Nitrogen deposition onto the United States and Western Europe: A synthesis of observations and models.

The documented acceleration of NH3 and NOx (NO + NO2) emissions over the last 150 years has accelerated N deposition, compromising air and water quality and altering the functioning of terrestrial and aquatic ecosystems worldwide. To construct continental-scale N budgets, we produced maps of N deposition fluxes from site-network observations for the United States and Western Europe. Increases in the rates of N cycling for these two regions of the world are large, and they have undergone profound modification of biospheric–atmospheric N exchanges, and ecosystem function. The maps are necessarily restricted to the network measured quantities and consist of statistically interpolated fields of aqueous NO3− and NH4+, gaseous HNO3 and NO2 (in Europe), and particulate NO3− and NH4+. There remain a number of gaps in the budgets, including organic N and NH3 deposition. The interpolated spatially continuous fields allow estimation of regionally integrated budget terms. Dry-deposition fluxes were the most problematic because of low station density and uncertainties associated with exchange mechanisms. We estimated dry N deposition fluxes by multiplying interpolated surface-air concentrations for each chemical species by model-calculated, spatially explicit deposition velocities. Deposition of the oxidized N species, by-products of fossil-fuel combustion, dominate the U.S. N deposition budget with 2.5 Tg of NOy-N out of a total of 3.7–4.5 Tg of N deposited annually onto the conterminous United States. Deposition of the reduced species, which are by-products of farming and animal husbandry, dominate the Western European N-deposition budget with a total of 4.3–6.3 Tg N deposited each year out of a total of 8.4–10.8 Tg N. Western Europe receives five times more N in precipitation than does the conterminous United States. Estimated N emissions exceed measured deposition in the United States by 5.3– 7.81 Tg N, suggesting significant N export or under-sampling of urban influence. In Europe, estimated emissions better balance measured deposition, with an imbalance of between −0.63 and 2.88 Tg N, suggesting that much of the N emitted in Europe is deposited there, with possible N import from the United States. The sampling network in Europe includes urban influences because of the greater population density of Western Europe. Our analysis of N deposition for both regions was limited by sampling density. The framework we present for quantification of patterns of N deposition provides a constraint on our understanding of continental biospheric–atmospheric N cycles. These spatially explicit wet and dry N fluxes also provide a tool for verifying regional and global models of atmospheric chemistry and transport, and they represent critical inputs into terrestrial models of biogeochemistry

Practices of climate change adaptation in the Pacific: survey of implementing agencies (phase II)

Various and diverse socio-economic, political and environmental challenges face the countries of the Pacific region. Over the last few decades, climate change has risen to increasing prominence as a key challenge and focal point for both national governments and communities to address. This has largely been a result of the ongoing climate change projections for the Pacific region, coupled with various observations by locals of changes to the climate, seasons and their local environment. Together, these observed and projected impacts of climate change can have profound social, economic and environmental implications for all Pacific Island Countries (PICs). To date, a series of broad-brush climate change related impacts have been reported in the literature; the impacts of which include a significant strain on crucial community sectors such as agriculture and fisheries, freshwater resources, human health, economic security, physical infrastructure and coastal resources

Climatic, edaphic, and biotic controls over storage and turnover of carbon in soils

Soil carbon, a major component of the global carbon inventory, has significant potential for change with changing climate and human land use. We applied the Century ecosystem model to a series of forest and grassland sites distributed globally to examine large-scale controls over soil carbon. Key site-specific parameters influencing soil carbon dynamics are soil texture and foliar lignin content; accordingly, we perturbed these variables at each site to establish a range of carbon concentrations and turnover times. We examined the simulated soil carbon stores, turnover times, and C:N ratios for correlations with patterns of independent variables. Results showed that soil carbon is related linearly to soil texture, increasing as clay content increases, that soil carbon stores and turnover time are related to mean annual temperature by negative exponential functions, and that heterotrophic respiration originates from recent detritus (∼50%), microbial turnover (∼30%), and soil organic matter (∼20%) with modest variations between forest and grassland ecosystems. The effect of changing temperature on soil organic carbon (SOC) estimated by Century is dSOC/dT= 183e−0.034T. Global extrapolation of this relationship leads to an estimated sensitivity of soil C storage to a temperature of −11.1 Pg° C−1, excluding extreme arid and organic soils. In Century, net primary production (NPP) and soil carbon are closely coupled through the N cycle, so that as temperatures increase, accelerated N release first results in fertilization responses, increasing C inputs. The Century-predicted effect of temperature on carbon storage is modified by as much as 100% by the N cycle feedback. Century-estimated soil C sensitivity (−11.1 Pg° C−1) is similar to losses predicted with a simple data-based calculation (−14.1 Pg° C−1). Inclusion of the N cycle is important for even first-order predictions of terrestrial carbon balance. If the NPP-SOC feedback is disrupted by land use or other disturbances, then SOC sensitivity can greatly exceed that estimated in our simulations. Century results further suggest that if climate change results in drying of organic soils (peats), soil carbon loss rates can be high

Climate change: scientific basis and status of the negotiations of the treaties

This interdisciplinary article, written by an atmospheric scientist and an international lawyer, highlights that there is convincing scientific evidence that climate change is underway, contrasted with the increasing intensity of climate change denialism and the weakening of international policy on climate change. It argues that we must choose the path of truly sustainable development across the board, creating business, science, and policies partnerships. It provides background for the Sustainable Companies Project on the science of climate change and the international negotiations on climate change

Research frontiers in the analysis of coupled biogeochemical cycles

Author Posting. © Ecological Society of America, 2011. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Frontiers in Ecology and the Environment 9 (2011): 74–80, doi:10.1890/100137.The analysis of coupled biogeochemical cycles (CBCs) addresses the scientific basis for some of today's major environmental problems. Drawing from information presented at a series of sessions on CBCs held at the 2009 Annual Meeting of the Ecological Society of America and from the research community's expertise, we identify several principal research themes that justify action and investment. Critical areas for research include: coupling of major element cycles to less studied yet equally important trace element cycles; analyzing CBCs across ecosystem boundaries; integrating experimental results into regional- and global-scale models; and expanding the analysis of human interactions with CBCs arising from human population growth, urbanization, and geoengineering. To advance the current understanding of CBCs and to address the environmental challenges of the 21st century, scientists must maintain and synthesize data from existing observational and experimental networks, develop new instrumentation networks, and adopt emerging technologies.We thank the National Science Foundation (NSF) and the Ecological Society of America (ESA) for their financial and logistical support of the Coupled Biogeochemical Cycles sessions held at the 2009 ESA Annual Meeting, and the publication of this special feature issue of Frontiers. ACF was supported by the NSF (DEB- 0743564) and the US Department of Energy’s (DOE’s) Office of Biological and Environmental Research (10- DOE-1053). SCD was supported by the Center for Microbial Oceanography, Research and Education (NSF EF-0424599). RBJ was supported by the NSF (DEB #0717191) and by the DOE’s National Institute for Climate Change Research

Variations in the predicted spatial distribution of atmospheric nitrogen deposition and their impact on carbon uptake by terrestrial ecosystems

Widespread mobilization of nitrogen into the atmosphere from industry, agriculture, and biomass burning and its subsequent deposition have the potential to alleviate nitrogen limitation of productivity in terrestrial ecosystems, and may contribute to enhanced terrestrial carbon uptake. To evaluate the importance of the spatial distribution of nitrogen deposition for carbon uptake and to better quantify its magnitude and uncertainty NOy-N deposition fields from five different three-dimensional chemical models, GCTM, GRANTOUR, IMAGES, MOGUNTIA, and ECHAM were used to drive NDEP, a perturbation model of terrestrial carbon uptake. Differences in atmospheric sources of NOx-N, transport, resolution, and representation of chemistry, contribute to the distinct spatial patterns of nitrogen deposition on the global land surface; these differences lead to distinct patterns of carbon uptake that vary between 0.7 and 1.3 Gt C yr−1 globally. Less than 10% of the nitrogen was deposited on forests which were most able to respond with increased carbon storage because of the wide C:N ratio of wood as well as its long lifetime. Addition of NHx-N to NOy-N deposition, increased global terrestrial carbon storage to between 1.5 and 2.0 Gt C yr−1, while the “missing terrestrial sink” is quite similar in magnitude. Thus global air pollution appears to be an important influence on the global carbon cycle. If N fertilization of the terrestrial biosphere accounts for the “missing” C sink or a substantial portion of it, we would expect significant reductions in its magnitude over the next century as terrestrial ecosystems become N saturated and O3 pollution expands

Seagrasses and seagrass habitats in Pacific small island developing states: potential loss of benefits via human disturbance and climate change

Seagrasses provide a wide range of services including food provision, water purification and coastal protection. Pacific small island developing states (PSIDS) have limited natural resources, challenging economies and a need for marine science research. Seagrasses occur in eleven PSIDS and nations are likely to benefit in different ways depending on habitat health, habitat cover and location, and species presence. Globally seagrass habitats are declining as a result of anthropogenic impacts including climate change and in PSIDS pressure on already stressed coastal ecosystems, will likely threaten seagrass survival particularly close to expanding urban settlements. Improved coastal and urban planning at local, national and regional scales is needed to reduce human impacts on vulnerable coastal areas. Research is required to generate knowledge-based solutions to support effective coastal management and protection of the existing seagrass habitats, including strenghened documentation the socio-economic and environmental services they provide. For PSIDS, protection of seagrass service benefits requires six priority actions: seagrass habitat mapping, regulation of coastal and upstream development, identification of specific threats at vulnerable locations, a critique of cost-effective restoration options, research devoted to seagrass studies and more explicit policy development

The use of Copernicus Marine Service products to describe the state of the Tropical Western Pacific Ocean around the Islands: a case study

Fiji served as President of the UN General Assembly in 2017, linking climate (SDG13) and ocean (SDG14) as the foundation of blue economies for island and coastal states around the world. The resulting United Nations Oceans outcome statement stressed “the importance of enhancing understanding of the health and role of our ocean and the stressors on its ecosystems, including through assessments on the state of the ocean, based on science and on traditional knowledge systems. We also stress the need to further increase marine scientific research to inform and support decision-making, and to promote knowledge hubs and networks to enhance the sharing of scientific data, best practices and ‘know-how.’” (UN, 2017). The Copernicus Marine Service Atlas for the Pacific Ocean States goes beyond the unique compilation of CMIP3 climate model projections and data tools compiled by the Pacific Climate Change Science Program (PCCSP, 2011, 2014). A complete overview of tropical Pacific observing network is available in the WMO publication library (GCOS, 2014a, 2014b). Our study focuses on the application of the available CMEMS products to the Pacific domain defined by PCCSP. As president of COP23, Prime Minister Frank Bainimarama has emphasized the importance of the climate and ocean connection and the need to protect ocean health to protect the planet: ‘We are all in the same canoe’ (https://cop23.com.fj/fijian-prime-minister-cop23-president-remarks-assuming-presidency-cop23/). The Copernicus Marine Service Atlas for Pacific Ocean States compiled by the author team responds directly to Fiji’s requests at the 2017 United Nation Oceans for SDG 14, life below water and the 2017 COP23 for SDG13, climate action which goes beyond the Pacific

Ocean science, data, and services for the UN 2030 Sustainable Development Goals

Relating the Sustainable Development Goal (SDG) 14 for Ocean and Life Below Water to the 16 remaining SDGs in the UN 2030 sustainable development agenda. A holistic approach that embraces sustainable Ocean stewardship informed by best available science, data and services to support society and the economy is required to create the ‘Future We Want’. The UN Decade of Ocean Science for Sustainable Development is an essential foundation to achieve this objective

Satellite-derived increases in net primary productivity across North America, 1982-1998

We used a new 17‐year, high spatial resolution satellite record and a carbon cycle model to explore how changing net primary productivity (NPP) contributed to a proposed carbon (C) sink in North America. We found a small but significant increase in NPP, 0.03 Pg C yr^(−2) or 8% over 17 years, that could explain a substantial fraction of the C sink. The largest increases occurred in the central and southeastern United States, eastern Canada, and northwestern North America, and were consistent with NPP trends derived from forest inventories and crop yields. Interannual NPP variability was small, implying that the large interannual variability in the C sink found in previous studies were driven by changes in heterotrophic respiration