Global wetland loss reconstruction (1700-2020)

Overview

This repository contains scripts to reconstruct the spatial distribution and timing of wetland loss through conversion to seven human land uses between 1700 and 2020. The scripts process and combine national and subnational records of drainage and conversion with land-use maps and simulated wetland extents. The v1.01 reconstruction estimate that 3.4 million km2 (confidence interval 2.9–3.8) of inland wetlands have been lost since 1700, primarily for conversion to croplands, or a net loss of 21% (confidence interval 16–23%) of global wetland area.

Objectives: Produce a geospatial estimate of global wetland cover

• Estimate natural wetland extent converted to cropland and rice culture.
• Analyze changes in wetland area, rates of change across geographic regions and over time.

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Input data

National and subnational statistics of drained area

Regional

121 Independent estimates of wetland loss over specified areas and time periods. Databases of historical records of wetland conversion have been compiled for meta-analyses of wetland conversion rates (Asselen et al. 2013; Davidson 2014; Dixon et al. 2016; Paudel et al. 2012). Older records cover larger ill-defined areas associated with current day borders.

Present-day wetland area

• WAD2M
• GIEMSv2
• GLWD level-3

Simulated wetland cover

• Simulations from WETCHIMP: ORCHIDEE, SDGVM & DLEM (Wania et al. 2013; Melton et al. 2013)
• LPJ-Wsl (Zhang et al. 2016)

Land use reconstruction from HYDE3.2

• Cropland
• Rice cultivation
• Pasture
• Urban area

Land use reconstruction from LUHv2

• Forestry (primary & secondary)