Y.Y. Liu, A.I.J.M. van Dijk, R.A.M. de Jeu, J.G. Canadell, M.F. McCabe, J.P. Evans, G. Wang
Nature Climate Change, 5,
Vegetation change plays a critical role in the Earth’s carbon (C) budget
and its associated radiative forcing in response to anthropogenic and
natural climate change1, 2, 3, 4.
Existing global estimates of aboveground biomass carbon (ABC) based on
field survey data provide brief snapshots that are mainly limited to
forest ecosystems5, 6, 7, 8.
Here we use an entirely new remote sensing approach to derive global
ABC estimates for both forest and non-forest biomes during the past two
decades from satellite passive microwave observations. We estimate a
global average ABC of 362 PgC over the period 1998–2002, of which 65% is
in forests and 17% in savannahs. Over the period 1993–2012, an
estimated −0.07 PgC yr−1 ABC was lost globally, mostly resulting from the loss of tropical forests (−0.26 PgC yr−1) and net gains in mixed forests over boreal and temperate regions (+0.13 PgC yr−1) and tropical savannahs and shrublands (+0.05 PgC yr−1).
Interannual ABC patterns are greatly influenced by the strong response
of water-limited ecosystems to rainfall variability, particularly
savannahs. From 2003 onwards, forest in Russia and China expanded and
tropical deforestation declined. Increased ABC associated with wetter
conditions in the savannahs of northern Australia and southern Africa
reversed global ABC loss, leading to an overall gain, consistent with
trends in the global carbon sink reported in recent studies.