Drought

Definition

Drought may be considered in general terms a consequence of a reduction over an extended period of time in the amount of precipitation that is received, usually over a season or more in length. It is a temporary aberration, unlike aridity, which is a permanent feature of the climate. Seasonal aridity (i.e., a well-defined dry season) also needs to be distinguished from drought. It should be noted that drought is a normal, recurrent feature of climate, and it occurs in virtually all climatic regimes (UNDDR).

Facts and figures

Droughts are often predictable: periods of unusual dryness are normal in all weather systems. Advance warning is possible (WHO).

By 2025, 1.8 billion people will experience absolute water scarcity, and 2/3 of the world will be living under water stressed conditions (UNCCD).

Drought can be defined according to meteorological, agricultural, hydrological and socio-economic criteria.

  • Meteorological, when precipitation departs from the long-term normal
  • Agricultural, when there is insufficient soil moisture to meet the needs of a particular crop at a particular time. Agricultural drought is typically evident after meteorological drought but before a hydrological drought
  • Hydrological, when deficiencies occur in surface and subsurface water supplies
  • Socio-economic, when human activities are affected by reduced precipitation and related water availability. This form of drought associates human activities with elements of meteorological, agricultural, and hydrological drought (FAO).

UN-SPIDER Regional Support Offices with hazard-specific expertise

Related content on the Knowledge Portal

  • Publishing institution:
  • Extensive time-series on vegetation and wealth of operational satellites from space provides ample opportunities to monitor vegetation developments and more and more accurate yield forecast. This MOOC provides an introduction to “Droughts”, answers questions on how it can be quantified, how it can be assessed and monitored from space. The role of cloud computing and (easy) access to satellite will also get attention. No prior knowledge to Earth Observation (EO) is required. The MOOC provides a ‘smooth’ introduction for agricultural scientist, water resources specialist and others who are interested in water and food security and the role EO plays nowadays related to this theme. Every week a new set of movie and short quizzes will be released. The MOOC will be open till the end of November 2022.

    Find more information here.

  • UN-SPIDER's Regional Support Office of Pakistan (SUPARCO) has provided a new Recommended Practice, using Google Earth Engine to identify the drought extent and severity by calculating different indices.

    Drought is a slow on-set disaster which affects agriculture and associated livelihood in many parts of the world. It causes stress to vegetation; hence the extent of a drought can be reflected by changes in the vegetation condition. Geospatial scientists have developed drought indices based on remote sensing data to effectively detect drought conditions.

    Droughts make considerable effects on agricultural and agro-pastoral areas due to their substantial dependency on rainfall. Agricultural drought monitoring is very important to maintain food security in the world. Satellite remote sensing is widely used for vegetation health monitoring and has become a powerful…

    read more
    Regional Support Offices mentioned:
    20/05/2022
  • On 10 May 2022, the United Nations Office for Outer Space Affairs (UNOOSA), the University of Energy and Natural Resources of Ghana, and the Prince Sultan Bin Abdulaziz International Prize for Water (PSIPW) inaugurated the 5th International Conference on the Use of Space Technology for Water Resources Management. The conference, held in Accra from 10 to 13 May 2022, aims to promote the use of space technology in water management in developing countries.

    During the opening segment of the conference, high ranking authorities noted that there have been many success stories related to the Sustainable Development Goals (SDGs), but unfortunately some of these were eroded by the COVID 19 pandemic. They remarked that Ghana is hosting this conference to see how best to foster new partnerships to address the SDGs, and to facilitate a constructive discussion on two key issues essential to sustainable development: Space technologies and sustainable use of water…

    read more
    12/06/2022
  • Drought is slow on-set disaster which affects agriculture and associated livelihood in many parts of the world. Drought causes stress to vegetation; hence the extent of a drought can be reflected by changes in the vegetation condition. Geospatial scientists have developed drought indices based on remote sensing data to effectively detect drought conditions. The Normalized Difference Vegetation Index (NDVI) is the normalized difference between near-infrared (NIR) and red reflectance. Simple and effective, it is one of the most widely used indices for detecting drought conditions. More recently…
    Regional Support Offices mentioned:
  • Natural disasters are becoming more frequent and intense across the globe. Enhancing resilience to increasing hazards, exposure, and vulnerability therefore requires leveraging of advanced geospatial technologies for better disaster mitigation and management. With continuous improvements in satellite data sensor acquisition parameters together with geo-computational approaches, geospatial technologies have emerged as the most powerful technology for all phases of disaster management. The course on advanced geospatial technologies for Disaster Risk Reduction (DRR) is scheduled from April 18 - 29, 2022 .

    Course Content

    • Overview of remote sensing & Geographic Information System
    • Application of satellite communication technology for disaster mitigation
    • Overview of UAV for disaster monitoring and mitigation
    • Emerging geo computation, online GIS & Geo-web services for DRR
    • Advanced application of Geospatial…
    read more
  • On the Iberian Peninsula Portal and Spain are facing a severe drought, that started in November 2021 and worsened in the following months. Officials in Portugal were forced to limit the use of hydroelectric dams for power production and irrigation, as some reservoirs started reaching significant lows.

    The extreme dimension of this event gets revealed on a pair of Landsat 8 OLI (Operational Land Imager) images, operated by NASA and USGS, comparing the state of the Alto Rabagão and Alto Lindoso reservoirs in northern Portugal from March 2021 to February 2022. 

    NASA 's earth observatory…

    read more
    21/02/2022
  • United Nations/Ghana/PSIPW - 5th International conference on the use of space technology for water resources management

     

    Introduction

    The United Nations Office for Outer Space Affairs (UNOOSA) and the Government of Ghana are jointly organizing a Conference with the support of the Prince Sultan Bin Abdulaziz International Prize for Water (PSIPW) to promote the use of space technology in water management to the benefit of developing countries.

    The Conference will be held in Accra, Ghana, from 10- 13 May 2022, hosted by the University of Energy and Natural Resources on behalf of the Government of Ghana.

    The Conference is the fifth international event focusing on applications of space technology for water in the series of conferences organised with financial…

    read more
  • Space-based Solutions for Disaster Risk Management and Emergency Response for Southern Africa

    UN-SPIDER and ZFL are holding a regional virtual expert meeting for Southern Africa, a region vulnerable to hydrometeorological, geological, coastal and biological hazards and gravely impacted by droughts in recent years.

    The objectives of this regional virtual expert meeting are:

    • To raise awareness regarding novel applications of satellite technologies in risk assessment, early warning systems, and disaster response operations;
    • To survey and examine efforts carried out by risk and disaster management institutions in Southern African countries on the use of space technologies and space-based information in disaster risk management, preparedness, response and recovery efforts;
    • To explore ways to enhance the use space technologies in disaster risk management and response and recovery applications in Southern Africa.…
    read more

Term Parents

UN-SPIDER Regional Support Offices with hazard-specific expertise