Methodology

Strata uses a Convergence of Evidence approach to identify

Strata aggregates spatial data for climate, environmental, and peace and security stress indicators. It combines these with data layers on population exposure and socioeconomic vulnerability to produce hotspot maps highlighting where climate, environmental and security stresses overlap and where they coincide with populations vulnerable to these stresses.

The combination of data layers is based on the convergence of evidence approach developed by the European Commission’s Joint Research Center. In this approach, each indicator is assigned a threshold value, above which the indicator is “red flagged”, indicating a “level of concern”. The hotspot map shows the sum of all the red flags across the chosen indicators, weighted by the population exposure and vulnerability.

See the user guidebook and scientific article for more detailed information about Strata’s methodology.

Strata’s methodology provides:

  • → A transparent, robust theoretical framework
  • → A user-friendly and highly customisable experience
  • → Aggregation and disaggregation of selected stresses
  • → Full summary of the environmental, climate and socio-economic vulnerability conditions across the globe
  • → A multilevel approach from a sub-national to a global scale
  • → Support to users in their choice of actions and solutions

Visualise

Strata offers a variety of ways to visualise analytical results

Strata’s central feature is the hotspot map that visualises where environmental and climate-related stresses converge with insecurity and socio-economic vulnerability.

The hotspot results can be viewed as:

  • → A map showing the raw output of the hotspot calculation at the pixel scale available based on the selected indicators;
  • District and regional-level maps, in which the hotspot data is aggregated within political boundaries;
  • Charts and diagrams that deepen insights into specific regions and indicators.

Hotspot map and statistics for Ethiopia

Users can view the separate data layers feeding into the Strata hotspot map, including the individual stresses, exposure and vulnerability scores. Further, users can choose from various basemap options to identify locations below the hotspots, including satellite, terrain and hybrid options.

The maps, charts, and diagrams can be downloaded in picture format and as a data layer. The Strata Guidebook provides more information about the methodology, customisation, visualisation, and interpretation of the outputs.

Customise

On the left hand panel, Strata allows users to select indicators from different thematic baskets and run dedicated analysis.

Instead of the threshold as defined by default, you can set your own threshold for this indicator. Before using advanced options, we recommend you read the section on indicators and thresholds in the User Guide since each indicator threshold is uniquely defined.

The code-free analysis and dashboard is powered by Earth Map. The data incorporated in Strata is sourced from public, trusted sources of which most are available on Google Earth Engine.

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FAQ

Frequently asked questions

    General

  • Who can use Strata?:

    Strata can be used by anyone interested in exploring the convergence of environmental and climate stressors with social and economic variables relevant to peace and stability. Strata has been developed for analysts, practitioners and policymakers in climate change adaptation, ecosystem management, and peace and security. Its objective is to streamline data and insights on climate-related risks to peace in their daily work and to support informed decision-making and policy and programme development. It can also be a useful tool for researchers and students.

  • Is Strata free?

    Yes, Strata is an environmental digital public good and is free to use.

  • How do I get started?

    Access the platform at strata.earthmap.org or browse our Quick Start Guide.

  • What can Strata do?

    Strata includes many features like a hotspot map highilighting areas at risks of environmental and climate stressors with social and economic variables relevant to peace and stability; visualisation of individual layers including climate projections; details statistics on the hotspots; a pixel inspector; and easy export and sharing options.

    • Tools, methodology and interpretation

    • What is the convergence of evidence approach, and how does it work?

      To combine the indicators across the three baskets into a hotspot map, Strata uses a methodology based on a Convergence of Evidence approach: a methodology developed by the European Commission Joint Research Centre for the World Atlas of Desertification.

      For each of the selected variables related to climate and environmental security, a threshold is defined above the level of that variable that is considered a stress. The Convergence of Evidence approach stacks all the data layers of the selected indicator and counts how many of them surpass a critical threshold. The hotspot map shows the sum of all the red flags, i.e., the number of indicators that passed their threshold across the chosen indicators, weighted by the population exposure and vulnerability. Some indicators have absolute thresholds fixed across all locations (e.g., peace and security); others have thresholds relative to past conditions (e.g. drought and deforestation) or relative to other locations (e.g. internally displaced people and access to healthcare).

    • Can Strata be used to predict future conditions?

      No, Strata has no predictive or future modelling capacity.

      However, STRATA does include supplementary information indicators of flood likelihood, precipitation, and temperature based on the International Panel on Climate Change (IPCC) Shared Socioeconomic Pathways (SSPs) 4.5 and 8.5, for the years 2030, 2050, and 2080. For more information and a detailed description of those auxiliary datasets available on Strata, consult the documentation above.

    • How does Strata define hotspots?

      Within Strata, a hotspot is a location where there is a convergence of stresses related to climate and environment, socioeconomic vulnerability, and peace and security. A hotspot implies that further attention is required in that location; it does not mean an event has occurred, nor does it imply any quantitative probability of anything occurring.

      • Data

      • What are the main indicators I can research through the platform?

        Strata works with baskets of indicators: * Climate and environment: Drought (agricultural), drought (meteorological), heatwave, deforestation, land degradation, flood likelihood, and coastal inundation risk. * Peace and security: Recent explosions/remote violence, recent violence against civilians, recent protests, recent riots, history of battles. * Socioeconomic vulnerability: Population density, percentage of elderly, children, and female population, number of internally displaced people, urban expansion, travel time to urban area, sanitation (freshwater availability), access to electricity and healthcare, irrigation, and food insecurity. * Climate projections: Predictive trends for flood likelihood (future), precipitation (future), and minimum and maximum temperature (future).

        Details of the data sources and thresholds used for each indicator can be found in the Overview of indicators and data sources

      • Where does the data used in Strata come from?

        Strata uses publicly available geospatial datasets, most of them derivatives of satellite imagery. All datasets incorporated into Strata have been tested and validated scientifically to a defined set of criteria relevant to climate security and the provision of safe and trusted data. The data sources for each indicator are specified on the online platform. Details on all the data sources are explicitly included in the Overview of Indicators.

      • What should I do if I believe a dataset is inaccurate?

        We are always looking to improve our data. If you are experiencing issues with a dataset or believe it is outdated or inaccurate, please contact our support team as described in the Contact tab.

      • How do I cite Strata?

        UNEP Strata 2024. United Nations Environment Programme. unepstrata.org (date accessed: Day Month Year).

        Please note that citation of the original data provider(s) is required for any map created on the platform. This is a requirement for the use of many datasets, and is standard good practice. Links and references to the original data providers can be found in the platform itself and in the Overview of indicators and data sources.

Got more questions? Contact us.