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- ItemSources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris(München : European Geopyhsical Union, 2012) Healy, R.M.; Sciare, J.; Poulain, L.; Kamili, K.; Merkel, M.; Müller, T.; Wiedensohler, A.; Eckhardt, S.; Stohl, A.; Sarda-Estève, R.; McGillicuddy, E.; O'Connor, I.P.; Sodeau, J.R.; Wenger, J.C.An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS) data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150–1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and Multi-Angle Absorption Photometer (MAAP) mass concentration measurements of organic carbon (OC), inorganic ions and black carbon (BC) (R2 = 0.91). Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC) particles into four classes: (i) EC attributed to biomass burning (ECbiomass), (ii) EC attributed to traffic (ECtraffic), (iii) EC internally mixed with OC and ammonium sulfate (ECOCSOx), and (iv) EC internally mixed with OC and ammonium nitrate (ECOCNOx). Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65–0.68 respectively, n = 552). The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568). Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88% and 12% of EC particle mass was apportioned to fossil fuel and biomass burning respectively using the ATOFMS data compared with 85% and 15% respectively for BC estimated from the aethalometer model. On average, the mass size distribution for EC particles is bimodal; the smaller mode is attributed to locally emitted, mostly externally mixed EC particles, while the larger mode is dominated by aged, internally mixed ECOCNOx particles associated with continental transport events. Periods of continental influence were identified using the Lagrangian Particle Dispersion Model (LPDM) "FLEXPART". A consistent minimum between the two EC mass size modes was observed at approximately 400 nm for the measurement period. EC particles below this size are attributed to local emissions using chemical mixing state information and contribute 79% of the scaled ATOFMS EC particle mass, while particles above this size are attributed to continental transport events and contribute 21% of the EC particle mass. These results clearly demonstrate the potential benefit of monitoring size-resolved mass concentrations for the separation of local and continental EC emissions. Knowledge of the relative input of these emissions is essential for assessing the effectiveness of local abatement strategies.
- ItemSoot reference materials for instrument calibration and intercomparisons: A workshop summary with recommendations(München : European Geopyhsical Union, 2012) Baumgardner, D.; Popovicheva, O.; Allan, J.; Bernardoni, V.; Cao, J.; Cavalli, F.; Cozic, J.; Courcoux, Y.; Diapouli, E.; Eleftheriadis, K.; Genberg, P.J.; Gonzalez, C.; Gysel, M.; John, A.; Kirchstetter, T.W.; Kuhlbusch, T.A.J.; Laborde, M.; Lack, D.; Müller, T.; Niessner, R.; Petzold, A.; Piazzalunga, A.; Putaud, J.P.; Schwarz, J.; Sheridan, P.; Subramanian, R.; Swietlicki, E.; Valli, G.; Vecchi, R.; Viana, M.Soot, which is produced from biomass burning and the incomplete combustion of fossil and biomass fuels, has been linked to regional and global climate change and to negative health problems. Scientists measure the properties of soot using a variety of methods in order to quantify source emissions and understand its atmospheric chemistry, reactivity under emission conditions, interaction with solar radiation, influence on clouds, and health impacts. A major obstacle currently limiting progress is the absence of established standards or reference materials for calibrating the many instruments used to measure the various properties of soot. The current state of availability and practicability of soot standard reference materials (SRMs) was reviewed by a group of 50 international experts during a workshop in June of 2011. The workshop was convened to summarize the current knowledge on soot measurement techniques, identify the measurement uncertainties and limitations related to the lack of soot SRMs, and identify attributes of SRMs that, if developed, would reduce measurement uncertainties. The workshop established that suitable SRMs are available for calibrating some, but not all, measurement methods. The community of users of the single-particle soot-photometer (SP2), an instrument using laser-induced incandescence, identified a suitable SRM, fullerene soot, but users of instruments that measure light absorption by soot collected on filters did not. Similarly, those who use thermal optical analysis (TOA) to analyze the organic and elemental carbon components of soot were not satisfied with current SRMs. The workshop, and subsequent, interactive discussions, produced a number of recommendations for the development of new SRMs, and their implementation, that would be suitable for the different soot measurement methods.
- ItemPollution events observed during CARIBIC flights in the upper troposphere between South China and the Philippines(München : European Geopyhsical Union, 2010) Lai, S.C.; Baker, A.K.; Schuck, T.J.; van Velthoven, P.; Oram, D.E.; Zahn, A.; Hermann, M.; Weigelt, A.; Slemr, F.; Brenninkmeijer, C.A.M.; Ziereis, H.A strong pollution episode in the upper troposphere between South China and the Philippines was observed during CARIBIC flights in April 2007. Five pollution events were observed, where enhancements in aerosol and trace gas concentrations including CO, CO2, CH4, non-methane hydrocarbons (NMHCs) and halocarbons were observed along the flight tracks during four sequential flights. The importance of the contribution of biomass/biofuel burning was investigated using chemical tracers, emission factor analysis, back-trajectory analysis and satellite images. The Indochinese peninsula was identified as the probable source region of biomass/biofuel burning. However, enhancements in the urban/industrial tracer C2Cl4 during the events also indicate a substantial contribution from urban anthropogenic emissions. An estimation of the contribution of fossil fuel versus biomass/biofuel to the CO enhancement was made, indicating a biomass/biofuel burning contribution of ~54 to ~92% of the observed CO enhancements. Biomass/biofuel burning was found to be the most important source category during the sampling period.
- ItemThe millennial atmospheric lifetime of anthropogenic CO2(Dordrecht [u.a.] : Springer, 2008) Archer, D.; Brovkin, V.The notion is pervasive in the climate science community and in the public at large that the climate impacts of fossil fuel CO2 release will only persist for a few centuries. This conclusion has no basis in theory or models of the atmosphere/ocean carbon cycle, which we review here. The largest fraction of the CO2 recovery will take place on time scales of centuries, as CO2 invades the ocean, but a significant fraction of the fossil fuel CO2, ranging in published models in the literature from 20-60%, remains airborne for a thousand years or longer. Ultimate recovery takes place on time scales of hundreds of thousands of years, a geologic longevity typically associated in public perceptions with nuclear waste. The glacial/interglacial climate cycles demonstrate that ice sheets and sea level respond dramatically to millennial-timescale changes in climate forcing. There are also potential positive feedbacks in the carbon cycle, including methane hydrates in the ocean, and peat frozen in permafrost, that are most sensitive to the long tail of the fossil fuel CO2 in the atmosphere. © 2008 The Author(s).
- ItemGeoengineering climate by stratospheric sulfur injections: Earth system vulnerability to technological failure(Dordrecht [u.a.] : Springer, 2009) Brovkin, V.; Petoukhov, V.; Claussen, M.; Bauer, E.; Archer, D.; Jaeger, C.We use a coupled climate-carbon cycle model of intermediate complexity to investigate scenarios of stratospheric sulfur injections as a measure to compensate for CO2-induced global warming. The baseline scenario includes the burning of 5,000 GtC of fossil fuels. A full compensation of CO2-induced warming requires a load of about 13 MtS in the stratosphere at the peak of atmospheric CO2 concentration. Keeping global warming below 2°C reduces this load to 9 MtS. Compensation of CO 2 forcing by stratospheric aerosols leads to a global reduction in precipitation, warmer winters in the high northern latitudes and cooler summers over northern hemisphere landmasses. The average surface ocean pH decreases by 0.7, reducing the calcifying ability of marine organisms. Because of the millennial persistence of the fossil fuel CO2 in the atmosphere, high levels of stratospheric aerosol loading would have to continue for thousands of years until CO2 was removed from the atmosphere. A termination of stratospheric aerosol loading results in abrupt global warming of up to 5°C within several decades, a vulnerability of the Earth system to technological failure. © 2008 The Author(s).
- ItemHarmonization of global land use change and management for the period 850–2100 (LUH2) for CMIP6(Katlenburg-Lindau : Copernicus, 2020) Hurtt, George C.; Chini, Louise; Sahajpal, Ritvik; Frolking, Steve; Bodirsky, Benjamin L.; Calvin, Katherine; Doelman, Jonathan C.; Fisk, Justin; Fujimori, Shinichiro; Klein Goldewijk, Kees; Hasegawa, Tomoko; Havlik, Peter; Heinimann, Andreas; Humpenöder, Florian; Jungclaus, Johan; Kaplan, Jed O.; Kennedy, Jennifer; Krisztin, Tamás; Lawrence, David; Lawrence, Peter; Ma, Lei; Mertz, Ole; Pongratz, Julia; Popp, Alexander; Poulter, Benjamin; Riahi, Keywan; Shevliakova, Elena; Stehfest, Elke; Thornton, Peter; Tubiello, Francesco N.; van Vuuren, Detlef P.; Zhang, XinHuman land use activities have resulted in large changes to the biogeochemical and biophysical properties of the Earth's surface, with consequences for climate and other ecosystem services. In the future, land use activities are likely to expand and/or intensify further to meet growing demands for food, fiber, and energy. As part of the World Climate Research Program Coupled Model Intercomparison Project (CMIP6), the international community has developed the next generation of advanced Earth system models (ESMs) to estimate the combined effects of human activities (e.g., land use and fossil fuel emissions) on the carbon–climate system. A new set of historical data based on the History of the Global Environment database (HYDE), and multiple alternative scenarios of the future (2015–2100) from Integrated Assessment Model (IAM) teams, is required as input for these models. With most ESM simulations for CMIP6 now completed, it is important to document the land use patterns used by those simulations. Here we present results from the Land-Use Harmonization 2 (LUH2) project, which smoothly connects updated historical reconstructions of land use with eight new future projections in the format required for ESMs. The harmonization strategy estimates the fractional land use patterns, underlying land use transitions, key agricultural management information, and resulting secondary lands annually, while minimizing the differences between the end of the historical reconstruction and IAM initial conditions and preserving changes depicted by the IAMs in the future. The new approach builds on a similar effort from CMIP5 and is now provided at higher resolution (0.25∘×0.25∘) over a longer time domain (850–2100, with extensions to 2300) with more detail (including multiple crop and pasture types and associated management practices) using more input datasets (including Landsat remote sensing data) and updated algorithms (wood harvest and shifting cultivation); it is assessed via a new diagnostic package. The new LUH2 products contain > 50 times the information content of the datasets used in CMIP5 and are designed to enable new and improved estimates of the combined effects of land use on the global carbon–climate system.
- ItemPhysical and virtual carbon metabolism of global cities([London] : Nature Publishing Group UK, 2020) Chen, Shaoqing; Chen, Bin; Feng, Kuishuang; Liu, Zhu; Fromer, Neil; Tan, Xianchun; Alsaedi, Ahmed; Hayat, Tasawar; Weisz, Helga; Schellnhuber, Hans Joachim; Hubacek, KlausUrban activities have profound and lasting effects on the global carbon balance. Here we develop a consistent metabolic approach that combines two complementary carbon accounts, the physical carbon balance and the fossil fuel-derived gaseous carbon footprint, to track carbon coming into, being added to urban stocks, and eventually leaving the city. We find that over 88% of the physical carbon in 16 global cities is imported from outside their urban boundaries, and this outsourcing of carbon is notably amplified by virtual emissions from upstream activities that contribute 33–68% to their total carbon inflows. While 13–33% of the carbon appropriated by cities is immediately combusted and released as CO2, between 8 and 24% is stored in durable household goods or becomes part of other urban stocks. Inventorying carbon consumed and stored for urban metabolism should be given more credit for the role it can play in stabilizing future global climate.
- ItemTaking stock of national climate policies to evaluate implementation of the Paris Agreement([London] : Nature Publishing Group UK, 2020) Roelfsema, Mark; van Soest, Heleen L.; Harmsen, Mathijs; van Vuuren, Detlef P.; Bertram, Christoph; den Elzen, Michel; Höhne, Niklas; Iacobuta, Gabriela; Krey, Volker; Kriegler, Elmar; Luderer, Gunnar; Riahi, Keywan; Ueckerdt, Falko; Després, Jacques; Drouet, Laurent; Emmerling, Johannes; Frank, Stefan; Fricko, Oliver; Gidden, Matthew; Humpenöder, Florian; Huppmann, Daniel; Fujimori, Shinichiro; Fragkiadakis, Kostas; Gi, Keii; Keramidas, Kimon; Köberle, Alexandre C.; Aleluia Reis, Lara; Rochedo, Pedro; Schaeffer, Roberto; Oshiro, Ken; Vrontisi, Zoi; Chen, Wenying; Iyer, Gokul C.; Edmonds, Jae; Kannavou, Maria; Jiang, Kejun; Mathur, Ritu; Safonov, George; Vishwanathan, Saritha SudharmmaMany countries have implemented national climate policies to accomplish pledged Nationally Determined Contributions and to contribute to the temperature objectives of the Paris Agreement on climate change. In 2023, the global stocktake will assess the combined effort of countries. Here, based on a public policy database and a multi-model scenario analysis, we show that implementation of current policies leaves a median emission gap of 22.4 to 28.2 GtCO2eq by 2030 with the optimal pathways to implement the well below 2 °C and 1.5 °C Paris goals. If Nationally Determined Contributions would be fully implemented, this gap would be reduced by a third. Interestingly, the countries evaluated were found to not achieve their pledged contributions with implemented policies (implementation gap), or to have an ambition gap with optimal pathways towards well below 2 °C. This shows that all countries would need to accelerate the implementation of policies for renewable technologies, while efficiency improvements are especially important in emerging countries and fossil-fuel-dependent countries.
- ItemCorrecting a fundamental error in greenhouse gas accounting related to bioenergy(Amsterdam [u.a.] : Elsevier, 2012) Haberl, H.; Sprinz, D.; Bonazountas, M.; Cocco, P.; Desaubies, Y.; Henze, M.; Hertel, O.; Johnson, R.K.; Kastrup, U.; Laconte, P.; Lange, E.; Novak, P.; Paavola, J.; Reenberg, A.; van den Hove, S.; Vermeire, T.; Wadhams, P.; Searchinger, T.Many international policies encourage a switch from fossil fuels to bioenergy based on the premise that its use would not result in carbon accumulation in the atmosphere. Frequently cited bioenergy goals would at least double the present global human use of plant material, the production of which already requires the dedication of roughly 75% of vegetated lands and more than 70% of water withdrawals. However, burning biomass for energy provision increases the amount of carbon in the air just like burning coal, oil or gas if harvesting the biomass decreases the amount of carbon stored in plants and soils, or reduces carbon sequestration. Neglecting this fact results in an accounting error that could be corrected by considering that only the use of 'additional biomass' - biomass from additional plant growth or biomass that would decompose rapidly if not used for bioenergy - can reduce carbon emissions. Failure to correct this accounting flaw will likely have substantial adverse consequences. The article presents recommendations for correcting greenhouse gas accounts related to bioenergy.
- ItemThe EMEP Intensive Measurement Period campaign, 2008-2009: Characterizing carbonaceous aerosol at nine rural sites in Europe(Katlenburg-Lindau : EGU, 2019) Yttri, Karl Espen; Simpson, David; Bergström, Robert; Kiss, Gyula; Szidat, Sönke; Ceburnis, Darius; Eckhardt, Sabine; Hueglin, Christoph; Nøjgaard, Jacob Klenø; Perrino, Cinzia; Pisso, Ignazio; Prevot, Andre Stephan Henry; Putaud, Jean-Philippe; Spindler, Gerald; Vana, Milan; Zhang, Yan-Lin; Aas, WencheCarbonaceous aerosol (total carbon, TCp) was source apportioned at nine European rural background sites, as part of the European Measurement and Evaluation Programme (EMEP) Intensive Measurement Periods in fall 2008 and winter/spring 2009. Five predefined fractions were apportioned based on ambient measurements: elemental and organic carbon, from combustion of biomass (ECbb and OCbb) and from fossil-fuel (ECff and OCff) sources, and remaining non-fossil organic carbon (OCrnf), dominated by natural sources.OCrnf made a larger contribution to TCp than anthropogenic sources (ECbb, OCbb, ECff, and OCff) at four out of nine sites in fall, reflecting the vegetative season, whereas anthropogenic sources dominated at all but one site in winter/spring. Biomass burning (OCbb + ECbb) was the major anthropogenic source at the central European sites in fall, whereas fossil-fuel (OCff + ECff) sources dominated at the southernmost and the two northernmost sites. Residential wood burning emissions explained 30 %-50 % of TCp at most sites in the first week of sampling in fall, showing that this source can be the dominant one, even outside the heating season. In winter/spring, biomass burning was the major anthropogenic source at all but two sites, reflecting increased residential wood burning emissions in the heating season. Fossil-fuel sources dominated EC at all sites in fall, whereas there was a shift towards biomass burning for the southernmost sites in winter/spring.Model calculations based on base-case emissions (mainly officially reported national emissions) strongly underpredicted observational derived levels of OCbb and ECbb outside Scandinavia. Emissions based on a consistent bottom-up inventory for residential wood burning (and including intermediate volatility compounds, IVOCs) improved model results compared to the base-case emissions, but modeled levels were still substantially underestimated compared to observational derived OCbb and ECbb levels at the southernmost sites.Our study shows that natural sources are a major contributor to carbonaceous aerosol in Europe, even in fall and in winter/spring, and that residential wood burning emissions are equally as large as or larger than that of fossil-fuel sources, depending on season and region. The poorly constrained residential wood burning emissions for large parts of Europe show the obvious need to improve emission inventories, with harmonization of emission factors between countries likely being the most important step to improve model calculations for biomass burning emissions, and European PM2.5 concentrations in general. © Author(s) 2019.