Perturbations in the carbon budget of the tropics

Abstract

The carbon budget of the tropics has been perturbed as a result of human influences. Here, we attempt to construct a ‘bottom-up’ analysis of the biological components of the budget as they are affected by human activities. There are major uncertainties in the extent and carbon content of different vegetation types, the rates of land-use change and forest degradation, but recent developments in satellite remote sensing have gone far towards reducing these uncertainties. Stocks of carbon as biomass in tropical forests and woodlands add up to 271 ± 16 Pg with an even greater quantity of carbon as soil organic matter. Carbon loss from deforestation, degradation, harvesting and peat fires is estimated as 2.01 ± 1.1 Pg annum−1; while carbon gain from forest and woodland growth is 1.85 ± 0.09 Pg annum−1. We conclude that tropical lands are on average a small carbon source to the atmosphere, a result that is consistent with the ‘top-down’ result from measurements in the atmosphere. If they were to be conserved, they would be a substantial carbon sink. Release of carbon as carbon dioxide from fossil fuel burning in the tropics is 0.74 Pg annum−1 or 0.57 MgC person−1 annum−1, much lower than the corresponding figures from developed regions of the world.

Effects of Pulse Density on Digital Terrain Models and Canopy Metrics Using Airborne Laser Scanning in a Tropical Rainforest

“…Tropical forests store large amounts of carbon as biomass and regrowth of tropical forests sequester 1.85 ± 0.09 Pg of carbon annually [1]. However, the annual loss of forest carbon due to deforestation and forest degradation in tropical areas is estimated to 2.01 ± 1.1 Pg [1].…”

El Carbono Acumulado en la Masa Arbórea de la Reserva Biológica Uyuca, Honduras

“…Este fenómeno se ha intensificado debido al aumento de las emisiones de CO2 producto del consumo de hidrocarburos (IPCC 2014). El ciclo del carbono está fuera de equilibrio como resultado del aumento de la combustión de combustibles fósiles por los países ricos y la eliminación de los bosques en los países tropicales (Grace et al 2014). A la vez, el CCG está causando alteraciones en los ciclos hídricos, sequías, inundaciones y otros desastres naturales que comprometen la existencia de la vida en el planeta.…”

Response of CO2 fluxes and productivity to water availability in two contrasting ecosystems in northern Benin (West Africa)

“…Consequently, most ecosystems (anthropogenic and natural) may be significantly modified in the context of climate change and high population growth in West Africa (IPCC 2013;Ajonina et al 2014). Few recent networks underlined that the knowledge of carbon exchanges between atmosphere and ecosystems remains very limited in West Africa (Bombelli et al 2009;Valentini et al 2014;Grace et al 2014). In this context, the analyses of photosynthesis and respiration of terrestrial ecosystems could be important to better understand vegetation responses to extreme climatic events as severe droughts or delayed rains.…”