46 research outputs found
COVIDâ19, nationalism, and the politics of crisis: A scholarly exchange
In this article, several scholars of nationalism discuss the potential for the COVIDâ19 pandemic to impact the development of nationalism and world politics. To structure the discussion, the contributors respond to three questions: (1) how should we understand the relationship between nationalism and COVIDâ19; (2) will COVIDâ19 fuel ethnic and nationalist conflict; and (3) will COVIDâ19 reinforce or erode the nationâstate in the long run? The contributors formulated their responses to these questions near to the outset of the pandemic, amid intense uncertainty. This made it acutely difficult, if not impossible, to make predictions. Nevertheless, it was felt that a historically and theoretically informed discussion would shed light on the types of political processes that could be triggered by the COVIDâ19 pandemic. In doing so, the aim is to help orient researchers and policyâmakers as they grapple with what has rapidly become the most urgent issue of our times
Recommended from our members
The effects of intercontinental emission sources on European air pollution levels
This study is based on model results from TF HTAP (Task
Force on Hemispheric Transport of Air Pollution) phase II, in which a set of
source receptor model experiments have been defined, reducing global (and
regional) anthropogenic emissions by 20 % in different source regions
throughout the globe, with the main focus on the year 2010. All the participating
models use the same set of anthropogenic emissions. Comparisons of model
results to measurements are shown for selected European surface sites and for
ozone sondes, but the main focus here is on the contributions to European
ozone levels from different world regions, and how and why these
contributions differ depending on the model. We investigate the origins by use of
a novel stepwise approach, combining simple tracer calculations and
calculations of CO and O3. To highlight the differences, we analyse the
vertical transects of the midlatitude effects from the 20 % emission
reductions.The spread in the model results increases from the simple CO tracer to CO and
then to ozone as the complexity of the physical and chemical processes
involved increase. As a result of non-linear ozone chemistry, the
contributions from non-European relative to European sources are larger
for ozone compared to the CO and the CO tracer.
For annually averaged ozone the contributions from the rest of
the world is larger than the effects from European emissions alone, with
the largest contributions from North America and eastern Asia. There are also
considerable contributions from other nearby regions to the east and from
international shipping.
The calculated contributions to European annual average ozone from other
major source regions relative to all contributions from all major
sources (RAIR â Relative Annual Intercontinental Response) have increased
from 43 % in HTAP1 to 82 % in HTAP2. This increase is mainly caused by a better
definition of Europe, with increased emissions outside of Europe relative to those in Europe,
and by including a nearby non-European source for external-to-Europe
regions.
European contributions to ozone
metrics reflecting human health and ecosystem damage, which mostly accumulated
in the summer months, are larger than for
annual ozone. Whereas ozone from European
sources peaks in the summer months, the largest contributions from non-European
sources are mostly calculated for the spring months, when ozone
production over the polluted continents starts to increase, while at the
same time the lifetime of ozone in the free troposphere is relatively long.
At the surface, contributions from non-European sources are of similar
magnitude for all European subregions considered, defined as TF HTAP
receptor regions (north-western, south-western, eastern and south-eastern Europe).</p
Long-range transport impacts on surface aerosol concentrations and the contributions to haze events in China: an HTAP2 multi-model study
Haze has been severely affecting the densely populated areas in China
recently. While many of the efforts have been devoted to investigating the
impact of local anthropogenic emission, limited attention has been paid to
the contribution from long-range transport. In this study, we apply
simulations from six participating models supplied through the Task Force on
Hemispheric Transport of Air Pollution phase 2 (HTAP2) exercise to
investigate the long-range transport impact of Europe (EUR) and
RussiaâBelarusâUkraine (RBU) on the surface air quality in eastern Asia
(EAS), with special focus on their contributions during the haze episodes in
China. The impact of 20 % anthropogenic emission perturbation from the
source region is extrapolated by a factor of 5 to estimate the full impact.
We find that the full impacts from EUR and RBU are 0.99 ”gâmâ3
(3.1 %) and 1.32 ”gâmâ3 (4.1 %) during haze episodes,
while the annual averaged full impacts are only 0.35 ”gâmâ3
(1.7 %) and 0.53 ”gâmâ3 (2.6 %). By estimating the aerosol
response within and above the planetary boundary layer (PBL), we find that
long-range transport from EUR within the PBL contributes to 22â38 % of the
total column density of aerosol response in EAS. Comparison with the HTAP
phase 1 (HTAP1) assessment reveals that from 2000 to 2010, the long-range
transport from Europe to eastern Asia has decreased significantly by a factor
of 2â10 for surface aerosol mass concentration due to the simultaneous
emission reduction in source regions and emission increase in the receptor
region. We also find the long-range transport from the Europe and RBU regions
increases the number of haze events in China by 0.15 % and 0.11 %, and
the North China Plain and southeastern China has 1â3 extra haze days (â<â3 %). This study is the first investigation into the contribution of
long-range transport to haze in China with multi-model experiments.</p
The EMEP MSC-W chemical transport model - technical description
The Meteorological Synthesizing Centre-West (MSC-W) of the European Monitoring and Evaluation Programme (EMEP) has been performing model calculations in support of the Convention on Long Range Transboundary Air Pollution (CLRTAP) for more than 30 years. The EMEP MSC-W chemical transport model is still one of the key tools within European air pollution policy assessments.
Traditionally, the model has covered all of Europe with a resolution of about 50 km Ă 50 km, and extending vertically from ground level to the tropopause (100 hPa). The model has changed extensively over the last ten years, however, with flexible processing of chemical schemes, meteorological inputs, and with nesting capability: the code is now applied on scales ranging from local (ca. 5 km grid size) to global (with 1 degree resolution). The model is used to simulate photo-oxidants and both inorganic and organic aerosols.
In 2008 the EMEP model was released for the first time as public domain code, along with all required input data for model runs for one year. The second release of the EMEP MSC-W model became available in mid 2011, and a new release is targeted for summer 2012. This publication is intended to document this third release of the EMEP MSC-W model. The model formulations are given, along with details of input data-sets which are used, and a brief background on some of the choices made in the formulation is presented. The model code itself is available at www.emep.int, along with the data required to run for a full year over Europe
Validation of reactive gases and aerosols in the MACC global analysis and forecast system
The European MACC (Monitoring Atmospheric Composition and Climate) project is preparing the operational Copernicus Atmosphere Monitoring Service (CAMS), one of the services of the European Copernicus Programme on Earth observation and environmental services. MACC uses data assimilation to combine in situ and remote sensing observations with global and regional models of atmospheric reactive gases, aerosols, and greenhouse gases, and is based on the Integrated Forecasting System of the European Centre for Medium-Range Weather Forecasts (ECMWF). The global component of the MACC service has a dedicated validation activity to document the quality of the atmospheric composition products. In this paper we discuss the approach to validation that has been developed over the past 3 years. Topics discussed are the validation requirements, the operational aspects, the measurement data sets used, the structure of the validation reports, the models and assimilation systems validated, the procedure to introduce new upgrades, and the scoring methods. One specific target of the MACC system concerns forecasting special events with high-pollution concentrations. Such events receive extra attention in the validation process. Finally, a summary is provided of the results from the validation of the latest set of daily global analysis and forecast products from the MACC system reported in November 2014