Amazon Deforestation and Climate Change in a Coupled Model Simulation

Abstract

The impacts of Amazon deforestation on climate change are investigated through the use of twin numerical experiments with an Atmospheric General Circulation Model (AGCM) with prescribed global sea surface temperature and the same AGCM coupled to an ocean GCM over the global-tropics (CGCM).An ensemble approach is adopted, with ten member ensemble-averages of a control simulation compared with perturbed simulations for three scenarios of Amazon deforestation. The latest 20 years of simulation from each experiment are analyzed. Local surface warming and rainfall reduction are simulated by both models over the Amazon basin, with the coupled model presenting rainfall reduction that is nearly 60% larger compared to its control run than those obtained by the AGCM. The results also indicated that both the fraction of the deforested area and the spatial continuity of vegetated area might be important for modulating global climate variability and change. Additionally, significant remote atmospheric responses to Amazon deforestation scenarios are detectable for the coupled simulations, which revealed global ocean and atmosphere circulation changes conducive to enhanced ocean-atmosphere variability over the Pacific Ocean. This, in turn, is interpreted as a manifestation of enhanced El Niño-Southern Oscillation (ENSO) activity over the Pacific and a positive feedback contributing to the extra rainfall reduction over the Amazon on the coupled simulations.

The representation of landscapes in global scale assessments of environmental change

“…Ecological restoration often focuses on reestablishing connections in the landscape such as ecological corridors to avoid isolation and create resilience against shifts in climate conditions by allowing migration of species (Heller and Zavaleta 2009;Jongman et al 2011). Designing appropriate conservation networks may help avoiding negative feedbacks of climate change on Amazon vegetation (Nobre et al 2009;Walker et al 2009). These examples indicate that while global environmental change emerges from local changes in landscapes also many options to mitigate and adapt to global changes are found in modifying the composition, spatial structure and management of these landscapes.…”

The Green Ocean: Precipitation Insights from the GoAmazon2014/5 Experiment

“…The inability of GCMs to adequately represent cumulus clouds and precipitation over the Amazon highlights one example of the observational needs for future improvement to GCM cloud parameterizations and the larger-scale 10 circulation connections therein (e.g., Richter and Xie, 2008;Nobre et al, 2009;Yin et al, 2013). A low-level barrier when developing useful observational constraints is the shortage of long-term datasets for reference within tropical regions such as the Amazon basin.…”

Mudanças climáticas e mitigação no setor florestal: REDD+, políticas nacionais e desenvolvimento sustentável local na Amazônia Legal

“…Estudos sugerem que o desmatamento na Amazônia irá provavelmente reduzir a precipitação e aumentar a temperatura na superfície e a extensão do período de seca na região (FINDELL et al, 2006;KILLEM;SOLÓRZANO, 2008;NOBRE et al, 2009). A destruição da Amazônia e as mudanças no ciclo hidrológico na região deverão impedir a reconstituição da floresta (SHUKLA et al, 2015).…”

“…Diante disso, a preservação das florestas tropicais tem ganhado especial atenção, tendo em vista seu potencial mitigador (BUSCH; FERETTI-GALLON, 2014) e, também, as consequências regionais do desmatamento e da degradação das florestas (NOBRE et al, 2009). Nesse contexto, a REDD+ (Reducing Emissions from Deforestation and Forest Degradation and Enhancement of Carbon Stocks) tem desenvolvido parcerias para disseminar conhecimento e alavancar fundos para a promoção de iniciativas de proteção às florestas dos países em desenvolvimento (ANGELSEN, 2012;UN-REDD, 2015).…”