Tropical forests and the global carbon cycle: impacts of atmospheric carbon dioxide, climate change and rate of deforestation

Abstract

The remaining carbon stocks in wet tropical forests are currently at risk because of anthropogenic deforestation, but also because of the possibility of release driven by climate change. To identify the relative roles of CO 2 increase, changing temperature and rainfall, and deforestation in the future, and the magnitude of their impact on atmospheric CO 2 concentrations, we have applied a dynamic global vegetation model, using multiple scenarios of tropical deforestation (extrapolated from two estimates of current rates) and multiple scenarios of changing climate (derived from four independent offline general circulation model simulations). Results show that deforestation will probably produce large losses of carbon, despite the uncertainty about the deforestation rates. Some climate models produce additional large fluxes due to increased drought stress caused by rising temperature and decreasing rainfall. One climate model, however, produces an additional carbon sink. Taken together, our estimates of additional carbon emissions during the twenty-first century, for all climate and deforestation scenarios, range from 101 to 367 Gt C, resulting in CO 2 concentration increases above background values between 29 and 129 p.p.m. An evaluation of the method indicates that better estimates of tropical carbon sources and sinks require improved assessments of current and future deforestation, and more consistent precipitation scenarios from climate models. Notwithstanding the uncertainties, continued tropical deforestation will most certainly play a very large role in the build-up of future greenhouse gas concentrations.

Remote Sensing-Based and Participatory Analysis of Forests, Agricultural Land Dynamics, and Potential Land Conservation Measures in Kloto District (Togo, West Africa)

“…In the sectors of Agriculture, Forestry and Other Land Use (AFOLU), agriculture remains the main impediment to forest sustainability due to population growth and increasing human needs for food, energy, water, shelter, etc. With a global total area of nearly 4 billion hectares (30% of the Earth's surface cover), forests play a tremendous role when it comes to carbon cycling and ecosystem sustainability in a changing climate [2][3][4][5]. However, population growth associated with increasing food demand, socioeconomic orientations of countries, and political situations underpin the alarming loss of forests and exacerbate land degradation in developing countries.…”

Analytic Webs Support the Synthesis of Ecological Data Sets

“…General circulation models (Cramer et al 2004, Meehl et al 2004) and direct measurements of ecosystem-atmosphere exchange using eddy covariance methods (Baldocchi et al 1988, Hollinger et al 1994, Barford et al 2001 provide data that are used to estimate sources or sinks for C; predict how changes to ecosystems will alter atmospheric CO 2 levels; and forecast how climate change will affect C storage. The data sets are processed with statistical and mathematical models that provide continuous estimates of CO 2 exchange rates.…”

Light-stimulated heat tolerance in leaves of two neotropical tree species, Ficus insipida and Calophyllum longifolium

“…Surface temperatures in the tropics are on the rise (Malhi and Wright 2004;Cramer et al 2004;Diffenbaugh and Scherer 2011). More frequent and prolonged drought periods combined with elevated air temperatures are to be expected (Jentsch and Beierkuhnlein 2008;Lintner et al 2012;Munasinghe et al 2012).…”