TSingh - climate change & landslide hazards.ppt
- 1. CLIMATE CHANGE CLIMATE CHANGE and and LANDSLIDE HAZARDS LANDSLIDE HAZARDS TRILOCHAN SINGH Earth Scientist < tskaith@rediffmail.com >
- 2. Climate Change Climate Change a change in distribution of weather pattern in climate system over long period of time, ranging from decades to millions of years.
- 3. Climate change and Weather change Climate is what you expect, Weather is what you get. Difference between the two is a measure of time. Weather is atmospheric conditions of an area over a short period of time. Weather represents day-to-day state of the atmosphere, i.e., temp., precipitation and wind. It shows variation from minute- to-minute, hour-to-hour, day-to- day, and season-to-season. Climate is atmospheric behaviour over long periods of time. Climate represents general weather conditions. It shows variations over time. Weather reflects short-term conditions of the atmosphere; while Climate is the average daily weather for an extended period of time at a certain location.
- 4. Earth's climate has remained dynamic throughout the 4.5 billion years long history of the Earth, showing changes through natural cycle periodically. These climate changes in the past geological time had profound influence on sea level, rainfall patterns, and temperature related weathering processes.
- 5. The Earth’s climate components have changed on many timescales in response to natural factors at different rate and different time periods, signatures of which have been imprinted on the rocks.
- 6. These diverse signatures include: -Fossil records of past plant and animal distribution; -sedimentary and geochemical indicators of former conditions of oceans and continents; and -surface features characteristic of past climate.
- 7. There have been significant climate changes on the Earth periodically in the geologic past in terms of the glacial and interglacial cycle. Glacial cycles have been recorded during : - 542 to 359 million years ago (late Ordovician and early Silurian), - 350 to 250 million years ago (late Carboniferous and early Permian), - 33.9 million years ago (at the Eocene-Oligocene boundary), and - 23 million years ago (at the Oligocene-Miocene boundary).
- 8. The prominent warm phases, on the other hand, have occurred during : -500 to 350 million years ago (late Cambrian to late Carboniferous) and -250 to 35 million years ago (late Permian to early Oligocene).
- 9. Glacial and interglacial cycles have remained prominent ever since approximately 3 million years ago (middle to late Pliocene). The most recent glacial cycle occurred between about last 120,000 and 11,500 years. Since then, the Earth has been in an interglacial cycle.
- 10. This present interglacial cycle, i.e., the Holocene period, has lasted about 11,700 years. According to Prof Heinz Wanner, President of the Oescheger Centre for Climate Change Research, the current Holocene period is a warming spell of just 12,000 years following a much lengthier ice age, which would likely resume in 20,000 to 30,000 years, if it wasn’t for human intervention. Emissions from cars, factories, and burning forests trap more of the sun’s energy, which leads to rising temp.
- 11. Climate change may increase precipitation and warmth, which in turn may change in the type, distribution and coverage of vegetation of a region. The effects of rapid climate change have also led to natural disasters in the past. Such an example occurred during 395-345 million years ago (Carboniferous), when climate change devasted the vast rainforests covering the equatorial region, and caused mass extinction of plants and animal species.
- 12. Similarly, mass extinction of dinosaurs nearly 100 -65 million years ago (middle to late Cretaceous) is also considered to be caused by the climate change.
- 13. Fossil fern from Alexander Island, Antarctic Peninsula (Lower Dinosaur jaw bone from James Ross Island, Antarctic Peninsula (Upper Cretaceous) Antarctica, the Earth’s icy southern pole, was a tropical paradise covered with swamps and plenty of lush vegetation nearly 85 million years ago (late Cretaceous), and it was situated close to the equator with no ice. Slice of ice core from Berkner Island, depth 120m. Trapped air bubbles (archive of the past atmosphere) are visible in the ice.
- 14. Present Africa Western Desert in Fayoum region, nearly 100 km SW of Cairo in Egypt, has been transformed from marine marine (in Eocene time) to continental continental (in Oligocene time) to present day desertic desertic conditions.
- 15. Elephas Tooth Elephas Tooth Crocodile Jaw Crocodile Jaw Petrified Wood fossil Petrified Wood fossil Desertic Landscape Desertic Landscape
- 16. Likewise there have been Likewise there have been many examples available in many examples available in the geological history. the geological history.
- 17. Causes of Climate Change in the Geologic Past : Tectonic and Neotectonic Activities
- 18. Tectonic Activity is the adjustment of the tectonic plates involving geological and geomorphological processes in the past geological history. Neotectonic Activity, on the other hand, implies this activity during the Quaternary Period, which is still continuing.
- 19. Amongst various causes of climate change, Continental Drift / Plate Tectonics is the one which is least known. Tectonic activities since geologic past have changed the shape, size, position, and elevation of the continents as well as the bathymetry of the oceans.
- 20. - 20 major tectonic plates, remained geodynamically active. - Movement reconfigures the landmass and ocean areas. - Affecting global & local patterns of climate and atmosphere-ocean circulation.
- 21. The position of the continents and seas are important in controlling the transfer of heat and moisture across the globe, and in turn, determining global climate. Geologic evidences indicate "mega-monsoonal" circulation pattern during the time of the Pangaea. Climate modelling suggests that the existence of the supercontinent was conducive to the establishment of monsoons.
- 22. The climate had been influenced by the morphogenetic processes occurring on the earth’s surface in the geologic past. For example, during the evolution of the Himalaya :
- 23. ..… climate remained quite warm and moist. The terrain was gentle and there was no mountain barrier at that time, i.e., 4.8 to 0.4 million years ago.
- 24. Sudden uplift of Tibetan Plateau by 1,000 to 2,500 m, about 10 to 5 million years ago (Late Miocene – Early Pliocene), made abrupt changes in the climate and initiated unique monsoon. It brought rains from the south-westerly air currents during summer and cold precipitation from north-easterlies during winters. Diversion of wind flow and creation of large cool areas caused snowfalls on the elevated mountains in the Higher Himalayan Terrane, while the Siwalik and Lesser Himalayan terranes were washed by heavy rains.
- 25. The Himalaya prevents the ingress of cold no Himalayan ranges to wring out moisture from the passing clouds, much of the continent would have been a thirsty, parched and desolated land. wintry winds from Siberia. If there were
- 26. is responsible for peculiar monsoon climate of the subcontinent and unique succession of six seasons, i.e., Vasant, Grishma, Varsha, Sharad, Shishir and Hemant. The Himalaya, 2,500 km long and 250-300 km wide mountain barrier, rising 500 - 8,000 m above the msl,
- 27. The reactivation of faults rejuvenated. The matured topography of Lesser Himalaya changed dramatically. As the mountain ranges rose, the antecedant rivers continued cutting their channels deeper and deeper without deviating from their original channels. The Himalaya rose more than 3,000 to 4,000 m in the late Quaternary Period. The rate of uplift was particularly fast about 0.9 to 0.8 m.y. ago.
- 28. On the other hand, neotectonic activities, which include endogenic movements, were responsible for rejuvenation of the exogenic processes causing disturbances in the isostatic balance.
- 29. Many of the hill ranges formed earlier were latitudinally cut by strike faults and thrusts, whereas certain sectors were stretched in E-W direction close to ITSZ while in N-S direction in middle zone.
- 30. As a consequences of reactivation of faults and thrusts, elongated uplifted ridges or grabens (delimited on two sides by faults) or elongated depressions were formed. The depressions gave rise to ‘Duns’, such as Pinjore Dun in Himachal; Dehra Dun and Kota Dun in Uttaranchal. Uplift of faulted blocks on the down stream side caused ponding of rivers, giving rise to huge lakes, such as Karewa Lake in Kashmir.
- 31. The consequence effect of vertical and horizontal The consequence effect of vertical and horizontal movements may be seen in form of the structural movements may be seen in form of the structural dislocation and deformation of the recent dislocation and deformation of the recent deposition and … deposition and … Fault Scarp Triangular Facets Landslides Change of river course Multilevel Terraces Ground subsidence Joints opening
- 32. As India continues to drift northward @ 5.64 cm/yr, the Himalaya is being pressed rather squeezed in between the Indian continent and Asia, which may be affecting the climate.
- 33. Climate change, particularly related to such neotectonic activities, is also expected to bring more Natural Disasters, such as - It is a global concern that the climatic change occurring today has been speeded up with the human interference. Landslides Floods Droughts
- 35. Climate change and natural disasters have rather increased over the past decade. International Strategy for Disaster Reduction (ISDR) Period No. of disasters People affected Economic loss 1994-2003 >2,000 2.5 billion US $ 690 billion
- 36. European Heatwave European Heatwave June – Aug. 2003 June – Aug. 2003 The 2003 heat wave triggered 35,000 deaths, as well as forest fires, caused billions of dollars worth of damage. A stadium under flood water in Thun, Switzerland. The European floods hit mainly Romania, Switzerland, Austria & Germany and several other countries in Central & Eastern Europe. The devastating floods killed at least 42 people. European Flood European Flood Aug. 2005 Aug. 2005 Responding to ongoing climate change
- 37. Nearly 550 people were left homeless after fire in the city of Voronezh Forest fire caused by the Heat Wave, S-of Moscow destroyed homes, killed people and devasted crops Russian PM surveying the affected villages Heat Wave in Russia Heat Wave in Russia July 2010 July 2010
- 38. France declared a national disaster after violent storms that caused 52 casualties and tremendous destruction to the property. Violent winds and torrential rain of the storm caused widespread damage and power cut. Wind damaged homes and property in France, and lost electric supply National Disaster National Disaster in France in France March 2010 March 2010
- 39. total devastation as 52 villages were totally raised to ground Cracks developed on the surface near Barudia village The Latur earthquake struck at 03:56 local time. The main area affected was Maharahtra and Western India. Latur Earthquake Latur Earthquake 30 September 1993 30 September 1993 The Bhuj earthquake occurred at 08:46 AM local time. The epicentre was about 9 km SSW of the village of Chobari, Kutch Distt. Bhuj Earthquake Bhuj Earthquake 26 January 2001 26 January 2001
- 40. An aerial view of the devastation caused by the fury of the super-cyclone Orissa Cyclone Orissa Cyclone 29 October 1999 29 October 1999 Indian W-Coast Indian W-Coast Tsunami Tsunami 26 December 2004 26 December 2004
- 41. At least 114 people were killed and 340 others injured in cloudbursts triggering torrential rain, leading to flash floods and mud slides. Cloud burst in Leh, J&K Cloud burst in Leh, J&K 6 August 2010 6 August 2010 Flash Flood in Uttarkashi Flash Flood in Uttarkashi (Uttarakhand) 28 June 2010 (Uttarakhand) 28 June 2010 Flash Flood in Almora Flash Flood in Almora (Uttarakhand): 18 Sept 2010 (Uttarakhand): 18 Sept 2010
- 42. Present Scenario As a part of the aforesaid natural cycle of Earth’s climate history, climate is changing once again in the present Era showing global warming, where global temperature is projected to rise up to 4 Celsius. ̊ Tropical cyclones are likely to become more frequent and intense, rainfall may increase, and sea level may rise up to nearly a meter with the increase of tropical sea surface temp. Thus, climate change is expected to continue natural disasters, such as drought, flooding, landslides, etc.
- 43. Himalayan Terrain in the last two decades - Observed rising temperature and erratic weather pattern - many glaciers have been receded - snow-melt water, formed glacial lakes in Higher Himalayan terrain - These glacial lakes, growing in both number and size - concern for hazards in the down reaches - causing Glacial Lake Outburst Flood (GLOF) - These, in turn, may be directly responsible for landslides. - Another parameter - increased rainfall in the Himalayan terrain - attributed not only to the flash floods but also landslide disasters
- 44. Climate change does not occur in a single day; rather it is a process that lasts for decades and centuries. Present trend of increase in temperature and rainfall is likely to continue in future also, which may have significant impacts on rapid melting of glaciers, causing water stresses. Therefore, climate change is directly responsible for landslide hazards.
- 45. UNDERSTANDING LANDSLIDE Landslides are downward and outward movements of soil or rock masses, that may be set off by one or more causes, under the influence of gravity.
- 46. LANDSLIDE HAZARDS Himalaya Very High North Eastern Hill Ranges High Western Ghats & Nilgiris Moderate to low Landslide is a serious geological hazard. Annual and recurring phenomenon. Major chronic problem, primarily because of rugged topography, steep hill slopes, heavy & prolonged rainfall. Developmental activities & exploitation of natural resources in hilly region have further aggravated the problem.
- 47. Landslides cause substantial damage to agriculture and forest wealth, roads & telecommunication, major engineering structures. It has a great impact on loss of life and property. It causes blocking of rivers channels, thereby forming huge lacks, which when burst creates flash flood causing much heavy loss. The nation suffers heavy monetary loss every year. It is enormous when cumulative figures are taken. Total estimated cost for loss of property is nearly Rs. 2 billions per annum in the landslide incidences. Thus, landslide hazards have very serious impact not only on socio-economic structure of the region, but also in disruption accompanied misery to human lives. EFFECT
- 49. CREEP BLOCK SLIDE Type of Landslides
- 50. CAUSES CAUSES Deforestation Cloud Burst Earthquake Shocks Extensive Erosion Hydrostatic Pressure Development and Engineering Activities Unscientific Farming Slope Failure Slope Failure
- 52. • Drainage Drainage culverts must have the capacity to take sediment load Otherwise it will choke
- 53. • Afforestation and Reinforced Vegetation Horticulture be given importance than agriculture, especially in hill terrain • Construction of Retaining Walls / Breast Walls • Grading of slopes • Grouting of Loose and Moistened Soils • Rock Bolts and Rock Anchors
- 54. • Other preventive measures : - Relocating or changing the location of the facility to avoid landslide prone areas. - Revetments, spurs, dykes, grains to protect slopes against river and stream erosion. - Plant the barren and sloppy areas in hills with suitable trees. - Display the public boards at the areas prone to landslides to avoid accidents. - District Administration should study the vulnerable areas and take appropriate preventive steps.
- 55. NEED OF THE TIME NEED OF THE TIME - ACTION PLAN - ACTION PLAN
- 56. Climate change has a direct bearing on the landslide hazards, hence it needs special attention. It will help in understanding causes of landslides, systematic planning of developmental activities and managing landslide affected areas to maintain environmental balance. Another important field of research is to study the historical landslides and their causes, particularly with respect to the climate at that time. Emphasis on effect of climate change on the frequency and intensity of rainfall, glacial lakes outburst flood, which are responsible for landslides.
- 57. It has become important to educate the general public, policy makers, planners, and political leaders about the prevention of landslide hazards & propagate awareness of the potential benefits of landslide disaster reduction at grass root level. Landslides have wide ranging impacts on the common man, changing their socio-economic conditions.
- 58. i) Innovative Reserach ii) Management at Government Level iii) Societal Awareness Three main elements emerges
- 59. The landslide hazards need attention for comprehensive plan for disaster preparedness and mitigation through : through : Set up of Meteorological Stations Set up of Meteorological Stations Building Database (old, active, dormant) Building Database (old, active, dormant) Landslide Hazard Zonation Maps Landslide Hazard Zonation Maps Landslide Risk Assessment Landslide Risk Assessment Monitoring & Analysis of Landslides Monitoring & Analysis of Landslides Human Resource Development Human Resource Development Dissemination of knowledge amongst the Dissemination of knowledge amongst the mass, policy makers and Public mass, policy makers and Public Leaders Leaders i) Innovated Research i) Innovated Research
- 60. ii) Management at the Government Level ii) Management at the Government Level “Prevention is better than cure” Considerably damage can be minimized if adequate preparedness levels are achieved. Considering the long-term problem and major economic risk, it is desirable to have : - short-term approach to response and recovery, and - long-term approach towards improving awareness, preparedness and risk reduction amongst the mass.
- 61. Landslides effect can be reduced by : - Restricting, prohibiting, or imposing conditions on hazard- zone activity. - Effective use of land-use policies and regulations. - Educating individuals on the past hazard history of a site. - Obtaining professional services of engineering geologist, geotechnical or civil engineer, for evaluation of site. Meaningful interaction between the scientists, technical experts, policy makers and common man on regular basis for extension of knowledge in better understanding of hazards mitigation and management. ii) Management at the Government Level ii) Management at the Government Level (contd) (contd)
- 62. Awareness amongst the local inhabitants is very important about : vulnerable zones of natural disasters; appropriate response to minimize the effect of these disasters; and developing capacity building to strengthen search, rescue and relief operations. In fact, sufficient material and funds are available with the government for relief and rehabilitation, however, these are not being utilized properly. Thus, participation of local people and local NGOs is very important, which can create a sense of responsibility. iii) Societal Awareness iii) Societal Awareness
- 63. Govt may adopt ‘the culture of prevention’ and focus on ‘disaster risk reduction disaster risk reduction’, which includes preparedness for adverse impacts of hazards so as to minimise vulnerabilities and disaster risks . This process may be integrated with National Action Plan on Climate Change. The strategy and policy may be designed suitable for different regions under different situations. This will ensure development of the safer community under sustainable environment.
- 64. Prof KS Valdiya, an eminent National Professor suggested that environmental security and hazard management programs must form essential part of the development for the mountainous States. He stressed the need of a public policy for hazard management, and suggested to form a State-level ‘Natural Hazards Management Commission’ in each State of the NE Region.
- 65. ... for your patient hearing!