Daily changes in global cloud cover and Earth transits of the heliospheric current sheet

Changes in cloud cover are found to occur for periods of a few days following Earth transits of the heliospheric current sheet (HCS), provided also that the transits occur in years of high stratospheric aerosol loading. Using global cloud products from the International Satellite Cloud Climatology Project (ISCCP) D1 data series, epoch superposition analyses were made for various samples of HCS events. For the period August 1991 to June 1994 for the stratospheric aerosol loading due to the Pinatubo eruption, the analysis of the data in 30° geomagnetic latitude intervals revealed that cloud anomalies that were significant and negative were located in the Southern Hemisphere high and middle latitudes, and anomalies that were significant and positive were found in both hemispheres at low latitudes. When the key days in the superposed epoch analysis were determined by minima in the relativistic electron flux, rather than by the HCS crossings, the location of the significant negative anomalies was in the northern high latitudes, and the location of the significant positive anomalies was in middle latitudes in the Northern Hemisphere. The spatial and temporal patterns of these cloud cover variations are in broad agreement with the expected opposite variations at high and low latitudes of the current density Jz in the global electric circuit caused by the relativistic electron flux variations, during periods when the aerosol loading has made a large increase in stratospheric resistivity

Global rainfall monitoring by SSM/I

Significant accomplishments in the last year of research are presented. During 1991, three main activities were undertaken: (1) development and testing of a preliminary global rainfall algorithm; (2) researching areas of strong surface scattering; and (3) formulation of a program of work for the WetNet PrecipWG. Focus of present research and plans for next year are briefly dismissed

Environmental migrants, climate ‘refugees’ and sun-seeking expats

The question of how migration patterns will be influenced by environmental and climate change has received much attention within policy and academic circles. This focus can be explained in part by fears voiced by an alarmist group of migration scholars regarding uncontrolled population movements over country borders at the hands of a changing climate. This chapter explores the undercurrents driving widespread interest in the interaction between climate change and migration. In so doing, it explores how narratives around migration have been shaped by the use of certain terminology or ways to define, theorise, facilitate and problematise the movement of people. Current understanding of the interactions between the environment and human migration are characterised by a high degree of complexity and uncertainty. A wide range of methods and theoretical frameworks have thus been developed that seek to expand our understanding of its dynamics. Despite methodological and conceptual advances within the field, we propose that future research and policy must consider the loaded nature of language and the ways in which terms such as ‘climate change’ and ‘migration’ are interpreted. Care must be taken to ensure that the development of actions and policy initiatives truly serve to protect and benefit affected people, whether they are on the move, have arrived in a new destination, or are immobile and want but are unable to move

Human Migration and Natural Resources: Global Assessment of an adaptive complex system

Availability, access to and use of natural resources are key intervening variables for understanding, analysing and managing local or global relationships between climatic or environmental changes and population distribution and movements. While much debate and research has focused on the effect of climate change on migration worldwide, surprisingly little attention has been paid to the role and governance of natural resources in this relationship. Since 2007 the International Resource Panel has provided independent, authoritative and policyrelevant scientific assessments on the status, trends and future state of natural resources. This report opens a discussion about the natural resource nexus with human mobility, using an integrative approach that considers multiple causalities and networks of interaction. The research in this report, which involved qualitative and quantitative methods, shows that the relationship between natural resources and migration calls for a consideration of human-environment interactions as a complex adaptive system. This report finds that natural resources have a significant impact on human mobility, but that the relationships are not linear. They can both mitigate or exacerbate involuntary migration, depending on specific ecological and economic constraints. Natural resources act as an intervening pathway between environmental change, climate change and human mobility. Hydropower projects represent the most direct connection between natural resource development and involuntary migration, and their expansion as a cleaner source of power generation in the years to come will need to be carefully managed. As an example of such complexity, mineral rushes can accentuate localized migration but may reduce voluntary international migration

Natural resources modulate the nexus between environmental shocks and human mobility

In the context of natural resource degradation, migration can act as means of adaptation both for those leaving and those supported by remittances. Migration can also result from an inability to adapt in-situ, with people forced to move, sometimes to situations of worse or of the same exposure to environmental threats. The deleterious impacts of resource degradation have been proposed in some situations to limit the ability to move. In this contribution, we use remote sensed information coupled with population density data for continental Africa to assess quantitatively the prevalence of migration and immobility in the context of one cause of resource degradation: drought. We find that the effect of drought on mobility is amplified with the frequency at which droughts are experienced and that higher income households appear more resilient to climatic shocks and are less likely to resort to mobility as an adaptation response

Exploring linkages between drought and HIV treatment adherence in Africa: a systematic review

Climate change is directly and indirectly linked to human health, including through access to treatment and care. Our systematic review presents a systems understanding of the nexus between drought and antiretroviral therapy (ART) adherence in HIV-positive individuals in the African setting. Narrative synthesis of 111 studies retrieved from Web of Science, PubMed/MEDLINE, and PsycINFO suggests that livelihoods and economic conditions, comorbidities and ART regimens, human mobility, and psychobehavioural dispositions and support systems interact in complex ways in the drought–ART adherence nexus in Africa. Economic and livelihood-related challenges appear to impose the strongest impact on human interactions, actions, and systems that culminate in non-adherence. Indeed, the complex pathways identified by our systems approach emphasise the need for more integrated research approaches to understanding this phenomenon and developing interventions

Variability of atmospheric dimethylsulphide over the southern Indian Ocean due to changes in ultraviolet radiation

Dimethylsulphide (DMS) is a climatically important component of global biogeochemical cycles, through its role in the sulphur cycle. Changes in ultraviolet radiation (UV) exhibit both positive and negative forcings on the dynamics of production and turnover of DMS and its precursor dimethylsulphoniopropionate (DMSP). In this study we investigate the net forcing of UV on atmospheric DMS. The work is based on a 10-year record of observed DMS at Amsterdam Island in the southern Indian Ocean, and satellite-based retrievals of surface UV and photosynthetically active radiation (PAR). The results show an inverse relationship between UV radiation and atmospheric DMS associated with extreme changes (defined as the greatest 5%) in daily UV, independent of changes in wind speed, sea surface temperature, and PAR

Exploring linkages between drought and HIV treatment adherence in Africa: A Systematic Review

Climate change is directly and indirectly linked to human health, including through access to treatment and care. Our systematic review presents a ‘systems’ understanding of the nexus between drought and antiretroviral treatment (ART) adherence in HIV-positive individuals in the African setting. Narrative synthesis of 111 studies retrieved from Web of Science, PubMed/Medline, and PsycINFO suggests that economic and livelihoods conditions, comorbidities and ART regimens, human mobility, and psycho-behavioural dispositions and support systems interact in complex ways in the drought-ART adherence nexus in Africa. Economic and livelihood-related challenges appear to impose the strongest impact on human interactions, actions and systems that culminate in non-adherence. Indeed, the complex pathways identified by our systems approach emphasise the need for more integrated research approaches to understanding this phenomenon and develop interventions

Economic, social and demographic impacts of drought on treatment adherence among people living with HIV in rural South Africa: A qualitative analysis

The 2015 El Niño-triggered drought in Southern Africa caused widespread economic and livelihood disruption in South Africa, imposing multiple physical and health challenges for rural populations including people living with HIV (PLHIV). We examined the economic, social and demographic impacts of drought drawing on 27 in-depth interviews in two cohorts of PLHIV in Hlabisa, uMkhanyakude district, KwaZulu-Natal. Thematic analysis revealed how drought-enforced soil water depletion, dried-up rivers, and dams culminated in a continuum of events such as loss of livestock, reduced agricultural production, and insufficient access to water and food which was understood to indirectly have a negative impact on HIV treatment adherence. This was mediated through disruptions in incomes, livelihoods and food systems, increased risk to general health, forced mobility and exacerbation of contextual vulnerabilities linked to poverty and unemployment. The systems approach, drawn from interview themes, hypothesises the complex pathways of plausible networks of impacts from drought through varying socioeconomic factors, exacerbating longstanding contextual precarity, and ultimately challenging HIV care utilisation. Understanding the multidimensional relationships between climate change, especially drought, and poor HIV care outcomes through the prism of contextual vulnerabilities is vital for shaping policy interventions