Key messages
- Climate and biodiversity are deeply intertwined; processes and institutions for managing and governing them must also become interlinked.
- The rates of change in both global mean temperature and biodiversity loss are higher than ever before during human history, and continue to rise.
- We are increasingly certain of the risks and amplification of harms due to their interdependencies.
Insight explained
The climate and biodiversity crises are intertwined, yet we have been addressing them separately. In 2019–2021, for the first time, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) and the IPCC together gathered international experts for a joint report on climate and biodiversity actions. More broadly, the Sustainable Development Goals (SDGs) express the need for joint action across all goals, setting out the ambition of all 193 UN member states to guide decision-making for synergistic and effective action.
Biodiversity loss and climate change both result from the dominant economic development and socio-political systems of modern societies, the drivers of which have promoted and incentivised environmentally damaging production and consumption models. Though these drivers manifest in a broad range of pressures and their expression varies locally, some impact both climate and biodiversity, such as deforestation and intensive agriculture.
Climate change drives environmental shifts that control biological processes from intracellular to ecosystem levels. At large scales we tend to see linear, smooth responses or declines, but individual species and ecosystems often show abrupt and unexpected declines on timescales shorter than any feasible reversal of global warming. Furthermore, climate-induced changes in species and ecosystems may amplify feedbacks reinforcing climate changes.
Climate impacts on society that are mediated by biodiversity occur through shifts in nature’s contributions to people. For example, changes in weather patterns, the length of growing seasons and the occurrence and intensity of extreme weather events affect pollinator diversity, in turn affecting food production. Coastal ecosystems such as mangroves and salt marshes are natural solutions to climate change mitigation by sequestering carbon, while also supporting adaptation to climate change impacts by absorbing wave energy during storms. These benefits are at risk due to their vulnerability to sea-level rise, flooding and climate warming.
Nature-based solutions can reduce climate change impacts and help restore biodiversity and the resilience of nature’s contributions to people, yet these contributions are less certain than often assumed (see Insight 4, Box 4). Hasty implementation, however, such as large-scale tree planting for carbon sequestration, can miss synergistic opportunities and cause harm to other aspects of nature. Safeguards are needed to ensure well-designed NbS deliver multiple benefits for people and nature. For example, synergies and trade-offs between biodiversity protection, climate mitigation and food production show that moderate ambition across all targets may achieve balance (see Insight 10), but that focusing on high ambition for just one target comes at the price of lower achievement in others.
Understanding and managing the joint impacts of climate and biodiversity change on society is challenging. Human risks from both climate change and biodiversity loss are less studied but growing evidence shows they are higher in low- and middle-income countries, where vulnerability and impacts of loss are also higher. For example, tropical regions have contributed the least to climate forcing yet face the highest potential for cascades and tipping dynamics. Data and dominant approaches for biodiversity conservation, climate information-gathering, and setting relevant local decisions and global policies are still strongly biased towards wealthier nations. Our ability to model and anticipate risks and shifts induced by biodiversity–climate changes is insufficient to incorporate them in policy responses, and their complexity challenges implementation.
Coral reefs threatened by climate and biodiversity threats
Coral reefs are among the first ecosystems being driven to collapse across multiple regions, e.g. the Caribbean, the Great Barrier Reef and the Eastern Tropical Pacific, potentially aggregating to global collapse. Western Indian Ocean coral reefs have been assessed as vulnerable to collapse, comprising four critically endangered ecoregions, three endangered ecoregions and four vulnerable ecoregions (Figure 5). Biodiversity–climate interactions underpin their risk of collapse – island reefs are typically at higher risk from increasing temperatures in the next three to four decades, while continental reefs have better climate futures but are at a higher risk from fishing and other local threats.
The differential vulnerability of the ecoregions highlights the narrow gradient in vulnerability among reefs and that very small increments in global temperatures may make a difference between some or all reef ecoregions crossing their point of collapse. The importance of coral reefs to coastal economies and livelihoods is illustrated in the differential vulnerability of ecoregions to fishing and temperature and the importance of maximising synergies among management actions to minimise both.
Implications & Recommendations
The intricate links between climate change mitigation and adaptation, biodiversity conservation actions and broader societal needs will require transformative change in how we govern social-ecological systems at all scales.
- Biodiversity and climate goals must be pursued jointly, and policies should coherently reflect the intertwined nature of these crises. To this end, the UNFCCC and CBD need to be better aligned and cross-convention collaborations enhanced. Some goals, such as for food production, may be achieved in isolation but at a cost to other goals, such as those related to biodiversity and climate. By contrast, well-aligned ambition across multiple goals can lead to success for all goals and maximise opportunities for co-benefits and synergies.
- Climate negotiators and decision-makers at all levels – international, national and local – must:
- prevent every increment of climate change (even a tenth of a degree of warming has immense impacts) to halt and reverse biodiversity loss;
- account for local/national particularities of context;
- ensure that conservation and climate actions are designed to include safeguards for people and nature (to avoid harmful financial incentives and risks from complex interactions) and aim for positive economic and social effects;
- re-appraise targets and indicators of economic and social development to transform systems that drive climate change and biodiversity loss. This includes addressing deeper socio-cultural factors, such as world views, attitudes and values, that underpin entrenched institutions that drive environmentally damaging production and consumption.
- Development in low- and middle-income countries should address climate change and biodiversity loss to increase resilience and support adaptation (see Insight 9). Financial incentives should be aligned to support systemic climate-resilient development including socially just NbS.
- The USD 100 billion climate finance commitment proposed as part of the UNFCCC process must be implemented with nature-positive safeguards and outcomes. High-income countries, such as among the G7, should dedicate 30% of their international climate finance towards NbS to simultaneously achieve climate and biodiversity outcomes.
- The Green Climate Fund, the Adaptation Fund and other climate funds (multilateral and bilateral) should strengthen their selection criteria for positive biodiversity protection effects, and incentivise project designs that maximise multiple benefits.
