (2012) Geophys. Res. Lett., doi:10.1029/2012GL053387

Euskirchen, E.S., et al. (2006) Glob. Change Biol., 12, 731-750.

Menzel, A., et al. 2006. Glob. Change Biol., 12, 1969-1976.

Min SK, Zhang X, Zweirs F (2008) Science 320: 518-520.

Rennert K J, Roe G, Putkonen J and Bitz C M (2009) J. Clim. 22 2302–15.

Schaefer, K., Denning A.S., Leonard O. (2005) Global Biogeochem. Cycles, 19, GB3017.

Schaeffer, S. M., Sharp, E., Schimel, J. P. & Welker, J. M. (2013). Soil- plant N processes in a High Arctic ecosystem, NW Greenland are altered by long-term experimental warming and higher rainfall. Glob. Change Biol., 11, 3529-39. doi: 10.1111/gcb.12318.

Semmens KA, Ramage J, Bartsch A, Liston GE. (2013). Environ. Res. Lett., 8, 014020.

White D, et al. (2007) J Geophys Res 112: G02S54. doi:10.1029/2006JG000353.