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Denne rapporten baserer seg på artikkelen “Acidification of the Nordic Seas” av Fransner mfl. (2022). I tillegg presenteres havforsuringstrender (=endring over tid) i Nordsjøen og Skagerrak og trender i antropogent karbon (Cant) i de nordiske hav, Nordsjøen og Skagerrak. Måledata fra de nordiske hav i perioden 1981 til 2019 viser at pH i snitt har avtatt med 0,0028 yr-1 som tilsvarer en pH-reduksjon på 0,11 over 39 år. Dette er dobbelt så mye som den modellerte pH-reduksjonen over perioden 1850-1980 i samme område (–0,05 over 130 år). Modellkjøringer viser at fram til slutten av dette århundret forventes det ytterlige endringer i pH i overflatevann på mellom –0.04 og –0.4 avhengig av hvilket utslippsscenario som brukes. Måledata fra ulike regioner i de nordiske hav viser at pH-trenden i overflatevann er av størrelse –0,002 til –0,003 yr-1. Trenden er primært drevet av økende løst uorganisk karbon (CT) som delvis skyldes opptak av atmosfærisk, og dermed også antropogent, CO2. I overflatevann i Norskebassenget og Islandshavet avtar pH raskere enn det som kan forklares av CO2-opptak fra atmosfæren alene, og resten av endringa skyldes at partialtrykket av CO2 (pCO2) i havoverflata over tid øker raskere enn atmosfærisk CO2. Dette kan skyldes både redusert primærproduksjon og økende havtemperatur. pH-endringene i overflatevann i de nordiske hav er statistisk signifikante bortsett fra i Barentshavsåpningen, der en relativt kraftig økning i total alkalinitet (AT) motvirker den negative pH-trenden. Havforsuringssignalet kan i noen regioner måles helt ned til 2000 m. Vann på 1000-2000 m dyp nærmer seg nå grensen for undermetning av aragonitt (kalsiumkarbonat). I Nordsjøen og Skagerrak finnes måledata fra periodene 2001-2015 og 2001-2019. Trendene i pH og metningsgrad av aragonitt (ΩAr) i Nordsjøen er svake og ikke signifikante, mens i Skagerrak på dyp større enn 200 m avtar pH signifikant, og dypere enn 500 m er pH-trenden –0.0044 yr-1. Trenden er primært drevet av endring i varmt og salt atlantisk vann som strømmer inn i området. Antropogent karbon (Cant) øker i de fleste deler av de nordiske hav, bortsett fra i Barentshavsåpningen. I Norskebassenget øker Cant signifikant på alle dyp, mens i Lofotenbassenget er Cant-økningen signifikant mellom 200 og 2000 m dyp. I Nordsjøen er ikke trendene i Cant signifikante, men i Skagerrak øker Cant signifikant på alle dyp. Det er generelt godt samsvar mellom trender i CT og Cant, og dette viser at økende mengde Cant i havet er den dominerende driveren for økende CT. Observerte forekomstene av korallrev i de nordiske hav lever stort sett på dyp som i dag er overmetta med aragonitt. Dette vil endres i framtida avhengig av hvilket utslippsscenario for CO2 som følges. Hvis CO2-utslippene fortsetter som i dag (RCP8.5) vil alt vann dypere enn ca. 20 m i de nordiske hav bli undermetta med aragonitt når vi nærmer oss slutten på dette århundret, og dette vil få dramatiske konsekvenser for korallrev i hele de nordiske hav.

Denne rapporten baserer seg på artikkelen “Acidification of the Nordic Seas” av Fransner mfl. (2022). I tillegg presenteres havforsuringstrender (=endring over tid) i Nordsjøen og Skagerrak og trender i antropogent karbon (Cant) i de nordiske hav, Nordsjøen og Skagerrak. Måledata fra de nordiske hav i perioden 1981 til 2019 viser at pH i snitt har avtatt med 0,0028 yr-1 som tilsvarer en pH-reduksjon på 0,11 over 39 år. Dette er dobbelt så mye som den modellerte pH-reduksjonen over perioden 1850-1980 i samme område (–0,05 over 130 år). Modellkjøringer viser at fram til slutten av dette århundret forventes det ytterlige endringer i pH i overflatevann på mellom –0.04 og –0.4 avhengig av hvilket utslippsscenario som brukes. Måledata fra ulike regioner i de nordiske hav viser at pH-trenden i overflatevann er av størrelse –0,002 til –0,003 yr-1. Trenden er primært drevet av økende løst uorganisk karbon (CT) som delvis skyldes opptak av atmosfærisk, og dermed også antropogent, CO2. I overflatevann i Norskebassenget og Islandshavet avtar pH raskere enn det som kan forklares av CO2-opptak fra atmosfæren alene, og resten av endringa skyldes at partialtrykket av CO2 (pCO2) i havoverflata over tid øker raskere enn atmosfærisk CO2. Dette kan skyldes både redusert primærproduksjon og økende havtemperatur. pH-endringene i overflatevann i de nordiske hav er statistisk signifikante bortsett fra i Barentshavsåpningen, der en relativt kraftig økning i total alkalinitet (AT) motvirker den negative pH-trenden. Havforsuringssignalet kan i noen regioner måles helt ned til 2000 m. Vann på 1000-2000 m dyp nærmer seg nå grensen for undermetning av aragonitt (kalsiumkarbonat). I Nordsjøen og Skagerrak finnes måledata fra periodene 2001-2015 og 2001-2019. Trendene i pH og metningsgrad av aragonitt (ΩAr) i Nordsjøen er svake og ikke signifikante, mens i Skagerrak på dyp større enn 200 m avtar pH signifikant, og dypere enn 500 m er pH-trenden –0.0044 yr-1. Trenden er primært drevet av endring i varmt og salt atlantisk vann som strømmer inn i området. Antropogent karbon (Cant) øker i de fleste deler av de nordiske hav, bortsett fra i Barentshavsåpningen. I Norskebassenget øker Cant signifikant på alle dyp, mens i Lofotenbassenget er Cant-økningen signifikant mellom 200 og 2000 m dyp. I Nordsjøen er ikke trendene i Cant signifikante, men i Skagerrak øker Cant signifikant på alle dyp. Det er generelt godt samsvar mellom trender i CT og Cant, og dette viser at økende mengde Cant i havet er den dominerende driveren for økende CT. Observerte forekomstene av korallrev i de nordiske hav lever stort sett på dyp som i dag er overmetta med aragonitt. Dette vil endres i framtida avhengig av hvilket utslippsscenario for CO2 som følges. Hvis CO2-utslippene fortsetter som i dag (RCP8.5) vil alt vann dypere enn ca. 20 m i de nordiske hav bli undermetta med aragonitt når vi nærmer oss slutten på dette århundret, og dette vil få dramatiske konsekvenser for korallrev i hele de nordiske hav. publishedVersion

We developed a simple method to refine existing open-ocean maps and extend them towards different coastal seas. Using a multi-linear regression we produced monthly maps of surface ocean fCO2 in the northern European coastal seas (the North Sea, the Baltic Sea, the Norwegian Coast and the Barents Sea) covering a time period from 1998 to 2016. A comparison with gridded Surface Ocean CO2 Atlas (SOCAT) v5 data revealed mean biases and standard deviations of 0 ± 26 µatm in the North Sea, 0 ± 16 µatm along the Norwegian Coast, 0 ± 19 µatm in the Barents Sea and 2 ± 42 µatm in the Baltic Sea. We used these maps to investigate trends in fCO2, pH and air–sea CO2 flux. The surface ocean fCO2 trends are smaller than the atmospheric trend in most of the studied regions. The only exception to this is the western part of the North Sea, where sea surface fCO2 increases by 2 µatm yr−1, which is similar to the atmospheric trend. The Baltic Sea does not show a significant trend. Here, the variability was much larger than the expected trends. Consistently, the pH trends were smaller than expected for an increase in fCO2 in pace with the rise of atmospheric CO2 levels. The calculated air–sea CO2 fluxes revealed that most regions were net sinks for CO2. Only the southern North Sea and the Baltic Sea emitted CO2 to the atmosphere. Especially in the northern regions the sink strength increased during the studied period.

The European Research Infrastructure Consortium “Integrated Carbon Observation System” (ICOS) aims at delivering high quality greenhouse gas (GHG) observations and derived data products (e.g., regional GHG-flux maps) for constraining the GHG balance on a European level, on a sustained long-term basis. The marine domain (ICOS-Oceans) currently consists of 11 Ship of Opportunity lines (SOOP – Ship of Opportunity Program) and 10 Fixed Ocean Stations (FOSs) spread across European waters, including the North Atlantic and Arctic Oceans and the Barents, North, Baltic, and Mediterranean Seas. The stations operate in a harmonized and standardized way based on community-proven protocols and methods for ocean GHG observations, improving operational conformity as well as quality control and assurance of the data. This enables the network to focus on long term research into the marine carbon cycle and the anthropogenic carbon sink, while preparing the network to include other GHG fluxes. ICOS data are processed on a near real-time basis and will be published on the ICOS Carbon Portal (CP), allowing monthly estimates of CO2 air-sea exchange to be quantified for European waters. ICOS establishes transparent operational data management routines following the FAIR (Findable, Accessible, Interoperable, and Reusable) guiding principles allowing amongst others reproducibility, interoperability, and traceability. The ICOS-Oceans network is actively integrating with the atmospheric (e.g., improved atmospheric measurements onboard SOOP lines) and ecosystem (e.g., oceanic direct gas flux measurements) domains of ICOS, and utilizes techniques developed by the ICOS Central Facilities and the CP. There is a strong interaction with the international ocean carbon cycle community to enhance interoperability and harmonize data flow. The future vision of ICOS-Oceans includes ship-based ocean survey sections to obtain a three-dimensional understanding of marine carbon cycle processes and optimize the existing network design. publishedVersion

Winter data of surface ocean temperature (SST), salinity (SSS) and CO 2 fugacity (fCO 2 ) collected on the VOS M/V Nuka Arctica in the subpolar North Atlantic between 2004 and 2017 are used to establish trends, drivers, and interannual variability. Over the period, waters cooled and freshened, and the fCO 2 increased at a rate similar to the atmospheric CO 2 growth rate. When accounting for the freshening, the inferred increase in dissolved inorganic carbon (DIC) was found to be approximately twice that expected from atmospheric CO 2 alone. This is attributed to the cooling. In the Irminger Sea, fCO 2 exhibited additional interannual variations driven by atmospheric forcing through winter mixing. As winter fCO 2 in the region is close to the atmospheric, the subpolar North Atlantic has varied between being slightly supersaturated and slightly undersaturated over the investigated period. ©2019. American Geophysical Union. All Rights Reserved.

Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere – the “global carbon budget” – is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFF) are based on energy statistics and cement production data, while emissions from land use change (ELUC), mainly deforestation, are based on land use and land use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), 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 ±1σ. For the last decade available (2009–2018), EFF was 9.5±0.5 GtC yr−1, ELUC 1.5±0.7 GtC yr−1, GATM 4.9±0.02 GtC yr−1 (2.3±0.01 ppm yr−1), SOCEAN 2.5±0.6 GtC yr−1, and SLAND 3.2±0.6 GtC yr−1, with a budget imbalance BIM of 0.4 GtC yr−1 indicating overestimated emissions and/or underestimated sinks. For the year 2018 alone, the growth in EFF was about 2.1 % and fossil emissions increased to 10.0±0.5 GtC yr−1, reaching 10 GtC yr−1 for the first time in history, ELUC was 1.5±0.7 GtC yr−1, for total anthropogenic CO2 emissions of 11.5±0.9 GtC yr−1 (42.5±3.3 GtCO2). Also for 2018, GATM was 5.1±0.2 GtC yr−1 (2.4±0.1 ppm yr−1), SOCEAN was 2.6±0.6 GtC yr−1, and SLAND was 3.5±0.7 GtC yr−1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 407.38±0.1 ppm averaged over 2018. For 2019, preliminary data for the first 6–10 months indicate a reduced growth in EFF of +0.6 % (range of −0.2 % to 1.5 %) based on national emissions projections for China, the USA, the EU, and India and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. Overall, the mean and trend in the five components of the global carbon budget are consistently estimated over the period 1959–2018, but discrepancies of up to 1 GtC yr−1 persist for the representation of semi-decadal variability in CO2 fluxes. A detailed comparison among individual estimates and the introduction of a broad range of observations shows (1) no consensus in the mean and trend in land use change emissions over the last decade, (2) a persistent low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) an apparent underestimation of the CO2 variability by ocean models outside the tropics. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set (Le Quéré et al., 2018a, b, 2016, 2015a, b, 2014, 2013). The data generated by this work are available at https://doi.org/10.18160/gcp-2019 (Friedlingstein et al., 2019).

Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere – the “global carbon budget” – is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFF) are based on energy statistics and cement production data, while emissions from land use change (ELUC), mainly deforestation, are based on land use and land use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), 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 ±1σ. For the last decade available (2009–2018), EFF was 9.5±0.5 GtC yr−1, ELUC 1.5±0.7 GtC yr−1, GATM 4.9±0.02 GtC yr−1 (2.3±0.01 ppm yr−1), SOCEAN 2.5±0.6 GtC yr−1, and SLAND 3.2±0.6 GtC yr−1, with a budget imbalance BIM of 0.4 GtC yr−1 indicating overestimated emissions and/or underestimated sinks. For the year 2018 alone, the growth in EFF was about 2.1 % and fossil emissions increased to 10.0±0.5 GtC yr−1, reaching 10 GtC yr−1 for the first time in history, ELUC was 1.5±0.7 GtC yr−1, for total anthropogenic CO2 emissions of 11.5±0.9 GtC yr−1 (42.5±3.3 GtCO2). Also for 2018, GATM was 5.1±0.2 GtC yr−1 (2.4±0.1 ppm yr−1), SOCEAN was 2.6±0.6 GtC yr−1, and SLAND was 3.5±0.7 GtC yr−1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 407.38±0.1 ppm averaged over 2018. For 2019, preliminary data for the first 6–10 months indicate a reduced growth in EFF of +0.6 % (range of −0.2 % to 1.5 %) based on national emissions projections for China, the USA, the EU, and India and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. Overall, the mean and trend in the five components of the global carbon budget are consistently estimated over the period 1959–2018, but discrepancies of up to 1 GtC yr−1 persist for the representation of semi-decadal variability in CO2 fluxes. A detailed comparison among individual estimates and the introduction of a broad range of observations shows (1) no consensus in the mean and trend in land use change emissions over the last decade, (2) a persistent low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) an apparent underestimation of the CO2 variability by ocean models outside the tropics. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set (Le Quéré et al., 2018a, b, 2016, 2015a, b, 2014, 2013). The data generated by this work are available at https://doi.org/10.18160/gcp-2019 (Friedlingstein et al., 2019)., Earth System Science Data, 11 (4), ISSN:1866-3516, ISSN:1866-3508

Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere-the "global carbon budget"-is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFF) are based on energy statistics and cement production data, while emissions from land use change (ELUC), mainly deforestation, are based on land use and land use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), 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 ±1σ. For the last decade available (2009-2018), EFF was 9:5±0:5 GtC yr-1, ELUC 1:5±0:7 GtC yr-1, GATM 4:9±0:02 GtC yr-1 (2:3±0:01 ppm yr-1), SOCEAN 2:5±0:6 GtC yr-1, and SLAND 3:2±0:6 GtC yr-1, with a budget imbalance BIM of 0.4 GtC yr-1 indicating overestimated emissions and/or underestimated sinks. For the year 2018 alone, the growth in EFF was about 2.1% and fossil emissions increased to 10:0±0:5 GtC yr-1, reaching 10 GtC yr-1 for the first time in history, ELUC was 1:5±0:7 GtC yr-1, for total anthropogenic CO2 emissions of 11:5±0:9 GtC yr-1 (42:5±3:3 GtCO2). Also for 2018, GATM was 5:1±0:2 GtC yr-1 (2:4±0:1 ppm yr-1), SOCEAN was 2:6±0:6 GtC yr-1, and SLAND was 3:5±0:7 GtC yr-1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 407:38±0:1 ppm averaged over 2018. For 2019, preliminary data for the first 6-10 months indicate a reduced growth in EFF of C0:6% (range of.0:2% to 1.5 %) based on national emissions projections for China, the USA, the EU, and India and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. Overall, the mean and trend in the five components of the global carbon budget are consistently estimated over the period 1959-2018, but discrepancies of up to 1 GtC yr-1 persist for the representation of semi-decadal variability in CO2 fluxes. A detailed comparison among individual estimates and the introduction of a broad range of observations shows (1) no consensus in the mean and trend in land use change emissions over the last decade, (2) a persistent low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) an apparent underestimation of the CO2 variability by ocean models outside the tropics. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set (Le Quéré et al., 2018a, b, 2016, 2015a, b, 2014, 2013). The data generated by this work are available at https://doi.org/10.18160/gcp-2019 (Friedlingstein et al., 2019).

We estimated monthly air–sea CO2 fluxes in the Arctic Ocean and its adjacent seas north of 60∘ N from 1997 to 2014. This was done by mapping partial pressure of CO2 in the surface water (pCO2w) using a self-organizing map (SOM) technique incorporating chlorophyll a concentration (Chl a), sea surface temperature, sea surface salinity, sea ice concentration, atmospheric CO2 mixing ratio, and geographical position. We applied new algorithms for extracting Chl a from satellite remote sensing reflectance with close examination of uncertainty of the obtained Chl a values. The overall relationship between pCO2w and Chl a was negative, whereas the relationship varied among seasons and regions. The addition of Chl a as a parameter in the SOM process enabled us to improve the estimate of pCO2w, particularly via better representation of its decline in spring, which resulted from biologically mediated pCO2w reduction. As a result of the inclusion of Chl a, the uncertainty in the CO2 flux estimate was reduced, with a net annual Arctic Ocean CO2 uptake of 180 ± 130 Tg C yr−1. Seasonal to interannual variation in the CO2 influx was also calculated.

The Surface Ocean CO2 Atlas (SOCAT) is a synthesis of quality-controlled fCO2 (fugacity of carbon dioxide) values for the global surface oceans and coastal seas with regular updates. Version 3 of SOCAT has 14.7 million fCO2 values from 3646 data sets covering the years 1957 to 2014. This latest version has an additional 4.6 million fCO2 values relative to version 2 and extends the record from 2011 to 2014. Version 3 also significantly increases the data availability for 2005 to 2013. SOCAT has an average of approximately 1.2 million surface water fCO2 values per year for the years 2006 to 2012. Quality and documentation of the data has improved. A new feature is the data set quality control (QC) flag of E for data from alternative sensors and platforms. The accuracy of surface water fCO2 has been defined for all data set QC flags. Automated range checking has been carried out for all data sets during their upload into SOCAT. The upgrade of the interactive Data Set Viewer (previously known as the Cruise Data Viewer) allows better interrogation of the SOCAT data collection and rapid creation of high-quality figures for scientific presentations. Automated data upload has been launched for version 4 and will enable more frequent SOCAT releases in the future. High-profile scientific applications of SOCAT include quantification of the ocean sink for atmospheric carbon dioxide and its long-term variation, detection of ocean acidification, as well as evaluation of coupled-climate and ocean-only biogeochemical models. Users of SOCAT data products are urged to acknowledge the contribution of data providers, as stated in the SOCAT Fair Data Use Statement. This ESSD (Earth System Science Data) "living data" publication documents the methods and data sets used for the assembly of this new version of the SOCAT data collection and compares these with those used for earlier versions of the data collection (Pfeil et al., 2013; Sabine et al., 2013; Bakker et al., 2014). Individual data set files, included in the synthesis product, can be downloaded here: doi:10.1594/PANGAEA.849770. The gridded products are available here: doi:10.3334/CDIAC/OTG.SOCAT_V3_GRID.

The effect of submarine carbon dioxide (CO2) vents on seawater carbonate chemistry have been determined using hydrographical and marine carbonate data obtained from two submarine hydrothermal vent fields, as well as a reference station, all near the Jan Mayen Island in the Norwegian-Greenland Sea. We have shown that one can successfully determine the excess carbon that enters the seawater from the vents by applying a modified version of a back-calculation technique, which is traditionally used to study the invasion of excess atmospheric CO2 in the surface ocean. As a result of this excess carbon, total dissolved inorganic carbon (CT) in the seawater surrounding the vents was on average 12 μmol kg−1 (1-30 μmol kg−1) higher compared to samples obtained from a reference station outside the venting areas. The observed excess CT was most significant between 100 m and 200 m but was noticeable in all depths with the exception of the upper 10-20 m. The absence of a venting CO2 signal in the surface water and the realism of the results are discussed. We believe the present method is promising for monitoring (detection and quantification) of CO2 leakage into the water column due to its high sensitivity and readiness for automation.

ECO2 Deliverable No D3.1

Denne rapporten gjelder undersøkelser av havforsuring som er utført av IMR, NIVA og BCCR i oppdrag fra Klif i 2011. Den er basert på målinger mellom Bergen-Kirknes og Tromsø-Longyearbyen utført av NIVA. Prøvetaking av vertikalen fra Torungen-Hirtshals, Svinøy-NW, Gimsøy-NW og Fugløya-Bjørnøya er utført av IMR. Resultatene fra Norskehavet viser en klar sesongvariasjon i øvre 100 m av vannsøylen, som for det meste er styrt av styrken på primærproduksjonen. I tillegg påvirkes karboninnholdet av kystvannet som brer seg vestover i løpet av sommeren. Metningsgraden for aragonitt (Ar) er mellom 1.95 til 1.6 på 300 m dyp. I Norskehavet befinner =1.6 seg på 500 m dyp, og i Nordsjøen på ca 200 m. I Norskehavet er det undermetning fra like under 1500 meters dyp av aragonitt og overmetning av kalsitt i hele vannsøylen. I Barentshavet lå Ar mellom 1.07-2.62 med min. verdier i kystområdet mellom Kirkenes og Tromsø i januar (1.07-2.03), mens Ar var 1.49-2.52 i desember, og karakterisert av en stor variasjon fra 1.67 til 2.62 som skyldes en økt biologisk produksjon. Historiske data er sammenlignet på Havforskningens hydrografiske seksjoner i 2011 og CARINA databasen. Primært ble data fra 1997-2011 i nord-vestlig retning fra Gimsøy og Svinøy benyttet for å studere trender i Norskehavet, men analysen omfatter også data fra Barentshavet. Trender viser en økning av karbonkonsentrasjonene målt i 2011 relativt til historiske data. Dette gjenspeiler hovedsakelig havets opptak av menneskeskapt CO2. Konklusjonen er at de fleste områder studert i denne rapporten er mettet i forhold til kalsitt, og undermetning av aragonitt viser seg på 1500 meters dyp i Norskehavet. Klif

Denne rapporten gjelder undersøkelser av havforsuring som er utført av NIVA, IMR og BCCR i oppdrag fra Klif. Den er basert på målinger fra tokt mellom Oslo - Kiel og Tromsø - Longyearbyen utført av NIVA i 2010, prøvetaking Torungen – Hirtshals utført av Havforskningsinstituttet og analysert ved BCCR i 2010, og analyser av historiske data gjennomført av BCCR. De sistnevnte data er primært fra 2001-2007 samlet fra to transekt som krysser Nordsjøen i øst-vestlig og nord-sørlig retning, men omfatter også toktdata fra sør i Nordsjøen i 1987. Resultatene viser en klar sesongvis variasjon som for det meste er styrt av styrken på primærproduksjonen gjennom året. Det er også funnet år-til-år endringer som er tilnærmet like store som sesongvariasjonene. Dette gjør det vanskelig å dokumentere endringene i pH som er ventet fra antropogen havforsuring. Vår nåværende evne til å observere dette signalet og generelt forstå dynamikken i observerte endringer er diskutert i rapporten. I den forbindelse blir det påpekt behov for multivariable, langsiktige måleprogram på faste stasjoner. De fleste områder studert i denne rapporten er mettet i forhold til kalsiumkarbonat Klif

Ocean Sciences Meeting, March 2-7, 2008, Orlando, Florida, Since the start of 2005 under the EU’s Carbo-Ocean project, we have participated in co-ordinated observations of sea surface pCO2 and related variables from a network of commercial vessels in the North Atlantic. Typically five vessels are operating at any one time. The observations can be used to reconstruct the sea-surface pCO2 field, and thence estimate air-sea fluxes, with unprecedented resolution and accuracy. Using the observations for the calendar year 2005, we use a variety of geostatistical methods to derive the precision with which regional fluxes can be obtained. The observations are generalized to the entire N Atlantic from 10N to 65N by exploiting relations between surface pCO2, SST and mixed layer depth. Using semi-variograms or an empirical technique of selective data deletion applied to the residuals, we obtain a 1-sigma uncertainty of 6% on the annual flux into the region as a whole. This is very much more precise than has been possible for any comparable region of the world (land or ocean) up to now

Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere – the “global carbon budget” – is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics, and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates and consistency within and among components, alongside methodology and data limitations. CO2 emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, respectively, while emissions from land-use change (ELUC), mainly deforestation, are based on combined evidence from land-cover change data, fire activity associated with deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated with data products based on surveys of ocean CO2 measurements. The global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models. We compare the mean land and ocean fluxes and their variability to estimates from three atmospheric inverse methods for three broad latitude bands. All uncertainties are reported as ±1σ, reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. For the last decade available (2006–2015), EFF was 9.3 ± 0.5 GtC yr−1, ELUC 1.0 ± 0.5 GtC yr−1, GATM 4.5 ± 0.1 GtC yr−1, SOCEAN 2.6 ± 0.5 GtC yr−1, and SLAND 3.1 ± 0.9 GtC yr−1. For year 2015 alone, the growth in EFF was approximately zero and emissions remained at 9.9 ± 0.5 GtC yr−1, showing a slowdown in growth of these emissions compared to the average growth of 1.8 % yr−1 that took place during 2006–2015. Also, for 2015, ELUC was 1.3 ± 0.5 GtC yr−1, GATM was 6.3 ± 0.2 GtC yr−1, SOCEAN was 3.0 ± 0.5 GtC yr−1, and SLAND was 1.9 ± 0.9 GtC yr−1. GATM was higher in 2015 compared to the past decade (2006–2015), reflecting a smaller SLAND for that year. The global atmospheric CO2 concentration reached 399.4 ± 0.1 ppm averaged over 2015. For 2016, preliminary data indicate the continuation of low growth in EFF with +0.2 % (range of −1.0 to +1.8 %) based on national emissions projections for China and USA, and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. In spite of the low growth of EFF in 2016, the growth rate in atmospheric CO2 concentration is expected to be relatively high because of the persistence of the smaller residual terrestrial sink (SLAND) in response to El Niño conditions of 2015–2016. From this projection of EFF and assumed constant ELUC for 2016, cumulative emissions of CO2 will reach 565 ± 55 GtC (2075 ± 205 GtCO2) for 1870–2016, about 75 % from EFF and 25 % from ELUC. This living data update documents changes in the methods and data sets used in this new carbon budget compared with previous publications of this data set (Le Quéré et al., 2015b, a, 2014, 2013). All observations presented here can be downloaded from the Carbon Dioxide Information Analysis Center (doi:10.3334/CDIAC/GCP_2016).

Accurate assessmen of anthropogenic carbon dioxide (CO₂) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere – the “global carbon budget” – is important to betterunderstand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics, and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates and consistency within and among components, alongside methodology and data limitations. CO₂ emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, respec- tively, while emissions from land-use change (ELUC), mainly deforestation, are based on combined evidence from land-cover change data, fire activity associated with deforestation, and models. The global atmospheric CO₂ concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO₂ sink (SOCEAN) is based on observations from the 1990s, while the an- nual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated with data products based on surveys of ocean CO₂ measurements. The global residual terrestrial CO₂ sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models. We compare the mean land and ocean fluxes and their variability to estimates from three atmospheric inverse methods for three broad latitude bands. All uncertainties are reported as ± 1σ, reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. For the last decade available (2006–2015), EFF was 9.3± 0.5 GtC yr⁻¹, ELUC 1.0± 0.5 GtC yr⁻¹,GATM 4.5± 0.1 GtC yr⁻¹, SOCEAN 2.6± 0.5 GtC yr⁻¹, and SLAND 3.1± 0.9 GtC yr⁻¹. For year 2015 alone, the growth in EFF was approximately zero and emissions remained at 9.9± 0.5 GtC yr⁻¹, showing a slowdown in growth of these emissions compared to the average growth of 1.8 % yr⁻¹ that took place during 2006–2015. Also, for 2015, ELUC was 1.3± 0.5 GtC yr⁻¹,GATM was 6.3± 0.2 GtC yr⁻¹, SOCEAN was 3.0± 0.5 GtC yr⁻¹, and SLAND was 1.9± 0.9 GtC yr⁻¹ GATM was higher in 2015 compared to the past decade (2006–2015), reflecting a smaller SLAND for that year. The global atmospheric CO₂ concentration reached 399.4± 0.1 ppm averaged over 2015. For 2016, preliminary data indicate the continuation of low growth in EFF with +0.2 % (range of −1.0 to + 1.8 %) based on national emissions projections for China and USA, and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. In spite of the low growth of EFF in 2016, the growth rate in atmospheric CO₂ concentration is expected to be relatively high because of the persistence of the smaller residual terrestrial sink (SLAND) in response to El Niño conditions of 2015–2016. From this projection of EFF and assumed constant ELUC for 2016, cumulative emissions of CO₂ will reach 565± 55 GtC (2075± 205 GtCO₂) for 1870–2016, about 75 % from EFF and 25 % from ELUC. This living data update documents changes in the methods and data sets used in this new carbon budget compared with previous publications of this data set (Le Quéré et al., 2015b, a, 2014, 2013).

Accurate assessment of anthropogenic carbon dioxide (CO₂) emissions and their redistributionamong the atmosphere, ocean, and terrestrial biosphere – the “global carbon budget” – is important to betterunderstand the global carbon cycle, support the development of climate policies, and project future climatechange. Here we describe data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO₂ emissions (EFF) are based on energy statistics and cement productiondata, while emissions from land use change (ELUC), mainly deforestation, are based on land use and land usechange data and bookkeeping models. Atmospheric CO₂ concentration is measured directly and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO₂ sink (SOCEAN) and terrestrial CO₂ sink (SLAND) are estimated with global process models constrained by observations. The resulting car-bon budget imbalance (BIM), the difference between the estimated total emissions and the estimated changesin the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as±1σ. For the last decade available (2009–2018), EFF was 9.5±0.5 GtC yr⁻¹, ELUC 1.5±0.7 GtC yr⁻¹, GATM4.9±0.02 GtC yr⁻¹ (2.3±0.01 ppm yr⁻¹), SOCEAN 2.5±0.6 GtC yr⁻¹, and SLAND 3.2±0.6 GtC yr⁻¹, with a budget imbalance BIM of 0.4 GtC yr⁻¹ indicating overestimated emissions and/or underestimated sinks. For the year 2018 alone, the growth in EFFwas about 2.1 %and fossil emissions increased to 10.0±0.5 GtC yr⁻¹, reaching 10 GtC yr⁻¹ for the first time in history, ELUC was 1.5±0.7 GtC yr⁻¹, for total anthropogenic CO emissions of 11.5±0.9 GtC yr⁻¹ (42.5±3.3 Gt CO₂). Alsofor 2018,GATM was 5.1±0.2 GtC yr⁻¹(2.4±0.1 ppm yr⁻¹), SOCEAN was 2.6±0.6 GtC yr⁻¹, and SLAND was 3.5±0.7 GtC yr⁻¹, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 407.38±0.1 ppmaveraged over 2018. For 2019, preliminary data for the first 6–10 months indicate a reduced growth in EFF of +0.6 % (range of −0.2 % to 1.5 %) based on national emissions projections for China, the USA, the EU, andIndia and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. Overall, the mean and trend in the five components of the global carbon budgetare consistently estimated over the period 1959–2018, but discrepancies of up to 1 GtC yr⁻¹ persist for the rep-resentation of semi-decadal variability in CO₂ fluxes. A detailed comparison among individual estimates and theintroduction of a broad range of observations shows (1) no consensus in the mean and trend in land use changeemissions over the last decade, (2) a persistent low agreement between the different methods on the magnitudeof the land CO₂ flux in the northern extra-tropics, and (3) an apparent underestimation of the CO₂ variability byocean models outside the tropics. This living data update documents changes in the methods and data sets usedin this new global carbon budget and the progress in understanding of the global carbon cycle compared withprevious publications of this data set (Le Quéré et al., 2018a, b, 2016, 2015a, b, 2014, 2013).