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

Actualités

Report cover page. Image: UNESCAP.

The United Nations Economic and Social Commission for Asia and the Pacific (ESCAP) has published a policy study concerning the impending climate risk scenarios in South Asia and their intersection with the COVID-19 pandemic. The aim of this report is to facilitate policy actions that could protect communities at risk as well as to lay the foundations of resilient recovery of the most vulnerable in South Asia. 

ESCAP has published two additional reports this year, one on the “Impact and Policy Responses for COVID-19 in Asia and the Pacific”, which presents an initial assessment of the COVID-19 pandemic in Asia and sub-regional report entitled “COVID-19 and South Asia: National Strategies and Subregional Cooperation for Accelerated Inclusive, Sustainable and Resilient Recovery”, which provides a comprehensive situation analysis of South Asia. This newly published policy study is hence an addition to the previous reports and sheds light on how to manage... read more

Publishing date: 23/07/2020
Image: UNFPA.

In the latest example of anticipatory humanitarian action, the United Nations released $5.2 million from the Central Emergency Response Fund (CERF) to help communities in Bangladesh prepare themselves ahead of major monsoon floods. The allocation of funds to agencies in the country to prepare to deliver support was triggered by a forecast from the Global Flood Awareness System (GloFAS), which predicted areas having a greater than 50 per cent chance of experiencing a severe flood between 14 and 16 July. Following a second forecast by the Government’s Flood Forecasting & Warning Centre (FFWC) on 11 July, aid workers began distributing the aid.

The swift assistance provided in Bangladesh comes as United Nations Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator Mark Lowcock has agreed to allocate up to $140 million from the UN... read more

Publishing date: 21/07/2020

Data Source

Advisory Support

UN-SPIDER conducted a Institutional Strengthening Mission in Sri Lanka from 24 to 28 April 2017. Th ISM was a follow-up to the technical advisory mission to Sri Lanka in 2011. Both the original mission and the follow-up activity were hosted by the Ministry of Disaster Management of Sri Lanka and its associated Disaster Management Centre.

Mission dates: 24/04/2017 to 28/04/2017

This mission was conducted with the Director of the Office for Outer Space Affairs as a way to strengthen the link between the National Emergency Commission of the Dominican Republic and UN-SPIDER, and took place from 18 July 2016 to 22 July 2016 in Santa Domingo, Dominican Republic.

Mission dates: 18/07/2016 to 22/07/2016

Recommended Practices

Observing rainfall is an essential component of detecting droughts and developing drought early warning systems. This recommended practice shows how to use satellite data to analyse precipitation timelines to gain information about the spatial ditribution of rainfall anomalies using the Standarized Precipitation Index (SPI).    

Événement

WCDM 2020 picture of floods. Image: WCDM

World Congress on Disaster Management (WCDM) is a unique initiative of DMICS to bring researchers, policy makers and practitioners from around the world in the same platform to discuss various challenging issues of disaster risk management. The mission of WCDM is to promote interaction of science, policy and practices to enhance understanding of risks and advance actions for reducing risks and building resilience to disasters.

The Conference will discuss various topics, including:

  • Remote Sensing, GIS and Drones for Disaster Risk Management
  • Early Warning of Hydro-Meteorological Disasters: Tasks Ahead
  • Early Warning of Earthquakes: How Far, How Near
  • Operationalising Early Warning of Landslides
  • Application of Artificial Intelligence for Managing Risks of Disasters
  • Emerging Technologies for Climate & Disaster Resistant Agriculture
The Conference will provide in-depth analysis of the following... read more
Global Congress on Climate Resilience and Disaster Risk Reduction logo. Image: CEED
The major thrives of this congress will be discuss and develop an integrated Climate Resilience Ecosystem that will address Future Disaster Risk Reduction and Capacity Development of Vulnerable Communities for Sustainable & Inclusive Growth and Subsequently publish a White Paper that will be submitted to the Government of India and the State Government.
 
The Conference will discuss different topics, including:
  • Application of GIS & Remote Sensing for Integrated Disaster Risk Reduction
  • Costal Vulnerability and Adaption strategies
  • Water Security and Risk Management
  • Management of Solid Waste for Sustainable Development
  • Climate and Carbon Financing
  • Sustainability and Inclusive Growth
  • Extreme weather Events
  • Global Warming and Coastal Risks
  • Multi hazard Early Warning Systems
  • Water Resource Sustainability and Security
  • Application of GIS& RS for... read more
EO4SD logo. Image ESA

The European Space Agency’s Earth Observation for Sustainable Development (EO4SD) Climate Resilience Cluster is hosting a free webinar to provide insight about the potential of Earth Observation (EO) to support climate-resilient decision making at the regional and national scale.

Drought is one of the main natural causes of agricultural, economic, and environmental damage. The effects of drought on the environment and agriculture are evident after a long period with a shortage of precipitation, making it very difficult to determine the onset of drought, its extent and end. The EO time-series datasets can build understanding about the scale of effects associated with different drought impacts, helping to develop early food security assessments in specific geographic areas or contingency planning and emergency preparedness for future shocks in a country. It can also improve understanding of the drivers and causes of food insecurity in areas and identify which... read more

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