Climate warming–related strengthening of the tropical hydrological cycle

The authors estimate climate warming–related twenty-first-century changes of moisture transports from the descending into the ascending regions in the tropics. Unlike previous studies that employ time and space averaging, here homogeneous high horizontal and vertical resolution data from an Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) climate model are used. This allows for estimating changes in much greater detail (e.g., the estimation of the distribution of ascending and descending regions, changes in the vertical profile, and separating changes of the inward and outward transports). Low-level inward and midlevel outward moisture transports of the convective regions in the tropics are found to increase in a simulated anthropogenically warmed climate as compared to a simulated twentieth-century atmosphere, indicating an intensification of the hydrological cycle. Since an increase of absolute inward transport exceeds the absolute increase of outward transport, the resulting budget is positive, meaning that more water is projected to converge in the moist tropics. The intensification is found mainly to be due to the higher amount of water in the atmosphere, while the contribution of weakening wind counteracts this response marginally. In addition the changing statistical properties of the vertical profile of the moisture transport are investigated and the importance of the substantial outflow of moisture from the moist tropics at midlevels is demonstrated.

Large-scale surface mass balance of ice sheets from a comprehensive atmospheric model

The surface mass balance for Greenland and Antarctica has been calculated using model data from an AMIP-type experiment for the period 1979–2001 using the ECHAM5 spectral transform model at different triangular truncations. There is a significant reduction in the calculated ablation for the highest model resolution, T319 with an equivalent grid distance of ca 40 km. As a consequence the T319 model has a positive surface mass balance for both ice sheets during the period. For Greenland, the models at lower resolution, T106 and T63, on the other hand, have a much stronger ablation leading to a negative surface mass balance. Calculations have also been undertaken for a climate change experiment using the IPCC scenario A1B, with a T213 resolution (corresponding to a grid distance of some 60 km) and comparing two 30-year periods from the end of the twentieth century and the end of the twenty-first century, respectively. For Greenland there is change of 495 km3/year, going from a positive to a negative surface mass balance corresponding to a sea level rise of 1.4 mm/year. For Antarctica there is an increase in the positive surface mass balance of 285 km3/year corresponding to a sea level fall by 0.8 mm/year. The surface mass balance changes of the two ice sheets lead to a sea level rise of 7 cm at the end of this century compared to end of the twentieth century. Other possible mass losses such as due to changes in the calving of icebergs are not considered. It appears that such changes must increase significantly, and several times more than the surface mass balance changes, if the ice sheets are to make a major contribution to sea level rise this century. The model calculations indicate large inter-annual variations in all relevant parameters making it impossible to identify robust trends from the examined periods at the end of the twentieth century. The calculated inter-annual variations are similar in magnitude to observations. The 30-year trend in SMB at the end of the twenty-first century is significant. The increase in precipitation on the ice sheets follows closely the Clausius-Clapeyron relation and is the main reason for the increase in the surface mass balance of Antarctica. On Greenland precipitation in the form of snow is gradually starting to decrease and cannot compensate for the increase in ablation. Another factor is the proportionally higher temperature increase on Greenland leading to a larger ablation. It follows that a modest increase in temperature will not be sufficient to compensate for the increase in accumulation, but this will change when temperature increases go beyond any critical limit. Calculations show that such a limit for Greenland might well be passed during this century. For Antarctica this will take much longer and probably well into following centuries.

Past and future conditions for polar stratospheric cloud formation simulated by the Canadian Middle Atmosphere Model

We analyze here the polar stratospheric temperatures in an ensemble of three 150-year integrations of the Canadian Middle Atmosphere Model (CMAM), an interactive chemistry-climate model which simulates ozone depletion and recovery, as well as climate change. A key motivation is to understand possible mechanisms for the observed trend in the extent of conditions favourable for polar stratospheric cloud (PSC) formation in the Arctic winter lower stratosphere. We find that in the Antarctic winter lower stratosphere, the low temperature extremes required for PSC formation increase in the model as ozone is depleted, but remain steady through the twenty-first century as the warming from ozone recovery roughly balances the cooling from climate change. Thus, ozone depletion itself plays a major role in the Antarctic trends in low temperature extremes. The model trend in low temperature extremes in the Arctic through the latter half of the twentieth century is weaker and less statistically robust than the observed trend. It is not projected to continue into the future. Ozone depletion in the Arctic is weaker in the CMAM than in observations, which may account for the weak past trend in low temperature extremes. In the future, radiative cooling in the Arctic winter due to climate change is more than compensated by an increase in dynamically driven downwelling over the pole.

Have aerosols caused the observed Atlantic multidecadal variability?

Identifying the prime drivers of the twentieth-century multidecadal variability in the Atlantic Ocean is crucial for predicting how the Atlantic will evolve in the coming decades and the resulting broad impacts on weather and precipitation patterns around the globe. Recently, Booth et al. showed that the Hadley Centre Global Environmental Model, version 2, Earth system configuration (HadGEM2-ES) closely reproduces the observed multidecadal variations of area-averaged North Atlantic sea surface temperature in the twentieth century. The multidecadal variations simulated in HadGEM2-ES are primarily driven by aerosol indirect effects that modify net surface shortwave radiation. On the basis of these results, Booth et al. concluded that aerosols are a prime driver of twentieth-century North Atlantic climate variability. However, here it is shown that there are major discrepancies between the HadGEM2-ES simulations and observations in the North Atlantic upper-ocean heat content, in the spatial pattern of multidecadal SST changes within and outside the North Atlantic, and in the subpolar North Atlantic sea surface salinity. These discrepancies may be strongly influenced by, and indeed in large part caused by, aerosol effects. It is also shown that the aerosol effects simulated in HadGEM2-ES cannot account for the observed anticorrelation between detrended multidecadal surface and subsurface temperature variations in the tropical North Atlantic. These discrepancies cast considerable doubt on the claim that aerosol forcing drives the bulk of this multidecadal variability.

The influence of anthropogenic aerosol on multi-decadal variations of historical global climate

Analysis of single forcing runs from CMIP5 (the fifth Coupled Model Intercomparison Project) simulations shows that the mid-twentieth century temperature hiatus, and the coincident decrease in precipitation, is likely to have been influenced strongly by anthropogenic aerosol forcing. Models that include a representation of the indirect effect of aerosol better reproduce inter-decadal variability in historical global-mean near-surface temperatures, particularly the cooling in the 1950s and 1960s, compared to models with representation of the aerosol direct effect only. Models with the indirect effect also show a more pronounced decrease in precipitation during this period, which is in better agreement with observations, and greater inter-decadal variability in the inter-hemispheric temperature difference. This study demonstrates the importance of representing aerosols, and their indirect effects, in general circulation models, and suggests that inter-model diversity in aerosol burden and representation of aerosol–cloud interaction can produce substantial variation in simulations of climate variability on multi decadal timescales.

Mediterranean cyclones and windstorms in a changing climate

Changes in the frequency and intensity of cyclones and associated windstorms affecting the Medi-terranean region simulated under enhanced Greenhouse Gas forcing conditions are investigated. The analysis is based on 7 climate model integrations performed with two coupled global models (ECHAM5 MPIOM and INGV CMCC), comparing the end of the twentieth century and at least the first half of the twenty-first century. As one of the models has a considerably enhanced resolution of the atmosphere and the ocean, it is also investigated whether the climate change signals are influenced by the model resolution. While the higher resolved simulation is closer to reanalysis climatology, both in terms of cyclones and windstorm distributions, there is no evidence for an influence of the resolution on the sign of the climate change signal. All model simulations show a reduction in the total number of cyclones crossing the Mediterranean region under climate change conditions. Exceptions are Morocco and the Levant region, where the models predict an increase in the number of cyclones. The reduction is especially strong for intense cyclones in terms of their Laplacian of pressure. The influence of the simulated positive shift in the NAO Index on the cyclone decrease is restricted to the Western Mediterranean region, where it explains 10–50 % of the simulated trend, depending on the individual simulation. With respect to windstorms, decreases are simulated over most of the Mediterranean basin. This overall reduction is due to a decrease in the number of events associated with local cyclones, while the number of events associated with cyclones outside of the Mediterranean region slightly increases. These systems are, however, less intense in terms of their integrated severity over the Mediterranean area, as they mostly affect the fringes of the region. In spite of the general reduction in total numbers, several cyclones and windstorms of intensity unknown under current climate conditions are identified for the scenario simulations. For these events, no common trend exists in the individual simulations. Thus, they may rather be attributed to long-term (e.g. decadal) variability than to the Greenhouse Gas forcing. Nevertheless, the result indicates that high-impact weather systems will remain an important risk in the Mediterranean Basin.

Typography papers, 9

This latest issue of the series of Typography papers opens with a beautifully illustrated article by the type designer Gerard Unger on ‘Romanesque’ letters. A further installment of Eric Kindel’s pathbreaking history of stencil letters is published in contributions by him, Fred Smeijers, and James Mosley. Maurice Göldner writes the first history of an early twentieth-century German typefounder, Brüder Butter. William Berkson and Peter Enneson recover the notion of ‘readability’ through a history of the collaboration between Matthew Luckiesh and the Linotype Company. Paul Luna discusses the role of pictures in dictionaries. Titus Nemeth describes a new form of Arabic type for metal composition. The whole gathering shows the remarkable variety and vitality of typography now.

No Haus Like Bau

The project consists of a live performance taking the 2005 IKEA riot as the starting point for a speculative history of a fictional future, culminating in a choreographed re-enactment of the original event. It is accompanied by a film series explores the possibility of collective action emerging from the capitalist relations inherent in the consumer riot. The performance, staged at the Berlin Biennale, continues this research into re-enactment and post-1989 politics, using a stage set made of flatpack furniture. Using the aesthetics of Modernism and the avant garde, the project transposes early twentieth century utopian ideology to a present day setting where mass uprisings are motivated by cheap commodities. By re-evaluating biomechanics and Bauhaus theatre theory, these explorations of consumerism and revolution propose that the mechanized movement developed in conjunction with industrial labour survives as a historical re-enactment in the wake of manufacturing work in the west. In the absence of a visual language apt to the contemporary, No Haus Like Bau uses re-enactment as a retrogarde tactic. Its purpose on the one hand is to invoke trajectories for alternate futures that never materialized at an originary moment. On the other hand, the clash of past forms with present content serves to accentuate the historical changes that have thrown into question these forms. Rather than reflecting the present, the projection of the past into a fictional future aims to destabilize the dominant narrative that suggests the current configuration of art, politics and human nature has always been this way. The project has been widely exhibited internationally and supported by Film London and Arts Council England. A theoretical essay on re-enactment as a strategy for performance has been published in Art Papers and in Memory [MIT]. The project also formed the basis of a solo exhibition at Te Tuhi Art Centre, Auckland.

Femininity, feminism and the terrorist

This chapter aims to discuss the relationship between femininity and representations of women involved in violence, focussing on visual representations. Miranda Alison has made the point that the repeated necessity to qualify the term 'combatant' with the descriptor 'female' draws attention to how women soldiers, female freedom fighters, female suicide bombers and female terrorists are exceptional figures. That the female combatant or the female terrorist is an aberration or a deviation from a masculine norm is undermined by the lengthy history of women as warriors, fighters, and terrorists. In that sense it is not so much that fighting women are rare but that there is amnesia within cultural memories concerning the woman fighter. However, in representations of conflict, the dominant image associated with femininity is passive; that is as the defenceless and the defended, or as the allegory of peace. Moreover, representations of men in wars as defeated or wounded means feminising such figures. Miriam Cooke, in her Women and the War Story, 1996, points out how a mythic war story provides men with political roles, in the politikon or public arena, whereas women are domesticated in the space of the oikon. In the mythic war story women may function as Mater Dolorosa, Patriotic Mother or Spartan Mother. It follows then that there are conditions in which it is permissible to represent women fighting on behalf of their children or in defence of the home, and in the absence of men. These images are also found in wider culture: Sarah Connor in Terminator or Ripley in Alien, for example. Images of the female terrorist raise new issues but I want to argue that it is also the case that discussing femininity and the terrorist must involve relating such imagery to representations of the female warrior over a longer timespan. Some questions have shifted since the late twentieth century. Dating from the early 1990s, most Western nations increasingly incorporated women into combat roles within their armed forces. This paper will aim to unpick some of the intricate connections between the increasing presence of women in the armed forces, what relationship this has to emancipation and the participation of women in violence classed as terrorist.

When 1+1=3

A survey of the techniques, uses, and meanings of colour overprinting as employed by printers, graphic arts technicians, and graphic designers, principally in the twentieth century.

Oi! Oi! Oi! : class locality and British punk

This article looks at the controversial music genre Oi! in relation to youth cultural identity in late 1970s’ and early 1980s’ Britain. As a form of British punk associated with skinheads, Oi! has oft-been dismissed as racist and bound up in the politics of the far right. It is argued here, however, that such a reading is too simplistic and ignores the more complex politics contained both within Oi! and the various youth cultural currents that revolved around the term ‘punk’ at this time. Taking as its starting point the Centre for Contemporary Cultural Studies’ conception of youth culture as a site of potential ‘resistance’, the article explores the substance and motifs of Oi!’s protest to locate its actual and perceived meaning within a far wider political and socio-economic context. More broadly, it seeks to demonstrate the value of historians examining youth culture as a formative and contested socio-cultural space within which young people discover, comprehend, and express their desires, opinions, and disaffections.

Marked by time

A concise study of two stencil-makers' catalogues published in Germany and the USA in the mid-twentieth century.

Antarctic Peninsula ice sheet evolution during the Cenozoic Era

The Antarctic Peninsula region is currently undergoing rapid environmental change, resulting in the thinning, acceleration and recession of glaciers and the sequential collapse of ice shelves. It is important to view these changes in the context of long-term palaeoenvironmental complexity and to understand the key processes controlling ice sheet growth and recession. In addition, numerical ice sheet models require detailed geological data for tuning and testing. Therefore, this paper systematically and holistically reviews published geological evidence for Antarctic Peninsula Ice Sheet variability for each key locality throughout the Cenozoic, and brings together the prevailing consensus of the extent, character and behaviour of the glaciations of the Antarctic Peninsula region. Major contributions include a downloadable database of 186 terrestrial and marine calibrated dates; an original reconstruction of the LGM ice sheet; and a new series of isochrones detailing ice sheet retreat following the LGM. Glaciation of Antarctica was initiated around the Eocene/Oligocene transition in East Antarctica. Palaeogene records of Antarctic Peninsula glaciation are primarily restricted to King George Island, where glacigenic sediments provide a record of early East Antarctic glaciations, but with modification of far-travelled erratics by local South Shetland Island ice caps. Evidence for Neogene glaciation is derived primarily from King George Island and James Ross Island, where glaciovolcanic strata indicate that ice thicknesses reached 500–850 m during glacials. This suggests that the Antarctic Peninsula Ice Sheet draped, rather than drowned, the topography. Marine geophysical investigations indicate multiple ice sheet advances during this time. Seismic profiling of continental shelf-slope deposits indicates up to ten large advances of the Antarctic Peninsula Ice Sheet during the Early Pleistocene, when the ice sheet was dominated by 40 kyr cycles. Glacials became more pronounced, reaching the continental shelf edge, and of longer duration during the Middle Pleistocene. During the Late Pleistocene, repeated glacials reached the shelf edge, but ice shelves inhibited iceberg rafting. The Last Glacial Maximum (LGM) occurred at 18 ka BP, after which transitional glaciomarine sediments on the continental shelf indicate ice-sheet retreat. The continental shelf contains large bathymetric troughs, which were repeatedly occupied by large ice streams during Pleistocene glaciations. Retreat after the LGM was episodic in the Weddell Sea, with multiple readvances and changes in ice-flow direction, but rapid in the Bellingshausen Sea. The late Holocene Epoch was characterised by repeated fluctuations in palaeoenvironmental conditions, with associated glacial readvances. However, this has been subsumed by rapid warming and ice-shelf collapse during the twentieth century.

The impacts of European and Asian anthropogenic sulphur dioxide emissions on Sahel rainfall

In this study, the atmospheric component of a state-of-the-art climate model (HadGEM2-ES) has been used to investigate the impacts of regional anthropogenic sulphur dioxide emissions on boreal summer Sahel rainfall. The study focuses on the transient response of the West African monsoon (WAM) to a sudden change in regional anthropogenic sulphur dioxide emissions, including land surface feedbacks, but without sea surface temperature (SST) feedbacks. The response occurs in two distinct phases: 1) fast adjustment of the atmosphere on a time scale of days to weeks (up to 3 weeks) through aerosol-radiation and aerosol-cloud interactions with weak hydrological cycle changes and surface feedbacks. 2) adjustment of the atmosphere and land surface with significant local hydrological cycle changes and changes in atmospheric circulation (beyond 3 weeks). European emissions lead to an increase in shortwave (SW) scattering by increased sulphate burden, leading to a decrease in surface downward SW radiation which causes surface cooling over North Africa, a weakening of the Saharan heat low and WAM, and a decrease in Sahel precipitation. In contrast, Asian emissions lead to very little change in sulphate burden over North Africa, but they induce an adjustment of the Walker Circulation which leads again to a weakening of the WAM and a decrease in Sahel precipitation. The responses to European and Asian emissions during the second phase exhibit similar large scale patterns of anomalous atmospheric circulation and hydrological variables, suggesting a preferred response. The results support the idea that sulphate aerosol emissions contributed to the observed decline in Sahel precipitation in the second half of the twentieth century.

Contemporary ordinary language philosophy

There is a widespread assumption that ordinary language philosophy was killed off sometime in the 1960s or 70s by a combination of Gricean pragmatics and the rapid development of systematic semantic theory. Contrary to that widespread assumption, however, contemporary versions of ordinary language philosophy are alive and flourishing, but going by various aliases—in particular (some versions of) "contextualism" and (some versions of) "experimental philosophy". And a growing group of contemporary philosophers are explicitly embracing the methods as well as the title of ordinary language philosophy and arguing that it has been unfairly maligned and was never decisively refuted. In this overview, I will outline the main projects and arguments employed by contemporary ordinary language philosophers, and make the case that updated versions of the arguments made by ordinary language philosophers in the middle of the twentieth century are attracting renewed attention.