MEAS are state-to-state agreements that can take the form of a „soft law“, which establish non-binding principles that parties must take into consideration when taking action to address a particular environmental problem, or „hard-law“, which set legally binding measures to achieve an environmental objective. An ancestry line is any series of agreements legally related to the fact that they modify, replace, expand or constitute other agreements having a legal link between them. The concept of a line – and the search for lines based on the knowledge of an online agreement – aims to help scientists and practitioners see the legal evolution of a problematic area in a way that is not normally easy to see. The draft defines agreements as an environment when their primary purpose is to manage or prevent human effects on natural resources; plant and animal species (including in agriculture, since agriculture modifies both); the atmosphere; oceans; watercourses; lakes; terrestrial habitats; and other elements of the natural world providing ecosystem services (Daily 1997). The main objective of the agreement was operational by searching for terms corresponding to this conception in titles, preambles or articles specifically defined by agreement objectives [search terms described in different tables below]. This excludes agreements on human health; Conflict; cultural conservation; trade; use of oceans, lakes and rivers; Space, nuclear radiation, transport, weather, labour and other similar issues, unless these agreements address environmental issues as their main concerns. The definition also excludes agreements whose impact on the environment is not a major objective. A broader definition including agreements based on their environmental impact, such as the one adopted by Burhenne (1974-2002), covers agreements on trade, regional economic integration, worker protection and arms control. This expansive definition may have considerable value, but a) differs considerably from the general use of language and (b) has the analytical disadvantage of requiring that agreement effects be identified before they can be classified as an environment and, if used to the letter and consistently, exclude an analysis of why some environmental agreements fail (because those that do not have an impact on the environment, . . .