Global Carbon Budget 2022 Friedlingstein, Pierre; O'Sullivan, Michael; Jones, Matthew W ...
Earth system science data,
11/2022, Letnik:
14, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Accurate assessment of anthropogenic carbon dioxide (CO.sub.2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better ...understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize data sets and methodologies to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO.sub.2 emissions (E.sub.FOS) are based on energy statistics and cement production data, while emissions from land-use change (E.sub.LUC ), mainly deforestation, are based on land use and land-use change data and bookkeeping models. Atmospheric CO.sub.2 concentration is measured directly, and its growth rate (G.sub.ATM) is computed from the annual changes in concentration. The ocean CO.sub.2 sink (S.sub.OCEAN) is estimated with global ocean biogeochemistry models and observation-based data products. The terrestrial CO.sub.2 sink (S.sub.LAND) is estimated with dynamic global vegetation models. The resulting carbon budget imbalance (B.sub.IM ), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1Ï.
Streams, rivers, lakes, and other inland waters are important agents in the coupling of biogeochemical cycles between continents, atmosphere, and oceans. The depiction of these roles in global-scale ...assessments of carbon (C) and other bioactive elements remains limited, yet recent findings suggest that C discharged to the oceans is only a fraction of that entering rivers from terrestrial ecosystems via soil respiration, leaching, chemical weathering, and physical erosion. Most of this C influx is returned to the atmosphere from inland waters as carbon dioxide (CO
2
) or buried in sedimentary deposits within impoundments, lakes, floodplains, and other wetlands. Carbon and mineral cycles are coupled by both erosion-–deposition processes and chemical weathering, with the latter producing dissolved inorganic C and carbonate buffering capacity that strongly modulate downstream pH, biological production of calcium-carbonate shells, and CO
2
outgassing in rivers, estuaries, and coastal zones. Human activities substantially affect all of these processes.
Puget Sound is a large estuary complex in the U.S. Pacific Northwest that is home to a diverse and economically important ecosystem threatened by anthropogenic impacts associated with climate change, ...urbanization, and ocean acidification. While ocean acidification has been studied in oceanic waters, little is known regarding its status in estuaries. Anthropogenically acidified coastal waters upwelling along the western North American continental margin can enter Puget Sound through the Strait of Juan de Fuca. In order to study the combined effects of ocean acidification and other natural and anthropogenic processes on Puget Sound waters, we made the first inorganic carbon measurements in this estuary on two survey cruises in February and August of 2008. Observed pH and aragonite saturation state values in surface and subsurface waters were substantially lower in parts of Puget Sound than would be expected from anthropogenic carbon dioxide (CO
2) uptake alone. We estimate that ocean acidification can account for 24–49% of the pH decrease in the deep waters of the Hood Canal sub-basin of Puget Sound relative to estimated pre-industrial values. The remaining change in pH between when seawater enters the sound and when it reaches this deep basin results from remineralization of organic matter due to natural or anthropogenically stimulated respiration processes within Puget Sound. Over time, however, the relative impact of ocean acidification could increase significantly, accounting for 49–82% of the pH decrease in subsurface waters for a doubling of atmospheric CO
2. These changes may have profound impacts on the Puget Sound ecosystem over the next several decades. These estimates suggest that the role ocean acidification will play in estuaries may be different from the open ocean.
The continental shelf region off the west coast of North America is seasonally exposed to water with a low aragonite saturation state by coastal upwelling of CO2-rich waters. To date, the spatial and ...temporal distribution of anthropogenic CO2 (Canth) within the CO2-rich waters is largely unknown. Here we adapt the multiple linear regression approach to utilize the GO-SHIP Repeat Hydrography data from the northeast Pacific to establish an annually updated relationship between Canth and potential density. This relationship was then used with the NOAA Ocean Acidification Program West Coast Ocean Acidification (WCOA) cruise data sets from 2007, 2011, 2012, and 2013 to determine the spatial variations of Canth in the upwelled water. Our results show large spatial differences in Canth in surface waters along the coast, with the lowest values (37–55 μmol kg−1) in strong upwelling regions off southern Oregon and northern California and higher values (51–63 μmol kg−1) to the north and south of this region. Coastal dissolved inorganic carbon concentrations are also elevated due to a natural remineralized component (Cbio), which represents carbon accumulated through net respiration in the seawater that has not yet degassed to the atmosphere. Average surface Canth is almost twice the surface remineralized component. In contrast, Canth is only about one third and one fifth of the remineralized component at 50 m and 100 m depth, respectively. Uptake of Canth has caused the aragonite saturation horizon to shoal by approximately 30–50 m since the preindustrial period so that undersaturated waters are well within the regions of the continental shelf that affect the shell dissolution of living pteropods. Our data show that the most severe biological impacts occur in the nearshore waters, where corrosive waters are closest to the surface. Since the pre-industrial times, pteropod shell dissolution has, on average, increased approximately 19–26% in both nearshore and offshore waters.
Display omitted
•The coastal waters off the US west coast are seasonally exposed to waters with low aragonite saturation.•Large spatial differences in Canth occur in surface waters along the coast.•Average surface Canth is almost twice the surface remineralized component (Cbio).•Uptake of Canth has caused the aragonite saturation horizon to shoal by approximately 30–50 m.•Pteropod shell dissolution has increased approximately 19–26% since the pre-industrial era.
Syntheses of carbonate chemistry spatial patterns are important for predicting ocean acidification impacts, but are lacking in coastal oceans. Here, we show that along the North American Atlantic and ...Gulf coasts the meridional distributions of dissolved inorganic carbon (DIC) and carbonate mineral saturation state (Ω) are controlled by partial equilibrium with the atmosphere resulting in relatively low DIC and high Ω in warm southern waters and the opposite in cold northern waters. However, pH and the partial pressure of CO
(pCO
) do not exhibit a simple spatial pattern and are controlled by local physical and net biological processes which impede equilibrium with the atmosphere. Along the Pacific coast, upwelling brings subsurface waters with low Ω and pH to the surface where net biological production works to raise their values. Different temperature sensitivities of carbonate properties and different timescales of influencing processes lead to contrasting property distributions within and among margins.
Oceanic uptake of anthropogenic carbon dioxide (CO
2
) from the atmosphere has changed ocean biogeochemistry and threatened the health of organisms through a process known as ocean acidification ...(OA). Such large-scale changes affect ecosystem functions and can have impacts on societal uses, fisheries resources, and economies. In many large estuaries, anthropogenic CO
2
-induced acidification is enhanced by strong stratification, long water residence times, eutrophication, and a weak acid-base buffer capacity. In this article, we review how a variety of processes influence aquatic acid-base properties in estuarine waters, including coastal upwelling, river-ocean mixing, air-water gas exchange, biological production and subsequent aerobic and anaerobic respiration, calcium carbonate (CaCO
3
) dissolution, and benthic inputs. We emphasize the spatial and temporal dynamics of partial pressure of CO
2
(
p
CO
2
), pH, and calcium carbonate mineral saturation states. Examples from three large estuaries-Chesapeake Bay, the Salish Sea, and Prince William Sound-are used to illustrate how natural and anthropogenic processes and climate change may manifest differently across estuaries, as well as the biological implications of OA on coastal calcifiers.
Global Carbon Budget 2021 Friedlingstein, Pierre; Jones, Matthew W; O'Sullivan, Michael ...
Earth system science data,
04/2022, Letnik:
14, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Accurate assessment of anthropogenic carbon dioxide (CO.sub.2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better ...understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize datasets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO.sub.2 emissions (E.sub.FOS) are based on energy statistics and cement production data, while emissions from land-use change (E.sub.LUC ), mainly deforestation, are based on land use and land-use change data and bookkeeping models. Atmospheric CO.sub.2 concentration is measured directly, and its growth rate (G.sub.ATM) is computed from the annual changes in concentration. The ocean CO.sub.2 sink (S.sub.OCEAN) is estimated with global ocean biogeochemistry models and observation-based data products. The terrestrial CO.sub.2 sink (S.sub.LAND) is estimated with dynamic global vegetation models. The resulting carbon budget imbalance (B.sub.IM ), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1Ï. For the first time, an approach is shown to reconcile the difference in our E.sub.LUC estimate with the one from national greenhouse gas inventories, supporting the assessment of collective countries' climate progress.
Carbonate chemistry variability is often poorly characterized in coastal regions and patterns of covariation with other biologically important variables such as temperature, oxygen concentration, and ...salinity are rarely evaluated. This absence of information hampers the design and interpretation of ocean acidification experiments that aim to characterize biological responses to future pCO2 levels relative to contemporary conditions. Here, we analyzed a large carbonate chemistry data set from Puget Sound, a fjord estuary on the U.S. west coast, and included measurements from three seasons (winter, summer, and fall). pCO2 exceeded the 2008-2011 mean atmospheric level (392 µatm) at all depths and seasons sampled except for the near-surface waters (< 10 m) in the summer. Further, undersaturated conditions with respect to the biogenic carbonate mineral aragonite were widespread (Ωar<1). We show that pCO2 values were relatively uniform throughout the water column and across regions in winter, enriched in subsurface waters in summer, and in the fall some values exceeded 2500 µatm in near-surface waters. Carbonate chemistry covaried to differing levels with temperature and oxygen depending primarily on season and secondarily on region. Salinity, which varied little (27 to 31), was weakly correlated with carbonate chemistry. We illustrate potential high-frequency changes in carbonate chemistry, temperature, and oxygen conditions experienced simultaneously by organisms in Puget Sound that undergo diel vertical migrations under present-day conditions. We used simple calculations to estimate future pCO2 and Ωar values experienced by diel vertical migrators based on an increase in atmospheric CO2. Given the potential for non-linear interactions between pCO2 and other abiotic variables on physiological and ecological processes, our results provide a basis for identifying control conditions in ocean acidification experiments for this region, but also highlight the wide range of carbonate chemistry conditions organisms may currently experience in this and similar coastal ecosystems.
Shelled pteropods are widely regarded as bioindicators for ocean acidification, because their fragile aragonite shells are susceptible to increasing ocean acidity. While short-term incubations have ...demonstrated that pteropod calcification is negatively impacted by ocean acidification, we know little about net calcification in response to varying ocean conditions in natural populations. Here, we examine in situ calcification of Limacina helicina pteropods collected from the California Current Ecosystem, a coastal upwelling system with strong spatial gradients in ocean carbonate chemistry, dissolved oxygen and temperature. Depth-averaged pH ranged from 8.03 in warmer offshore waters to 7.77 in cold CO
-rich waters nearshore. Based on high-resolution micro-CT technology, we showed that shell thickness declined by ~ 37% along the upwelling gradient from offshore to nearshore water. Dissolution marks covered only ~ 2% of the shell surface area and were not associated with the observed variation in shell thickness. We thus infer that pteropods make thinner shells where upwelling brings more acidified and colder waters to the surface. Probably the thinner shells do not result from enhanced dissolution, but are due to a decline in calcification. Reduced calcification of pteropods is likely to have major ecological and biogeochemical implications for the cycling of calcium carbonate in the oceans.
We present a synthesis of available estimates of primary production, organic carbon burial, and lake‐atmosphere carbon dioxide exchange data for large lakes of the world. All three fluxes showed ...significant relationships with latitude and related climate variables, with lower production, higher evasion of carbon dioxide, and higher burial efficiency at higher latitudes. There was no relationship between raw organic carbon mass accumulation rates and latitude. Our estimates suggest that an order of magnitude more carbon is lost to the atmosphere by evasion than is buried in sediments at a global scale, with total global production, evasion, and burial fluxes of approximately 250, 90, and 7 Tg C yr−1. Finally, the data suggest a trend from autotrophy in low‐latitude large lakes to heterotrophy and increasing reliance on allochthonous carbon sources in lakes at higher latitudes.
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