Nutrient constraints on the Amazon carbon sink: from field measurements to model projections

2020 ◽  
Author(s):  
Katrin Fleischer ◽  
Carlos Alberto Quesada ◽  
David Lapola ◽  
Lucia Fuchslueger ◽  
Laynara Lugli ◽  
...  
Keyword(s):  
Climate Change ◽  
Atmospheric Carbon Dioxide ◽  
Amazon Basin ◽  
Carbon Sink ◽  
Soil Phosphorus ◽  
Field Measurements ◽  
Ecosystem Model ◽  
Future Research ◽  
The Future ◽  
Increasing Demand

<p>The Amazon rainforest faces immense pressures from human-induced deforestation and climate change and its future existence is largely indeterminate. Accurately projecting the forest’s response to future conditions, and thus preparing for the best possible outcome, requires a sound process-based understanding of its ecological and biogeochemical functioning. The intact forest acts as a sink of atmospheric carbon dioxide (CO<sub>2</sub>), however, this invaluable function is slowing down for unclear reasons, according to long-term plot measurements of tree growth. Earth system models, on the other hand, assume a continuous sink of carbon into the 21<sup>st</sup> century, predominantly driven by CO<sub>2</sub> fertilization, concurrently buffering against adverse effects by climate change. Advancing empirical and experimental evidence points to strong nutrient constraints on the Amazon carbon sink, foremostly by phosphorus and other cations, so that the projected strength of the future carbon sink is certainly unrealistic. It is highly uncertain, however, to which degree nutrients are and will diminish elevated CO<sub>2</sub>-induced productivity, and to which extent plant-based mechanisms may upregulate phosphorus supply or optimize phosphorus use to facilitate the increasing demand by elevated CO<sub>2</sub>. Site-scale ecosystem model ensemble analysis underscores the diverging hypotheses on phosphorus feedbacks we are currently facing. In addition, heterogeneous soil phosphorus availability across the Amazon basin, in combination with a hyperdiverse plant community, challenges current efforts to project phosphorus constraints on the future of the Amazon carbon sink. We here give an outlook of current progress and future research needs of model-experiment integration to tackle this pressing question.</p>

Climate Change and Forests

2020 ◽  
Vol 12 (1) ◽  
pp. 23-43
Author(s):  
Brent Sohngen
Keyword(s):  
Climate Change ◽  
Carbon Sink ◽  
Wood Products ◽  
Biomass Energy ◽  
Future Research ◽  
Research Directions ◽  
The Future ◽  
Carbon Fertilization ◽  
Future Research Directions ◽  
Advance Knowledge

Forests have become an important carbon sink in the last century, with management and carbon fertilization offsetting nearly all of the carbon emitted due to deforestation and conversion of land into agricultural uses. Society appears already to have decided that forests will play an equally ambitious role in the future. Given this, economists are needed to help better understand the efficiency of efforts society may undertake to expand forests, protect them from losses, manage them more intensively, or convert them into wood products, including biomass energy. A rich literature exists on this topic, but a number of critical information gaps persist, representing important opportunities for economists to advance knowledge in the future. This article reviews the literature on forests and climate change and provides some thoughts on potential future research directions.

The future of cool temperate bogs

2002 ◽  
Vol 29 (1) ◽  
pp. 3-20 ◽  
Author(s):  
Peter D. Moore
Keyword(s):  
Climate Change ◽  
Atmospheric Carbon Dioxide ◽  
Carbon Sink ◽  
Western World ◽  
Summer Drought ◽  
Oxidation Of Methane ◽  
Living Things ◽  
The Future ◽  
Atmospheric Carbon ◽  
Carbon Dioxide Levels

The temperate peatlands are extensive, covering around 3.5 million km2 of land. They contain about 455 Gt of carbon, almost equivalent to the carbon stored in all of the living things on the surface of the planet, and representing around 25% of all the soil carbon on earth. These bogs are a sink for atmospheric carbon and their carbon uptake accounts for about 12% of current human emissions. They vary considerably in their form and structure and are an important resource for scientific research, including the study of past environments and climate change, and they are also valuable in environmental education. They are low in biodiversity, but their fauna and flora are distinctive and many groups are confined to this habitat. For all these reasons, the future conservation of peatlands is a matter for concern. Threats to peatlands come from direct human exploitation in the form of peat harvesting for energy and horticulture, and drainage for forestry. Rising environmental awareness should control both of these processes in the western world, but continued northern peatland losses are likely locally, especially in Asia. Peatland drainage for forestry or agriculture will result in losses of carbon to the atmosphere, adding to the greenhouse effect. Human population pressures, industrialization and urbanization are unlikely to have an important direct and immediate influence in the boreal zone. Fragmentation of the habitat is not an important consideration because bogs are by their very nature ‘island’ habitats. Acidification by aerial pollution may be a local problem close to sources, but the habitat is naturally acid and should not be severely affected. The input of aerial nutrients, however, particularly nitrogen, could have widespread impact on bogs, enhancing their productivity and altering their vegetation composition. The physical rehabilitation of bogs damaged by human activities presents many problems, particularly relating to the re-establishment of peat structure and vegetation, but the process can result in the re-formation of a carbon sink so it is worth the effort. Climate change is the most important consideration in its impact on bogs. Higher temperature (especially if accompanied by raised atmospheric carbon dioxide levels and increased nitrate deposition) will enhance productivity, but will also result in faster decomposition rates. The outcome of these opposing factors for peat formation will ultimately depend on the future pattern of precipitation. If, as seems most likely, summer conditions become warmer and drier in continental regions and winters become milder and wetter, the summer drought could cause peat loss and bog contraction. An excess of decomposition will lead to bogs becoming a carbon source and thus a positive feedback in global warming. Emissions of methane and nitrous oxide would add to the greenhouse gas problem, but likely oxidation of methane and low N2O production may well mean that this impact will not prove to be significant. Tree invasion of bogs as a consequence of summer drought could locally lead to increased water loss through transpiration, and higher heat absorption through albedo change. This will enhance the drying effect on the bog surface. Oceanic mires will be less severely affected if the expected increase in precipitation takes place in these regions. The most important overall factor in determining the future of the northern bogs is likely to be the quantity and pattern (both spatially and temporally) of future precipitation in the zone.

scholarly journals Soil nitrogen cycle unresponsive to decadal long climate change in a Tasmanian grassland

2019 ◽  
Vol 147 (1) ◽  
pp. 99-107 ◽  
Author(s):  
Tobias Rütting ◽  
Mark J. Hovenden
Keyword(s):  
Climate Change ◽  
Atmospheric Carbon Dioxide ◽  
Carbon Sink ◽  
Vegetation Type ◽  
Terrestrial Ecosystems ◽  
Soil N ◽  
Mineral N ◽  
N Dynamics ◽  
Terrestrial Carbon Sink ◽  
Soil Nitrogen Cycle

AbstractIncreases in atmospheric carbon dioxide (CO2) and global air temperature affect all terrestrial ecosystems and often lead to enhanced ecosystem productivity, which in turn dampens the rise in atmospheric CO2 by removing CO2 from the atmosphere. As most terrestrial ecosystems are limited in their productivity by the availability of nitrogen (N), there is concern about the persistence of this terrestrial carbon sink, as these ecosystems might develop a progressive N limitation (PNL). An increase in the gross soil N turnover may alleviate PNL, as more mineral N is made available for plant uptake. So far, climate change experiments have mainly manipulated one climatic factor only, but there is evidence that single-factor experiments usually overestimate the effects of climate change on terrestrial ecosystems. In this study, we investigated how simultaneous, decadal-long increases in CO2 and temperature affect the soil gross N dynamics in a native Tasmanian grassland under C3 and C4 vegetation. Our laboratory 15N labeling experiment showed that average gross N mineralization ranged from 4.9 to 11.3 µg N g−1 day−1 across the treatment combinations, while gross nitrification was about ten-times lower. Considering all treatment combinations, no significant effect of climatic treatments or vegetation type (C3 versus C4 grasses) on soil N cycling was observed.

scholarly journals Nitrogen Fixation in a Changing Arctic Ocean: An Overlooked Source of Nitrogen?

2020 ◽  
Vol 11 ◽  
Author(s):  
Lisa W. von Friesen ◽  
Lasse Riemann
Keyword(s):  
Climate Change ◽  
Nitrogen Fixation ◽  
Primary Production ◽  
Arctic Ocean ◽  
Current Knowledge ◽  
Carbon Sink ◽  
Spatial Scales ◽  
The Arctic ◽  
Future Research ◽  
The Arctic Ocean

The Arctic Ocean is the smallest ocean on Earth, yet estimated to play a substantial role as a global carbon sink. As climate change is rapidly changing fundamental components of the Arctic, it is of local and global importance to understand and predict consequences for its carbon dynamics. Primary production in the Arctic Ocean is often nitrogen-limited, and this is predicted to increase in some regions. It is therefore of critical interest that biological nitrogen fixation, a process where some bacteria and archaea termed diazotrophs convert nitrogen gas to bioavailable ammonia, has now been detected in the Arctic Ocean. Several studies report diverse and active diazotrophs on various temporal and spatial scales across the Arctic Ocean. Their ecology and biogeochemical impact remain poorly known, and nitrogen fixation is so far absent from models of primary production in the Arctic Ocean. The composition of the diazotroph community appears distinct from other oceans – challenging paradigms of function and regulation of nitrogen fixation. There is evidence of both symbiotic cyanobacterial nitrogen fixation and heterotrophic diazotrophy, but large regions are not yet sampled, and the sparse quantitative data hamper conclusive insights. Hence, it remains to be determined to what extent nitrogen fixation represents a hitherto overlooked source of new nitrogen to consider when predicting future productivity of the Arctic Ocean. Here, we discuss current knowledge on diazotroph distribution, composition, and activity in pelagic and sea ice-associated environments of the Arctic Ocean. Based on this, we identify gaps and outline pertinent research questions in the context of a climate change-influenced Arctic Ocean – with the aim of guiding and encouraging future research on nitrogen fixation in this region.

scholarly journals The Impacts of Ocean Acidification on Marine Ecosystems and Reliant Human Communities

2020 ◽  
Vol 45 (1) ◽  
pp. 83-112 ◽  
Author(s):  
Scott C. Doney ◽  
D. Shallin Busch ◽  
Sarah R. Cooley ◽  
Kristy J. Kroeker
Keyword(s):  
Climate Change ◽  
Ocean Acidification ◽  
Atmospheric Carbon Dioxide ◽  
Information Needs ◽  
Field Studies ◽  
Future Climate Change ◽  
Future Research ◽  
Shoreline Protection ◽  
Biological Impacts ◽  
Estuarine Coastal

Rising atmospheric carbon dioxide (CO2) levels, from fossil fuel combustion and deforestation, along with agriculture and land-use practices are causing wholesale increases in seawater CO2 and inorganic carbon levels; reductions in pH; and alterations in acid-base chemistry of estuarine, coastal, and surface open-ocean waters. On the basis of laboratory experiments and field studies of naturally elevated CO2 marine environments, widespread biological impacts of human-driven ocean acidification have been posited, ranging from changes in organism physiology and population dynamics to altered communities and ecosystems. Acidification, in conjunction with other climate change–related environmental stresses, particularly under future climate change and further elevated atmospheric CO2 levels, potentially puts at risk many of the valuable ecosystem services that the ocean provides to society, such as fisheries, aquaculture, and shoreline protection. Thisreview emphasizes both current scientific understanding and knowledge gaps, highlighting directions for future research and recognizing the information needs of policymakers and stakeholders.

scholarly journals An ecohydrological sketch of climate change impacts on water and natural ecosystems for The Netherlands: bridging the gap between science and society

2012 ◽  
Vol 9 (5) ◽  
pp. 6311-6344
Author(s):  
J. P. M. Witte ◽  
J. Runhaar ◽  
R. van Ek ◽  
D. C. J. van der Hoek ◽  
R. P. Bartholomeus ◽  
...  
Keyword(s):  
Climate Change ◽  
The Netherlands ◽  
Future Climate ◽  
Plant Performance ◽  
Future Research ◽  
Natural Ecosystems ◽  
Adaptation Measures ◽  
Raised Bogs ◽  
The Future ◽  
Sketch Map

Abstract. For policy making and spatial planning, information is needed about the impacts of climate change on natural ecosystems. To provide this information, commonly hydrological and ecological models are used. We give arguments for our assessment that modelling only is insufficient for determining the impacts of climate changes on natural ecosystems at regional scales. Instead, we proposed a combination of hydrological simulations, a literature review and process-knowledge on climate-hydrology-vegetation interactions, to compile a sketch-map that indicates climate change effects on a number of ecosystems in The Netherlands. Soon after its introduction, copies of our sketch-map appeared in policy documents and in a commercial and popular atlas of The Netherlands. Moreover, the map led to a question in the Dutch parliament about the survivability of bog reserves in the future climate. Apparently, there was an urgent need for the information provided by the map. The map shows that climate change will presumably have the largest influence on ecosystems in The Netherlands that depend on precipitation as the major water source, like heathlands, dry grasslands, rain-fed moorland pools and raised bogs. Also highly susceptible are fens in reserves surrounded by deeply drained polders, because such fens depend on the inlet of surface water, of which quality is likely to deteriorate upon climate change. While the map is indicative for directions of change, in view of the uncertainties of our study no conclusions should be drawn that may have far-reaching consequences, such as giving up certain nature targets that might no longer be feasible in the future climate. Instead, we advise to anticipate on the potential threats from climate change by taking a number of adaptation measures that enhance the robustness of nature reserves. To improve climate change projections on hydrology and ecosystems, future research should especially focus on feedbacks of vegetation on the water balance, on processes that directly influence plant performance and on the ecological effects of weather extremes.

Methods for Assessing Journalistic Decisions, Advocacy Strategies, and Climate Change Communication Practices

2017 ◽  
Author(s):  
Senja Post
Keyword(s):  
Climate Change ◽  
Longitudinal Research ◽  
Future Research ◽  
Climate Change Communication ◽  
Communication Behaviors ◽  
Change Communication ◽  
The Future ◽  
Communication Practices ◽  
Advocacy Strategies ◽  
Diverse Groups

Research in the field of journalistic decisions, advocacy strategies, and communication practices is very heterogeneous, comprising diverse groups of actors and research questions. Not surprisingly, various methods have been applied to assess actors’ motives, strategies, intentions, and communication behaviors. This article provides an overview of the most common methods applied—i.e., qualitative and quantitative approaches to textual analyses, interviewing techniques, observational and experimental research. After discussing the major strengths and weaknesses of each method, an outlook on future research is given. One challenge of the future study of climate change communication will be to account for its dynamics, with various actors reacting to one another in their public communication. To better approximate such dynamics in the future, more longitudinal research will be needed.

Combating Climate Change Through Enhanced Weathering of Agricultural Soils

Elements ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 253-258 ◽  
Author(s):  
M. Grace Andrews ◽  
Lyla L. Taylor
Keyword(s):  
Climate Change ◽  
Atmospheric Carbon Dioxide ◽  
Chemical Weathering ◽  
Agricultural Soils ◽  
Natural Weathering ◽  
Future Research ◽  
Co2 Removal ◽  
Potential Efficacy ◽  
Removal Technology ◽  
Carbon Dioxide Co2

Rising levels of atmospheric carbon dioxide (CO2) are driving increases in global temperatures. Enhanced weathering of silicate rocks is a CO2 removal technology that could help mitigate anthropogenic climate change. Enhanced weathering adds powdered silicate rock to agricultural lands, accelerating natural chemical weathering, and is expected to rapidly draw down atmospheric CO2. However, differences between enhanced and natural weathering result in significant uncertainties about its potential efficacy. This article summarizes the research into enhanced weathering and the uncertainties of enhanced weathering due to the key differences with natural weathering, as well as future research directions.

scholarly journals Potential Transient Response of Terrestrial Vegetation and Carbon in Northern North America from Climate Change

Climate ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 113
Author(s):  
Steven A. Flanagan ◽  
George C. Hurtt ◽  
Justin P. Fisk ◽  
Ritvik Sahajpal ◽  
Maosheng Zhao ◽  
...  
Keyword(s):  
Climate Change ◽  
North America ◽  
Time Scales ◽  
Transient Response ◽  
Landscape Heterogeneity ◽  
Carbon Sink ◽  
Terrestrial Ecosystems ◽  
Ecosystem Model ◽  
Terrestrial Vegetation ◽  
Equilibrium Response

Terrestrial ecosystems and their vegetation are linked to climate. With the potential of accelerated climate change from anthropogenic forcing, there is a need to further evaluate the transient response of ecosystems, their vegetation, and their influence on the carbon balance, to this change. The equilibrium response of ecosystems to climate change has been estimated in previous studies in global domains. However, research on the transient response of terrestrial vegetation to climate change is often limited to domains at the sub-continent scale. Estimation of the transient response of vegetation requires the use of mechanistic models to predict the consequences of competition, dispersal, landscape heterogeneity, disturbance, and other factors, where it becomes computationally prohibitive at scales larger than sub-continental. Here, we used a pseudo-spatial ecosystem model with a vegetation migration sub-model that reduced computational intensity and predicted the transient response of vegetation and carbon to climate change in northern North America. The ecosystem model was first run with a current climatology at half-degree resolution for 1000 years to establish current vegetation and carbon distribution. From that distribution, climate was changed to a future climatology and the ecosystem model run for an additional 2000 simulation years. A model experimental design with different combinations of vegetation dispersal rates, dispersal modes, and disturbance rates produced 18 potential change scenarios. Results indicated that potential redistribution of terrestrial vegetation from climate change was strongly impacted by dispersal rates, moderately affected by disturbance rates, and marginally impacted by dispersal mode. For carbon, the sensitivities were opposite. A potential transient net carbon sink greater than that predicted by the equilibrium response was estimated on time scales of decades–centuries, but diminished over longer time scales. Continued research should further explore the interactions between competition, dispersal, and disturbance, particularly in regards to vegetation redistribution.

Climate Change and Agriculture

2016 ◽  
pp. 393-415 ◽  
Author(s):  
Sunil Lalasaheb Londhe
Keyword(s):  
Climate Change ◽  
Atmospheric Carbon Dioxide ◽  
Crop Production ◽  
Agricultural Sector ◽  
Great Depth ◽  
Mitigation Measures ◽  
Agriculture Sector ◽  
The Future ◽  
Food Security And Nutrition ◽  
Earth’S Climate

Increasing evidence shows that shifts in Earth's climate have already occurred and indicates that changes will continue in the coming years. This chapter is an attempt to distil what is known about the likely effects of climate change on food security and nutrition in coming decades. Apart from few exceptions, the likely impacts of climate change on agricultural sector in the future are not understood in any great depth. There are many uncertainties as to how changes in temperature, rainfall and atmospheric carbon dioxide concentrations will interact in relation to agricultural productivity. The consequences of climate change on various important aspects of agriculture such as crop production, livestock, availability of water, pest and diseases etc. are discussed and summarized. Each of this aspect of agriculture sector will have certain impact which may be positive or negative. The chapter also discusses on the possible mitigation measures and adaptations for agriculture production in the future climate change scenarios.

Sign in / Sign up

Export Citation Format

Share Document