Elina Marmer

Multimodel estimates of intercontinental source-receptor relationships for ozone pollution

Understanding the surface O-3 response over a receptor region to emission changes over a foreign source region is key to evaluating the potential gains from an international approach to abate ozone (O-3) pollution. We apply an ensemble of 21 global and hemispheric chemical transport models to estimate the spatial average surface O-3 response over east Asia (EA), Europe (EU), North America (NA), and south Asia (SA) to 20% decreases in anthropogenic emissions of the O-3 precursors, NOx, NMVOC, and CO (individually and combined), from each of these regions. We find that the ensemble mean surface O-3 concentrations in the base case (year 2001) simulation matches available observations throughout the year over EU but overestimates them by > 10 ppb during summer and early fall over the eastern United States and Japan. The sum of the O-3 responses to NOx, CO, and NMVOC decreases separately is approximately equal to that from a simultaneous reduction of all precursors. We define a continental-scale import sensitivity as the ratio of the O-3 response to the 20% reductions in foreign versus domestic (i.e., over the source region itself) emissions. For example, the combined reduction of emissions from the three foreign regions produces an ensemble spatial mean decrease of 0.6 ppb over EU (0.4 ppb from NA), less than the 0.8 ppb from the reduction of EU emissions, leading to an import sensitivity ratio of 0.7. The ensemble mean surface O-3 response to foreign emissions is largest in spring and late fall (0.7-0.9 ppb decrease in all regions from the combined precursor reductions in the three foreign regions), with import sensitivities ranging from 0.5 to 1.1 (responses to domestic emission reductions are 0.8-1.6 ppb). High O-3 values are much more sensitive to domestic emissions than to foreign emissions, as indicated by lower import sensitivities of 0.2 to 0.3 during July in EA, EU, and NA when O-3 levels are typically highest and by the weaker relative response of annual incidences of daily maximum 8-h average O-3 above 60 ppb to emission reductions in a foreign region(< 10-20% of that to domestic) as compared to the annual mean response (up to 50% of that to domestic). Applying the ensemble annual mean results to changes in anthropogenic emissions from 1996 to 2002, we estimate a Northern Hemispheric increase in background surface O-3 of about 0.1 ppb a(-1), at the low end of the 0.1-0.5 ppb a(-1) derived from observations. From an additional simulation in which global atmospheric methane was reduced, we infer that 20% reductions in anthropogenic methane emissions from a foreign source region would yield an O-3 response in a receptor region that roughly equals that produced by combined 20% reductions of anthropogenic NOx, NMVOC, and CO emissions from the foreign source

The influence of ozone precursor emissions from four world regions on tropospheric composition and radiative climate forcing

0.4 2.6 to 1.9 1.3 Gg for NOx reductions, 0.1 1.2 to 0.9 0.8 Gg for NMVOC reductions, and 0.09 0.5 to 0.9 0.8 Gg for CO reductions, suggesting additional research is needed. The 100-year global warming potentials (GWP100) are calculated for the global CH4 reduction (20.9 3.7 without stratospheric O3 or water vapor, 24.2 4.2 including those components), and for the regional NOx, NMVOC, and CO reductions (18.7 25.9 to 1.9 8.7 for NOx, 4.8 1.7 to 8.3 1.9 for NMVOC, and 1.5 0.4 to 1.7 0.5 for CO). Variation in GWP100 for NOx, NMVOC, and CO suggests that regionally specific GWPs may be necessary and could support the inclusion

A multi‐model study of the hemispheric transport and deposition of oxidised nitrogen

Fifteen chemistry-transport models are used to quantify, for the first time, the export of oxidised nitrogen (NOy) to and from four regions (Europe, North America, South Asia, and East Asia), and to estimate the uncertainty in the results. Between 12 and 24% of the NOx emitted is exported from each region annually. The strongest impact of each source region on a foreign region is: Europe on East Asia, North America on Europe, South Asia on East Asia, and East Asia on North America. Europe exports the most NOy, and East Asia the least. East Asia receives the most NOy from the other regions. Between 8 and 15% of NOx emitted in each region is transported over distances larger than 1000 km, with 3–10% ultimately deposited over the foreign regions.

Impacts of intercontinental transport of anthropogenic fine particulate matter on human mortality

Fine particulate matter with diameter of 2.5xa0μm or less (PM2.5) is associated with premature mortality and can travel long distances, impacting air quality and health on intercontinental scales. We estimate the mortality impacts of 20xa0% anthropogenic primary PM2.5 and PM2.5 precursor emission reductions in each of four major industrial regions (North America, Europe, East Asia, and South Asia) using an ensemble of global chemical transport model simulations coordinated by the Task Force on Hemispheric Transport of Air Pollution and epidemiologically-derived concentration-response functions. We estimate that while 93–97xa0% of avoided deaths from reducing emissions in all four regions occur within the source region, 3–7xa0% (11,500; 95xa0% confidence interval, 8,800–14,200) occur outside the source region from concentrations transported between continents. Approximately 17 and 13xa0% of global deaths avoided by reducing North America and Europe emissions occur extraregionally, owing to large downwind populations, compared with 4 and 2xa0% for South and East Asia. The coarse resolution global models used here may underestimate intraregional health benefits occurring on local scales, affecting these relative contributions of extraregional versus intraregional health benefits. Compared with a previous study of 20xa0% ozone precursor emission reductions, we find that despite greater transport efficiency for ozone, absolute mortality impacts of intercontinental PM2.5 transport are comparable or greater for neighboring source-receptor pairs, due to the stronger effect of PM2.5 on mortality. However, uncertainties in modeling and concentration-response relationships are large for both estimates.

Climate and air quality impacts of combined climate change and air pollution policy scenarios

This report describes an assessment of the co-benefits for air pollution of recently developed climate mitigation scenarios that inform the European Union policy making. The climate mitigation scenarios were obtained with the POLES equilibrium model for a business-as-usual and greenhouse gas reduction case. In the present work, these scenarios were expanded to air pollution emissions. The resulting set of global -spatially and sector disaggregated- air pollution emissions were evaluated with the global chemistry transport model TM5, to calculate levels of particulate matter and ozone. Subsequently, air pollution impacts on human health, ecosystems and climate were evaluated. The resulting set of four scenarios thus reflect various combinations of worldwide air pollution and climate policies: BAU (no further climate and air pollution policies since the 2000 base-year); CARB (climate policy only), BAP (no further climate policy, but progressive air pollution policies, to address worldwide increasing levels of air pollution) and CAP (combination of ambitious climate and air pollution policies). The implementation of a global climate policy (CARB) has substantial co-benefits for reducing air pollutant emissions. Compared to BAU, in 2050 global emissions of SO2 are reduced by ca. 75 %, NOx by 55 %, CO (40 %) and other pollutants VOC, OC and BC) about 25% %. These emission reductions result from cleaner technologies and decreased fuel demand, and correspond to a CO2 emission reduction of more than 60 %. Advanced air pollution abatement technologies can obtain similar air pollutant reductions ranging between 35 % (NOx), 45 % (OC, BC), 60 % (SO2) and 70% (CO), however in this case the CO2 emissions reach unabated levels of 55 Pg CO2/yr. The combined air pollution and climate policy case (CAP) further reduces BAP air pollution emissions by 10-30 %. Noticeable are the decreases of methane emissions by ca. 60 %, which have important impacts on ozone air quality and climate. The environmental benefits of the emission reductions are substantial. In 2050, average global life expectancy increases by 3.2 months/person for BAP (compared to BAU) and further increases by 3.7 to 6.9 months/person if additionally climate policies are introduced (CAP). Compared to 2000, only the CAP scenario leads to global improvement of life-expectancy (by about 3 months/person), while all other scenarios lead to higher particulate concentration and lower life expectancies, mainly driven by pollution developments in South and East Asia. These improvements in CAP are due to decreasing concentrations of primary (OC, BC) and secondary (SO4, NO3) aerosol. This work shows that combining air pollution and climate policies is in some regions the only way to stabilize or decrease the levels of air pollution and reducing impacts on human health. The global average life expectancy, however, masks large regional differences: e.g. current and future levels of air pollution in Asia are much larger than in Europe or the United States. Crop losses due to ozone are reduced by 4.7 % by implementing progressive air pollution policies, and could be reduced by another 2 %, by introducing additional climate policies. Climate policies target at limiting long-term (2100) climate change. On the intermediate time-scales (2030-2050), however, there might be important trade-offs to be considered in climate and air pollution policies, since reducing particulate matter and precursor (especially sulfur) emissions, are likely to lead to a net positive radiative forcing and a warming of climate. Since reductions of particulate matter and ozone are necessary to protect human health and vegetation, combined air pollution and climate policies are more beneficial for both climate and air pollution than stand-alone policies. There is scope to preferentially mitigate emissions of Black Carbon and methane, which is beneficial for climate and human health.

Between the heat and the hardships. Climate change and mixed migration flows in Morocco

As a sending, transit and destination country, Morocco is in many regards a hot spot of human migration. Moroccan emigrants living abroad strongly contribute to the country’s economy, supported by emigration policy. In regions stricken by droughts, migrant social networks can be resourceful in increasing resilience and adaptive capacities of the communities of origin. Migrants can trigger innovations across regions through co-development activities and the transfer of knowledge, technology and remittances, preventing conflicts by linking strategies for development in the communities of origin and destination. Incoming migrants from West Africa and the Sahel, whose livelihoods are at stake due to a complex nexus of cultural, economic, political, environmental and climatic factors, are facing major hurdles in Morocco, with additional challenges in the aftermath of the ‘Arab Spring’. The transitory settlement of West Africans in Moroccan cities has led to noticeable changes in the appropriation and degradation of spaces and places in the absence of interventions by the Moroccan government to offer legal protection and institutional support for most of African immigrants, while Europe increases its measures to prevent them from entering. West African immigrants become trapped in this situation and most often experience hostility, racism and violence. This paper addresses the multiple challenges, with a particular focus on ex-fishermen who, because of resource depletion in their origin countries due to climate variability and overfishing, have decided to migrate to Morocco. It also examines the initiatives and capacity development undertaken by West African migrants in Morocco to protect themselves in the absence of effective legal and social systems. To diminish the hardships, reduce environmental vulnerability and create new opportunities, West African immigrants in Morocco take issues in their own hands, build resilience to transform their realities and improve their livelihoods.

„Man denkt, man kann sich alles erlauben, weil sie Schwarz sind“ – Schüler_innen afrikanischer Herkunft über Rassismus in ihren Schulbüchern

Die Diskussion um Rassismus bei der Darstellung von „Afrika“ und Schwarzsein in deutschen Schulbuchern hat sich festgefahren. Wahrend zahlreiche Schulbuchanalysen die Aufrechterhaltung kolonialer Perspektiven kritisieren, bestehen einige Schulbuchverlage und Kultusministerien darauf, sich weitgehend an eine politisch korrekte Darstellung zu halten. Es gibt jedoch kaum Untersuchungen daruber, was diese umstrittenen „Afrika“-Bilder bei Schulerinnen und Schulern eigentlich bewirken.

Fallstudie: „Entwicklung“ in Schulbüchern

Eine Analyse gegenwartig verwendeter Schulbucher in den Fachern Erdkunde und Sozialwissenschaften ergibt, dass Menschen aus dem globalen Suden immer noch als passiv und hilfsbedurftig reprasentiert werden. „Uberbevolkerung“ wird als Hauptursache von Armut dargestellt, Entwicklungszusammenarbeit als Losung von Problemen im Suden, und Kolonialismus als ein ambivalentes Unterfangen mit sowohl positiven als auch negativen Aspekten.