This handbook focuses on the statistics on affected population by disastrous events. Glossary of Humanitarian Terms by ReliefWeb defines a disaster as "a serious disruption of the functioning of a community or a society causing widespread human, material, economic or environmental losses which exceed the ability of the affected community or society to cope using its own resources (Relief Web, 2008)." EM-DAT
, a standardized global disaster database, defines disasters by classifying them into nine subgroups, including geophysical, hydrological, and biological disasters (CRED, n.d.). It includes an ongoing pandemic, Coronavirus disease 2019 (COVID-19), which threatens to reverse the progress of SDGs as the crisis highlights the importance of timely and quality statistics (United Nations, 2020). Another notable disaster database used by 110 Member States is the DesInventar disaster loss accounting system, which also covers affected population by various disastrous events. These are nationally owned databases that provide information on disaster losses and damages at sub-national levels and cover events of all scales. Disaster data usually cover affected population in the context of a wide range of disastrous events. This handbook discusses population statistics in the context of adverse events resulting from natural processes of the Earth such as floods, hurricanes, earthquakes, and other geologic processes as these often induce the movements of people. This handbook also covers population statistics affected by biological hazards such as the spread of communicable diseases and pandemics; these are not only disasters themselves, but also induced by disastrous environmental events (Loebach et al. 2019) and considered to be associated with human mobility (Dalziel et al. 2013) (Wesolowski et al. 2012). Disasters often induce displacement where people are forced or obliged to relocate. According to the Guiding Principles on Internal Displacement published by the United Nations Commission on Human Rights, internally displaced people are defined as "persons or groups of persons who have been forced or obliged to flee or leave their homes or places of habitual residence in particular as a result of or in order to avoid the effects of armed conflict, situations of generalized violence, violations of human rights, or natural or human-made disasters and who have not crossed an internationally recognized State border" (United Nations, 1998). In these regards, this handbook specifically discusses population statistics in the context of disasters where movements of people are induced, obliged, and matter. Precisely speaking, these statistics are not as other official statics described in the methodological guides of tourism, migration, and dynamic population statistics. The scope of displacement and disaster statistics is largely defined by user needs. For example, population statistics are useful baselines for operational needs such as disaster risk management and emergency response. Likewise, time-series data on population distribution and movements are needed for post-disaster assessment and monitoring impacts, as well as for international reporting (United Nations, 2019). A potential application of displacement and disaster statistics is in the Sendai Framework Monitoring process since one of the indicators looks into percentage of population exposed to or at risk from disasters protected through pre-emptive evacuation following early warning (Target G, Indicator G-6). Another application is in the DesInventar system mentioned earlier, as countries have the option of recording the number of people displaced and people evacuated as a result of disasters faced.
