Cloud condensation nuclei measurements at Mace Head, Ireland, over the period 1994–2002

Analyses of cloud condensation nuclei (CCN) number concentrations (cm^− 3) measured at the Mace Head Atmospheric Research Station, near Carna, County Galway, Ireland, using a DH Associates Model M1 static thermal diffusion cloud chamber over the period from March 1994 to September 2002 are presented in this work. Air masses are defined as being ‘marine’ if they originate from a wind direction of 180–300° and ‘continental’ air masses are defined as originating from a wind direction of 45–135°. Air masses without such filtering were classified as ‘undefined’ air masses. Air masses were found to be dominated by marine sector air, re-affirming Mace Head as a baseline atmospheric research station. CCN levels for specific air masses at Mace Head were found to be comparable with earlier studies both at Mace Head and elsewhere. Monthly averaged clean marine (wind direction of 180–300° and black carbon absorption coefficient < 1.425 Mm^− 1) CCN and marine CCN varied between 15–247 cm^− 3 and 54–670 cm^− 3, respectively. As expected, significant increases in number concentration were found in continentally sourced CCN over that of marine CCN and were found to follow a log-normal distribution significantly tighter than that of clean marine air masses. No significant trend was found for CCN over the 9-year period. While polluted continental air masses showed a slight increase in CCN concentrations over the winter months, most likely due to increased fuel usage and a lower mixed boundary layer, the dominance of marine sector air arriving at Mace Head, which generally consists of background CCN concentrations, reduced seasonal differences for polluted air. Marine air showed a distinct seasonal pattern, with elevated values occurring over the spring and summer seasons. This is thought to be due to enhanced biogenic aerosol production as a result of phytoplankton bloom activity in the North Atlantic.     

START — the road from Bellagio

The START initiative (co-sponsored by IGBP, WCRP and HDP) has as its primary objective development of regional frameworks to support regional research related to global change, associated capacity building and synthesis scientific assessments related to policy development. START now has six regional networks under development in South-East Asia, Northern Africa, East Asia, South Asia, the Meditteranean, and Southern Africa. Issues before START include the coordination of regional activities with that of sponsoring programmes, the need for a more elaborated HDP, and the development of thematic programming that will secure multi-donor, multi-year support.     

A MASCOTTE-based characterization of MCSs over Spain, 2000–2002

A 3-year Mesoscale Convective Systems (MCSs) database, which extends from 2000 to 2002, has been built for the Iberian Peninsula and the Balearic Islands using the objective method MASCOTTE (MAximum Spatial COrrelation Technique). It was originally developed to track the evolution of convective systems over the Amazon region; after modifications, it is able to track MCS evolution even with an hour and a half of missed images and provides essential information of both dynamical and morphological characteristics of MCSs. MASCOTTE is tested against a visual and subjective method, and is found to offer advantages such as automation and a simple and efficient operation that make it very useful for building large MCS databases.Thirty-five MCSs were found between June and October, most of them originated along the Mediterranean coast and near the Pyrenees, showing an increasing occurrence from June to September, when the maximum is found. The regions most influenced by MCS occurrences are Balearic Islands, Valencia, Catalonia, Murcia and the Basque Country. The MCSs tend to be small, short-lived and linear, usually moving eastward or northeastward with low velocities.The MCSs-associated precipitation presents high variability, ranging from 80 to 0 mm h⁻¹ as maximum hourly records. Two different convective regions are identified based on MCS behavior in extreme precipitation events: Northern Spain (the Basque Country) with abundant and continuous precipitation regime but little MCS influence, and the Mediterranean coast, where precipitation is sporadic but much more intense.     

Beyond the circle of poison: Significant shifts in the global pesticide complex, 1976–2008

Almost 30 years after its introduction, the “circle of poison” remains a common conceptualization of the global pesticide complex among scholars and especially in popular understanding. The circle of poison describes a situation in which, pesticides banned in industrialized countries continue to be manufactured there and exported to developing countries, are then used in developing countries almost entirely on export crops, and return to industrialized countries as pesticide residues on food. Using secondary data and a case study of pesticide use in Costa Rica, I review the applicability of the circle of poison conceptualization to the current global pesticide complex. I argue that (1) the circle of poison is no longer accurate due to important global changes in pesticide regulation, production, trade, sales, and use driven by a number of dynamic economic, social, and ecological processes; (2) using industrialized countries’ pesticide regulations as proxies for safety should be replaced by multi-characteristic risk assessments; and (3) revisions of the circle of poison conceptualization should be updated because of export farmers’ adoption of newer classes of pesticides. The paper concludes by offering a new characterization of the global pesticide complex vis-à-vis pesticide use in developing countries: pesticide divergence by market orientation.     

Trends in chemical composition of precipitation in Nanjing, China, during 1992–2003

In this study, variations of the chemical composition of precipitation in Nanjing, China, over a 12-year period (1992–2003) are presented. The average annual concentration of pH value was 5.15, ranging from 4.93 to 5.36, and there was no significant trend in the acidity of precipitation. SO₄²⁻, Cl⁻ and NO₃⁻ were the main anions, while Ca²⁺, NH₄⁺ and Mg²⁺ were the main cations. The concentrations of these main ions were very high compared to those reported in many other areas around the world. Most of the ions came from anthropogenic and crustal sources. High correlations were found among dust-derived cations Ca²⁺, Mg²⁺and K⁺, between Cl⁻ and SO₄²⁻, between Cl⁻ and NH₄⁺ and between acidic anions and dust-derived cations, such as SO₄²⁻ and Ca²⁺, SO₄²⁻ and K⁺, Cl⁻ and Ca²⁺, Cl⁻ and K⁺, F⁻ and Mg²⁺ and F⁻ and K⁺. A significant decreasing trend was observed in concentration of SO₄²⁻ because of the abatement strategies for SO₂ emissions and energy policy change, while a significant increasing trend was found in the contribution of NO₃⁻ to acidification due to the rapidly growing number of motor vehicles. A significant decreasing trend was found in dust-derived cation Ca²⁺ due to more stringent controls of industrial dust emissions and rapid urbanization reducing the amount of open land, while the contribution of NH₄⁺ to neutralization increased relatively.     

‘Energy security’ and ‘climate change’: Constructing UK energy discursive realities

Recently, in the United Kingdom, two issues have dominated the energy policy agenda: effective climate change mitigation and energy security. Whilst evolving government policy has led to government support for new build nuclear power as part of the nation's future energy mix, limited attention has been devoted to examining how arguments were constructed to lead ‘naturally’ to nuclear new build as an option for addressing these two issues. Using Critical Discourse Analysis this paper analyses the struggles within the climate change mitigation and energy security discourses in generating and/or replacing meanings. In particular, it examines how construction of the dominant (hegemonic) discourses led ‘naturally’ to the necessity of new build nuclear power. This paper draws upon 24 stakeholder interviews to examine the hegemonic and counter-hegemonic discourses. It outlines how climate change and energy security were perceived as motivators for energy policy; it shows how the combination of the dominant construction of climate change as an environmental issue and the construction of energy security as a ‘gas gap’ lent weight to the argument for nuclear new build. Struggling against these discourses is a counter-hegemonic discourse centred around climate change as a symptom of unsustainability and energy security as a lack of energy diversity. The latter, rather than ‘naturally’ proposing an urgent need for nuclear new build, lead to the argument for readdressing the focus of, and use of resources by, society - reducing energy demand and increasing energy supply diversity.     

Condensed water in tropical cyclone “Oliver”, 8 February 1993

On February 8, 1993, the NASA DC-8 aircraft profiled from 10,000 to 37,000 feet (3.1–11.3 km) pressure altitude in a stratified section of tropical cyclone “Oliver” over the Coral Sea northeast of Australia. Size, shape and phase of cloud and precipitation particles were measured with a 2-D Greyscale probe. Cloud/ precipitation particles changed from liquid to ice as soon as the freezing level was reached near 17,000 feet (5.2 km) pressure altitude. The cloud was completely glaciated at −5°C. There was no correlation between ice particle habit and ambient temperature. In the liquid phase, the precipitation-cloud drop concentration was 4.0 × 10³ m⁻³, the geometric mean diameter D_g=0.5−0.7 mm, and the liquid water content 0.7−1.9 g m⁻³. The largest particles anywhere in the cloud, dominated by fused dendrites at concentrations similar to that of raindrops (2.5 × 10³ m⁻³) but a higher condensed water content (5.4 g m⁻³ estimated) were found in the mixed phase; condensed water is removed very effectively from the mixed layer due to high settling velocities of the large mixed particles. The highest number concentration (4.9 × 10⁴ m⁻³), smallest size (D_g=0.3−0.4 mm), largest surface area (up to 2.6 × 10² cm² m⁻³ at 0.4−1.0 g m⁻³ of condensate) existed in the ice phase at the coldest temperature (−40°C) at 35,000 feet (10.7 km). Each cloud contained aerosol (haze particles) in addition to cloud particles. The aerosol total surface area exceeded that of the cirrus particles at the coldest temperature. Thus, aerosols must play a significant role in the upscattering of solar radiation. Light extinction (6.2 km⁻¹) and backscatter (0.8 sr⁻¹ km⁻¹) was highest in the coldest portion of the cirrus cloud at the highest altitude.     

Compounds, creativity and complexity in climate change communication: The case of ‘carbon indulgences’

This article deals with climate change from a linguistic perspective. Climate change is an extremely complex issue that has exercised the minds of experts and policy makers with renewed urgency in recent years. It has prompted an explosion of writing in the media, on the internet and in the domain of popular science and literature, as well as a proliferation of new compounds around the word ‘carbon’ as a hub, such as ‘carbon indulgence’, a new compound that will be studied in this article. Through a linguistic analysis of lexical and discourse formations around such ‘carbon compounds’ we aim to contribute to a broader understanding of the meaning of climate change. Lexical carbon compounds are used here as indicators for observing how human symbolic cultures change and adapt in response to environmental threats and how symbolic innovation and transmission occurs.     

The electrification of dust-lofting gust fronts (‘haboobs’) in the Sahel

Two Doppler radars and a suite of auxiliary surface observations are used to document the electrical, aerosol and aerodynamic properties of dust-lofting gust fronts near Niamey, Niger during the AMMA (African Monsoon Multidisciplinary Analysis). Electrification with dominant negative polarity is a common behavior, consistent with earlier studies on dust devils and the Harmattan wind in dry environments.     

Mean turbulent properties of the stable boundary layer observed during the “coast” experiment

An acoustic Doppler sounder has been used to document the behaviour of the stable atmospheric boundary layer during the “Coast” experiment, in April-May, 1983, on a homogeneous terrain near the Dutch coast. It has been shown that kaimal's model of the spectrum of velocity in the stable surface layer can be applied and that surface-layer parameterization can be used in the whole stable surface layer. Velocity spectra have been computed between .0005 c.p.s. and .1 c.p.s. and for the stability range for z/L between 0 and 10. It is to be noted that the information has been obtained using only sodar data.     

Research and communication in the “invisible college” of the Human Dimensions of Global Change

The human dimensions of global change research community includes scholars in the natural and social sciences working in universities and government laboratories who share common interests and who communicate with each other through journals, workshops, and conferences and via the Internet. Information and communication technologies, in particular, e-mail, listservs, and the WWW, where speed and low cost are key features, from the backbone of an “electronic invisible college”. The results of a survey of scientists attending the Laxenburg conference in 1997 illustrates the transdisciplinary and international nature of HDGC research, the local and international scale of research, their commitment to public policy, and their increased use of the Internet for networking, data acquisition and analysis, and publication.     

Some economics of ‘dangerous’ climate change: Reflections on the Stern Review

The Stern Review on the Economics of Climate Change concluded that there can be “no doubt” the economic risks of business-as-usual (BAU) climate change are “very severe” [Stern, 2006. The Economics of Climate Change. HM Treasury, London, p. 188]. The total cost of climate change was estimated to be equivalent to a one-off, permanent 5–20% loss in global mean per-capita consumption today. And the marginal damage cost of a tonne of carbon emitted today was estimated to be around $312 [p. 344]. Both of these estimates are higher than most reported in the previous literature. Subsequently, a number of critiques have appeared, arguing that discounting is the principal explanation for this discrepancy. Discounting is important, but in this paper we emphasise that how one approaches the economics of risk and uncertainty, and how one attempts to model the very closely related issue of low-probability/high-damage scenarios (which we connect to the recent discussion of ‘dangerous’ climate change), can matter just as much. We demonstrate these arguments empirically, using the same models applied in the Stern Review. Together, the issues of risk and uncertainty on the one hand, and ‘dangerous’ climate change on the other, raise very strongly questions about the limits of a welfare-economic approach, where the loss of natural capital might be irreversible and impossible to compensate. Thus we also critically reflect on the state-of-the-art in integrated assessment modelling. There will always be an imperative to carry out integrated assessment modelling, bringing together scientific ‘fact’ and value judgement systematically. But we agree with those cautioning against a literal interpretation of current estimates. Ironically, the Stern Review is one of those voices. A fixation with cost-benefit analysis misses the point that arguments for stabilisation should, and are, built on broader foundations.