Online Appendix for "What We Know (and Could Know) about International Environmental Agreements"

Below we provide supplementary materials for the following article:

Ronald B. Mitchell, Liliana B. Andonova, Mark Axelrod, Jörg Balsiger, Thomas Bernauer, Jessica F. Green, James Hollway, Rakhyun E. Kim and Jean-Frédéric Morin. 2020. What We Know (and Could Know) About International Environmental Agreements. Global Environmental Politics 20:1 (February), 103-121.

Dataset replication materials and copies of original figures

Replication materials are available HERE. These include three Stata datasets, a Stata command (.do) file, and four scheme files that control graphic parameters. They are contained in a .zip file. Interested scholars can download the zip file, extract all files and folders, read the readme.txt file, and then run the file to generate the figures used in the article.

Original copies of the figures in the article are here:

Initial sources for identifying IEAs to initially establish the IEADB

The sources used to initially identify IEAs and establish the IEADB are listed here:

Criteria for inclusion of IEAs in the IEADB

For a more detailed discussion of how the IEADB decides to include legal instruments proposed for inclusion, see the discussion at:

Treatment of European Union environmental agreements

The IEADB excludes European Union (EU) environmental directives that, although legally binding, are treated as “legislative acts” that more closely resemble national laws within a federal system and, in any event, are well-documented by the EU.

Collecting reliable data and promoting data reliability

The IEADB makes every effort to ensure all information on the site is accurate, complete, and up to date, although it cannot make guarantees regarding the accuracy of the information. In searching for and assessing potential inclusion of international agreements, their texts, membership information, performance indicator data, and the like, the IEADB seek to gather data from official government and intergovernmental sources or institutional sources generally considered to be reliable. For some older IEAs and IEAs among lower-income states, primary sources may be unavailable. In such cases, we rely on secondary sources that brought these IEAs to the project’s attention and include data only from secondary sources that the IEADB Director assesses as sufficiently reliable. Since approximately 2007, additions of any IEAs or related data to the IEADB include documentation of the original source of the data (original sources were not systematically captured for initial entries in the dataset). All existing IEADB data has been collected directly by the IEADB Director or, where collected by others, has been authenticated against original sources by the IEADB Director. To facilitate ongoing improvement in data quality, users of the dataset are encouraged to provide feedback to the IEADB Director if errors are found.

Assigning IEAs to subject categories

Each agreement, when added to the IEADB, is “tagged” with those words found in its title or preamble that were used to identify the agreement as meeting the IEADB’s definition of environmental (see definition at” For a very few treaties that clearly had a primary focus on environmental issues but whose title or preamble did not include obviously “environmental” words, we have found environmental words either in their first few articles or in assessments made by Giordano in creating a comprehensive list of wildlife treaties (Giordano 2002).
To assign IEAs to subject categories for this article, we simplified and systematized the IEADB’s existing subject categorization. A subset of the IEADB Board of Contributors reviewed tags and subjects assigned to all MEAs in the dataset, which had developed organically as an artifact of assigning tags and subjects to individual MEAs over several years. We reviewed MEA with the goal of systematizing, consolidating, and reducing redundancy and variation among the set of tags and corresponding subject categories. In preparing the current article, we mapped a revised set of 235 potential tags to a set of 8 subject codes. Stata code searched the title of each IEA for all potential tags, coding each for all tags found and, for IEAs with multiple subject codes, assigning the highest-ranked subject code from the following list as the single, dominant, subject code.
1. Climate
2. Species
3. Pollution
4. Energy
5. Habitat
6. Freshwater
7. Human Sphere
8. Other
Thus, a multi-subject IEA addressing river pollution would be treated as Pollution (rather than Freshwater) and one protecting waterfowl in wetlands would be treated as Species (rather than Habitat).

List of codes used for subject assignment – Link
Catalog of unique subj_terms assigned to IEAs – Link

Assigning IEAs to lineages

Lineages consist of the legal linkages between some initial treaty, any modifying protocols or amendments, any legal emanations (e.g., that broaden its scope), and any follow-on or replacing treaties. IEAs are identified as part of a lineage based on evidence from its legal text identifying a legal relationship in which it modifies, extends, or replaces (or is modified, extended, or replaced by) another IEA. The lineage concept is conceptually similar to a parent-child relationship. The first IEA in a lineage is an Agreement (i.e., treaty, convention, accord, or other major legal instrument). Protocols or Amendments become part of a lineage if they modify or extend that initial IEA. In some cases, later Agreements (as opposed to Protocols and Amendments) may significantly modify or extend and even terminate and replace an initial IEA, so long as their texts explicitly identify the legal relationship to an earlier Agreement in that lineage. As noted in the article, the “international whaling” lineage includes the 1946 International Convention for the Regulation of Whaling but also includes the 1931 and 1936 treaties which it replaced, as they had lapsed during World War II. For a list of all MEA lineages, see

Two clarifying points deserve mention in relation to how IEADB lineages differ from IEADB subjects. First, each of the eight subject categories used in this article contain numerous lineages. For example, the Species category contains scores of legally-distinct lineages, including those related to whaling, numerous fisheries regimes, and CITES. Second, as lineages are defined by legal relationships, when efforts to regulate a given environmental problem are undertaken by different groups of states, they are assigned to different lineages. For example, international regulations to protect the Mediterranean are found in both the Mediterranean Action Plan (MedPlan) lineage and the Mediterranean Shores Protection lineage, since those are legally-separate regulatory efforts.