Climate change has become a global discourse in the last two decades, with world leaders emphasizing the need to limit global warming to 1.5°C by the end of the century. Climate change can be understood as long-term shifts in temperature and weather patterns that can occur naturally or as a result of human activity. Since the 1800s, human activity, notably burning fossil fuels such as coal, oil, and gas, has been the leading cause of climate change (United Nations, n.d.). This combustion produces greenhouse gas emissions that trap the sun’s heat and raise temperatures. The impacts of rising temperatures include environmental degradation, natural disasters, extreme weather, food and water insecurity, economic disruption, conflict, rising sea levels, melting polar ice, forest fires, and declining biodiversity (United Nations, n.d.). Climate change is already a significant threat to international peace and security.

It is an urgent global problem that requires concerted efforts from various stakeholders, including governments, civil society, and the scientific community. Epistemic communities play an essential role in articulating the cause-effect relationships of complex problems, helping countries identify their interests, proposing specific policies, and disseminating new ideas that can change behavior patterns and influence international policy coordination (Haas, 1992). One of the epistemic communities that plays a role in encouraging cooperation in dealing with global issues regarding climate change is the Intergovernmental Panel on Climate Change (IPCC). The IPCC is one of the UN bodies established in 1988. It has 195 member countries that are members of a collaboration between environmental scientists, government policy experts, and practitioners tasked with reviewing the science related to climate change (IPCC, n.d.). Its authoritative reports inform international climate change policy and negotiations.

The main activities of the IPCC are to prepare assessment reports, special reports, and methodological reports on the scientific, technical, and socio-economic knowledge of climate change, its future impacts and risks, and to propose policy options for mitigating the rate of climate change (IPCC, n.d.). IPCC reports include summaries for policymakers prepared by the authors and approved by the IPCC Plenary Session. They are widely recognized by their member states and the international climate change-focused community (IPCC, n.d.). Throughout five assessment reports so far, and now in its sixth cycle, the IPCC has provided the scientific basis and justification for a global climate change regime centered on the United Nations Framework Convention on Climate Change (UNFCCC) regarding what counts as dangerous human interference in the climate system; and what policy actions and goals the international community needs to implement if the world is to avoid the worst outcomes of climate change (IPCC 1988, 1990, 2007, 2018).

The IPCC is widely recognized as the global authority on climate science (Paglia & Parker, 2020). Its assessment reports have provided the scientific foundation for establishing and developing the international climate regime, as the IPCC’s first assessment report (1990) was instrumental in establishing the UNFCCC, the core of global climate change policy (Paglia & Parker, 2020). Many countries refer to the IPCC’s work in their national climate assessments, and the organization’s authoritative reports are crucial in UN climate negotiations. For example, the fifth assessment report (2014) strongly influenced the Paris Agreement’s (2015) goals regarding temperature targets and other fundamental aspects of the agreement (Paglia & Parker, 2020).

IPCC reports provide information that many countries base on to understand the urgency of and formulate policies related to climate change at the national and international levels. IPCC scientific research offers policy recommendations and helps build international cooperation coalitions to act on climate change. One example is the IPCC report “Renewable Energy Sources and Climate Change Mitigation” (Edenhofer et al., 2012), adopted as a reference for the German government policy “Energiewende” which aims to increase the use of renewable energy and reduce carbon emissions (Clean Energy Wire, n.d.). Germany passed a national climate law in 2019 and amended it in 2021, which sets annual reduction targets for sectors such as industry and transport until 2030 (Appunn et al., 2024). Germany aims to become greenhouse gas neutral by 2045, setting a target to reduce emissions by at least 65% by 2030 (Appunn et al., 2024). Germany’s renewable energy policy, driven by the scientific evidence presented in IPCC reports, has successfully increased the share of renewable energy in its energy consumption and gradually reduced dependence on fossil energy. In addition to Germany, the IPCC encourages policy implementation by other countries and strengthens joint efforts through international cooperation to face the challenges of climate change.