Drought

Lake Chad has shrunk dramatically over the last four decades due to a decrease in rainfall and an increase in the amount of water used for irrigation projects. Its surface area was 25 000 sq km in the early 1960s, compared with 1350 sq km in 2001. Image acquired 19 December 2007 by the MERIS (Medium Resolution Imaging Spectrometer) instrument aboard ESA’s Envisat satellite. Image: ESA, CC BY-SA 3.0 IGO.

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).

Related content on the Knowledge Portal

Événement

Participants at the virtual expert meeting. Image: UNOOSA.

En décadas recientes muchas comunidades en América Latina y el Caribe han experimentado desastres ocasionados por inundaciones, sequías, deslizamientos, terremotos, erupciones volcánicas y maremotos o tsunamis que han erosionado los logros asociados a procesos de desarrollo. Además, en este año 2020 la pandemia ocasionada por el virus COVID-19 ha impactado a muchos países del mundo, forzando a los gobiernos, al sector privado, a la sociedad civil y a organismos regionales e internacionales a modificar sus planes de trabajo. De manera paralela, varios países del Este de África, del Sudoeste de Asia y de América Latina están experimentando los impactos de la plaga de langosta.  

Convencidos que las tecnologías espaciales pueden jugar un papel preponderante en apoyar los esfuerzos que llevan a cabo las instituciones en materia de gestión para la reducción de riesgos, la preparación, la respuesta y la recuperación en caso de desastres; la Asamblea General de las Naciones Unidas... read more

Image: UFSM.

The Federal University of Santa Maria of Brazil (UFSM), in its role as a UN-SPIDER Regional Support Office (RSO), and UN-SPIDER joined forces to conduct a virtual seminar on the use of the UN-SPIDER Recommended Practices to process satellite imagery to map the geographic extent of floods, and to elaborate a series of maps that allow government agencies, as well as regional and international organizations, to assess the severity of droughts in particular years in comparison to droughts in other years. The webinar, conducted on 4 August 2020, brought together more than 30 officers of government agencies of Mozambique, as well as researchers, faculty members and students from various universities.

During the event, researchers from UFSM made participants aware of efforts by the... read more

Regional Support Offices mentioned:

The coronavirus pandemic is compounding the impact of drought, which is already affecting more lives than ever with serious impact on health, the economy and the environment.

Droughts cannot be avoided but their impact can be mitigated by adopting a pro-active approach to drought risk management. In this webinar, a special focus will be given to innovative tools and measures, including monitoring and early warning systems, assessment and risk mitigation measures, in the context of the current pandemic.

... read more

Synthetic Aperture Radar (SAR) data can be acquired day and night, even in cloudy conditions, providing a dense time-series suitable for trend analysis and change detection.  Environmental applications for SAR data include:

  •     forest inventory, biomass estimation and condition monitoring
  •    ... read more

Actualités

Screenshot of the Earth Map platform.

Google and the Food and Agriculture Organization (FAO) of the United Nations have launched a new tool that provides access to multidimensional maps and statistics showing key climate and environmental trends. Earth Map draws on the processing power of Google Earth Engine and aims to help develop insights based on satellite and FAO’s agriculturally-relevant data alike. It follows the joint development by Google and FAO of the Collect Earth platform for forest and land cover assessments, and integrates with the... read more

Publishing date: 18/09/2020
A SpaceX Falcon 9 rocket launches the SAOCOM 1B satellite. Image: Manuel Mazzanti/CONAE

The Argentinean SAOCOM 1B satellite was successfully launched into orbit on 30 August 2020. Developed by the National Argentinean Space Commission (CONAE), this new satellite will join SAOCOM 1A and four Italian COSMO-SkyMed to complete the joint Italian-Argentinean Satellite System for Emergency Management (SIASGE). Like its predecessor, SAOCOM 1B was built in Argentina through a joint effort with private companies and universities. It will operate at an elevation of 620 kilometers above the surface of the Earth. A SpaceX Falcon 9 booster launched the satellite from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida, United States of America.

The SAOCOM 1B satellite has been fitted with a Synthetic Aperture Radar (SAR) sensor that makes use of microwaves in the electromagnetic L-band, which goes through clouds... read more

Publishing date: 14/09/2020
Regional Support Offices mentioned:
Screenshot of the FAO Hand-in-Hand geospatial platform.

The Food and Agriculture Organization of the United Nations (FAO) has launched a geospatial data platform that aims to help build stronger food and agriculture sectors post COVID-19. The Hand-in-Hand system provides access to a wide range of data on food, agriculture, socioeconomics and natural resources.

The platform features over one million geospatial layers and thousands of statistics series related to food security, crops, soil, land, water, climate, fisheries, livestock, forestry and more. It also includes information on COVID-19's impact on food and agriculture. A video describing the tool and its use cases is available online.

... read more
Publishing date: 09/09/2020
Tropical cyclone Fani over the eastern coast of India on 2 May 2019. Image: NASA.

According to the latest issue of an annual disaster statistics report, floods were the deadliest type of disasters in 2019, followed by extreme... read more

Publishing date: 20/08/2020
Areas flooded and damaged following cyclone Idai, northwest of Beira. Image: European Union/Christian Jepsen.

In recent years, Mozambique has suffered severe floods and droughts that have impacted urban and rural communities throughout the country. In the March and April 2019, tropical cyclones Idai and Kenneth triggered major floods in Mozambique, Malawi, Zimbabwe, and Comoros.  The Port of Beira was hard hit, as cyclone Idai destroyed transmission lines and bridges, leaving the port without access to these lifelines for several days.   In contrast the powerful El Niño event of 2016 triggered major droughts that affected most of the country. Thousands of farmers lost their crops and their cattle and had to rely on humanitarian assistance to cope with the impacts of this event.

Taking... read more

Publishing date: 10/08/2020
Regional Support Offices mentioned:

Data Source

Publishing institution: Food and Agriculture Organization of the United Nations (FAO)
The online platform features over one million geospatial layers and thousands of statistics series related to food security, crops, soil, land, water, climate, fisheries, livestock, forestry and more. It also includes information on COVID-19's impact on food and agriculture.

Pages

Hazard group

Terms in the same hazard group

Zircon - This is a contributing Drupal Theme
Design by WeebPal.