GC020-04
Carbon and beyond: Interactive global change impacts on Amazon biogeochemical cycles
Monday, 7 December 2020: 20:42
Virtual
Fiona Soper1, Kristofer R Covey2, Sunitha R Pangala3, Angelo Bernadino4, Luana S Basso5, Henrique L. G. Cassol Sr.6, Philip Martin Fearnside7, Sidney Novoa8, Henrique O Sawakuchi9, Thomas Lovejoy10, Jose A Marengo11, Carlos Peres12, Paula Bernasconi13, Gabriela Bielefeld Nardoto14, Ismael Nobre15, Rita G Mesquita16, Flavia Pinto17, Bruce Hoffman18, Carolina Freitas19, Rafael L de Assis20, Alexis Anne Bahl21, Aurora Elmore22 and Jonathon Baillie22, (1)McGill University, Montreal, QC, Canada, (2)Yale University, New Haven, CT, United States, (3)Lancaster University, Lancaster, United Kingdom, (4)Universidade Federal do Espírito Santo, Vitoria, Brazil, (5)IPEN Nuclear Energy Research Institute, Sao Paulo, Brazil, (6)INPE National Institute for Space Research, Sao Jose dos Campos, Brazil, (7)Homer, AK, United States, (8)Conservacion Amazonica - ACCA, Lima, Peru, (9)CENA-USP, Piracicaba, Brazil, (10)George Mason University, Fairfax, United States, (11)CCST INPE, Cachoeira Paulista, Brazil, (12)University of East Anglia, Norwich, United Kingdom, (13)Instituto Centro de Vida (ICV), Mato Grasso, Brazil, (14)UNB University of Brasilia, Brasilia, Brazil, (15)Universidade Estadual de Campinas, Sao Paulo, Brazil, (16)INPA National Institute of Amazonian Research, Biological Dynamics of Forest Fragments Project, Manaus, Brazil, (17)National Institute for Research in the Amazon (INPA), Boa Vista, Brazil, (18)The Amazon Conservation Team, Paramaribo, Suriname, (19)Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil, (20)Biological Dynamics of Forest Fragments Project, Manaus, Brazil, (21)Johns Hopkins University, Baltimore, MD, United States, (22)National Geographic Society, Washington DC, United States
Abstract:
The Amazon is at the center of an intensifying conversation about multiple anthropogenic impacts, both direct (e.g. land use change) and indirect (climate and hydrologic change). Thus far, research has focused primarily on the cycling and storage of carbon (C) and its implications for global climate. Missing is a holistic consideration of the interactions between these anthropogenic impacts and the full suite of climate forcing agents originating in the basin, including other greenhouse gases (methane, nitrous oxide), biogenic volatile organic compounds (BVOCs), black C, transpiration and albedo. Doing so is complicated by the very large variation in biophysical, ecological, cultural and political factors across the large area of the basin. Here, we synthesize the current understanding of 1) the nature, extent, rates and drivers of all major anthropogenic changes, and 2) their expected magnitude and direction of effect on each major climate forcing agent. Studied anthropogenic impacts span a range of scales and include deforestation, agricultural conversion, hydrologic and climatic regime change, reservoir construction, fire, mining/oil extraction, hunting, severe storms and others. We identify key knowledge gaps and identify likely impacts on the net climate forcing effect of the region.
We conclude that the current net positive radiative forcing of non-CO2 agents in the Amazon (in particular methane, nitrous oxide and black C) is likely be equal to or greater than the more often considered CO2 climate impact. If unchecked, the majority of anthropogenic change agents are likely to further increase net radiative forcing from the region, both by reducing C uptake and increasing emission of other agents. Most significant rate and response uncertainties are associated with 1) methane production in seasonally inundated areas and effects of temperature/hydrologic change 2) patterns and radiative forcing impacts of BVOCs, 3) impacts of spatially/temporally variable phenomena such as severe storms and 4) biogeochemical and ecological resiliency of freshwater systems. Given the large contribution of these less-recognized forcing agents, a continuing focus on a single metric of climate service is incompatible with understanding and managing the biogeochemistry of climate in a rapidly changing Amazon.
