AGW Observer

Observations of anthropogenic global warming

Papers on Amazon and global warming

Posted by Ari Jokimäki on February 1, 2010

This is a list of papers on the effect of global warming to the Amazon rainforest. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

UPDATE (February 3, 2010): 2 x Phillips et al. (2009) added, thanks to Skeptical Science for pointing them out (see the comment section below).

Drought Sensitivity of the Amazon Rainforest – Phillips et al. (2009) “We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. … Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 x 1015 to 1.6 x 1015 grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change.” [Full text] [Conference abstract]

Changes in Amazonian Forest Biomass, Dynamics, and Composition, 1980–2002 – Phillips et al. (2009) “Long-term, on-the-ground monitoring of forest plots distributed across Amazonia provides a powerful means to quantify stocks and fluxes of biomass and biodiversity. Here we examine the evidence for concerted changes in the structure, dynamics, and functional composition of old-growth Amazonian forests over recent decades. … The most likely driver(s) of changes are recent increases in the supply of resources such as atmospheric carbon dioxide, which would increase net primary productivity, increasing tree growth and recruitment, and, in turn, mortality. In the future the growth response of remaining undisturbed Amazonian forests is likely to saturate, and there is a risk of these ecosystems transitioning from sink to source driven by higher respiration (temperature), higher mortality (drought), or compositional change (functional shifts toward lighterwooded plants).” [Full text]

Exploring the likelihood and mechanism of a climate-change-induced dieback of the Amazon rainforest – Malhi et al. (2009) “We examine the evidence for the possibility that 21st-century climate change may cause a large-scale “dieback” or degradation of Amazonian rainforest. … We then examine climate simulations by 19 global climate models (GCMs) in this context and find that most tend to underestimate current rainfall. … Our analysis suggests that dry-season water stress is likely to increase in E. Amazonia over the 21st century, but the region tends toward a climate more appropriate to seasonal forest than to savanna.” [Full text]

Interactions among Amazon land use, forests and climate: prospects for a near-term forest tipping point – Nepstad et al. (2008) “Rising worldwide demands for biofuel and meat are creating powerful new incentives for agro-industrial expansion into Amazon forest regions. Forest fires, drought and logging increase susceptibility to further burning while deforestation and smoke can inhibit rainfall, exacerbating fire risk. If sea surface temperature anomalies (such as El Niño episodes) and associated Amazon droughts of the last decade continue into the future, approximately 55% of the forests of the Amazon will be cleared, logged, damaged by drought or burned over the next 20 years, emitting 15–26 Pg of carbon to the atmosphere.” [Full text]

Towards quantifying uncertainty in predictions of Amazon ‘dieback’ – Huntingford et al. (2008) “We analyse how the modelled vegetation cover in Amazonia responds to (i) uncertainty in the parameters specified in the atmosphere component of HadCM3 and their associated influence on predicted surface climate. … The potential for human-induced climate change to trigger the loss of Amazon rainforest appears robust within the context of the uncertainties explored in this paper.” [Full text]

Climate Change, Deforestation, and the Fate of the Amazon – Malhi et al. (2008) “The forest biome of Amazonia is one of Earth’s greatest biological treasures and a major component of the Earth system. This century, it faces the dual threats of deforestation and stress from climate change. Here, we summarize some of the latest findings and thinking on these threats, explore the consequences for the forest ecosystem and its human residents, and outline options for the future of Amazonia.” [Full text]

New views on an old forest: assessing the longevity, resilience and future of the Amazon rainforest – Maslin et al. (2005) “The aim of this paper is to investigate the longevity and diversity of the Amazonian rainforest and to assess its likely future. Palaeoclimate and palaeoecological records suggest that the Amazon rainforest originated in the late Cretaceous and has been a permanent feature of South America for at least the last 55 million years. The Amazon rainforest has survived the high temperatures of the Early Eocene climate optimum, the gradual Cenozoic cooling, and the drier and lower carbon dioxide levels of the Quaternary glacial periods. Two new theories for the great diversity of the Amazon rainforest are discussed – the canopy density hypothesis and the precessional-forced seasonality hypothesis. We suggest the Amazon rainforest should not be viewed as a geologically ephemeral feature of South America, but rather as a constant feature of the global Cenozoic biosphere. The forest is now, however, entering a set of climatic conditions with no past analogue. The predicted future hotter and more arid tropical climates may have a disastrous effect on the Amazon rainforest.” [Full text]

The role of ecosystem-atmosphere interactions in simulated Amazonian precipitation decrease and forest dieback under global climate warming – Betts et al. (2004) “A suite of simulations with the HadCM3LC coupled climate-carbon cycle model is used to examine the various forcings and feedbacks involved in the simulated precipitation decrease and forest dieback. Rising atmospheric CO2 is found to contribute 20% to the precipitation reduction through the physiological forcing of stomatal closure, with 80% of the reduction being seen when stomatal closure was excluded and only radiative forcing by CO2 was included. … The precipitation reduction is enhanced by 20% by the biogeophysical feedback, and 5% by the carbon cycle feedback from the forest dieback.” [Full text]

Contrasting simulated past and future responses of the Amazonian forest to atmospheric change – Cowling et al. (2004) “We contrasted HadCM3LC simulations of Amazonian forest at the last glacial maximum (LGM; 21 kyr ago) and a Younger Dryas–like period (13–12 kyr ago) with predicted responses of future warming to provide estimates of the climatic limits under which the Amazon forest remains relatively stable. Our simulations indicate that despite lower atmospheric CO2 concentrations and increased aridity during the LGM, Amazonia remains mostly forested, and that the cooling climate of the Younger Dryas–like period in fact causes a trend toward increased above–ground carbon balance relative to today. … Although elevated atmospheric CO2 contributes to a positive enhancement of plant carbon and water balance, decreased stomatal conductance and increased plant and soil respiration cause a positive feedback that amplifies localized drying and climate warming. We speculate that the Amazonian forest is currently near its critical resiliency threshold, and that even minor climate warming may be sufficient to promote deleterious feedbacks on forest integrity.” [Full text]

Using a GCM analogue model to investigate the potential for Amazonian forest dieback – Huntingford et al. (2004) “A combined GCM analogue model and GCM land surface representation is used to investigate the influences of climatology and land surface parameterisation on modelled Amazonian vegetation change. … The timing of forest dieback is found to be sensitive to the initial pre-industrial climate, as well as uncertainties in the representation of land-atmosphere CO2 exchange. … Further advances are required in both GCM rainfall simulation and land-surface process representation before a clearer picture will emerge on the timing of possible Amazonian forest dieback.”

A crisis in the making: responses of Amazonian forests to land use and climate change – Laurance (1998) “At least three global-change phenomena are having major impacts on Amazonian forests: (1) accelerating deforestation and logging; (2) rapidly changing patterns of forest loss; and (3) interactions between human land-use and climatic variability. Additional alterations caused by climatic change, rising concentrations of atmospheric carbon dioxide, mining, overhunting and other large-scale phenomena could also have important effects on the Amazon ecosystem.”

2 Responses to “Papers on Amazon and global warming”

  1. Timely list, many thanks, Ari! Here’s a few others:

    Drought Sensitivity of the Amazon Rainforest
    http://www.sciencemag.org/cgi/content/abstract/323/5919/1344?siteid=sci&ijkey=93KA4UC7rkg4g&keytype=ref
    Full Paper: http://www.saber.ula.ve/bitstream/123456789/27334/1/drought_sensitivity.pdf

    Drought sensitivity of the Amazon carbon sink (alas, no abstract)
    http://adsabs.harvard.edu/abs/2009E&ES….6d2004P

    Changes in Amazonian Forest Biomass, Dynamics, and Composition, 1980–2002
    Full paper: http://www.geog.leeds.ac.uk/projects/rainfor/papers/2008GM000739-KE-Phillips.pdf

  2. Ari Jokimäki said

    Thanks for these. One of them (the middle one) seemed to be a conference presentation of the same subject as the first paper, so I just included it as a link with the first paper.

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