Causes Of Climate Variability Research Articles

The Wet: Shifting Seasons, Climate Change and Natural Cycles in Cape York Peninsula, Queensland

ABSTRACTLand managers in Cape York Peninsula, far northeast Australia, hold different ideas around the causes of climate variability. Understandings of changes in climate are underpinned by particular environmental knowledges, values, and practices. These understandings are articulated in the context of the wet season, when land managers must adapt to the changing duration and intensity of the rainfall each year. The wet and dry seasons function as cyclical agents that precipitate different modes of living and working among different groups of people in Cape York. Where settler‐descended cattle graziers tend to frame climate variability as ‘natural cycles’, Aboriginal rangers link climate variability to anthropogenic climate change. The tendency among Aboriginal rangers to link these changes to anthropogenic climate change is a result of the interpenetration of a Western scientific land management model with an Aboriginal land management model in the formal co‐management of protected areas. From this context, a ‘spatial vernacular’ of interculturally produced climate‐related knowledge emerges. The explanatory models different land managers draw on to understand climate variation in relation to seasonal water, changes to the wet season, and the increased frequency of extreme weather events are linked to their livelihoods, lifeways, and the forms of environmental knowledge they value.

The role of integrated watershed management in climate change adaptation for small-scale farmers in Southwest Ethiopia

Climate change severely affects smallholder farmers in developing countries such as Ethiopia. To overcome the impacts, the government of Ethiopia has been undertaking a massive adaptation programs including integrated watershed management practices. However, there is a limited understanding of climate change, adaptation strategies, and the effect and acceptance of the implemented techniques. The objective of this study was to assess climate variability, farmers’ climate change adaptation strategies, and the role of watershed management in climate change adaptation. A multi-stage sampling technique was used to select 255 household heads from three rural kebeles (lowest administrative unit of government) in high, mid, and low-elevation areas. The household survey, focus group discussion, and key informant interview record were used to collect data. In addition, long term meteorology record was used. Data were analyzed using descriptive statistics and a multinomial logit model. The results showed that more than 80% of the farmers, in each elevation, perceived climate variability such as increasing temperature and rainfall fluctuations. The perceived variability is more pronounced in the low-elevation areas. The meteorology record also showed fluctuation in rainfall. About 90% of respondents in each elevation area perceived population pressure, cultivation, and deforestation as the major causes of climate variability. About 90% of respondents perceived crop yield decline due to climate variability. In drought years, crop yield and livestock production decline by ∼50% compared to the average year. Adjustment of crop planting time, crop diversification, selling household assets, participating in off-farm activities, and using government aid were practiced as climate change adaptation measures. About 70% of farmers perceived the positive role of watershed management in climate change adaptation. On average, 36–43% of the farmers in the study area participated in watershed management activities such as the construction of bunds and tree planting, which assist in coping with climate variability impacts. Farm size, sex, education, and farming experience positively and significantly affect the adaptation practices of the farmers. Policymakers and practitioners need to consider the issues related to climate variability and watershed management as a strategy for climate change adaptation. Policy intervention by the Federal government on sustainable watershed management and rural livelihood strategies could assist in sustainable environmental management and climate change adaptation.

ASSESSMENT OF THE PERCEPTION OF CLIMATE VARIABILITY AND ITS EFFECT ON FOOD CROP PRODUCTION IN BAMA LOCAL GOVERNMENT AREA OF BORNO STATE, NIGERIA

The study assessed food crop farmer’s perception of climate variability and its effects on food crop production in Bama LGA Borno State, Nigeria. Multi stage sampling was used in drawing 100 respondents for this study. Information was collected using structured questionnaires. Both descriptive and inferential statistics were used to analyze the data. Descriptive statistics used includes frequencies, means and percentages. The inferential statistics used was multiple regressions model. The result revealed that majority of 71% where male and dominated food crop production, 76% were also married. Furthermore, 56% had 5-8 household members. 20% had tertiary education, while 43% had primary education. The result revealed that 45% had 5-8ha of land for food crop production. An overwhelming majority of 90% perceived those gases released from factories/industries and auto mobile ranked 1st as responsible for causing climate variability. 87% ranked deforestation as 2nd cause of climate variability, while 10% ranked traditional neglect as the 12th and least cause of climate variability. For the effect of climate variability on food crop production, majority of 95% ranked decrease in crop yield as the 1st effect of climate variability, 94% ranked reduced income from crop yield as the 2nd effect of climate variability. The least perceived effect of climate variability was reduced cover crop which was ranked by 50% of the respondents in 14th place. The result of factors influencing the perceived effect of climate variability was positive and significant at P≤0.05 and P≤0.01, respectively. The coefficient of gender was positive and significant at P≤0.05 which implies that every male had higher chance of being affected by the effect of climate variability than their female counter part. The study recommended more campaign on climate variability for rural farmers. Also, government, non-governmental organizations and policy makers should create an avenue where more female farmers could participate and have access to arable land.

Impacts and Adaptation Strategies on Climate Variability and Change of Coastal Communities along Banate Bay

People living in the coastal communities are first and foremost vulnerable to climate change, both socio-economically and environmentally. This paper discusses the adaptation strategies used by the local people of Banate Bay in combating the impacts of climate variability and change. A questionnaire was constructed and administered to the residents of the different communities along Banate Bay. Results showed that majority of the respondents are males, aged 30-40 years, married with no education, with less than five family members with the income of less than P50, 000 per annum and have stayed in the community for ten years but less than 20 years. In terms of respondents’ perceptions on climate variability and change, all categories are rated and interpreted as strongly agree, which means that the respondents are knowledgeable and aware of the situation in relation to climate change and variability. On the causes of climate change variability and change the respondents were highly aware; this indicates that the respondents are knowledgeable of the causes of climate variability and change. Further, the study implies that people living in the coastal areas of Banate Bay are aware of the impacts of climate variability and change. The residents are highly aware of the adaptation strategies which will make them resilient to climate variability and change.

Late Holocene climatic variability in Subarctic Canada: Insights from a high-resolution lake record from the central Northwest Territories.

We examined late Holocene (ca. 3300 yr BP to present-day) climate variability in the central Northwest Territories (Canadian Subarctic) using a diatom and sedimentological record from Danny’s Lake (63.48ºN, 112.54ºW), located 40 km southwest of the modern-day treeline. High-resolution sampling paired with a robust age model (25 radiocarbon dates) allowed for the examination of both lake hydroecological conditions (30-year intervals; diatoms) and sedimentological changes in the watershed (12-year intervals; grain size records) over the late Holocene. Time series analysis of key lake ecological indicators (diatom species Aulacoseira alpigena, Pseudostaurosira brevistriata and Achnanthidium minutissimum) and sedimentological parameters, reflective of catchment processes (coarse silt fraction), suggests significant intermittent variations in turbidity, pH and light penetration within the lake basin. In the diatom record, we observed discontinuous periodicities in the range of ca. 69, 88–100, 115–132, 141–188, 562, 750 and 900 years (>90% and >95% confidence intervals), whereas the coarse silt fraction was characterized by periodicities in the >901 and <61-year range (>95% confidence interval). Periodicities in the proxy data from the Danny’s Lake sediment core align with changes in total solar irradiance over the past ca. 3300 yr BP and we hypothesize a link to the Suess Cycle, Gleissberg Cycle and Pacific Decadal Oscillation via occasional inland propagation of shifting air masses over the Pacific Ocean. This research represents an important baseline study of the underlying causes of climate variability in the Canadian Subarctic and provides details on the long-term climate variability that has persisted in this region through the past three thousand years.

Perceived synergy between deforestation and/or forest degradation and climate variability and change in the Ejisu-Juaben Municipality, Ghana

AbstractPerceptual studies on the environment and natural resources are important, if unsustainable use of these resources is to be abated. This paper unravels the hitherto unknown drivers of deforestation and/or forest degradation, and the causes of climate variability and change (CVC), by assessing their synergy based on participants self-reported cases in the Ejisu-Juaben Municipality, Ashanti Region, Ghana. Drawing on the criterion and simple random sampling techniques to sample 360 respondents from 4 different communities and adopting the empiricist paradigm to derive trends and patterns in responses, this study demonstrated the bi-directional association between forest degradation and climate change. Results suggested that participants across the various socio-economic status fields were adequately informed, and knowledgeable about changes in climatic variables. Participants’ perceived the loss of forest, extinction of tree species and changing forest to savanna lands as indications of deforestation. Respondents with basic education and/or high school education adequately predicted that CVC factors influence decisions regarding forest removal compared with the uneducated. Removing one hectare of vegetation cover change per year (being it an increase or decrease in the area) (1 ha/year+/-/) or about three hectares (3 ha/year+/-), at a rate of 60%, and forest cover at rates of 57% were perceived as significant drivers of CVC. In recommendation, policies targeted at reducing forest degradation and deforestation and contributing to the fight against CVC in the Municipality should henceforth take into consideration the opinions of the indigenes in addition to scientific evidence in order to ensure the effectiveness of such policies.

Views from the Antipodes: the ‘forest influence’ debate in the Australian and New Zealand press, 1827–1956

ABSTRACTDuring the late nineteenth and early twentieth centuries the newspaper press was the leading public forum in the protracted debate over the supposed climatological effects of forests. Journalists acted as key intermediaries in the dispute between parliament, science and the public. The press was also a powerful pressure group in its own right. Newspaper reports contextualised the forest influence issue by linking it to three interrelated concerns: the cause of climate variability and change, the environmental impact of humans, and the need for forest conservation. This paper examines the role of the Australasian press in the debate along with the changing nature of the arguments and some aspects of its historical geography. Results are summarised from a systematic longitudinal survey that analysed over 1400 articles relevant to the forest influence debate published in 141 Australian and New Zealand newspapers between the years 1827 and 1956. The study concludes that the press was instrumental in politicising all sides of the debate and later in perpetuating it in popular culture long after both governments and institutional science had dismissed the idea that humans could alter climates by manipulating forests.

Farmers’ Knowledge and Perceptions to Climate Variability in North West Cameroon

&lt;p&gt;&lt;em&gt;Global climate variability exerts negative impacts especially on agriculture-dependent economies. Contemporary climate modelling suggests that farming households in developing countries will bear the greatest brunt from climate variability. However, information on farmers’ knowledge and perceptions to climate variability and possible influence on household adaptation strategies especially in developing countries is scarce. This paper assesses farmers’ knowledge and perceptions to climate variability, based on a case study from the North Western region of Cameroon.&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;A structured questionnaire was used in a &lt;/em&gt;&lt;em&gt;cross sectional survey to collect data on knowledge and perceptions to climate variability, from 272 farmers in six randomly selected villages in the North West Region of Cameroon. Data was analyzed using the Statistical Package for Social Sciences (SPSS version 17.0) and Excel.&lt;/em&gt;&lt;em&gt; Over 97% of respondents demonstrated contextual knowledge of climate variability. Perceptions to the causes of climate variability were quite diverse. While 20% of respondents had no idea, around 40% attributed climate variability to human activities, 20% to industrial activities and 20% to the anger of the gods. &lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;We conclude with the need for climate variability research to increasingly pay attention to farmers’ indigenous knowledge and perceptions as prerequisites to building resilience amongst farmers in Cameroon.&lt;/em&gt;&lt;/p&gt;

Climate Variability and Change, Impacts and Adaptation Strategies in Dutsin-Ma Local Government Area of Katsina State, Nigeria

This paper aimed at examining local peoples’ perceptions on climate variability and change and strategies adopted in combating the impacts of the changes in Dutsin-Ma Local Government Area of Katsina State. A total of 242 questionnaires were administered to households’ heads in the eleven wards of the Local Government Area. Descriptive statistics such as frequency distribution, percentage and mean scores were used in data analysis. The result revealed that majority of the local people have a very good knowledge of climate variability and change in terms of higher temperature, higher rainfall intensity and variability, and the occurrence of extreme weather events such as flood and drought. Findings also revealed that community disobeying God, deforestation, bush burning, combustion of fossil fuel and pollution were the major causes of climate variability and change as perceived by the respondents. The most significant impacts of climate variability and change as perceived by the local people were decline in crop yields, decline in forest resources, water shortages and decrease in soil fertility. These impacts have resulted to rural-urban migration in the area. Sustainable adaptation strategies adopted by the local people are water harvesting, the use of fertilizer/animals dung to improve crop yield, irrigation agriculture, planting of crop varieties and drought resistant crops. It is recommended that strategies for combating impacts of climate variability and change should take into account the traditional and religious beliefs of the people; and there is need to educate the local people to appreciate the scientific basis of climate variability and change.

Analysis of climate variability in the Manas River Valley, North-Western China (1956–2006)

This paper examines the short-run climate variability (change in the levels of temperature and precipitation) with a focus on the Manas River Valley, North-Western China, over the past 50 years (1956 to 2006) using data collected from four meteorological stations. The results show that the annual mean temperature had a positive trend, with temperature increasing at 0.4 °C per decade. Application of the Mann-Kendall test revealed that the overall positive trend became statistically significant at the p = 0.95 level only after 1988. The increase in temperature was most marked in winter and spring (0.8 and 0.7 °C per decade, respectively), absent in summer and very small in autumn (0.1 °C per decade). Concerning precipitation, our results indicate a negative but not significant trend for the period between 1956 and 1982, while annual total precipitation tended to increase thereafter and the increase was mainly during the crop growing-season. Concerning variability in temperature and precipitation, the characteristic time scales were identified by application of wavelet analysis. For temperature the quasi-decadal variations were found on time scales between approximately 5 and 15 years, with a peak in wavelet variance on a time scale of 9 years. For precipitation, the most striking features were a precipitation increase (6.7 mm per decade) during the crop growing season. Irregularities and abrupt changes in both temperature and precipitation were more common at scales less than 10 years, indicating the complexity and uncertainty in the short-period climate variability. Possible causes of climate variability in the Manas River Valley may include anthropogenic factors such as intensive human activity and the expansion of both farmland and irrigation. Global climate variability might also have some impacts on the local climate variability; analyses of local and regional climate trends can better inform local adaptation actions for global impacts.

Climate variability, predictability and climate risks: a european perspective

The aim of climate research is to increase our knowledge about the nature of climate and the causes of climate variability and change. Increasing our understanding of the physical processes on various spatial and temporal scales will ultimately reduce uncertainty and improve our capabilities to predict climate on monthly to seasonal timescales and allow us to separate the anthropogenic and natural causes of long term climate change.

The climate of the Altiplano: observed current conditions and mechanisms of past changes

The large-scale controls on the climate of the South American Altiplano are investigated using local observations, reanalysis data and general circulation model experiments. The objective is to gain understanding of causes of climate variability and climate change by relating mechanisms that operate on timescales ranging from the intraseasonal to the glacial–interglacial. Our results suggest that, on all timescales, the climatic conditions on the Altiplano are closely related to the upper-air circulation, with an easterly zonal flow aloft favoring wet conditions and westerly flow causing dry conditions. Different factors influence the upper-air circulation on the different timescales. Intraseasonal variability is a reflection of the position and intensity of the Bolivian High, which is modulated by Rossby waves emanating from the midlatitude South Pacific. The annual cycle of dry winter and wet summer conditions is caused by the seasonal expansion of the equatorial easterlies in the upper troposphere, rather than direct insolation forcing over the Altiplano or moisture changes in the source area. Interannual variability is primarily related to changes in the mean zonal flow over the Altiplano, reflecting changes in meridional baroclinicity between tropical and subtropical latitudes, which in turn is a response to sea-surface temperature changes in the tropical Pacific. Orbitally forced changes in the land–sea contrast drive continental-scale circulation changes, which significantly alter the zonal flow over the Altiplano. On glacial–interglacial timescales, the contrast in heating between northern and southern hemispheres during the glacial leads to upper-air easterly anomalies throughout the tropics. On modern timescales the marked submonthly, seasonal and interannual changes of moisture over the Altiplano cannot be accounted for by moisture changes in the humid tropical lowlands. However, the model experiments suggest that cooler conditions during a glacial reduce moisture availability from the tropical lowlands, which counteracts the effect of the upper-level circulation, resulting in little overall change in precipitation. This observational and modeling analysis provides a physical framework for relating the mechanisms of both internal and forced climate change on the Altiplano on a wide range of timescales.

Agrometeorological adaptation strategies to increasing climate variability and climate change

This paper starts with summarizing the indications for climate change as they are reviewed in the most recent WMO global climate system reviews. There are indications in the paper for increasing climate variability in certain areas. Some of the principal causes of increasing climate variability and climate change (ICV & CC) are a mixture of external and internal factors to the climate system. Of changes over the past century, increases in greenhouse gases have probably been the most important cause of climate change. Continued warming of global climate is expected to occur if atmospheric greenhouse gases keep increasing, with global climate models projecting an increase in mean temperature by 1–3°C by 2100 a.d. Upon these general background trends interannual climate variability has operated. Volcanic eruptions that inject significant amounts of sulphate aerosols into the stratosphere cause a cooling of global climate in the order of 0.5°C for a period of 12–24 months. The ENSO (El Niño/Southern Osciallation) is the major cause of climate variability on seasonal to interannual time scales. Since 1976 El Niño episodes of the Southern Oscillation have increased in frequency, and become more extreme. There has yet been little analysis of short-term extreme events, such as high intensity rainfall, tropical storms, tornadoes, high winds, extreme temperatures and droughts to show if the frequency and intensity of these have changed. However, for some of these events in some areas an increase is occurring while in other areas no changes have currently occurred. Changes in extremes cause significant impacts on agriculture. Strategies to fight slower variations have already been widely proposed and require application. Agrometeorologists can assist the agricultural community in developing strategies to adapt to ICV & CC that should be validated on-farm for improved extension advisories, together with farmers. To enhance adaptation and promote sustainable development, strategic planning studies for assessment of natural resources, technological change and innovation are required to increase productivity, with sustainable economic growth that preserves finite natural resources. The ten most essential agricultural umbrella projects with agrometeorological priority components in the literature that either modify the consequences of ICV & CC and/or mitigate their causes have been selected. The Commission for Agricultural Meteorology has pledged to guide the implementation of projects that assist adaptation strategies to ICV & CC within the WMO Agrometeorological Programme.

THE USE OF CLIMATE INFORMATION IN COMMERCIAL AGRICULTURE IN SOUTHEAST AFRICA

The El Niño–Southern Oscillation (ENSO) phenomenon is one of the predominant causes of climate variability in southern and eastern Africa. It thus has a considerable impact on agriculture in the region. This paper will define the ENSO signal in terms of its relevance to commercial agriculture in southern and eastern Africa. The ENSO signal is often generalized in terms of either a drought year or heavy rains over a season. Analysis reveals, however, that the ENSO signal shows great variability both within and between events with obvious implications for the use of climate information by potential users. Information requirements also vary substantially from user to user. The ENSO effect is first isolated through superposed epoch analysis of rainfall data on a variety of time scales. This analysis clearly shows the variability of the signal. For example, ENSO impacts the reliability of the start of the rains in Zambia, whereas in southern Tanzania ENSO has a greater influence on the seasonal distribution of rainfall. The significance of these variations for commercial agriculture is very much related to the particular operation that is affected. Semi-structured interviews with commercial operators in Swaziland were used to assess the impact that climate variability might have on their activities. Focused interviews produced historical time lines to illustrate the influence on decisions that climate information could have. The results show that the use of climate information varies considerably between companies. A preliminary assessment highlights certain constraints on use, primarily in terms of forecast timing and scale. Recommendations for further work include a thorough exploration of the constraints issue as well as economic assessment of the perceived value of forecasts, including how these estimates are reached. [Key words: El Niño–Southern Oscillation, Africa-southeastern, climate variability, agriculture.]

The relationship between the simulated climatic variability modes of the tropical Atlantic

Two main modes of climatic variability occur in the tropical Atlantic Ocean at inter-annual time-scales: the equatorial mode, similar to the El Nino phenomenon in the Pacific Ocean, and the meridional mode, or dipole-like mode, with no Pacific counterpart. The Atlantic equatorial mode is characterized by the occurrence of alternating warm and cold episodes at the equator, on the eastern side of the basin. These events are associated with abnormal variations in the zonal equatorial slope of the thermocline. The meridional mode is characterized by an inter-hemispheric gradient in the sea-surface temperature (SST). The mean position of the Inter-tropical Convergence Zone (ITCZ) separates positive and negative SST signals. It was recently shown with observational indices that there is significant correlation between these two climatic modes of variability. This study goes one step further, by using a multi-year numerical simulation, where an oceanic general circulation model is forced by the 1979-1993 ECMWF reanalysis. Model computed indices representing the two main modes of variability compare well with observations. The two inter-annual modes of variability are shown to have the same physics as the annual variability does, which is related to the latitudinal displacement of the ITCZ. Furthermore, it is suggested that the ocean dynamics (as opposed to thermodynamic processes) is the principal cause of climate variability in the region.

Comment [on “Unknowns about climate variability render treaty targets premature”

In a recent Forum piece that discusses climate variability (Eos, December 16, 1997), S. F. Singer claims that “a higher CO2 level may be less dangerous to the climate system than a lower one.” The basis for this reasoning is the observation that during the last Ice Age, CO2 levels (∼200 ppmV) were lower than pre‐Industrial Revolution Holocene levels (∼280 ppmV), yet the climate system was apparently more unstable than during the Holocene.Singer neglects to add that, in addition to CO2, other Ice Age global boundary conditions were very different from today's, notably larger continental ice sheets in the Northern Hemisphere, higher levels of aerosols, and colder sea‐surface temperatures. Climatic variations associated with these boundary conditions are not completely understood, but clearly singling out CO2 grossly oversimplifies the complexity of the climate system and the underlying causes of climate variability.