The Office for National Statistics’s (ONS’s) Data Science Campus has developed a new tool, which can help countries around the world to keep track of changes to the surface area of large bodies of water.

The new tool has the potential to help countries monitor and measure changes to large scale water ecosystems over time, which could be caused by impacts from human interactions with the environment such as climate change. The tool takes processed imagery from the Global Surface Water Explorer (GSWE), as developed by the United Nations, the European Commission Joint Research Centre and Google, and uses a number of processes to transform this into tables and maps, which can be used by governments to create clear measurements to show changes over time.

Early analysis of using the tool on UK data suggests that, when looking at large bodies of water, from 1984 to 2019:

  • 50% of the UK's permanent surface inland water was in Scotland, while Northern Ireland contained 31% and England and Wales together only contained 19%

  • Northern Ireland had the area with the largest concentration of inland surface water, which included Loch Neagh, the UK's largest lake

  • England held an average of 57% and 43% of all temporary and seasonal inland surface waters respectively

When taking into account anomalies such as heavy cloud cover, which might affect the quality of satellite imagery data on certain years, the overall extent of permanent water seems to have stayed relatively stable. There is some evidence of a slight increase since 1984 but more detailed analysis is needed to understand the full extent of this.

The United Nations requires countries around the world to report "changes in the extent of water-related ecosystems over time" as part of the Sustainable Development Goals (SDGs), which they describe as providing the world with a "blueprint to achieve a better and more sustainable future for all".

As a result, the UK is for the first time able to publicly report progress on the clean water and sanitation SDG indicator (6.6.1), 'Measuring how large bodies of water are changing', to monitor the impact of climate change and other stressors on water at a national level.

Joanne Evans, Head of International Collaboration for Sustainable Development Goals at the ONS, said:

"With this tool we are finally able to give a measure to track changes to precious water sources. The important thing about this tool is that because it uses a publicly available global data source, countries around the world, including those in the developing world who are most likely to be negatively affected by climate change, can also use it for free.

"At the ONS we have an important duty to report data on behalf of the UK for the United Nations' SDGs to help provide comparable measures for the country's progress on a range of environmental and sustainability issues. This tool helps us to get closer to ensuring we are giving a full picture of progress towards a more sustainable future."

Full report and blog can be read on the Data Science Campus website.

Notes to editors
  • These data used Landsat imagery with a pixel resolution of 30 metres (900 square metres), which therefore means that we do not have data for smaller water bodies (including small lakes, rivers and streams).

  • In addition, the tool currently only gives data on open water, which cannot yet be separated into natural water bodies (for example, lakes) and man-made water bodies (for example, reservoirs).

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