IPCC_Managing Risks of Extreme Events.pdf - Climate Access

Chapter 9Case Studiesof impact. Based on the level of consistency among models, and physicalreasoning, it is likely that tropical cyclone-related rainfall rates willincrease with greenhouse warming. It is likely that the global frequencyof tropical cyclones will either decrease or remain essentiallyunchanged. An increase in mean tropical cyclone maximum wind speedis likely, although increases may not occur in all tropical regions. Whileit is likely that overall global frequency will either decrease or remainessentially unchanged, it is more likely than not that the frequency ofthe most intense storms will increase substantially in some oceanbasins. Although there is evidence that surface sea temperature (SST) inthe tropics has increased due to increasing greenhouse gases, theincreasing SST does not yet have a fully understood physical link toincreasingly strong tropical cyclones (Section 3.4.4).9.2.5.2. Indian Ocean CyclonesAlthough only 15% of world tropical cyclones occur in the North IndianOcean (Reale et al., 2009), Bangladesh and India account for 86% ofmortality from tropical cyclones (UNISDR, 2009c). The 2011 GlobalAssessment Report (UNISDR, 2011b) provides strong evidence thatweather-related mortality risk is highly concentrated in countries withlow GDP and weak governance. Many of the countries exposed totropical cyclones in the North Indian Ocean are characterized by highpopulation density and vulnerability and low GDP.9.2.5.2.1. Description of events – Indian Ocean cyclonesIn 2007, Cyclone Sidr made landfall in Bangladesh on 15 November andcaused over 3,400 fatalities (Paul, 2009). Cyclone Nargis hit Myanmaron 2 May 2008 and caused over 138,000 fatalities (CRED, 2009; Yokoiand Takayabu, 2010), making it the eighth deadliest cyclone ever recorded(Fritz et al., 2009). Sidr and Nargis were both Category 4 cyclones ofsimilar severity; affecting coastal areas with a comparable number ofpeople exposed (see Table 9-2). Although Bangladesh and Myanmarboth are considered least developed countries (Giuliani and Peduzzi,2011), these two comparable events had vastly different impacts. Thereasons for the differences follow.9.2.5.2.2. Interventions – Indian Ocean cyclonesBangladesh has a significant history of large-scale disasters (e.g., CyclonesBhola in 1970 and Gorky in 1991; see Table 9-2). The Government ofBangladesh has made serious efforts aimed at DRR from tropical cyclones.It has worked in partnership with donors, nongovernmental organizations(NGOs), humanitarian organizations and, most importantly, withcoastal communities themselves (Paul, 2009).First, they constructed multi-storied cyclone shelters with capacity for500 to 2,500 people (Paul and Rahman, 2006) that were built in coastalregions, providing safe refuge from storm surges for coastal populations.Also, killas (raised earthen platforms), which accommodate 300 to 400livestock, have been constructed in cyclone-prone areas to safeguardlivestock from storm surges (Paul, 2009).Second, there has been a continued effort to improve forecasting andwarning capacity in Bangladesh. A Storm Warning Center has beenestablished in the Meteorological Department. System capacity has beenenhanced to alert a wide range of user agencies with early warningsand special bulletins, soon after the formation of tropical depressions inthe Bay of Bengal. Periodic training and drilling practices are conductedat the local level for cyclone preparedness program (CPP) volunteers foreffective dissemination of cyclone warnings and for raising awarenessamong the population in vulnerable communities.Third, the coastal volunteer network (established under the CPP) hasproved to be effective in disseminating cyclone warnings among thecoastal communities. These enable time-critical actions on the ground,including safe evacuation of vulnerable populations to cyclone shelters(Paul, 2009). With more than sevenfold increase in cyclone shelters andtwofold increase in volunteers from 1991 to 2007, 3 million people weresafely evacuated prior to landfall of Sidr in 2007 (Government ofBangladesh, 2008).In addition, a coastal reforestation program, including planting in theSundarbans, was initiated in Bangladesh in the late 1960s, coveringriverine coastal belt and abandoned embankments (Saenger and Siddiqi,1993). Sidr made landfall on the western coast of Bangladesh, which isTable 9-2 | Key data for extreme cyclones in Bangladesh, Myanmar, and Mexico. Sources: García et al., 2006; National Hurricane Center, 2006; Government of Bangladesh, 2008;Karim and Mimura, 2008; Webster, 2008; CRED, 2009; Paul, 2009; Giuliani and Peduzzi, 2011.CycloneEventYearStorm Surge (m)Maximum WindSpeed (km h -1 )Category(Saffir-Simpson)Number of AffectedPeople(approximate in millions)Mortality(approximate)Bhola 1970 6 - 9223 3 1 300,000 - 500,000UnknownGorky 1991 6 - 7.5260 4 15.4 138,000 1.8Sidr 2007 5 - 6 245 4 8 - 104,200 2.3Nargis 2008 ~ 4 235 4 2 - 8138,000 4.0Stan a 2005 Negligible 130 1 3 - 81,726 3.9Wilma 2005 12.8 295 5 10 b 62 (8 in Mexico) 29 (7.5 in Mexico)Notes:aMost of damage and mortality caused by landslides and river flooding.bAffecting Jamaica, Bahamas, Haiti, Cayman Islands, Belize, Honduras, El Salvador, Nicaragua, Honduras, Yucatán Peninsula (Mexico), and Florida (USA).Damages(US$ billion)503