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

SAM Satellite

Landsat 1 was launched on July 23, 1972; at that time the satellite was known as the Earth Resources Technology Satellite (ERTS). It was the first Earth-observing satellite to be launched with the express intent to study and monitor our planet’s landmasses. To perform the monitoring, Landsat 1 carried two instruments: a camera system built by the Radio Corporation of America (RCA) called the Return Beam Vidicon (RBV), and the Multispectral Scanner (MSS) built by the Hughes Aircraft Company. The RBV was supposed to be the prime instrument, but the MSS data were found to be superior. In addition, the RBV instrument was the source of an electrical transient that caused the satellite to briefly lose altitude control, according to the Landsat 1 Program Manager, Stan Weiland.
To help understand the data and to explore the potential applications of this new technology, NASA oversaw 300 private research investigators. Nearly one third of these were international scientists. These... read more

Launch date:
23/07/1972

News

UN-SPIDER / ZFL Regional Virtual Expert Meeting for Southern Africa

Southern Africa is exposed to hydrometeorological, geological, coastal and biological hazards.  The region has been hard hit by droughts in recent years. Tropical cyclone Idai triggered massive floods in Mozambique, Malawi, and Zimbabwe in March 2019, and in 2020 several countries experience a severe locust outbreak.  And unfortunately, COVID-19 continues to impact all countries in this region.

To continue efforts to promote the use of space technologies in disaster risk management, emergency response and recovery efforts, UN-SPIDER and the Centre for Remote Sensing of Land Surfaces of the University of Bonn (ZFL) joined forces to organize the UN-SPIDER / ZFL Regional Virtual Expert Meeting for Southern Africa "Space-based Solutions for Disaster Risk Management and Emergency Response" from 13 to 15 July 2021. This regional expert meeting contributed to the efforts conducted by UN-SPIDER on disaster risk reduction, preparedness, early warning systems, disaster response... read more

Publishing date: 20/07/2021
Special Report on Drought 2021

Droughts have extensive and profound repercussions on populations, livelihoods, ecosystems, and economies. The most vulnerable people are unduly affected by their financial consequences. Although droughts affect millions, lead to food shortages, poverty, and inequality, their immense and widespread effects are often underreported.

Climate change is aggravating the intensity, duration, and prevalence of droughts globally through rising temperatures and disturbances of rainfall patterns. Within the next 80 years, climate change will be the primary cause of the increased drought exposure of 129 countries (Smirnov et al., 2016). As global temperatures rise due to climate change, pressing action is needed to manage the risks related to droughts, and to diminish their destructive impact on human lives, livelihoods, and ecosystems.

On 17 June 2021, the... read more

Publishing date: 18/06/2021
Participants at the UN-SPIDER/ANDMA meeting

The United Nations Platform for Space-based Information for Disaster Management and Emergency Response (UN-SPIDER) and the Office of the State Ministry for Disaster Management and Humanitarian Affairs of the Islamic Republic of Afghanistan (ANDMA) carried out a virtual thematic meeting on ‘Assessing Drought and Water Resources Conservation Using Earth Observation’, in collaboration with Delta State University and the International Water Management Institute (IWMI). All key stakeholders involved in disaster risk reduction, especially dealing with drought, attended the meeting which was chaired by His Excellency Deputy Minister Mohammad Qasim Haidari. This meeting, held on 26 May 2021, is part of the UN-SPIDER Technical Advisory Support to Afghanistan. It was attended by 48 participants representing national and international organisations supporting the activities related to disaster management in... read more

Publishing date: 09/06/2021
The Niger Delta. Image: ESA.

In recent decades, communities in Nigeria have experienced disasters triggered by floods, droughts, landslides, coastal erosion, oil spills, and other natural and technological hazards that have eroded hard-won development gains. Taking note of advances in space technologies and other technological innovations.

Since 2008, the UN-SPIDER programme of the Office for Outer Space Affairs of the United Nations (UNOOSA) has been providing technical advisory support to several African countries in order to facilitate the use of space technologies and space-based information in disaster risk, preparedness, response and recovery activities.  Taking note of the advances in space technologies and other technological advances, in June 2009 the National Space Research and Development Agency of Nigeria (NASRDA) signed a cooperation agreement with UNOOSA to become a Regional Support Office; and in June 2011 UN-SPIDER conducted a technical advisory mission to Nigeria to take note of... read more

Publishing date: 14/04/2021
Regional Support Offices mentioned:

Event

Introduction

Space-based applications related to Earth Observation and geospatial data play an important role in supporting disaster risk reduction, ... read more

Regional Support Offices mentioned:
The Niger Delta. Image: ESA.

To continue efforts to make use of the opportunities made available by the space community, UN-SPIDER, NASRDA, NEMA, NIHSA and the Centre for Remote Sensing of Land Surfaces of the University of Bonn (ZFL) joined forces to carry out the UN-SPIDER/NASRDA/NEMA/NIHSA/ZFL National Virtual Expert Meeting on the use of Space-based Solutions for Disaster Risk Management and Emergency Response in Nigeria. The virtual expert meeting focused on the use of space technologies to improve disaster risk reduction in Nigeria. Specifically, the goal of the meeting was to contribute to the efforts conducted by NEMA in the area of disaster risk reduction, preparedness, early warning systems, disaster response and recovery efforts. Outcomesof this Expert Meeting included, but were not limited to:

  • Enhancing space-based disaster management efforts in Nigeria
  • Improving capacity to use earth observation data to manage disasters in Nigeria
  • ... read more

Data Source

Copernicus Open Access Hub. Image Credit: ESA.
Publishing institution: European Space Agency (ESA)
The Copernicus Open Access Hub provides complete, free and open access to Sentinel missions data.

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