Good Practice Guidance SDG Indicator 15.3.1 Proportion of land that is degraded over total land area Version 2.0 – Advanced unedited version March 2021 Citation Sims, N.C., Newnham, G.J., England, J.R., Guerschman, J., Cox, S.J.D., Roxburgh, S.H., Viscarra Rossel, R.A., Fritz, S. and Wheeler, I. 2021. Good Practice Guidance. SDG Indicator 15.3.1, Proportion of Land That Is Degraded Over Total Land Area. Version 2.0. United Nations Convention to Combat Desertification, Bonn, Germany. Published in 2021 by United Nations Convention to Combat Desertification (UNCCD), Bonn, Germany © 2017 UNCCD. All rights reserved. ISBN 978-92-95118-28-7 (hard copy) ISBN 978-92-95118-29-4 (e-copy) Acknowledgements This Good Practice Guidance for SDG Indicator 15.3.1 was edited from a report prepared by Commonwealth Scientific and Industrial Research Organisation (CSIRO) for the United Nations Convention to Combat Desertification (UNCCD). Lead Authors Neil C. Sims (CSIRO), Glenn J. Newnham (CSIRO), Jacqueline R. England (CSIRO), Juan Guerschman (CSIRO), Simon J. D. Cox (CSIRO), Stephen H. Roxburgh (CSIRO), Raphael A. Viscarra Rossel (Curtin University), Steffen Fritz (IIASA) and Ichsani Wheeler (OpenGeoHub). Contributors and Reviewers Sasha Alexander, Pablo Viegas Aurelio, Megan Balks , Niels Batjes, Costanza Calzolari, Michael Cherlet, Bram Edens , Gabriel Daldegan, Alastair Graham, Mariano Gonzalez-Roglich, Nichole Harari, Antje Hecheltjen , Uta Heiden, Martin Herold , Alfredo Huete, Eva Ivitis, Ian Jarvis, Flora Kerblat, Brian Killough, Andre Kooiman, Xiaosong Li, Erik Lindquist, Hanspeter Liniger, Richard Lucas, Anna Luise, Zhongkui Luo, Graham von Maltitz, Sara Minelli, Cristine Morgan, Norman Mueller, Brian O’Connor, Barron J. Orr, Marc Paganini, Keith Paustian, Laura Poggio, Harifidy Rakoto Ratsimba, Marcelo Rezende, Ronald Vargas, Yusuf Yigini, Alex Zvoleff. Publication Coordinator: Sara Minelli Design and layout: Disclaimer The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the United Nations Convention to Combat Desertification (UNCCD) concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or products of manufacturers, whether or not these have been patented, does not imply that these have been endorsed or recommended by the UNCCD in preference to others of a similar nature that are not mentioned. The views expressed in this information product are those of the authors or contributors and do not necessarily reflect the views or policies of the UNCCD. The views expressed in this information product are those of the authors and do not necessarily reflect the views or policies of the UNCCD. This publication was made possible with the support of the Global Support Programme funded by Global Environment Facility. Good Practice Guidance | SDG Indicator 15.3.1 ii Foreword (TBP) Good Practice Guidance | SDG Indicator 15.3.1 iii Executive Summary This Good Practice Guidance (GPG) document provides guidance on how to calculate the extent of land degradation for reporting on United Nations (UN) Sustainable Development Goal (SDG) Indicator 15.3.1: the proportion of land that is degraded over total land area. This guidance supports implementation of the Tier I methods for Indicator 15.3.1 adopted by the UN Statistical Commission1, and the development of analytical methods for measuring its three sub-indicators, which are: 1. Trends in land cover 2. Trends in land productivity 3. Trends in carbon stocks (above and below ground), which is currently represented by soil organic carbon (SOC) stocks. The Indicator is calculated by integrating the sub-indicators using a one-out-all-out (1OAO) method, in which a significant reduction or negative change in any one of the three sub-indicators is considered to comprise land degradation. Significant reductions can be identified using statistical criteria, or by a qualitative assessment of the magnitude of change. The Indicator is reported as a binary quantification (i.e., degraded/not degraded) of the extent of degraded land in hectares, and expressed as the proportion (percentage) of land that is degraded over total land area. Version 2 of the GPG incorporates a number of advances in the quality and availability of datasets, as well as analytical methods for calculating Indicator 15.3.1 and its sub-indicators that have emerged since publication of Version 1 of the GPG (Sims et al. 2017). These advances have been identified through research, stakeholder engagement, including analysis of recommendations from countries reporting on Indicator 15.3.1 in the first reporting period in 2018, and reviews of drafts of this report by global experts in relevant fields. This report also incorporates new developments from the growing number of publications and initiatives focussed on improving the quality and availability of data and analytics for the SDGs in general, and Indicator 15.3.1 and Land Degradation Neutrality (LDN) in particular. While the measurements of Indicator 15.3.1 form only one part of the assessment of LDN, the relationship between the Indicator and LDN is discussed in more detail in Version 2 (this document), and additional guidance on the calculation and use of measurements during the baseline period should clarify the interpretation of Indicator 15.3.1 for monitoring LDN. The guidance covers three sub-indicators. The Land Cover sub-indicator reports degradation in land cover change based on a national assessment of the positive or negative aspects of transitions from one land cover type to another. In Version 2, this chapter highlights the need for countries to first consider the main drivers of land cover change, and then to determine which transitions to identify as degraded for reporting on Indicator 15.3.1. This chapter incorporates updates to the quality of available land cover datasets and classification methods. 1 https://unstats.un.org/sdgs/metadata/files/Metadata-15-03-01.pdf Good Practice Guidance | SDG Indicator 15.3.1 iv The Land Productivity sub-indicator reports productivity degradation using Earth Observation (EO) data to monitor changes in Net Primary Productivity (NPP) of vegetation. This assessment is based on three metrics, calculated from a time series of annual NPP observations, that are designed to identify changes in the trajectory and level of productivity. The statistical methods for assessment of each of the three metrics have been simplified and improved in Version 2 of the GPG, and they can now be interpreted in terms of the severity of degradation and the confidence of the assessment. A revision of the methods for combining the metrics also enables degradation to be identified in a range of additional phases of the long-term productivity cycle, including situations in which productivity is stable for a long period of time, or is increasing but where the level of productivity is low. The Carbon Stocks sub-indicator has been significantly revised in light of updates and new guidance from the 2019 Refinement to the Intergovernmental Panel on Climate Change (IPCC) 2006 Guidelines for National Greenhouse Gas Inventories, and now includes expanded guidance on the methods for assessment of ‘significant’ change in Soil Organic Carbon (SOC) stocks. This chapter now also incorporates updates to the data sources available for estimating change in SOC stocks since the publication of version 1 of the GPG. In addition to improved guidance on the calculation of the methods, Version 2 provides more guidance on the interpretation and reporting of degradation, based on country recommendations following the 2018 reporting period. This includes guidance on how to identify false positive or false negative outcomes in cases where the degradation analysis of the 1OAO process may produce a counterintuitive outcome, such as where land remediation activities to remove invasive weeds reduces the apparent NPP in EO data, which would normally indicate degradation despite this being an activity to improve the condition of the land. Additional guidance is provided on recalculating the time-series data sets, following the adoption of new and improved datasets into the analysis, based on similar guidance provided by the IPCC. In most cases there is likely to be an overlapping period where both the former and new datasets are available, and the differences measured between them can be used to interpret or estimate missing values. Guidance on assessing the magnitude of degradation, and on identifying ‘brightspots’ and ‘hotspots’ is a new addition to the GPG. This information can be used to balance ‘losses’ to degradation against ‘gains’ in the area that improves from a degraded state. It can also be used to identify local areas of the highest degradation severity, which may be useful in optimising efforts to restore degraded lands, or avoid degrading new land in future, consistent with the achievement of LDN. Good Practice Guidance | SDG Indicator 15.3.1 v Contents Executive Summary ....................................................................................................................... iv Glossary of terms, definitions and concepts ...................................................................................... xii 1 Introduction ..........................................................................................................................