Legal indicators have recently come to be seen as new tools for scientifically assessing the conditions under which environmental law is actually applied. They provide a response to the repeated observation made at international meetings that environmental law remains unapplied or poorly applied. They therefore offer precise indications as to why the law is not being applied, helping decision-makers to better formulate and assess the content of legislative reforms to be undertaken.

This innovative tool is now recognized as indispensable. It can be used in both national and international law. Its usefulness is recognized by: (i) Resolution 050 of the 2021 IUCN World Congress held in Marseille; (ii) § 5-3 of the Annex to Resolution No. 4 of the 2020 Kyoto Congress of the International Law Association; (iii) § 4-a) of the 5th UNEP Montevideo Programme for Environmental Law adopted by Resolution 4/20 of the 4th United Nations Environment Assembly in Nairobi in 2019; (iv) Article 6-8 of the 2018 Escazú Agreement; (v) Decision IG.24 /1 of the 21st meeting of the Conference of the Parties to the Barcelona Convention in Naples in 2019; (iv) UNEP's Environmental Rule of Law of 2019 (section 6-3), republished in 2023 (recommendation 6-2-1).

As a tool for evaluating environmental policies, legal indicators are also intended to be used to assess the effectiveness of plans, programs and directives contained in soft law instruments under international law. This is why the CIDCE has undertaken to measure the effective implementation of the Sustainable Development Goals (SDGs) of the 2030 Agenda contained in the 2015 United Nations General Assembly Resolution 70/1.

Among the 17 SDGs, SDG 14 is dedicated to oceans, seas and coastal areas: “conserve and sustainably use oceans, seas and marine resources for sustainable development”. It is subject to regular monitoring in each state and collective international review at high-level UN political forums. In 2015, the UN decided to dedicate international meetings specifically to SDG 14.

From June 9 to 13, 2025, the 3rd United Nations Ocean Conference - UNOC 2025 - will be held in Nice. The work program of this ocean summit aims to take stock of the effective implementation of SDG 14, with a view to strengthening its effectiveness. As such, United Nations General Assembly resolution 78/128 of December 21, 2023 calls on the Nice Conference to:
4-b Identify new ways to support the implementation of Goal 14;
4-f Identify challenges and obstacles to achieving all the targets associated with Goal 14, as well as opportunities and innovative ways to reach these targets.
4-h To ensure further efficiency and effectiveness in support of Goal 14.

Therefore CIDCE, an international NGO in special consultative status with the United Nations, has taken the initiative of measuring the current conditions of application of SDG 14 in the national laws of several countries, using legal indicators according to the method it has developed . These countries are:
- In Europe: France (Atlantic and Mediterranean), Malta and Portugal;
- In Africa: Tunisia
- America: Brazil, Chile, Colombia and Costa Rica.
- Asia: China.

How to cite: Vassallo, L., Prieur, M., and Brouwer, L.: Assessment of the effectiveness of SDG 14 in view of the3rd United Nations Ocean Conference (UNOC 2025), One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-256, https://doi.org/10.5194/oos2025-256, 2025.

The Bohai Sea (BS) is the unique semi-closed inland sea of China, characterized by degraded water quality due to significant terrestrial pollution input. In order to improve its water quality, a dedicated action named “Uphill Battles for Integrated Bohai Sea Management” (UBIBSM, 2018–2020) was implemented by the Chinese government. To evaluate the action effectiveness toward water quality improvement, variability of the satellite-observed water transparency (Secchi disk depth, Z_SD) was explored, with special emphasis on the nearshore waters (within 20 km from the coastline) prone to terrestrial influence. (1) Compared to the status before the action began (2011–2017), majority (87.3%) of the nearshore waters turned clear during the action implementation period (2018–2020), characterized by the elevated Z_SD by 11.6%±12.1%. (2) Nevertheless, the improvement was not spatially uniform, with higher Z_SD improvement in provinces of Hebei, Liaoning, and Shandong (13.2%±16.5%, 13.2%±11.6%, 10.8%±10.2%, respectively) followed by Tianjin (6.2%±4.7%). (3) Bayesian trend analysis found the abrupt Z_SD improvement in April 2018, which coincided with the initiation of UBIBSM, implying the water quality response to pollution control. More importantly, the independent statistics of land-based pollutant discharge also indicated that the significant reduction of terrestrial pollutant input during the UBIBSM action was the main driver of observed Z_SD improvement. (4) Compared with previous pollution control actions in the BS, UBIBSM was found to be the most successful one during the past 20 years, in terms of transparency improvement over nearshore waters. The presented results proved the UBIBSM-achieved remarkable water quality improvement, taking the advantage of long-term consistent and objective data record from satellite ocean color observation.

How to cite: Cui, T.: Satellite-observed significant improvement in nearshore transparency of the Bohai Sea during pollution control, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-426, https://doi.org/10.5194/oos2025-426, 2025.

The Colombian marine and coastal areas are exposed to multiple stressors as a result of anthropic activities such as agriculture, mining, port activities and tourism, among others. added to this is the lack of wastewater treatment and basic sanitation systems in the coastal human settlements, which contributes to the inadequate disposal of liquid and solid waste, exacerbating marine pollution.

The coastal ecosystems in Colombia have environmental importance and offer multiple ecosystem services. For this reason, the country is developing actions to protect, conserve and use them in a sustainable way, which have been based on updated scientific information. In this sense, the National Monitoring Program, known as the Surveillance Network for the Protection and Conservation of Marine and Coastal Waters of Colombia (REDCAM, by its Spanish acronym), has been providing data and information since 2001 that contributes to decision-making.

This monitoring program is an inter-institutional network that collects, systematizes and analyzes information on the quality of marine and coastal water and sediments; it has been in operation for 24 years and has more than 350 stations distributed on the Caribbean and Pacific coasts. REDCAM currently has a time series of more than six hundred thousand environmental records, which are open for consultation by the public.

The information produce in the framework of REDCAM is used to produce the annual diagnostic report on the Colombia marine and coastal waters quality. The report includes the analysis of multiple variables indicating the conditions of the marine environment, and the Marine and Coastal Water Quality Index – ICAM, which is an official statistical operation in Colombia that contributes to the government's goals in public policy instruments.

On the other hand, the REDCAM data allow the country to report the indicators of Sustainable Development Goal 14 (Life Below Water) that aim to conserve and sustainably use the oceans, seas and marine resources, reducing marine pollution of all kinds, including marine debris and nutrient pollution, and minimizing the effects of ocean acidification. From Colombia, INVEMAR has been making progress in the creation of technical capacities to provide the information required for the reporting of indicators 14.1.1.a (coastal eutrophication index), 14.1.1.b (density of floating plastic debris), and 14.3.1 (mean acidity of the sea), which are measured in a set of representative sampling stations for the country.

How to cite: Espinosa, L., Vivas-Aguas, J., obando-Madera, P., and Bernal, C.: Conservation and Protection of Marine and Coastal Waters in Colombia: REDCAM as a Strategy for Sustainable Development, One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-1436, https://doi.org/10.5194/oos2025-1436, 2025.