Climate change and energy - Air pollution and climate change

Title

Reference

Nature Geoscience 5, 261–265(2012)

doi:10.1038/ngeo1421

Author(s)

S. Park, P. Croteau, K. A. Boering, D. M. Etheridge, D. Ferretti, P. J. Fraser, K-R. Kim, P. B. Krummel, R. L. Langenfelds, T. D. van Ommen, L. P. Steele & C. M. Trudinger

Study type

Peer Review Journal   

Abstract

The atmospheric nitrous oxide mixing ratio has increased by 20% since 1750. Given that nitrous oxide is both a long-lived greenhouse gas and a stratospheric ozone-depleting substance, this increase is of global concern. However, the magnitude and geographic distribution of nitrous oxide sources, and how they have changed over time, is uncertain. A key unknown is the influence of the stratospheric circulation, which brings air depleted in nitrous oxide to the surface. Here, we report the oxygen and intramolecular nitrogen isotopic compositions of nitrous oxide in firn air samples from Antarctica and archived air samples from Cape Grim, Tasmania, spanning 1940–2005. We detect seasonal cycles in the isotopic composition of nitrous oxide at Cape Grim. The phases and amplitudes of these seasonal cycles allow us to distinguish between the influence of the stratospheric sink and the oceanic source at this site, demonstrating that isotope measurements can help in the attribution and quantification of surface sources in general. Large interannual variations and long-term decreasing trends in isotope composition are also apparent. These long-term trends allow us to distinguish between natural and anthropogenic sources of nitrous oxide, and confirm that the rise in atmospheric nitrous oxide levels is largely the result of an increased reliance on nitrogen-based fertilizers.

Policy theme(s)

Agriculture >> Agricultural pollution >> Fertiliser pollution
Air pollution >> Source of emissions >> Industrial emissions
Air pollution >> Impact of emissions >> Climate change impacts
Climate change and energy >> Greenhouse gas emissions >> Air pollution and climate change

Keywords

Entry Source:

Shortlisted for Science for Environment Policy News Alert

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http://www.nature.com/ngeo/journal/v5/n4/abs/ngeo1421.html?lang=en?WT.ec_id=NGEO-201204
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boering@berkeley.edu.

Title

Global Air Quality and Health Co-benefits of Mitigating Near-Term Climate Change through Methane and Black Carbon Emission Controls

Reference

Author(s)

Susan C. Anenberg, Joel Schwartz, et al

Study type

Peer Review Journal    

Abstract

Background: Tropospheric ozone and black carbon (BC), a component of fine particulate matter (PM ≤ 2.5 µm in aerodynamic diameter; PM2.5), are associated with premature mortality and they disrupt global and regional climate.
Objectives: We examined the air quality and health benefits of 14 specific emission control measures targeting BC and methane, an ozone precursor, that were selected because of their potential to reduce the rate of climate change over the next 20–40 years.
Methods: We simulated the impacts of mitigation measures on outdoor concentrations of PM2.5 and ozone using two composition-climate models, and calculated associated changes in premature PM2.5- and ozone-related deaths using epidemiologically derived concentration–response functions.
Results: We estimated that, for PM2.5 and ozone, respectively, fully implementing these measures could reduce global population-weighted average surface concentrations by 23–34% and 7–17% and avoid 0.6–4.4 and 0.04–0.52 million annual premature deaths globally in 2030. More than 80% of the health benefits are estimated to occur in Asia. We estimated that BC mitigation measures would achieve approximately 98% of the deaths that would be avoided if all BC and methane mitigation measures were implemented, due to reduced BC and associated reductions of nonmethane ozone precursor and organic carbon emissions as well as stronger mortality relationships for PM2.5 relative to ozone. Although subject to large uncertainty, these estimates and conclusions are not strongly dependent on assumptions for the concentration–response function.
Conclusions: In addition to climate benefits, our findings indicate that the methane and BC emission control measures would have substantial co-benefits for air quality and public health worldwide, potentially reversing trends of increasing air pollution concentrations and mortality in Africa and South, West, and Central Asia. These projected benefits are independent of carbon dioxide mitigation measures. Benefits of BC measures are underestimated because we did not account for benefits from reduced indoor exposures and because outdoor exposure estimates were limited by model spatial resolution.

Policy theme(s)

Air pollution >> Impact of emissions >> Climate change impacts
Air pollution >> Impact of emissions >> Health impacts
Climate change and energy >> Greenhouse gas emissions >> Air pollution and climate change
Environment and health >> Health risks >> Air pollution

Keywords

air quality, climate change, health impact analysis, outdoor air, particulate matter

Entry Source:

Selected for Science for Environment Policy News Alert

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http://ehp03.niehs.nih.gov/article/fetchArticle.action;jsessionid=5EC26FBB6E8096CA4F92E260AB01E1E9?articleURI=info%3Adoi%2F10.1289%2Fehp.1104301
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anenberg.susan@epa.gov

Title

Reference

Nature Geoscience 5,318–321(2012)
doi:10.1038/ngeo1452

Author(s)

E. A. Kort, S. C. Wofsy, B. C. Daube, M. Diao, J. W. Elkins, R. S. Gao, E. J. Hintsa, D. F. Hurst, R. Jimenez, F. L. Moore, J. R. Spackman & M. A. Zondlo

Study type

Peer Review Journal    

Abstract

Uncertainty in the future atmospheric burden of methane, a potent greenhouse gas, represents an important challenge to the development of realistic climate projections. The Arctic is home to large reservoirs of methane, in the form of permafrost soils and methane hydrates, which are vulnerable to destabilization in a warming climate. Furthermore, methane is produced in the surface ocean and the surface waters of the Arctic Ocean are supersaturated with respect to methane. However, the fate of this oceanic methane is uncertain. Here, we use airborne observations of methane to assess methane efflux from the remote Arctic Ocean, up to latitudes of 82° north. We report layers of increased methane concentrations near the surface ocean, with little or no enhancement in carbon monoxide levels, indicative of a non-combustion source. We further show that high methane concentrations are restricted to areas over open leads and regions with fractional sea-ice cover. Based on the observed gradients in methane concentration, we estimate that sea–air fluxes amount to around 2 mg d−1 m−2, comparable to emissions seen on the Siberian shelf. We suggest that the surface waters of the Arctic Ocean represent a potentially important source of methane, which could prove sensitive to changes in sea-ice cover.

Policy theme(s)

Air pollution >> Source of emissions >> Terrestrial emissions
Climate change and energy >> Greenhouse gas emissions >> Terrestrial emissions
Climate change and energy >> Greenhouse gas emissions >> Air pollution and climate change

Keywords

Entry Source:

Shortlisted for Science for Environment Policy News Alert

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http://www.nature.com/ngeo/journal/v5/n5/abs/ngeo1452.html?lang=en?WT.ec_id=NGEO-201205

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Eric.A.Kort@jpl.nasa.gov

Title

Reference

Environmental Science & Technology. 46 (8), 4275-4282  DOI:10.1021/es203325a

Author(s)

Barrett, S. R. H. et al

Study type

Peer Review Journal    

Abstract

In jurisdictions including the US and the EU ground transportation and marine fuels have recently been required to contain lower concentrations of sulfur, which has resulted in reduced atmospheric SOx emissions. In contrast, the maximum sulfur content of aviation fuel has remained unchanged at 3000 ppm (although sulfur levels average 600 ppm in practice). We assess the costs and benefits of a potential ultra-low sulfur (15 ppm) jet fuel standard (“ULSJ”). We estimate that global implementation of ULSJ will cost US$1–4bn per year and prevent 900–4000 air quality-related premature mortalities per year. Radiative forcing associated with reduction in atmospheric sulfate, nitrate, and ammonium loading is estimated at +3.4 mW/m2 (equivalent to about 1/10th of the warming due to CO2 emissions from aviation) and ULSJ increases life cycle CO2 emissions by approximately 2%. The public health benefits are dominated by the reduction in cruise SOx emissions, so a key uncertainty is the atmospheric modeling of vertical transport of pollution from cruise altitudes to the ground. Comparisons of modeled and measured vertical profiles of CO, PAN, O3, and 7Be indicate that this uncertainty is low relative to uncertainties regarding the value of statistical life and the toxicity of fine particulate matter.

Policy theme(s)

Air pollution >> Impact of emissions >> Climate change impacts
Air pollution >> Impact of emissions >> Health impacts
Climate change and energy >> Greenhouse gas emissions >> Air pollution and climate change

Keywords

Entry Source:

Shortlisted for Science for Environment Policy News Alert

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http://pubs.acs.org/doi/abs/10.1021/es203325a
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sbarrett@mit.edu

Title

Recent Northern Hemisphere tropical expansion primarily driven by black carbon and tropospheric ozone

Reference

Nature, 485,
350–354 (17 May 2012)
doi:10.1038/nature11097

Author(s)

Study type

Peer Review Journal    

Abstract

Observational analyses have shown the width of the tropical belt increasing in recent decades as the world has warmed. This expansion is important because it is associated with shifts in large-scale atmospheric circulation and major climate zones. Although recent studies have attributed tropical expansion in the Southern Hemisphere to ozone depletion, the drivers of Northern Hemisphere expansion are not well known and the expansion has not so far been reproduced by climate models. Here we use a climate model with detailed aerosol physics to show that increases in heterogeneous warming agents—including black carbon aerosols and tropospheric ozone—are noticeably better than greenhouse gases at driving expansion, and can account for the observed summertime maximum in tropical expansion. Mechanistically, atmospheric heating from black carbon and tropospheric ozone has occurred at the mid-latitudes, generating a poleward shift of the tropospheric jet, thereby relocating the main division between tropical and temperate air masses. Although we still underestimate tropical expansion, the true aerosol forcing is poorly known and could also be underestimated. Thus, although the insensitivity of models needs further investigation, black carbon and tropospheric ozone, both of which are strongly influenced by human activities, are the most likely causes of observed Northern Hemisphere tropical expansion.

Policy theme(s)

Air pollution >> Impact of emissions >> Climate change impacts
Climate change and energy >> Greenhouse gas emissions >> Air pollution and climate change

Keywords

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Selected for Science for Environment Policy News Alert

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http://www.nature.com/nature/journal/v485/n7398/full/nature11097.html
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rjallen@ucr.edu

Title

Preserving Montreal Protocol Climate Benefits by Limiting HFCs

Reference

Science, 2012; 335 (6071): 922
DOI: 10.1126/science.1216414

Author(s)

G. J. M. Velders, A. R. Ravishankara, M. K. Miller, M. J. Molina, J. Alcamo, J. S. Daniel, D. W. Fahey, S. A. Montzka, S. Reimann

Study type

Peer Review Journal     

Abstract

The Montreal Protocol is perhaps the most successful international environmental treaty, responsible for global phaseout of the consumption and production of ozone-depleting substances (ODSs), e.g., chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). Hydrofluorocarbons (HFCs), which do not destroy stratospheric ozone, were considered long-term substitutes for ODSs and are not controlled by the Montreal Protocol. Because most HFCs are potent greenhouse gases (GHGs), they are included in the Kyoto Protocol. But climate benefits provided by this protocol are limited as they apply only to developed countries and over a short time (2008–2012). As we describe below, with no impending global controls on HFCs, inclusion of HFCs under the Montreal Protocol offers a path, starting in the short term, to preserve the climate benefits already achieved by this protocol.

Policy theme(s)

Air pollution >> Impact of emissions >> Climate change impacts
Air pollution >> Impact of emissions >> Ozone layer impacts
Climate change and energy >> Greenhouse gas emissions >> Air pollution and climate change

Keywords

Entry Source:

Selected for Science for Environment Policy News Alert

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http://www.sciencemag.org/content/335/6071/922.summary
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guus.velders@rivm.nl

Title

Earth's energy imbalance and implications

Reference

Atmospheric Chemistry and Physics, 11, 13421-13449, 2011
Part EU Funded
(Open Access)

Author(s)

J. Hansen, M. Sato, P. Kharecha, and K. von Schuckmann

Study type

Peer Review Journal    

Abstract

Abstract. Improving observations of ocean heat content show that Earth is absorbing more energy from the Sun than it is radiating to space as heat, even during the recent solar minimum. The inferred planetary energy imbalance, 0.58 ± 0.15 W m−2 during the 6-yr period 2005–2010, confirms the dominant role of the human-made greenhouse effect in driving global climate change. Observed surface temperature change and ocean heat gain together constrain the net climate forcing and ocean mixing rates. We conclude that most climate models mix heat too efficiently into the deep ocean and as a result underestimate the negative forcing by human-made aerosols. Aerosol climate forcing today is inferred to be −1.6 ± 0.3 W m−2, implying substantial aerosol indirect climate forcing via cloud changes. Continued failure to quantify the specific origins of this large forcing is untenable, as knowledge of changing aerosol effects is needed to understand future climate change. We conclude that recent slowdown of ocean heat uptake was caused by a delayed rebound effect from Mount Pinatubo aerosols and a deep prolonged solar minimum. Observed sea level rise during the Argo float era is readily accounted for by ice melt and ocean thermal expansion, but the ascendency of ice melt leads us to anticipate acceleration of the rate of sea level rise this decade.

Policy theme(s)

Climate change and energy >> Greenhouse gas emissions >> Air pollution and climate change

Keywords

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Selected for Science for Environment Policy News Alert

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http://www.atmos-chem-phys.net/11/13421/2011/acp-11-13421-2011.html
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james.e.hansen@nasa.gov

Title

Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security

Reference

Science 13 January 2012:
Vol. 335 no. 6065 pp. 183-189
DOI: 10.1126/science.1210026

Author(s)

Drew Shindell , Johan C. I. Kuylenstierna, Elisabetta Vignati, et al

Study type

Peer Review Journal    

Abstract

Tropospheric ozone and black carbon (BC) contribute to both degraded air quality and global warming. We considered ~400 emission control measures to reduce these pollutants by using current technology and experience. We identified 14 measures targeting methane and BC emissions that reduce projected global mean warming ~0.5°C by 2050. This strategy avoids 0.7 to 4.7 million annual premature deaths from outdoor air pollution and increases annual crop yields by 30 to 135 million metric tons due to ozone reductions in 2030 and beyond. Benefits of methane emissions reductions are valued at $700 to $5000 per metric ton, which is well above typical marginal abatement costs (less than $250). The selected controls target different sources and influence climate on shorter time scales than those of carbon dioxide–reduction measures. Implementing both substantially reduces the risks of crossing the 2°C threshold.

Policy theme(s)

Agriculture >> Agricultural management >> Food security
Air pollution >> Impact of emissions >> Health impacts
Air pollution >> Managing emissions >> Reduction measures
Climate change and energy >> Greenhouse gas emissions >> Air pollution and climate change

Keywords

Entry Source:

Selected for Science for Environment Policy News Alert

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http://www.sciencemag.org/content/335/6065/183.abstract?sid=f40702ab-13ca-4dc4-8b1a-c1b0414daebe

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drew.t.shindell@nasa.gov

Title

Cost-effective control of air quality and greenhouse gases in Europe: Modeling and policy applications

Reference

Environmental Modelling and Software
Volume 26, Issue 12, December 2011, Pages 1489–1501
EU Funded

Author(s)

Study type

Peer Review Journal   

Abstract

Environmental policies in Europe have successfully eliminated the most visible and immediate harmful effects of air pollution in the last decades. However, there is ample and robust scientific evidence that even at present rates Europe's emissions to the atmosphere pose a significant threat to human health, ecosystems and the global climate, though in a less visible and immediate way. As many of the 'low hanging fruits' have been harvested by now, further action will place higher demands on economic resources, especially at a time when resources are strained by an economic crisis. In addition, interactions and interdependencies of the various measures could even lead to counter-productive outcomes of strategies if they are ignored.
Integrated assessment models, such as the GAINS (Greenhouse gas – Air pollution Interactions and Synergies) model, have been developed to identify portfolios of measures that improve air quality and reduce greenhouse gas emissions at least cost. Such models bring together scientific knowledge and quality-controlled data on future socio-economic driving forces of emissions, on the technical and economic features of the available emission control options, on the chemical transformation and dispersion of pollutants in the atmosphere, and the resulting impacts on human health and the environment. The GAINS model and its predecessor have been used to inform the key negotiations on air pollution control agreements in Europe during the last two decades.

This paper describes the methodological approach of the GAINS model and its components. It presents a recent policy analysis that explores the likely future development of emissions and air quality in Europe in the absence of further policy measures, and assesses the potential and costs for further environmental improvements. To inform the forthcoming negotiations on the revision of the Gothenburg Protocol of the Convention on Long-range Transboundary Air Pollution, the paper discusses the implications of alternative formulations of environmental policy targets on a cost-effective allocation of further mitigation measures.

Policy theme(s)

Air pollution >> Managing emissions >> Reduction measures
Climate change and energy >> Greenhouse gas emissions >> Air pollution and climate change

Keywords

Air pollution; Integrated assessment; Cost-effectiveness; GAINS model;
Convention on Long-range transboundary air pollution; Science–policy interface;
Decision support

Entry Source:

Shortlisted for Science for Environment Policy News Alert

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http://www.sciencedirect.com/science/article/pii/S1364815211001733

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amann@iiasa.ac.at

Title

The climate penalty for clean fossil fuel combustion

Reference

Atmospheric Chemistry and Physics, 11, 12917-12924, 2011

Author(s)

W. Junkermann, B. Vogel, and M. A. Sutton

Study type

Peer Review Journal   

Abstract

To cope with the world's growing demand for energy, a large number of coal-fired power plants are currently in operation or under construction. To prevent environmental damage from acidic sulphur and particulate emissions, many such installations are equipped with flue gas cleaning technology that reduces the emitted amounts of sulphur dioxide (SO2) and nitrogen dioxide (NO2). However, the consequences of this technology for aerosol emissions, and in particular the regional scale impact on cloud microphysics, have not been studied until now. We performed airborne investigations to measure aerosol size distributions in the air masses downwind of coal-fired power installations. We show how the current generation of clean technology reduces the emission of sulphur and fine particulate matter, but leads to an unanticipated increase in the direct emission of ultrafine particles (1–10 nm median diameter) which are highly effective precursors of cloud condensation nuclei (CCN). Our analysis shows how these additional ultrafine particles probably modify cloud microphysics, as well as precipitation intensity and distribution on a regional scale downwind of emission sources. Effectively, the number of small water droplets might be increased, thus reducing the water available for large droplets and rain formation. The possible corresponding changes in the precipitation budget with a shift from more frequent steady rain to occasionally more vigorous rain events, or even a significant regional reduction of annual precipitation, introduce an unanticipated risk for regional climate and agricultural production, especially in semi-arid climate zones.

Policy theme(s)

Air pollution >> Source of emissions >> Industrial emissions
Climate change and energy >> Greenhouse gas emissions >> Air pollution and climate change

Keywords

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Selected for Science for Environment Policy News Alert

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http://www.atmos-chem-phys.net/11/12917/2011/acp-11-12917-2011.html
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Contact the study author at:

Wolfgang.junkermann@kit.edu