The characteristics and trends of rainfall on sub-Antarctic Marion Island and associated air circulation patterns
- Authors: Mapuka, Fortunate Nomsa
- Date: 2020
- Language: English
- Type: Thesis , Masters , MSc(Geography)
- Identifier: http://hdl.handle.net/10353/18698 , vital:42725
- Description: Marion Island (46°54ʹS, 37°45ʹE) located in the Southern Ocean possesses one of the most oceanic climates on earth and sensitive to climate change. Climatologically, the sub-Antarctic is inadequately represented in the climate literature and this research therefore attempts to establish the recent changes that have occurred on Marion Island with regards to annual rainfall totals, monthly rainfall, rain days and non-rain days during the period from 1980 to 2018. This study found that annual rainfall has decreased by 24% from 2196.7 mm to 1678.57 mm from 1980 to 2018 and that the last decade (2010-2018) is the driest on record. The decrease in annual rainfall on Marion Island can be directly linked to the decreases recorded in monthly and daily rainfall. Rainfall in autumn has reduced by 35% over the last 40 years and the decrease in autumn rainfall is in part directly related to an increase in anticyclonic air circulation during which Marion Island is not influenced by any mid-latitudinal depressions. The frequency of rain days measured on Marion Island significantly decreased. Daily rainfall measuring less than 5 mm of rain a day contribute 50% of the total number of rain days. However, these high frequency low depth rainfall days contribute very little rainfall to annual totals. On Marion Island rain days that measure 10 mm and above contribute 65% of the total annual rainfall and it is also these type of high magnitude rain days that have significantly decreased since 1980. Multi-day consecutive rain events contribute the greatest proportion of rainfall to the annual rainfall totals (~40%). Linear statistics shows that the contribution to rainfall amount from these multi-day rainfall has halved since 1980. The frequency of non-rain days and consecutive non-rain days have significantly increased. The increased frequency of anticyclonic air circulation over Marion Island and the decrease of the traveling low-pressure systems affecting Marion Island are the probable cause of the increase in non-rain days. It is suggested that this increase in consecutive non-rain days has the most significant impact on the island’s biodiversity and landscape
- Full Text:
- Date Issued: 2020
- Authors: Mapuka, Fortunate Nomsa
- Date: 2020
- Language: English
- Type: Thesis , Masters , MSc(Geography)
- Identifier: http://hdl.handle.net/10353/18698 , vital:42725
- Description: Marion Island (46°54ʹS, 37°45ʹE) located in the Southern Ocean possesses one of the most oceanic climates on earth and sensitive to climate change. Climatologically, the sub-Antarctic is inadequately represented in the climate literature and this research therefore attempts to establish the recent changes that have occurred on Marion Island with regards to annual rainfall totals, monthly rainfall, rain days and non-rain days during the period from 1980 to 2018. This study found that annual rainfall has decreased by 24% from 2196.7 mm to 1678.57 mm from 1980 to 2018 and that the last decade (2010-2018) is the driest on record. The decrease in annual rainfall on Marion Island can be directly linked to the decreases recorded in monthly and daily rainfall. Rainfall in autumn has reduced by 35% over the last 40 years and the decrease in autumn rainfall is in part directly related to an increase in anticyclonic air circulation during which Marion Island is not influenced by any mid-latitudinal depressions. The frequency of rain days measured on Marion Island significantly decreased. Daily rainfall measuring less than 5 mm of rain a day contribute 50% of the total number of rain days. However, these high frequency low depth rainfall days contribute very little rainfall to annual totals. On Marion Island rain days that measure 10 mm and above contribute 65% of the total annual rainfall and it is also these type of high magnitude rain days that have significantly decreased since 1980. Multi-day consecutive rain events contribute the greatest proportion of rainfall to the annual rainfall totals (~40%). Linear statistics shows that the contribution to rainfall amount from these multi-day rainfall has halved since 1980. The frequency of non-rain days and consecutive non-rain days have significantly increased. The increased frequency of anticyclonic air circulation over Marion Island and the decrease of the traveling low-pressure systems affecting Marion Island are the probable cause of the increase in non-rain days. It is suggested that this increase in consecutive non-rain days has the most significant impact on the island’s biodiversity and landscape
- Full Text:
- Date Issued: 2020
Towards a reconstruction of Marion Island’s glacial history
- Authors: Rudolph, Elizabeth
- Date: 2020
- Subjects: Glacial landforms Geomorphological mapping
- Language: English
- Type: Thesis , Doctoral , PhD (Geography)
- Identifier: http://hdl.handle.net/10353/18531 , vital:42581
- Description: Southern Hemisphere glacial chronologies can provide valuable insights into interactions between glaciation and past climate changes. The sub-Antarctic Islands provide a valuable terrestrial record of glacial chronologies for the Southern Hemisphere, since they are unique, not only in size and topography, but also in oceanic situation when compared to other continental landmasses (e.g. Antarctica or Patagonia). On sub-Antarctic Marion Island, southern Indian Ocean, the exact timing and extent of the local Last Glacial Maximum is not yet known as glacial reconstructions have mostly been based on palynological proxies and relative-age dating techniques. This study presents 29 cosmogenic 36Cl exposure ages of deglaciated bedrock surfaces and moraine deposits from Marion Island. In addition, a comprehensive glacial-geomorphological map, which in conjunction with exposure ages provide improved temporal and spatial constraints for the island’s glacial history. Results show that the ice reached a local Last Glacial Maximum before 56 ka ago and retreated, with minor stillstands, until ~17 ka. This early deglaciation left island surfaces below 850 m a.s.l. ice-free after ~19 ka, and any subsequent advances during the Late Glacial or Holocene cooling periods would have been restricted to the interior. This glacial chronology is similar to that of some other sub-Antarctic Islands (e.g. the Kerguelen archipelago, Auckland and Campbell islands, and possibly South Georgia) and a number of other Southern Hemisphere glaciers (e.g. in Patagonia and New Zealand) and adds to evidence that suggest the Southern Hemisphere was in a glacial maximum earlier than the global LGM. A combination of climatic drivers such as declining temperatures, a northward migration of oceanic fronts and the Southern Hemisphere Westerly Winds (causing precipitation changes), as well as the physiography of Marion Island, created optimal conditions for glacier growth during Marine Isotope Stage 4 (MIS 4; ~65 ka ago) instead of the global LGM in MIS 2 (~18 ka). These findings redefine the glacial history of Marion Island, and have implications for future investigations on post-glacial landscape development and ecological succession.
- Full Text:
- Date Issued: 2020
- Authors: Rudolph, Elizabeth
- Date: 2020
- Subjects: Glacial landforms Geomorphological mapping
- Language: English
- Type: Thesis , Doctoral , PhD (Geography)
- Identifier: http://hdl.handle.net/10353/18531 , vital:42581
- Description: Southern Hemisphere glacial chronologies can provide valuable insights into interactions between glaciation and past climate changes. The sub-Antarctic Islands provide a valuable terrestrial record of glacial chronologies for the Southern Hemisphere, since they are unique, not only in size and topography, but also in oceanic situation when compared to other continental landmasses (e.g. Antarctica or Patagonia). On sub-Antarctic Marion Island, southern Indian Ocean, the exact timing and extent of the local Last Glacial Maximum is not yet known as glacial reconstructions have mostly been based on palynological proxies and relative-age dating techniques. This study presents 29 cosmogenic 36Cl exposure ages of deglaciated bedrock surfaces and moraine deposits from Marion Island. In addition, a comprehensive glacial-geomorphological map, which in conjunction with exposure ages provide improved temporal and spatial constraints for the island’s glacial history. Results show that the ice reached a local Last Glacial Maximum before 56 ka ago and retreated, with minor stillstands, until ~17 ka. This early deglaciation left island surfaces below 850 m a.s.l. ice-free after ~19 ka, and any subsequent advances during the Late Glacial or Holocene cooling periods would have been restricted to the interior. This glacial chronology is similar to that of some other sub-Antarctic Islands (e.g. the Kerguelen archipelago, Auckland and Campbell islands, and possibly South Georgia) and a number of other Southern Hemisphere glaciers (e.g. in Patagonia and New Zealand) and adds to evidence that suggest the Southern Hemisphere was in a glacial maximum earlier than the global LGM. A combination of climatic drivers such as declining temperatures, a northward migration of oceanic fronts and the Southern Hemisphere Westerly Winds (causing precipitation changes), as well as the physiography of Marion Island, created optimal conditions for glacier growth during Marine Isotope Stage 4 (MIS 4; ~65 ka ago) instead of the global LGM in MIS 2 (~18 ka). These findings redefine the glacial history of Marion Island, and have implications for future investigations on post-glacial landscape development and ecological succession.
- Full Text:
- Date Issued: 2020
Assessment of the human health implications of climate variability in East London, Eastern Cape, South Africa
- Orimoloye, Israel Ropo https://orcid.org/0000-0001-5058-2799
- Authors: Orimoloye, Israel Ropo https://orcid.org/0000-0001-5058-2799
- Date: 2018
- Subjects: Climatic changes http://id.loc.gov/authorities/subjects/sh85027037
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19715 , vital:43171
- Description: Impacts associated with climate variability and extreme heat are already obvious in varying degrees and expected to be disruptive in the near future across the globe especially in the urban regions. Urban areas have distinctive features that leave their residents and properties vulnerable to extreme climate events. Global temperatures continue to change, reaching new levels almost every year for the past two decades. However, even though the causes are debated it is evident that climate variability is real. Climate variability and disaster risk are threats to human health that adversely reinforce each other. Better knowledge on the association between climate change, variability and extreme weather-related illness is needed and can aid strategies to reduce vulnerabilities. The impacts of climate variability on the health of residents in East London (EL) area in the Eastern Cape Province, South Africa were explored through four interdependent research segments. The first section examined the climate variability and urban surface thermal characteristics implication on human health using Remote Sensing (RS) and Geographic Information System (GIS) techniques. Remote sensing was used to assess the Land Surface Temperature (LST) and estimated Radiation (R) of East London area from Landsat Thematic Mapper (TM) images for 1986, 1996, 2006 as well as from Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) for 2016 spanning a period of 30 years. Rapid urbanization and land cover changes in this area have contributed significantly to this drastic change in the natural land surface characteristics (increased land surface temperature and surface solar radiation). For instance, vegetation cover declined by about 358.812km2 while built-up areas increased by 175.473km2 during this period which correlates with the area thermal characteristics changes. Radiation levels also increased over the years with values exceeding the global solar radiation index. Exposure to increased surface radiation poses risks of heat stroke, skin cancer and heart disease to the local population. Consequently, this study provides pertinent information on human health sustainability and epidemiological case management. The second part explored past temperature and humidity trends (1986-2016) and projects future trends (2017-2030). The historical data of meteorological variables were obtained from the archives of the South African Weather Service and analyzed using the ordinary least square regression model in GRETL (GNU Regression Econometric and Time-series Library) statistical software. This study discovered a local consistency between models and the observations add to existing knowledge and this is crucial in knowing the shifts in climatic change as well as recognizing variability and its conflicting effects on human health, environment, agriculture, ecological sustainability and socioeconomic status in the region. The third segment assessed the potential impacts of climate variability on health using existing heat indices during the study period. The results demonstrated that in East London from 1986 to 2016 during summer and autumn (December to May) of various years exceeded high heat index values. It is obvious that summer and autumn months are more vulnerable to heat extreme and humidex. The humidex and Heat Index (HI) increased annually by 0.03 percent and 0.9 percent respectively throughout the study period. The increment in the various indices showed highly significant ill-health and environmental impacts on humans especially with prolonged exposure. The last segment appraised the association between climatic elements and epidemiological incidences of the study area between 2012 and 2016. The epidemiology incidences data were obtained from the archives of the Cecilia Makiwane Hospital in East London area and National Tertiary Service Grant (NTSG) database for the period. The results have showed that there exists significant effects of climate variability on the health of East London residents and these have been identified to have negative impacts on health of the people in the area. This study also revealed noticeable impacts of extreme heat on human health and a positive correlation between meteorological components (HI and temperature) and epidemiological cases (cardiovascular, skin cancer and diarrhea) during the study period. , Thesis (PhD) (Geography) -- University of Fort Hare, 2018
- Full Text:
- Date Issued: 2018
- Authors: Orimoloye, Israel Ropo https://orcid.org/0000-0001-5058-2799
- Date: 2018
- Subjects: Climatic changes http://id.loc.gov/authorities/subjects/sh85027037
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19715 , vital:43171
- Description: Impacts associated with climate variability and extreme heat are already obvious in varying degrees and expected to be disruptive in the near future across the globe especially in the urban regions. Urban areas have distinctive features that leave their residents and properties vulnerable to extreme climate events. Global temperatures continue to change, reaching new levels almost every year for the past two decades. However, even though the causes are debated it is evident that climate variability is real. Climate variability and disaster risk are threats to human health that adversely reinforce each other. Better knowledge on the association between climate change, variability and extreme weather-related illness is needed and can aid strategies to reduce vulnerabilities. The impacts of climate variability on the health of residents in East London (EL) area in the Eastern Cape Province, South Africa were explored through four interdependent research segments. The first section examined the climate variability and urban surface thermal characteristics implication on human health using Remote Sensing (RS) and Geographic Information System (GIS) techniques. Remote sensing was used to assess the Land Surface Temperature (LST) and estimated Radiation (R) of East London area from Landsat Thematic Mapper (TM) images for 1986, 1996, 2006 as well as from Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) for 2016 spanning a period of 30 years. Rapid urbanization and land cover changes in this area have contributed significantly to this drastic change in the natural land surface characteristics (increased land surface temperature and surface solar radiation). For instance, vegetation cover declined by about 358.812km2 while built-up areas increased by 175.473km2 during this period which correlates with the area thermal characteristics changes. Radiation levels also increased over the years with values exceeding the global solar radiation index. Exposure to increased surface radiation poses risks of heat stroke, skin cancer and heart disease to the local population. Consequently, this study provides pertinent information on human health sustainability and epidemiological case management. The second part explored past temperature and humidity trends (1986-2016) and projects future trends (2017-2030). The historical data of meteorological variables were obtained from the archives of the South African Weather Service and analyzed using the ordinary least square regression model in GRETL (GNU Regression Econometric and Time-series Library) statistical software. This study discovered a local consistency between models and the observations add to existing knowledge and this is crucial in knowing the shifts in climatic change as well as recognizing variability and its conflicting effects on human health, environment, agriculture, ecological sustainability and socioeconomic status in the region. The third segment assessed the potential impacts of climate variability on health using existing heat indices during the study period. The results demonstrated that in East London from 1986 to 2016 during summer and autumn (December to May) of various years exceeded high heat index values. It is obvious that summer and autumn months are more vulnerable to heat extreme and humidex. The humidex and Heat Index (HI) increased annually by 0.03 percent and 0.9 percent respectively throughout the study period. The increment in the various indices showed highly significant ill-health and environmental impacts on humans especially with prolonged exposure. The last segment appraised the association between climatic elements and epidemiological incidences of the study area between 2012 and 2016. The epidemiology incidences data were obtained from the archives of the Cecilia Makiwane Hospital in East London area and National Tertiary Service Grant (NTSG) database for the period. The results have showed that there exists significant effects of climate variability on the health of East London residents and these have been identified to have negative impacts on health of the people in the area. This study also revealed noticeable impacts of extreme heat on human health and a positive correlation between meteorological components (HI and temperature) and epidemiological cases (cardiovascular, skin cancer and diarrhea) during the study period. , Thesis (PhD) (Geography) -- University of Fort Hare, 2018
- Full Text:
- Date Issued: 2018
Assessment of the human health implications of climate variability in East London, Eastern Cape, South Africa
- Authors: Orimoloye, Israel Ropo
- Date: 2018
- Subjects: Climatic changes -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Geography
- Identifier: http://hdl.handle.net/10353/10113 , vital:35346
- Description: Impacts associated with climate variability and extreme heat are already obvious in varying degrees and expected to be disruptive in the near future across the globe especially in the urban regions. Urban areas have distinctive features that leave their residents and properties vulnerable to extreme climate events. Global temperatures continue to change, reaching new levels almost every year for the past two decades. However, even though the causes are debated it is evident that climate variability is real. Climate variability and disaster risk are threats to human health that adversely reinforce each other. Better knowledge on the association between climate change, variability and extreme weather-related illness is needed and can aid strategies to reduce vulnerabilities. The impacts of climate variability on the health of residents in East London (EL) area in the Eastern Cape Province, South Africa were explored through four interdependent research segments. The first section examined the climate variability and urban surface thermal characteristics implication on human health using Remote Sensing (RS) and Geographic Information System (GIS) techniques. Remote sensing was used to assess the Land Surface Temperature (LST) and estimated Radiation (R) of East London area from Landsat Thematic Mapper (TM) images for 1986, 1996, 2006 as well as from Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) for 2016 spanning a period of 30 years. Rapid urbanization and land cover changes in this area have contributed significantly to this drastic change in the natural land surface characteristics (increased land surface temperature and surface solar radiation). For instance, vegetation cover declined by about 358.812km2 while built-up areas increased by 175.473km2 during this period which correlates with the area thermal characteristics changes. Radiation levels also increased over the years with values exceeding the global solar radiation index. Exposure to increased surface radiation poses risks of heat stroke, skin cancer and heart disease to the local population. Consequently, this study provides pertinent information on human health sustainability and epidemiological case management. The second part explored past temperature and humidity trends (1986-2016) and projects future trends (2017-2030). The historical data of meteorological variables were obtained from the archives of the South African Weather Service and analyzed using the ordinary least square regression model in GRETL (GNU Regression Econometric and Time-series Library) statistical software. This study discovered a local consistency between models and the observations add to existing knowledge and this is crucial in knowing the shifts in climatic change as well as recognizing variability and its conflicting effects on human health, environment, agriculture, ecological sustainability and socioeconomic status in the region. The third segment assessed the potential impacts of climate variability on health using existing heat indices during the study period. The results demonstrated that in East London from 1986 to 2016 during summer and autumn (December to May) of various years exceeded high heat index values. It is obvious that summer and autumn months are more vulnerable to heat extreme and humidex. The humidex and Heat Index (HI) increased annually by 0.03percent and 0.9percent respectively throughout the study period. The increment in the various indices showed highly significant ill-health and environmental impacts on humans especially with prolonged exposure. The last segment appraised the association between climatic elements and epidemiological incidences of the study area between 2012 and 2016. The epidemiology incidences data were obtained from the archives of the Cecilia Makiwane Hospital in East London area and National Tertiary Service Grant (NTSG) database for the period. The results have showed that there exists significant effects of climate variability on the health of East London residents and these have been identified to have negative impacts on health of the people in the area. This study also revealed noticeable impacts of extreme heat on human health and a positive correlation between meteorological components (HI and temperature) and epidemiological cases (cardiovascular, skin cancer and diarrhea) during the study period.
- Full Text:
- Date Issued: 2018
- Authors: Orimoloye, Israel Ropo
- Date: 2018
- Subjects: Climatic changes -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Geography
- Identifier: http://hdl.handle.net/10353/10113 , vital:35346
- Description: Impacts associated with climate variability and extreme heat are already obvious in varying degrees and expected to be disruptive in the near future across the globe especially in the urban regions. Urban areas have distinctive features that leave their residents and properties vulnerable to extreme climate events. Global temperatures continue to change, reaching new levels almost every year for the past two decades. However, even though the causes are debated it is evident that climate variability is real. Climate variability and disaster risk are threats to human health that adversely reinforce each other. Better knowledge on the association between climate change, variability and extreme weather-related illness is needed and can aid strategies to reduce vulnerabilities. The impacts of climate variability on the health of residents in East London (EL) area in the Eastern Cape Province, South Africa were explored through four interdependent research segments. The first section examined the climate variability and urban surface thermal characteristics implication on human health using Remote Sensing (RS) and Geographic Information System (GIS) techniques. Remote sensing was used to assess the Land Surface Temperature (LST) and estimated Radiation (R) of East London area from Landsat Thematic Mapper (TM) images for 1986, 1996, 2006 as well as from Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) for 2016 spanning a period of 30 years. Rapid urbanization and land cover changes in this area have contributed significantly to this drastic change in the natural land surface characteristics (increased land surface temperature and surface solar radiation). For instance, vegetation cover declined by about 358.812km2 while built-up areas increased by 175.473km2 during this period which correlates with the area thermal characteristics changes. Radiation levels also increased over the years with values exceeding the global solar radiation index. Exposure to increased surface radiation poses risks of heat stroke, skin cancer and heart disease to the local population. Consequently, this study provides pertinent information on human health sustainability and epidemiological case management. The second part explored past temperature and humidity trends (1986-2016) and projects future trends (2017-2030). The historical data of meteorological variables were obtained from the archives of the South African Weather Service and analyzed using the ordinary least square regression model in GRETL (GNU Regression Econometric and Time-series Library) statistical software. This study discovered a local consistency between models and the observations add to existing knowledge and this is crucial in knowing the shifts in climatic change as well as recognizing variability and its conflicting effects on human health, environment, agriculture, ecological sustainability and socioeconomic status in the region. The third segment assessed the potential impacts of climate variability on health using existing heat indices during the study period. The results demonstrated that in East London from 1986 to 2016 during summer and autumn (December to May) of various years exceeded high heat index values. It is obvious that summer and autumn months are more vulnerable to heat extreme and humidex. The humidex and Heat Index (HI) increased annually by 0.03percent and 0.9percent respectively throughout the study period. The increment in the various indices showed highly significant ill-health and environmental impacts on humans especially with prolonged exposure. The last segment appraised the association between climatic elements and epidemiological incidences of the study area between 2012 and 2016. The epidemiology incidences data were obtained from the archives of the Cecilia Makiwane Hospital in East London area and National Tertiary Service Grant (NTSG) database for the period. The results have showed that there exists significant effects of climate variability on the health of East London residents and these have been identified to have negative impacts on health of the people in the area. This study also revealed noticeable impacts of extreme heat on human health and a positive correlation between meteorological components (HI and temperature) and epidemiological cases (cardiovascular, skin cancer and diarrhea) during the study period.
- Full Text:
- Date Issued: 2018
On high-altitude and high- latitude frost environments
- Authors: Hansen, Christel Dorothee
- Date: 2018
- Subjects: Frost -- Drakensberg Mountains , Frost -- Prince Edward Islands -- Marion Island , Frost -- Antarctica -- Queen Maud Land , Climatic geomorphology -- Southern Hemisphere , Permafrost -- Southern Hemisphere , Periglacial processes -- Southern Hemisphere , Frost environments -- Southern Hemisphere
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62383 , vital:28169
- Description: Frost environments occur throughout the world, with associated processes occurring across climatic zones. Climatic geomorphology proposes that climatic zones, largely derived from annual average air temperature and precipitation values, have specific landforms and processes active within that zone. This study offers unique insights into the frost environments of three locations in the Southern Hemisphere, namely the Eastern Cape Drakensberg of South Africa, sub-Antarctic Marion Island, and Dronning Maud Land of Antarctica. The Drakensberg ranges from temperate to alpine, Marion Island is hyper-maritime, and Dronning Maud Land a polar desert. Drivers and forcings on the ground frost regime are identified, as are future climatic scenarios. Altitude and latitude were identified as the most important locational drivers, while air temperature showed highest correlation with freezing events. The initiation of a freeze event correlated strongly with maximum ground temperatures. Vegetation cover was found to ameliorate frost cycles, thereby increasing ground temperatures. Dronning Maud Land of Antarctica is characterised by annual frost (permafrost), with limited seasonal thaw in summer. Thawing cycles reflected the depth of the active layer, which ranged from just under 60 cm for Robertskollen (at lowest altitude) to less than 15 cm on Slettfjell (at greatest altitude). Marion Island had the most active frost environment, exhibiting both seasonal frost, and ubiquitous shallow diurnal frost cycles. The Drakensberg were largely frost-free, with limited seasonal frost and few diurnal freeze- thaw events. Diurnal frost processes were found to be azonal, and present at all three study locations. Evidence of landforms derived from diurnal frost processes were evident in each zone. Equifinality/convergence of form was present to a degree. The presence of patterned ground, which was not wholly derived from frost processes, suggests a measure of equifinality. Furthermore, openwork block deposits, of which not all are either blockstreams nor blockfields, are not necessarily the result of frost processes. The periglacial environment is poorly defined and methods to delineate this environment, as well as other climatic zones, should include additional parameters. Delineating zones on annual (and limited) monthly averages based on predominantly temperature, is not sufficient. While concepts of climatic geomorphology may be applied in a general sense, this framework is not suited to working at smaller scales. Specifically, periglacial environments should be delineated using ground moisture, as well as air temperature. Furthermore, vegetation and snow cover are important, as are soil textural properties.
- Full Text:
- Date Issued: 2018
- Authors: Hansen, Christel Dorothee
- Date: 2018
- Subjects: Frost -- Drakensberg Mountains , Frost -- Prince Edward Islands -- Marion Island , Frost -- Antarctica -- Queen Maud Land , Climatic geomorphology -- Southern Hemisphere , Permafrost -- Southern Hemisphere , Periglacial processes -- Southern Hemisphere , Frost environments -- Southern Hemisphere
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62383 , vital:28169
- Description: Frost environments occur throughout the world, with associated processes occurring across climatic zones. Climatic geomorphology proposes that climatic zones, largely derived from annual average air temperature and precipitation values, have specific landforms and processes active within that zone. This study offers unique insights into the frost environments of three locations in the Southern Hemisphere, namely the Eastern Cape Drakensberg of South Africa, sub-Antarctic Marion Island, and Dronning Maud Land of Antarctica. The Drakensberg ranges from temperate to alpine, Marion Island is hyper-maritime, and Dronning Maud Land a polar desert. Drivers and forcings on the ground frost regime are identified, as are future climatic scenarios. Altitude and latitude were identified as the most important locational drivers, while air temperature showed highest correlation with freezing events. The initiation of a freeze event correlated strongly with maximum ground temperatures. Vegetation cover was found to ameliorate frost cycles, thereby increasing ground temperatures. Dronning Maud Land of Antarctica is characterised by annual frost (permafrost), with limited seasonal thaw in summer. Thawing cycles reflected the depth of the active layer, which ranged from just under 60 cm for Robertskollen (at lowest altitude) to less than 15 cm on Slettfjell (at greatest altitude). Marion Island had the most active frost environment, exhibiting both seasonal frost, and ubiquitous shallow diurnal frost cycles. The Drakensberg were largely frost-free, with limited seasonal frost and few diurnal freeze- thaw events. Diurnal frost processes were found to be azonal, and present at all three study locations. Evidence of landforms derived from diurnal frost processes were evident in each zone. Equifinality/convergence of form was present to a degree. The presence of patterned ground, which was not wholly derived from frost processes, suggests a measure of equifinality. Furthermore, openwork block deposits, of which not all are either blockstreams nor blockfields, are not necessarily the result of frost processes. The periglacial environment is poorly defined and methods to delineate this environment, as well as other climatic zones, should include additional parameters. Delineating zones on annual (and limited) monthly averages based on predominantly temperature, is not sufficient. While concepts of climatic geomorphology may be applied in a general sense, this framework is not suited to working at smaller scales. Specifically, periglacial environments should be delineated using ground moisture, as well as air temperature. Furthermore, vegetation and snow cover are important, as are soil textural properties.
- Full Text:
- Date Issued: 2018
The implications of landfill closure for waste reclaimers in rural local municipalities : the case of Fort Beaufort landfill, Raymond Mhlaba Local Municipality, Eastern Cape South Africa
- Authors: Ntongana, Kwasa
- Date: 2018
- Subjects: Refuse and refuse disposal Sanitary landfills Waste disposal sites -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: http://hdl.handle.net/10353/6027 , vital:29482
- Description: Poverty and unemployment in the rural areas of the Eastern Cape is forcing thousands of vulnerable people into waste picking. There is growing recognition that waste re-claimers contribute to the local economy, to public health and to environmental sustainability. However, they often face low social status, tragic living and working conditions, and little support from local governments. The waste reclaimers of the Raymond Mhlaba Municipal area are unemployed, experiencing a poorer quality of life and feeling even more socially and economically excluded from the rest of society because of the “limitations” on landfill salvaging currently. Moreover, they have developed feelings of resentment and anger that have resulted in defiant acts of trespassing and theft. This social development study highlights the implications of landfill closure for waste salvagers in Raymond Mhlaba Local Municipality. Landfilling has been the main method for municipal waste disposal in Raymond Mhlaba Local Municipality. To combat the effects of uncontrolled release of landfill gases, the uncontrolled release of leachate that may affect water quality many landfills in the Eastern Cape are being considered for close down and for rehabilitation. To consider as well is the socio-economic backlog and anticipated population growth in the province, which means that landfill salvaging will continue to be an important source of revenue for the poor and homeless. This research used observation, semi-structured one-on-one interviewing, focus group interviewing and questionnaires as well as conducted a review of waste management policy-related documents and secondary data analysis in this qualitative research to analyse the social and the economic impacts. The research found that waste reclaimers in the Raymond Mhlaba Local Municipality area disagreed with the closure of the Fort Beaufort landfill because of what the researcher assumed to be a lack of general environmental awareness and because of their vulnerability to poverty. Research findings also highlight that waste reclamation can be considered as a viable option to minimize waste at landfills and waste reclaimers have shown an increasing interest and commitment to being trained formally to continue reclamation work. This study has suggested disadvantages in rural landfill closure, without feasible alternatives. Focus must move away from extending waste collection and closing down landfills and instead improve final disposal and initiating minimisation- recycling programs as part of their strategies through the formation of waste cooperatives. This research suggests formalizing and controlling waste recovery to cater for the immediate and most basic needs of the poor. The recommendations will hopefully influence thinking about waste management policy planning and implementation in general, and be of service to furthering Raymond Mhlaba Local Municipality achieve goals of sustainable employment creation and poverty alleviation.
- Full Text:
- Date Issued: 2018
- Authors: Ntongana, Kwasa
- Date: 2018
- Subjects: Refuse and refuse disposal Sanitary landfills Waste disposal sites -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: http://hdl.handle.net/10353/6027 , vital:29482
- Description: Poverty and unemployment in the rural areas of the Eastern Cape is forcing thousands of vulnerable people into waste picking. There is growing recognition that waste re-claimers contribute to the local economy, to public health and to environmental sustainability. However, they often face low social status, tragic living and working conditions, and little support from local governments. The waste reclaimers of the Raymond Mhlaba Municipal area are unemployed, experiencing a poorer quality of life and feeling even more socially and economically excluded from the rest of society because of the “limitations” on landfill salvaging currently. Moreover, they have developed feelings of resentment and anger that have resulted in defiant acts of trespassing and theft. This social development study highlights the implications of landfill closure for waste salvagers in Raymond Mhlaba Local Municipality. Landfilling has been the main method for municipal waste disposal in Raymond Mhlaba Local Municipality. To combat the effects of uncontrolled release of landfill gases, the uncontrolled release of leachate that may affect water quality many landfills in the Eastern Cape are being considered for close down and for rehabilitation. To consider as well is the socio-economic backlog and anticipated population growth in the province, which means that landfill salvaging will continue to be an important source of revenue for the poor and homeless. This research used observation, semi-structured one-on-one interviewing, focus group interviewing and questionnaires as well as conducted a review of waste management policy-related documents and secondary data analysis in this qualitative research to analyse the social and the economic impacts. The research found that waste reclaimers in the Raymond Mhlaba Local Municipality area disagreed with the closure of the Fort Beaufort landfill because of what the researcher assumed to be a lack of general environmental awareness and because of their vulnerability to poverty. Research findings also highlight that waste reclamation can be considered as a viable option to minimize waste at landfills and waste reclaimers have shown an increasing interest and commitment to being trained formally to continue reclamation work. This study has suggested disadvantages in rural landfill closure, without feasible alternatives. Focus must move away from extending waste collection and closing down landfills and instead improve final disposal and initiating minimisation- recycling programs as part of their strategies through the formation of waste cooperatives. This research suggests formalizing and controlling waste recovery to cater for the immediate and most basic needs of the poor. The recommendations will hopefully influence thinking about waste management policy planning and implementation in general, and be of service to furthering Raymond Mhlaba Local Municipality achieve goals of sustainable employment creation and poverty alleviation.
- Full Text:
- Date Issued: 2018
Environmental management in military activities of the South African National Defence Force
- Authors: Magagula, Hezekiel Bheki
- Date: 2016
- Subjects: South Africa -- South African Defence Force Military bases -- Environmental aspects Hazardous waste site remediation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5927 , vital:29430
- Description: This thesis presents research findings on current environmental management practices used by the South African National Defence Force (SANDF). Two case studies are presented; the first is the Grahamstown Military Installation (6 South African Infantry Battalion) and the second the South African Army Combat Training Centre (42 Brigade). A combination of three sampling techniques, namely, the stratified, purposive and link-tracing (snowball) samplings were employed and structured questionnaires and semi-structured interviews with key SANDF officials were used as primary data. In addition, secondary data sources in the form of inter alia the first and second editions of the Environmental Management Plan for Defence (2001 & 2008 respectively); the development and implementation of environmental education and training in the military: a joint United States-Republic of South Africa Environmental Working Group Project (2003); Overarching Strategic Statement for 2011; Integrated Environmental Management Information Series: Linking Environmental Impact Assessment and Environmental Management Systems (2004); The Department of Defence Strategic Plan (2010): Republic of South Africa and the South African Defence Review (2012) were studied. In addition, field observations were also carried out within the two military installations training areas between July, 2011 and November, 2013. Primary data on the conditions of training areas, waste removal after training exercises, pollution prevention measures, and rehabilitation efforts to restore degraded training ranges were collected. Furthermore, composite surface sediment samples and water samples were collected for analysis. A total of fifty-six surface sediments and thirty water samples were analysed for the concentrations of heavy metals using the ICP-MS. These attitudes and perceptions are predominantly positive. Statistical analysis (ANOVA) did not reveal any significant differences in responses, especially, between military ranks. However, sporadic significant differences were found in five of the statements in the questionnaire from respondents with different service periods. Furthermore, the emphasis placed on environmental protection within defence force activities worldwide has compelled the South African Department of Defence and Military Veterans (DoDMV) to regulate the management of the environment within its properties. Yet, these efforts have faced numerous challenges ranging from financial to human resource deficiencies. It was found that environmental management practices and programmes at different military installations vary significantly. Consequently, six environmental management programmes were identified at South African Army Combat Training Centre, while only one environmental management programme was identified at Grahamstown Military Installation. This programme is a collaborative effort between the SANDF/DoDMV and the Department of Water Affairs and Sanitation to eradicate invasive alien plant species. In the light of the analysis of official documents and interviews with respondents, it was established that the DoDMV does not have a budget for environmental management services and environmental management is yet to be incorporated into formal military training programmes. There is a severe shortage of environmentally qualified and knowledgeable personnel within the SANDF. Subsequently, all these drawbacks lead to the failure of the implementation of the Defence Force’s Environmental Management System (EMS) and inadequate management of the environment at military installations of the SANDF. Consequently, these challenges have severely compromised the commitment of the SANDF to honour its environmental management obligations. Such deficiencies tend to undermine the sustainable utilisation of the national assets entrusted to the Defence Force. Therefore, this thesis argues that environmental management programmes for the SANDF are based on a very weak foundation. This thesis proposes an ideal model for the successful implementation of the EMS and management of the environment at SANDF military installations. The analysis of water and soil samples led to the identification and quantification of heavy mental pollutants. The concentrations of heavy metals in water samples were varying between <0.01 to <0.05mg/l, but generally constant. Thus, no significant or meaningful statistical results were obtained. Pearson’s correlation coefficient was used to analyse the concentrations of heavy metals obtained in the sediment samples.
- Full Text:
- Date Issued: 2016
- Authors: Magagula, Hezekiel Bheki
- Date: 2016
- Subjects: South Africa -- South African Defence Force Military bases -- Environmental aspects Hazardous waste site remediation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5927 , vital:29430
- Description: This thesis presents research findings on current environmental management practices used by the South African National Defence Force (SANDF). Two case studies are presented; the first is the Grahamstown Military Installation (6 South African Infantry Battalion) and the second the South African Army Combat Training Centre (42 Brigade). A combination of three sampling techniques, namely, the stratified, purposive and link-tracing (snowball) samplings were employed and structured questionnaires and semi-structured interviews with key SANDF officials were used as primary data. In addition, secondary data sources in the form of inter alia the first and second editions of the Environmental Management Plan for Defence (2001 & 2008 respectively); the development and implementation of environmental education and training in the military: a joint United States-Republic of South Africa Environmental Working Group Project (2003); Overarching Strategic Statement for 2011; Integrated Environmental Management Information Series: Linking Environmental Impact Assessment and Environmental Management Systems (2004); The Department of Defence Strategic Plan (2010): Republic of South Africa and the South African Defence Review (2012) were studied. In addition, field observations were also carried out within the two military installations training areas between July, 2011 and November, 2013. Primary data on the conditions of training areas, waste removal after training exercises, pollution prevention measures, and rehabilitation efforts to restore degraded training ranges were collected. Furthermore, composite surface sediment samples and water samples were collected for analysis. A total of fifty-six surface sediments and thirty water samples were analysed for the concentrations of heavy metals using the ICP-MS. These attitudes and perceptions are predominantly positive. Statistical analysis (ANOVA) did not reveal any significant differences in responses, especially, between military ranks. However, sporadic significant differences were found in five of the statements in the questionnaire from respondents with different service periods. Furthermore, the emphasis placed on environmental protection within defence force activities worldwide has compelled the South African Department of Defence and Military Veterans (DoDMV) to regulate the management of the environment within its properties. Yet, these efforts have faced numerous challenges ranging from financial to human resource deficiencies. It was found that environmental management practices and programmes at different military installations vary significantly. Consequently, six environmental management programmes were identified at South African Army Combat Training Centre, while only one environmental management programme was identified at Grahamstown Military Installation. This programme is a collaborative effort between the SANDF/DoDMV and the Department of Water Affairs and Sanitation to eradicate invasive alien plant species. In the light of the analysis of official documents and interviews with respondents, it was established that the DoDMV does not have a budget for environmental management services and environmental management is yet to be incorporated into formal military training programmes. There is a severe shortage of environmentally qualified and knowledgeable personnel within the SANDF. Subsequently, all these drawbacks lead to the failure of the implementation of the Defence Force’s Environmental Management System (EMS) and inadequate management of the environment at military installations of the SANDF. Consequently, these challenges have severely compromised the commitment of the SANDF to honour its environmental management obligations. Such deficiencies tend to undermine the sustainable utilisation of the national assets entrusted to the Defence Force. Therefore, this thesis argues that environmental management programmes for the SANDF are based on a very weak foundation. This thesis proposes an ideal model for the successful implementation of the EMS and management of the environment at SANDF military installations. The analysis of water and soil samples led to the identification and quantification of heavy mental pollutants. The concentrations of heavy metals in water samples were varying between <0.01 to <0.05mg/l, but generally constant. Thus, no significant or meaningful statistical results were obtained. Pearson’s correlation coefficient was used to analyse the concentrations of heavy metals obtained in the sediment samples.
- Full Text:
- Date Issued: 2016
An exploration of perceptions, adaptive capacity and food security in the Ngqushwa local municipality, Eastern Cape, South Africa
- Authors: Mazinyo, Sonwabo Perez
- Date: 2015
- Subjects: Food security -- South Africa -- Eastern Cape Climatic changes -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/19043 , vital:40107
- Description: Approximately sixty percent of Africans depend on rainfed agriculture for their livelihoods. South Africa is evidenced to be susceptible to inclement climate which impacts on rural livelihoods as well as on farming systems. While South Africa is considered to be food sufficient, it is estimated that approximately 35percent of the population is vulnerable to food insecurity. Therefore with the application of surveys and interviews this study investigates the factors influencing household, subsistence and small-scale farmer perceptions of vulnerability to climate variability as well as the determinants of adaptive capacity. A sample of 308 households is surveyed and four focus group discussions are administered in Ngqushwa Local Municipality as a case study. Furthermore, the study also focuses on the biophysical changes or factors (scientific analysis of the prevailing climatic regimes–rainfall trends); the interrogation of the impact of food systems on both food prices as well as its implications on food sovereignty. The study also interrogates the relationship between crop yield and rainfall data over a 30-year period. Therefore the study adopts a mixed method approach to ensure triangulation. The study finds that rural communities are able to perceive climate variability and its related changes as well as its negative impact on crop production, food access and availability. The perceived rainfall trends also corroborate this Pearson product-moment correlation coefficient reveals that there is a strong correlation between crop yields and rainfall (r = 0.69). Meteorological analyses also show that the rainfall trend has been significantly variable over 112 years (1900 - 2011) with several dry spells threatening the subsistence and small-scale farmers’ sustainable livelihoods. The food systems pose threats to food safety, food security and historical food sovereignty for the rural community of Ngqushwa Local Municipality. Adaptive capacity is greatly impaired by the lack of co-ordination of adaptation strategies, which communally benefit the majority of the farming respondents in the study area. Therefore vulnerability to climate variability impacts on the ability of the respondents to achieve food security. The study also finds that there is perceived competition between the farmers and wild life for the natural resources. The respondents’ perception is that climate variability and change is responsible for such competition. The study recommends that the national, provincial and local governments must foster a new food production model that is not based on the agro-business model and its attendant technologies but on one that is based on robust agro-ecological farming techniques which enhance adaptive capacity; which foster food safety; which promote food sovereignty; and which reduce vulnerability in a sustainable manner. Given the extent of climate variability in the study area the restoration of the NLM weather station infrastructure can also aid the farmers in taking advantage of a robust early warning system for better estimation of climate trends which enhance crop production.
- Full Text:
- Date Issued: 2015
- Authors: Mazinyo, Sonwabo Perez
- Date: 2015
- Subjects: Food security -- South Africa -- Eastern Cape Climatic changes -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/19043 , vital:40107
- Description: Approximately sixty percent of Africans depend on rainfed agriculture for their livelihoods. South Africa is evidenced to be susceptible to inclement climate which impacts on rural livelihoods as well as on farming systems. While South Africa is considered to be food sufficient, it is estimated that approximately 35percent of the population is vulnerable to food insecurity. Therefore with the application of surveys and interviews this study investigates the factors influencing household, subsistence and small-scale farmer perceptions of vulnerability to climate variability as well as the determinants of adaptive capacity. A sample of 308 households is surveyed and four focus group discussions are administered in Ngqushwa Local Municipality as a case study. Furthermore, the study also focuses on the biophysical changes or factors (scientific analysis of the prevailing climatic regimes–rainfall trends); the interrogation of the impact of food systems on both food prices as well as its implications on food sovereignty. The study also interrogates the relationship between crop yield and rainfall data over a 30-year period. Therefore the study adopts a mixed method approach to ensure triangulation. The study finds that rural communities are able to perceive climate variability and its related changes as well as its negative impact on crop production, food access and availability. The perceived rainfall trends also corroborate this Pearson product-moment correlation coefficient reveals that there is a strong correlation between crop yields and rainfall (r = 0.69). Meteorological analyses also show that the rainfall trend has been significantly variable over 112 years (1900 - 2011) with several dry spells threatening the subsistence and small-scale farmers’ sustainable livelihoods. The food systems pose threats to food safety, food security and historical food sovereignty for the rural community of Ngqushwa Local Municipality. Adaptive capacity is greatly impaired by the lack of co-ordination of adaptation strategies, which communally benefit the majority of the farming respondents in the study area. Therefore vulnerability to climate variability impacts on the ability of the respondents to achieve food security. The study also finds that there is perceived competition between the farmers and wild life for the natural resources. The respondents’ perception is that climate variability and change is responsible for such competition. The study recommends that the national, provincial and local governments must foster a new food production model that is not based on the agro-business model and its attendant technologies but on one that is based on robust agro-ecological farming techniques which enhance adaptive capacity; which foster food safety; which promote food sovereignty; and which reduce vulnerability in a sustainable manner. Given the extent of climate variability in the study area the restoration of the NLM weather station infrastructure can also aid the farmers in taking advantage of a robust early warning system for better estimation of climate trends which enhance crop production.
- Full Text:
- Date Issued: 2015
An exploration of perceptions, adaptive capacity and food security in the Ngqushwa local municipality, Eastern Cape, South Africa
- Mazinyo, Sonwabo Perez, Zhou, Leocadia
- Authors: Mazinyo, Sonwabo Perez , Zhou, Leocadia
- Date: 2015
- Subjects: Food security -- South Africa -- Eastern Cape Climatic changes -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/19032 , vital:40106
- Description: Approximately sixty percent of Africans depend on rainfed agriculture for their livelihoods. South Africa is evidenced to be susceptible to inclement climate which impacts on rural livelihoods as well as on farming systems. While South Africa is considered to be food sufficient, it is estimated that approximately 35% of the population is vulnerable to food insecurity. Therefore with the application of surveys and interviews this study investigates the factors influencing household, subsistence and small-scale farmer perceptions of vulnerability to climate variability as well as the determinants of adaptive capacity. A sample of 308 households is surveyed and four focus group discussions are administered in Ngqushwa Local Municipality as a case study. Furthermore, the study also focuses on the biophysical changes or factors (scientific analysis of the prevailing climatic regimes–rainfall trends); the interrogation of the impact of food systems on both food prices as well as its implications on food sovereignty. The study also interrogates the relationship between crop yield and rainfall data over a 30-year period. Therefore the study adopts a mixed method approach to ensure triangulation. The study finds that rural communities are able to perceive climate variability and its related changes as well as its negative impact on crop production, food access and availability. The perceived rainfall trends also corroborate this Pearson product-moment correlation coefficient reveals that there is a strong correlation between crop yields and rainfall (r = 0.69). Meteorological analyses also show that the rainfall trend has been significantly variable over 112 years (1900 - 2011) with several dry spells threatening the subsistence and small-scale farmers’ sustainable livelihoods. The food systems pose threats to food safety, food security and historical food sovereignty for the rural community of Ngqushwa Local Municipality. Adaptive capacity is greatly impaired by the lack of co-ordination of adaptation strategies, which communally benefit the majority of the farming respondents in the study area. Therefore vulnerability to climate variability impacts on the ability of the respondents to achieve food security. The study also finds that there is perceived competition between the farmers and wild life for the natural resources. The respondents’ perception is that climate variability and change is responsible for such competition. The study recommends that the national, provincial and local governments must foster a new food production model that is not based on the agro-business model and its attendant technologies but on one that is based on robust agro-ecological farming techniques which enhance adaptive capacity; which foster food safety; which promote food sovereignty; and which reduce vulnerability in a sustainable manner. Given the extent of climate variability in the study area the restoration of the NLM weather station infrastructure can also aid the farmers in taking advantage of a robust early warning system for better estimation of climate trends which enhance crop production.
- Full Text:
- Date Issued: 2015
- Authors: Mazinyo, Sonwabo Perez , Zhou, Leocadia
- Date: 2015
- Subjects: Food security -- South Africa -- Eastern Cape Climatic changes -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/19032 , vital:40106
- Description: Approximately sixty percent of Africans depend on rainfed agriculture for their livelihoods. South Africa is evidenced to be susceptible to inclement climate which impacts on rural livelihoods as well as on farming systems. While South Africa is considered to be food sufficient, it is estimated that approximately 35% of the population is vulnerable to food insecurity. Therefore with the application of surveys and interviews this study investigates the factors influencing household, subsistence and small-scale farmer perceptions of vulnerability to climate variability as well as the determinants of adaptive capacity. A sample of 308 households is surveyed and four focus group discussions are administered in Ngqushwa Local Municipality as a case study. Furthermore, the study also focuses on the biophysical changes or factors (scientific analysis of the prevailing climatic regimes–rainfall trends); the interrogation of the impact of food systems on both food prices as well as its implications on food sovereignty. The study also interrogates the relationship between crop yield and rainfall data over a 30-year period. Therefore the study adopts a mixed method approach to ensure triangulation. The study finds that rural communities are able to perceive climate variability and its related changes as well as its negative impact on crop production, food access and availability. The perceived rainfall trends also corroborate this Pearson product-moment correlation coefficient reveals that there is a strong correlation between crop yields and rainfall (r = 0.69). Meteorological analyses also show that the rainfall trend has been significantly variable over 112 years (1900 - 2011) with several dry spells threatening the subsistence and small-scale farmers’ sustainable livelihoods. The food systems pose threats to food safety, food security and historical food sovereignty for the rural community of Ngqushwa Local Municipality. Adaptive capacity is greatly impaired by the lack of co-ordination of adaptation strategies, which communally benefit the majority of the farming respondents in the study area. Therefore vulnerability to climate variability impacts on the ability of the respondents to achieve food security. The study also finds that there is perceived competition between the farmers and wild life for the natural resources. The respondents’ perception is that climate variability and change is responsible for such competition. The study recommends that the national, provincial and local governments must foster a new food production model that is not based on the agro-business model and its attendant technologies but on one that is based on robust agro-ecological farming techniques which enhance adaptive capacity; which foster food safety; which promote food sovereignty; and which reduce vulnerability in a sustainable manner. Given the extent of climate variability in the study area the restoration of the NLM weather station infrastructure can also aid the farmers in taking advantage of a robust early warning system for better estimation of climate trends which enhance crop production.
- Full Text:
- Date Issued: 2015
The characterisation of an openwork block deposit, northern buttress, Vesleskarvet, Dronning Maud Land, Antarctica.
- Authors: Hansen, Christel Dorothee
- Date: 2014
- Subjects: Formations (Geology) -- Antarctica -- Queen Maud Land , Geology, Structural -- Antarctica -- Queen Maud Land , Weathering -- Antarctica -- Queen Maud Land , Climatic changes -- Antarctica -- Queen Maud Land , Physical geography -- Antarctica -- Queen Maud Land , Paleoclimatology -- Antarctica
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4878 , http://hdl.handle.net/10962/d1013138
- Description: Investigating openwork block accumulation has the potential to further our understanding of rock weathering, the control of geological structure on landforms, the production of substrates for biological colonisation and the impacts of climate change on landform development and dynamics. Various models for the development of these landforms have been proposed. This includes in situ weathering, frost heave and wedging. Furthermore, it has been suggested that cold-based ice has the potential to preserve these features rather than to obliterate them. Blocky deposits are also frequently used as proxy evidence for interpreting palaeoclimates. The morphology and processes acting on a blockfield located on the Northern Buttress of the Vesleskarvet Nunataks, Dronning Maud Land, Antarctica (2°W, 71°S) were investigated and characterised. Given block dimensions and orientations that closely resembled the parent material and only small differences in aspect related characteristics observed, the blockfield was found to be autochthonous with in situ block production and of a young (Holocene) age. Small differences in rock hardness measurements suggest some form of aspect control on rock weathering. South-facing sides of clasts were found to be the least weathered. In comparison, consistently low rock hardness rebound values for the north-facing aspects suggest that these are the most weathered sides. Additional indicators of weathering, such as flaking and pitting, support analyses conducted for rock hardness rebound values. Solar radiation received, slope gradients and snow cover were found to influence weathering of clasts across the study site. Furthermore, ambient temperatures and wind speed significantly influenced near-surface ground temperatures dynamics. However, the lack of a matrix and paucity of fine material in textural analyses suggest a limited weathering environment. It is suggested that the retreat of the Antarctic ice sheet during the last LGM led to unloading of the surface, causing dilatation and subsequent fracturing of the bedrock along pre-existing joints, leading to in situ clast supply. Subsequent weathering and erosion along other points or lines of weakness then yielded fines and slight edge rounding of clasts.
- Full Text:
- Date Issued: 2014
- Authors: Hansen, Christel Dorothee
- Date: 2014
- Subjects: Formations (Geology) -- Antarctica -- Queen Maud Land , Geology, Structural -- Antarctica -- Queen Maud Land , Weathering -- Antarctica -- Queen Maud Land , Climatic changes -- Antarctica -- Queen Maud Land , Physical geography -- Antarctica -- Queen Maud Land , Paleoclimatology -- Antarctica
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4878 , http://hdl.handle.net/10962/d1013138
- Description: Investigating openwork block accumulation has the potential to further our understanding of rock weathering, the control of geological structure on landforms, the production of substrates for biological colonisation and the impacts of climate change on landform development and dynamics. Various models for the development of these landforms have been proposed. This includes in situ weathering, frost heave and wedging. Furthermore, it has been suggested that cold-based ice has the potential to preserve these features rather than to obliterate them. Blocky deposits are also frequently used as proxy evidence for interpreting palaeoclimates. The morphology and processes acting on a blockfield located on the Northern Buttress of the Vesleskarvet Nunataks, Dronning Maud Land, Antarctica (2°W, 71°S) were investigated and characterised. Given block dimensions and orientations that closely resembled the parent material and only small differences in aspect related characteristics observed, the blockfield was found to be autochthonous with in situ block production and of a young (Holocene) age. Small differences in rock hardness measurements suggest some form of aspect control on rock weathering. South-facing sides of clasts were found to be the least weathered. In comparison, consistently low rock hardness rebound values for the north-facing aspects suggest that these are the most weathered sides. Additional indicators of weathering, such as flaking and pitting, support analyses conducted for rock hardness rebound values. Solar radiation received, slope gradients and snow cover were found to influence weathering of clasts across the study site. Furthermore, ambient temperatures and wind speed significantly influenced near-surface ground temperatures dynamics. However, the lack of a matrix and paucity of fine material in textural analyses suggest a limited weathering environment. It is suggested that the retreat of the Antarctic ice sheet during the last LGM led to unloading of the surface, causing dilatation and subsequent fracturing of the bedrock along pre-existing joints, leading to in situ clast supply. Subsequent weathering and erosion along other points or lines of weakness then yielded fines and slight edge rounding of clasts.
- Full Text:
- Date Issued: 2014
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