Latest content: Oceans and natural resources

This report draws together the findings of five country case studies on sea level rise commissioned by the Commonwealth Secretariat’s Climate Change and Oceans Directorate and updated in 2026: Guyana, Kiribati, Papua New Guinea, Tonga and Tuvalu. Spanning a low-lying mainland coastal plain in South America and four Pacific small island developing states (SIDS), the five studies together offer a comparative view of how Commonwealth coastal nations are experiencing, and responding to, rising seas.

Tuvalu is the world’s fourth-smallest nation and a Pacific small island developing state (SIDS) and least developed country (LDC) with a total land area of 26 km². Its climate change vulnerabilities centre around sea level rise and its compounding effects, with the average height of its atoll and reef islands above sea level being less than 3 metres, and a maximum elevation of 4.6 metres.

This case study provides an overview of the key vulnerabilities and impacts of sea level rise and climate change in Tuvalu, examining the country’s national adaptation strategies and reviewing the role of two main projects aligned with the National Adaptation Plans of Action.

This case study examines the impacts of sea level rise on Tonga and assesses the effectiveness of climate change adaptation measures implemented under the country’s Joint National Action Plan 2 on Climate Change and Disaster Risk Management (2018–2028). Tonga, ranked as the second most at-risk country for natural hazards in the 2017 World Risk Report, has faced sea level rise of 7.3 millimetres (mm) per year since 1993, more than twice the global average of 3.2mm per year. With 80 per cent of its population and critical infrastructure located within 1 kilometre (km) of the shoreline, the urgency for effective adaptation is paramount.

Papua New Guinea (PNG), with a population of more than 10 million people and approximately 800 languages, faces significant and growing threats from sea level rise. The country’s long coastline (approximately 17,110 km) extends along 15 maritime provinces, with 59 per cent of the national population situated in these maritime provinces. Many rural coastal villages are vulnerable to sea level rise, coastal flooding and related weather events. In the last 15 years, four catastrophic flood events along with coastal floods have affected some 8,000 people each year, causing US$10–20 million in damage annually, displacing 500 people and killing five.

An assessment of adaptation effectiveness, drawing on the five criteria used by the UN Environment Programme in its Adaptation Gap Report - comprehensiveness, inclusiveness, implementability, integration, and monitoring and evaluation - reveals that PNG faces substantial challenges across all dimensions.

This case study examines the effectiveness of adaptation measures to sea level rise in Kiribati, with a particular focus on infrastructure interventions. Kiribati comprises 32 atolls scattered over 3.5 million square kilometres (km²) of ocean with a total land area of only 811km². The islands are low-lying coral atolls with nutrient-poor soils, limited freshwater resources and high dependence on marine resources for food security.

Guyana’s Low Coastal Plain, situated between 0.5 to 1m below sea level at high tide, is home to approximately 90 per cent of the country’s population and accounts for over 50 per cent of its gross domestic product (GDP). This case study examines the intersection of sea level rise with coastal adaptation policies, strategies and infrastructure in Guyana, drawing on published research, government documents and stakeholder engagement.

The Apia Commonwealth Ocean Declaration unanimously agreed to by all 56 Commonwealth countries, sounds a clarion call for the restoration, protection and sustainable use of the ocean.

This report provides a high-level overview of progress in implementing the Declaration. It highlights that there have been important advances by Commonwealth countries.

The UK Carbon Border Adjustment Mechanism, operational from 1 January 2027, imposes a carbon tax administered by His Majesty’s Revenue and Customs (HMRC) on selected carbon-intensive sectors: aluminium, cement, fertiliser, hydrogen, and iron and steel. The mechanism is designed to mirror the UK Emissions Trading Scheme (UK ETS), ensuring parity between domestic producers and importers.

This paper examines the UK CBAM through five analytical lenses.

1. Design and implementation architecture.
2. Effectiveness in preventing carbon leakage.
3. Compatibility with WTO law.
4. Alignment with UNFCCC just transition principles.
5. Fiscal impact on the 56 Commonwealth countries, with detailed case studies of Sierra Leone and Trinidad and Tobago.

The BBNJ Agreement is the third implementing agreement under the 1982 United Nations Convention on the Law of the Sea and, like its parent treaty, it has been structured around a complex package of indivisible issues. Each element carries its own unique set of obligations, rights and duties for States Parties
under the BBNJ Agreement. This briefing note summarises the four key elements.

This paper supplements the Commonwealth Model Mining Feasibility Study Guidelines by providing the conceptual underpinnings and governance frameworks required for their consistent interpretation and use.

These model guidelines set out how governments can use feasibility studies to ensure that mining projects are responsibly planned and sustainably managed, and provide community benefits and investor confidence.