Risks of Pre-Monsoon Extreme Rainfall Events of Bangladesh: Is Anthropogenic Climate Change Playing a Role? (original) (raw)
Hydrology and Earth System Sciences Discussions
Anthropogenic climate change is likely to increase the frequency of extreme weather events in future. Previous studies have robustly shown how and where climate change has already changed the risks of weather extremes. However, developing countries have been somewhat underrepresented in these studies, despite high vulnerability and limited capacities to adapt. How additional global warming would affect the future risks of extreme rainfall events in Bangladesh needs to be addressed to limit adverse impacts. Our study focuses on understanding and quantifying the relative risks of seasonal extreme rainfall events in 15
Trends in extreme rainfall events of Bangladesh
Theoretical and Applied Climatology, 2011
A study of the variability of the extreme rainfall events in Bangladesh during the time period 1958-2007 is presented in this paper. Quality controlled homogeneous daily precipitation records of nine stations distributed over Bangladesh is used for the study. Total fifteen annual and seasonal indices of rainfall are examined. Variability of annual and seasonal rainfall trends is also assessed. The Mann-Kendall statistic and Sen's Slope model are used to measure the trends and the magnitude of the change respectively. A significant increase of annual and pre-monsoon rainfall in Bangladesh is observed. In general, an increasing trend in heavy precipitation days and decreasing trends in consecutive dry days are observed. Significant changes in most of the extreme rainfall indices are observed in the stations situated in Northwest Bangladesh.
Spatial and Temporal Changes of Climatic Variables and Its Impact on Natural Disasters in Bangladesh
American Journal of Environmental Protection, 2014
Bangladesh is confronted with a big challenge to mitigate the significant impact of climate change. Due to the climate change, Bangladesh has already experienced average maximum temperature rising, minimum temperature decreasing, rainfall, relative humidity and cloud coverage decreasing resulting frequent and severe floods, tropical cyclone, extensive river bank erosion and drought. This paper focuses mainly to identify the spatial and temporal changes of climatic variables namely temperature, rainfall, humidity and cloud coverage of Bangladesh using data from Bangladesh Meteorological Department (BMD), Bangladesh Water Development Board (BWDB) and Bangladesh Agricultural Research Institute (BARC) at 32 stations and also find out the adverse impacts of climate change especially on natural disasters of Bangladesh. To determine the climatic variability an inclusive meteorological estimation was carried out for the period of 2007-2011 and the results were compared with the period 1987-1991. The results of the climatic variability show that the average maximum temperature is increasing at a rate of 0.03°C per year but the annual minimum temperature is decreasing at a rate of 0.003°C per year. On the other hand, the annual rainfall, relative humidity and cloud coverage decreased by 0.63 mm, 0.013 percent and 0.007 respectively per year. For these climatic changes during the period 1970 to 2013, one hundred thirty four (134) major and minor cyclones hit the coastal regions of Bangladesh and almost two-third (88) of them hit in the period of 1992-2013 which is very alarming for our survival. On the other hand, it shows that the intensity and frequency of extreme flood events have significantly increased and the most extensive floods in the period
Modeling recent climate change induced extreme events in Bangladesh: a review
Bangladesh is a resourceful and densely populated country that has been experiencing frequent disasters viz. cyclones, tidal surges, floods, salinity intrusions, droughts etc. which cause large damage to lives and properties every year. The frequency and intensity of the extreme events have increased significantly in recent decades due to climate change and global warming. This review paper synthesizes extreme climatic events in Bangladesh in the context of the climate modeling data. The modeling results of extreme events showed significant trends in Bangladesh due to climate change. The results of these climate models are significant to show the importance of climate modeling in Bangladesh and it will help to promote research on climate modeling in least developed countries like Bangladesh. Please cite this article as: Dastagir, M.R., Modeling recent climate change induced extreme events in Bangladesh: a review. Weather and Climate Extremes (2015), http://dx.Weather and Climate Extremes ∎ (∎∎∎∎) ∎∎∎-∎∎∎ Please cite this article as: Dastagir, M.R., Modeling recent climate change induced extreme events in Bangladesh: a review. Weather and Climate Extremes (2015), http://dx.Please cite this article as: Dastagir, M.R., Modeling recent climate change induced extreme events in Bangladesh: a review. Weather and Climate Extremes (2015), http://dx.Please cite this article as: Dastagir, M.R., Modeling recent climate change induced extreme events in Bangladesh: a review. Weather and Climate Extremes (2015), http://dx.Please cite this article as: Dastagir, M.R., Modeling recent climate change induced extreme events in Bangladesh: a review. Weather and Climate Extremes (2015), http://dx.
Drought risk assessment in the western part of Bangladesh
Natural Hazards, 2008
Though drought is a recurrent phenomenon in Bangladesh, very little attention has been so far paid to the mitigation and preparedness of droughts. This article presents a method for spatial assessment of drought risk in Bangladesh. A conceptual framework, which emphasizes the combined role of hazard and vulnerability in defining risk, is used for the study. Standardized precipitation index method in a GIS environment is used to map the spatial extents of drought hazards in different time steps. The key social and physical factors that define drought vulnerability in the context of Bangladesh are identified and corresponding thematic maps in district level are prepared. Composite drought vulnerability map is developed through the integration of those thematic maps. The risk is computed as the product of the hazard and vulnerability. The result shows that droughts pose highest risk to the northern and northwestern districts of Bangladesh.
2018
Anthropogenic climate change is likely to increase the frequency risk of extreme weather events in the future. The term ‘risk’ here means the probability of occurrence of a hazard, e.g., an extreme rainfall event that can trigger sudden flash-flood, landslide or flood. Previous studies have robustly shown how and where climate change has already changed the risks of weather 15 extremes. However, developing countries have been somewhat underrepresented in these studies, despite high vulnerability and limited capacities to adapt. How additional global warming would affect the future risks of extreme rainfall events in Bangladesh needs to be addressed to limit adverse impacts. Our study focuses on understanding and quantifying the relative risks of extreme rainfall events in Bangladesh under the Paris Agreement temperature goals of 1.5°C and 2°C warming above pre-industrial levels. In particular, we investigate the influence of anthropogenic aerosols on these risks given their likely f...
Natural hazards and livestock damage in Bangladesh
Natural Hazards, 2019
Natural hazards are very common in Bangladesh that take place every year and damage crops, livestock and settlements. Data on livestock, flood, drought, cyclone, tide, thunderstorm, hailstorm, waterlogging, tornado and economic damages were collected from the existing literature for 2009-2014. Hotspots of natural hazards and damaged area coverage were determined based on total score, and IDRISI3.2 was used to prepare maps. About 10-32% areas in Bangladesh are moderate to very high natural hazard-prone. Moderate and high drought vulnerabilities were observed in about 14% areas for livestock production. Low and very low flood hazards for livestock could be found in about 22-44% areas. Hotspots for cyclones covered about 17% areas, high and very high storm/tides in about 22% areas and no safe zone against thunderstorm. Hailstorm damages more livestock in north and northwest part of the country covering about 23.8% areas. Moderate damages by tornado are distributed in 84% areas. Waterlogging hotspots are in southern part of Bangladesh that covers about 7% areas and livestock in about 52% areas suffered from low to moderate waterlogging problems. As a whole, natural hazards mentioned above are responsible for economic loss of < 1-35 million US$ and < 1-11.8 million US$ in livestock and poultry sectors depending on locations. Such loss in livestock sector is like to be increased in future because of climate change impacts, indicating that proper shelter and early warning systems must be in place to minimize damages in livestock sector from natural hazards.
2018
Anthropogenic climate change is likely to increase the frequency of extreme weather events in future. Previous studies have robustly shown how and where climate change has already changed the risks of weather extremes. However, developing countries have been somewhat underrepresented in these studies, despite high vulnerability and limited capacities to adapt. How additional global warming would affect the future risks of extreme rainfall events in Bangladesh needs to be addressed to limit adverse impacts. Our study focuses on understanding and quantifying the relative risks of seasonal extreme rainfall events in 15 Bangladesh under the Paris Agreement temperature goals of 1.5°C and 2°C warming above pre-industrial levels. In particular, we investigate the influence of anthropogenic aerosols on these risks given their likely future reduction and resulting amplification of global warming. Using large ensemble regional climate model simulations from weather@home under different forcing scenarios, we compare the risks of rainfall events under pre-industrial (natural), current (actual), 1.5°C, and 2.0°C warmer and greenhouse gas only (anthropogenic aerosols removed) conditions. We find that the risk of a 1 in 100 year rainfall event has already increased 20 significantly compared with pre-industrial levels across parts of Bangladesh, with additional increases likely for 1.5 and 2.0 degree warming (of up to 5.5 times higher, with an uncertainty range of 3.5 to 7.8 times). Impacts were observed during both the pre-monsoon and monsoon periods, but were spatially variable across the country in terms of the level of impact. Results also show that reduction in anthropogenic aerosols plays an important role in determining the overall future climate change impacts; by exacerbating the effects of GHG induced global warming and thereby increasing the rainfall intensity. We highlight that the net 25 aerosol effect varies from region to region within Bangladesh, which leads to different outcomes of aerosol reduction on extreme rainfall statistics, and must therefore be considered in future risk assessments. Whilst there is a substantial reduction in the impacts resulting from 1.5°C compared with 2°C warming, the difference is spatially and temporally variable, specifically with respect to seasonal extreme rainfall events. 30 1 Introduction The 2015 Paris Agreement of the United Nations Framework Convention on Climate Change (UNFCCC), on "Holding the increase in the global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C" (Department of the Environment and Energy, 2015), needs strong support from research on the nature, benefits and feasibility of this challenging goal. This Agreement calls for the quantification and comparison between the 35 impacts of 1.5C versus 2.0C warmer global temperatures on different climate related aspects such as extreme weather events. While assessing both risks and vulnerabilities to incremental increases in global mean temperature, the discrimination of the impacts of different radiative forcing contributions as well as the quantification of spatially varying changes in risk are crucially important. For example, highly unusual heat extremes that are virtually absent in the present climate in South Asia, would affect around 15% of land area of this region under 1.5°C and around 20% of land area under 2°C warming (The World 40 Bank, 2012). The increase in heavy monsoon rainfall intensity for South Asia is projected to be 7% under 1.5°C and 10% under 2°C warming compared to pre-industrial conditions (Schleussner et al., 2016). Populations of this region largely depend on the stability of the monsoon, which provides water resources for agricultural production (The World Bank, 2012). It is
Dynamics of Extreme Rainfall and Its Impact on Forest and Land Fires in the Eastern Coast of Sumatra
Science and Technology Indonesia
This article examines the extreme climate events on the Eastern Coast of Sumatra over four decades (1981-2019) based on the extreme rainfall index defined using the Expert Team on Climate Change Detection and Indices (ETCCDI). The indices used include Consecutive Dry Day (CDD and the total rainfall per year (PRCPTOT). Theses indices were calculated and are based on the daily observation data from eight quality-controlled weather stations. While overall trends in extreme rainfall indices are not significant, there is a noticeable trend towards drought, with CDD rising by 1.23 days per decade and PRCPTOT decreased by 3.16 mm/year. The correlation between the Dipole Mode Index (DMI) and extreme rainfall indices in the August-September-October-November (ASON) period was positive, with CDD increasing with the more positive DMI value. On the other hand, the PRCPTOT index showed a decrease as the DMI more positive. The ENSO index and CDD are positively correlated during the dry season, whi...
Changes in Historical Precipitation Extremes over Bangladesh
2018
With the exception of the relatively dry western region of Rajshahi, where the annua 1600 mm, most parts of the country receive at least 2300 mm of rainfall per year. Because of its location just south the Himalayas, the region of Sylhet in northeastern Bangladesh receives the greatest average precipitation. About 80 % rain falls during the monsoon season. Climate change is one of the biggest issues confronting humanity in the 21st give rise to changes in weather patterns, and an increase in the frequency and severity of extreme events. Climate c extremes towards conditions that will stress vulnerable countries such as Bangladesh. Changes in mean temperature values could lead to amplified responses to their extreme values. The objective of the present research includes the precipitation extreme indices for selected meteorological stations in Bangladesh. Precipitation data from 1961-Bangladesh Meteorological Department (BMD) are used in this analysis. BMD data from a total of 22 stations are research. 11 extreme indices related to precipitation are considered in the present study. The precipitation ex calculated using RClimDex, which is written in statistical software package R. The maximum 1-day precipitati maximum 5-day precipitation (RX5day); simple daily intensity index (SDII); numbers of heavy (R10mm), very he extremely heavy (R50mm) precipitation days; consecutive wet days (CWD); very wet days (R95p), extremely wet days (total wet-day precipitation (PRCPTOT) have been increasing in most of the BMD stations. Only consecutive dry days to be decreasing. The trends of the precipitation extreme indices indicate a higher precipitation in the future.
Bangladesh currently ranks as one of the world's foremost disaster-prone country. The situation is aggravated, all the more by its being the most densely populated country in the world. Drought is the most complex but least understood of all natural hazards in Bangladesh. Timely information about the onset of drought, extent, intensity, duration and impacts can limit drought related losses of life, human suffering and decrease damage to economy and environment.
Severe local convective storms in Bangladesh: Part I. Climatology
Atmospheric Research, 2010
This paper presents the climatology of severe local convective storms in Bangladesh. We collected sufficient severe local convective storm events over a long period (2,324 events from 1990 to 2005) to compile reliable climatological statistics by surveying the literature. Severe local convective storms frequently occur during the pre-monsoon season from March to May, peaking in April. The highest frequency was found to be at 16-17 Local Standard Time (LST) and 20-21 LST, with lower activity around midnight and early morning. It was also found that the occurrence of severe local convective storms is more concentrated in the central region of Bangladesh, and tends to spread northward during the pre-monsoon season.