Chapter 4: Land Degradation - IPCC

1 Final Government Distribution Chapter 4: IPCC SRCCL Subject to Copy-editing 4-1 Total pages: 186 Chapter 4: Land Degradation 1 2 Coordinating Lead Authors: Lennart Olsson (Sweden), Humberto Barbosa (Brazil) 3 Lead Authors: Suruchi Bhadwal (India), Annette Cowie (Australia), Kenel Delusca (Haiti), Dulce 4 Flores-Renteria (Mexico), Kathleen Hermans (Germany), Esteban Jobbagy (Argentina), Werner Kurz 5 (Canada), Diqiang Li (China), Denis Jean Sonwa (Cameroon), Lindsay Stringer (United Kingdom) 6 Contributing Authors: Timothy Crews (The United States of America), Martin Dallimer (United 7 Kingdom), Joris Eekhout (The Netherlands), Karlheinz Erb (Italy), Eamon Haughey (Ireland), 8 Richard Houghton (The United States of America), Muhammad Mohsin Iqbal (Pakistan), Francis X.

2 9 Johnson (The United States of America), Woo-Kyun Lee (The Republic of Korea), John Morton 10 (United Kingdom), Felipe Garcia Oliva (Mexico), Jan Petzold (Germany), Mohammad Rahimi (Iran), 11 Florence Renou-Wilson (Ireland), Anna Tengberg (Sweden), Louis Verchot (Colombia/The United 12 States of America), Katharine Vincent (South Africa) 13 Review Editors: Jos Manuel Moreno Rodriguez (Spain), Carolina Vera (Argentina) 14 Chapter Scientist: Aliyu Salisu Barau (Nigeria) 15 Date of Draft: 07/08/2019 16 17 Final Government Distribution Chapter 4: IPCC SRCCL Subject to Copy-editing 4-2 Total pages: 186 1 Table of Contents 2 Chapter 4: Land Degradation .. 4-1 3 Executive Summary .. 4-4 4 Introduction.

3 4-8 5 Scope of the Chapter .. 4-8 6 Perspectives of land Degradation .. 4-8 7 Definition of land Degradation .. 4-9 8 Land Degradation in previous IPCC reports .. 4-10 9 Sustainable land management and sustainable forest management .. 4-11 10 The human dimension of land Degradation and forest Degradation .. 4-14 11 Land Degradation in the context of climate change .. 4-15 12 Processes of land Degradation .. 4-16 13 Drivers of land Degradation .. 4-25 14 Attribution in the case of land Degradation .. 4-26 15 Approaches to assessing land Degradation .. 4-30 16 Status and current trends of land Degradation .. 4-33 17 Land 4-33 18 Forest Degradation .. 4-36 19 Projections of land Degradation in a changing climate.

4 4-40 20 Direct impacts on land 4-40 21 Indirect impacts on land Degradation .. 4-45 22 Impacts of bioenergy and technologies for CO2 removal (CDR) on land Degradation .. 4-46 23 Potential scale of bioenergy and land-based CDR .. 4-46 24 Risks of land Degradation from expansion of bioenergy and land-based CDR .. 4-46 25 Potential contributions of land-based CDR to reducing and reversing land degradation26 4-47 27 Traditional biomass provision and land Degradation .. 4-48 28 Impacts of land Degradation on climate .. 4-49 29 Impacts on greenhouse gases .. 4-50 30 Physical impacts .. 4-51 31 Impacts of climate-related land Degradation on poverty and livelihoods .. 4-53 32 Relationships between land Degradation , climate change and poverty.

5 4-53 33 Impacts of climate related land Degradation on food security .. 4-56 34 Impacts of climate-related land Degradation on migration and conflict .. 4-57 35 Addressing land Degradation in the context of climate change .. 4-58 36 Final Government Distribution Chapter 4: IPCC SRCCL Subject to Copy-editing 4-3 Total pages: 186 Actions on the ground to address land Degradation .. 4-59 1 Local and indigenous knowledge for addressing land Degradation .. 4-63 2 Reducing deforestation and forest Degradation and increasing afforestation .. 4-64 3 Sustainable forest management and CO2 removal technologies .. 4-65 4 Policy responses to land Degradation .. 4-67 5 Resilience and thresholds .. 4-69 6 Barriers to implementation of sustainable land management.

6 4-71 7 Case-studies .. 4-73 8 Urban green infrastructure .. 4-74 9 Perennial Grains and Soil Organic Carbon .. 4-76 10 Reversing land Degradation through reforestation .. 4-79 11 Degradation and management of peat soils .. 4-82 12 Biochar .. 4-84 13 Management of land Degradation induced by tropical cyclones .. 4-87 14 Saltwater intrusion .. 4-89 15 Avoiding coastal maladaptation .. 4-91 16 Knowledge gaps and key uncertainties .. 4-92 17 Frequently Asked Questions .. 4-93 18 References .. 4-94 19 20 21 Final Government Distribution Chapter 4: IPCC SRCCL Subject to Copy-editing 4-4 Total pages: 186 Executive Summary 1 Land Degradation affects people and ecosystems throughout the planet and is both affected by 2 climate change and contributes to it.

7 In this report, land Degradation is defined as a negative trend 3 in land condition, caused by direct or indirect human-induced processes including anthropogenic 4 climate change, expressed as long-term reduction or loss of at least one of the following: biological 5 productivity, ecological integrity, or value to humans. Forest Degradation is land Degradation which 6 occurs in forest land. Deforestation is the conversion of forest to non-forest land and can result in land 7 Degradation . { } 8 Land Degradation adversely affects people s livelihoods (very high confidence ) and occurs over a 9 quarter of the Earth s ice-free land area (medium confidence ). The majority of the to 10 billion affected people (low confidence ) are living in poverty in developing countries (medium 11 confidence ).

8 Land use changes and unsustainable land management are direct human causes of land 12 Degradation (very high confidence ), with agriculture being a dominant sector driving Degradation 13 (very high confidence ). Soil loss from conventionally tilled land exceeds the rate of soil formation by 14 >2 orders of magnitude (medium confidence ). Land Degradation affects humans in multiple ways, 15 interacting with social, political, cultural and economic aspects, including markets, technology, 16 inequality and demographic change (very high confidence ). Land Degradation impacts extend beyond 17 the land surface itself, affecting marine and freshwater systems, as well as people and ecosystems far 18 away from the local sites of Degradation (very high confidence ).

9 { , , , , , , 19 Table } 20 Climate change exacerbates the rate and magnitude of several ongoing land Degradation 21 processes and introduces new Degradation patterns (high confidence ). Human-induced global 22 warming has already caused observed changes in two drivers of land Degradation : increased 23 frequency, intensity and/or amount of heavy precipitation (medium confidence ), and increased heat 24 stress (high confidence ). Global warming beyond that of present-day will further exacerbate ongoing 25 land Degradation processes through increasing floods (medium confidence ), drought frequency and 26 severity (medium confidence ), intensified cyclones (medium confidence ), and sea-level rise (very high 27 confidence ), with outcomes being modulated by land management (very high confidence ).

10 Permafrost 28 thawing due to warming (high confidence ), and coastal erosion due to sea level rise and impacts of 29 changing storm paths (low confidence ), are examples of land Degradation affecting places in which it 30 has not typically been a problem. Erosion of coastal areas because of sea level rise will increase 31 worldwide (high confidence ). In cyclone prone areas the combination of sea level rise and more 32 intense cyclones will cause land Degradation with serious consequences for people and livelihoods 33 (very high confidence ). { , , , , , , Table } 34 Land Degradation and climate change, both individually and in combination, have profound 35 implications for natural resource-based livelihood systems and societal groups (high 36 confidence ).