National mitigation potential from natural climate solutions in the tropics

Abstract

Better land stewardship is needed to achieve the Paris Agreement's temperature goal, particularly in the tropics, where greenhouse gas emissions from the destruction of ecosystems are largest, and where the potential for additional land carbon storage is greatest. As countries enhance their nationally determined contributions (NDCs) to the Paris Agreement, confusion persists about the potential contribution of better land stewardship to meeting the Agreement's goal to hold global warming below 2°C. We assess cost-effective tropical country-level potential of natural climate solutions (NCS)-protection, improved management and restoration of ecosystems-to deliver climate mitigation linked with sustainable development goals (SDGs). We identify groups of countries with distinctive NCS portfolios, and we explore factors (governance, financial capacity) influencing the feasibility of unlocking national NCS potential. Cost-effective tropical NCS offers globally significant climate mitigation in the coming decades (6.56 Pg CO₂e yr^-1 at less than 100 US$ per Mg CO₂e). In half of the tropical countries, cost-effective NCS could mitigate over half of national emissions. In more than a quarter of tropical countries, cost-effective NCS potential is greater than national emissions. We identify countries where, with international financing and political will, NCS can cost-effectively deliver the majority of enhanced NDCs while transforming national economies and contributing to SDGs. This article is part of the theme issue 'Climate change and ecosystems: threats, opportunities and solutions'.

Keywords: Paris Agreement; climate mitigation; land management; natural climate solutions; protection; restoration.

Figure 1.

Pantropical climate mitigation potential of three types of NCS pathways (protect, manage, restore), and 12 individual pathways, across three tropical regions (Latin America, Africa, Asia), constrained to ‘cost-effective’ levels (less than US$100 per Mg CO₂e). The percentage of total mitigation potential is reported on the left for each type of pathway. (Online version in colour.)

Figure 2.

Countries are classified into one of three groups (‘protect,’ ‘manage’ or ‘restore’) depending on the pathway type contributing the majority (greater than 50%) of mitigation potential—or into a fourth group (‘mixed’) if no pathway type contributed the majority (a). For example, Zambia is ‘mixed’ (40% of total NCS are ‘protect’ pathways, 40% ‘restore’ and 20% ‘manage’). The 10 countries with the largest total NCS potential in each group are identified by name in (a). NCS countries are further classified into seven groups based on the cover type (forest, agriculture, wetland) of pathways contributing the most mitigation potential (b). Red outlines identify countries where greater than 10% of NCS is from wetland pathways that deliver multiple ecosystem services. See table 1 for individual pathways associated with each country group. DRC, Democratic Republic of the Congo; PNG, Papua New Guinea.

Figure 3.

(a) Top 40 tropical countries in terms of total cost-effective NCS (sum of 12 NCS pathways). (b) Tropical countries in which cost-effective NCS potential is equivalent to 50% or more of current total national GHG emissions, and (c) tropical countries where NCS (assuming implementation cost at US$50 per Mg CO₂e) represent greater than 10% of gross domestic product (GDP). (Online version in colour.)

Figure 4.

Tropical countries (circles) are displayed with respect to governance (y-axis), as reflected by the mean of the six Worldwide Governance Indicators, and cost-effective NCS (sum of 12 pathways, assuming mean implementation cost of US$50 per Mg CO₂e) as percentage of GDP (x-axis, displayed as logarithmic). Larger circles identify countries where cost-effective NCS is greater than 50% of total national GHG emissions (versus countries where NCS is less than 50% of GHG emissions identified by smaller circles). Countries in the upper-right section of this graph, with above average (−0.61) governance and where NCS > 5% of GDP, may indicate opportunities for international investment in NCS, particularly those with larger circles. CAR, Central African Republic; DRC, Democratic Republic of the Congo; PNG, Papua New Guinea.