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

Data Source

News

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:
Agricultural drought in Ethiopia. Image: WFP/Stephanie Savariaud

In recent years, droughts have been impacting several regions of the world on a more frequent and severe basis. The long-lasting effects of such droughts are taking a toll on farmers and their livelihoods, forcing some of them to seek alternate sources of income through migration to cities in their countries and in other countries in extreme cases. The World Meteorological Organization identifies droughts as the most damaging natural hazard due to their long-term socio-economic impact. According to the Food and Agriculture Organization of the United Nations (FAO), droughts are the “single greatest culprit of agricultural production loss”.

A drought generally refers to “an extended period of unusually low precipitation that produces a shortage... read more

Publishing date: 22/03/2021
Crops in Kenya. Image: RCMRD.

A variety of environmental and man-made factors can have a detrimental effect on the yield of farmers worldwide. A programme launched in Kenya, funded by SERVIR in collaboration with NASA Harvest and the Swiss Re Foundation, uses Earth observation (EO) data to assess crop damage and prioritise the mobilisation of financial aid to farmers.

SERVIR is a joint initiative by the U.S. Agency for International Development (USAID) and NASA’s Earth Applied Sciences Program that works with “leading regional organizations world-wide to help developing countries use information provided by Earth observing satellites and geospatial technologies for managing climate risks and land use”. SERVIR both provides access to EO... read more

Publishing date: 03/03/2021
Cover of the JRC Atlas of the Human Planet 2020 report. Image: Joint Research Centre (JRC) of the European Commission.

A new report outlines the impact of Global Human Settlement Layer (GHSL) data on various policy areas. The 2020 edition of the “Atlas of the Human Planet”, recently published and launched virtually by the Joint Research Centre (JRC) of the European Commission as a deliverable to the Group on Earth Observations (GEO) Human Planet Initiative, explores the impact of GHSL data on various policy areas, including disaster risk management.

GHSL data refers to “global spatial information, evidence-based analytics and knowledge describing the human presence on the planet”. This data relies on spatial information from Landsat 8, Sentinel-1 and Sentinel-2. It is mainly cost-free and... read more

Publishing date: 18/02/2021
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A knowledge platform for adaptation action on climate change recently updated the information, layout and logo of their website. With this step, adaptationcommunity.net aims to improve the user experience of the online platform and consequently facilitate the access to a wide variety of resources on climate change adaptation action, including tools working with Earth observation data.

Adaptation action in the context of climate change refers to “adjustments in ecological, social, or economic systems in response to actual or expected climatic stimuli and their effects or impacts. It refers to changes in processes, practices, and structures to moderate potential damages or to benefit from opportunities... read more

Publishing date: 12/02/2021

Event

The Niger Delta. Image: ESA.

To continue efforts to make use of the opportunities made available by the space community, UN-SPIDER, NASRDA, NEMA 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/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
  • Raising... read more
Artwork for Hydrospace-GEOGloWS 2021. Image: ESA.

The European Space Agency, in the context of the "Earth Observations Science for Society" Programme, and CNES are organising a sequel event to Hydrospace2015, called 4th Space for Hydrology Workshop - "Inland Water Storage and Runoff: Modeling, In Situ Data and Remote Sensing", Monday 7 - Friday 11 June 2021, hosted at ESA-ESRIN, Frascati, Italy. This time around the Hydrospace Workshop is organised in collaboration with the GEO Global Water Sustainability Initiative (GEOGloWS) - see the Objectives page - looking for opportunities to explore joint solutions with a broader view on key science questions for Research and Development, up to Operational use of remote sensing information. The aim of getting together during 4~4.5 days is to strengthen the collaboration between the four critical water communities: in situ, modelling and space observation scientists as well as “non-scientific” users such as water managers to address the needs of the application community.

Banner for the Planet Labs/Copernicus EMS Virtual Panel. Image: Planet Labs/Copernicus EMS.

The role of the Earth Observation industry in emergency situations and crisis response has significantly grown in recent years. Climate change brought forest fires, floods and other emergency states that have put Earth Observation and its data to the forefront. Data provided by the Earth Observation industry provides insights that allow emergency services to put their action plan in place appropriately and act timely. During this panel we will talk about Earth Observation data's role in emergency prevention, response and recovery mapping in the context of Copernicus Emergency Management Services and other emergency services.

Panelists:

  • Jens Danzeglocke, Space Administration & Earth Observation, German Aerospace Center (DLR)
  • Franck Ranera, Strategic Partner Development Manager, Serco
  • Philippe Campenon, Government Sales, Planet Labs
  • Moderator: Annett Wania, Innovation Project Manager, Planet Labs

The event will take... read more

SEDAC POPGRID Viewer. Image: NASA

Having reliable and timely population distribution data can make a life or death difference for individuals facing crises or living in conflict-ridden regions. These data are also essential for development decision-making and planning and for monitoring progress towards the UN Sustainable Development Goals (SDGs) established by the international community. We need to know where people are located, what conditions they are facing, what infrastructure is available, and what basic services they can access. We also need to ensure that no one is left off the map in pursuit of meeting the SDGs. 

Gridded population data, which often use remote sensing inputs to improve the spatial allocation of population within a country, are vital for all these purposes. Together with the  growing variety of applications that require spatial population data, there is now a bewildering array of population grids, and users need to know which ones are most suitable for their applications.

... read more

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