Estimates

3.4 Displacement trend from 1970to 2014IDMC has used probabilistic modellingto generate coarse-grained displacementestimates going back to 1970. Wecontinue to develop the model, with arecent focus on increasing the size ofour data sample for the calibration of theestimates.The model is dependent on the qualityand availability of global data. A number ofimportant caveats should be kept in mind.Firstly, the sample sizes are too small tomake inferences about individual countries.Secondly, extreme hazards occur relativelyinfrequently. Those that occur onceevery 100, 500 or 1,000 years are unlikely tobe captured in four decades of data and bytheir very nature, they are hard to quantify.Meanwhile, its latest iteration alreadyprovides a reasonable approximation ofthe general historical trend and some validationof expected displacement patternsthat are also reflected in our data for 2008to 2014 (see annex A.2).Latest findings show that the totalnumber of people displaced in 2014,though lower than the average for thepast seven years, is part of a longer-termupward trend in displacement since 1970.Even adjusting for population growth,the average amount of displacement associatedwith disasters has increased by60 per cent in a little over four decades.(see figure 3.4.a). 3This is driven mostly by the increasingconcentration of people in exposedlocations, combined with their growingvulnerability. 4 More frequent and intenseextreme weather events associated withclimate change are expected to accentuatethe trend. 5Data behind the modelled trend alsoshows large variations year to year. Thisincludes a peak in 1998, when almosttwice as many people were displacedthan in any other since 1970. This is furtherdiscussed in box 3.1.Figure 3.4: Modelled global displacement trend for 1970 to 2014 (per million inhabitants)7,0006,000People displaced per million inhabitants People displaced per million inhabitants5,0004,0003,0002,0001,000019701980Source: IDMC data as of 1 June 20157,0006,0005,0004,0003,0002,000Modelled trendb) Trend by associated hazard typeRelated to weather hazardsRelated to geophysical hazardsModelled trend1990200020082014IDMC annual data1,00022 Global Estimates 2015019701980Modelled trend1990200020082014IDMC annual data