Climate change is reshaping the world’s most biologically rich areas, known as biodiversity hotspots. These regions—home to an outsized proportion of Earth’s plant and animal species—are facing unprecedented stress from rising temperatures, shifting precipitation, and more frequent extreme weather events. The consequences extend far beyond local ecosystems, affecting global climate regulation, food security, and the livelihoods of billions of people. Understanding how climate change influences these critical areas is essential for designing effective conservation strategies and safeguarding the natural heritage upon which all life depends.

Defining Biodiversity Hotspots

Biodiversity hotspots are biogeographic regions that harbor an exceptional concentration of endemic species—species found nowhere else on Earth—and have experienced significant habitat loss. Conservation International recognizes 36 such hotspots worldwide, covering only about 2.4% of the planet’s land surface but containing more than half of Earth’s vascular plant species and nearly 43% of terrestrial vertebrate species. Examples include the Tropical Andes, the Mediterranean Basin, the Caribbean Islands, and the Indo-Burma region. These areas are characterized by high levels of species richness and endemism, but also by extreme vulnerability to human pressures and environmental change. The very qualities that make them unique—narrow ecological niches, limited geographic ranges, and specialized life history traits—also render them particularly sensitive to rapid climate shifts.

Mechanisms of Climate Change Impact on Biodiversity Hotspots

Temperature Rise and Thermal Stress

Global average temperatures have increased by approximately 1.1°C since pre-industrial times, with many biodiversity hotspots warming at rates above the global mean. For species adapted to cool, stable climates—such as those in montane hotspots like the Eastern Afromontane or the Tropical Andes—even a small temperature increase can push them beyond their physiological limits. In the tropical lowlands, rising temperatures can cause heat stress, reduce reproductive success, and increase mortality. For example, amphibians, which are already the most threatened vertebrate group, face heightened risks due to their permeable skin and dependence on moisture.

Altered Precipitation Patterns and Drought

Climate change is disrupting rainfall regimes, leading to more intense droughts in some hotspots and heavier, more erratic rainfall in others. The Mediterranean Basin has experienced a significant decline in precipitation since the mid-20th century, exacerbating water scarcity and wildfire risk. In contrast, the Western Ghats and Sri Lanka hotspot is seeing more extreme monsoon rains that trigger landslides and habitat destruction. Such shifts affect plant phenology, seed germination, and pollinator activity, cascading through entire food webs.

Sea Level Rise and Coastal Hotspots

Coastal and island biodiversity hotspots, including the Caribbean Islands, Polynesia-Micronesia, and the Mediterranean Basin, are threatened by rising sea levels. Mangrove forests, seagrass beds, and coral reefs—ecosystems that provide critical habitat and coastal protection—are being inundated or damaged by saltwater intrusion. Coral bleaching events, driven by marine heatwaves, have become more frequent and severe, devastating reef-dependent species.

Extreme Weather Events

Intensified hurricanes, cyclones, and wildfires are striking hotspots with greater frequency and intensity. The Atlantic Forest of Brazil, already fragmented by deforestation, suffers from more frequent droughts that fuel megafires. Typhoons in the Philippines and Indo-Burma region cause widespread defoliation, soil erosion, and mortality of vulnerable species. These acute events often interact with chronic stressors, making recovery difficult or impossible.

Species Range Shifts and Phenological Mismatches

As temperatures rise, many species are shifting their ranges poleward or to higher elevations in search of suitable conditions. In the Succulent Karoo of South Africa, for instance, plant communities are moving uphill, but soils and available habitat may be limited at higher altitudes. Such shifts can lead to phenological mismatches, where the timing of life cycle events—such as flowering, migration, or breeding—becomes out of sync with food availability or pollinator activity. This is especially critical in hotspots like the Cape Floristic Region, where many plant species rely on highly specific insect or bird pollinators.

Case Studies of Vulnerable Hotspots

The Amazon Rainforest

Covering approximately 6.7 million square kilometers, the Amazon is the world’s largest tropical rainforest and a biodiversity hotspot of global significance. It harbors at least 10% of known species. Climate change is causing the Amazon to experience more frequent and intense droughts, such as the 2015–2016 El Niño event that killed billions of trees. Deforestation for agriculture and mining compounds these impacts, reducing the forest’s ability to generate rainfall through evapotranspiration. A study published in Nature Climate Change warns that up to 40% of the Amazon could shift from rainforest to savanna by 2050 under high emission scenarios, with catastrophic consequences for biodiversity and carbon storage.

Learn more about Amazon climate threats from the World Wildlife Fund.

The Congo Basin

Second only to the Amazon in size, the Congo Basin rainforest spans six countries and is a hotspot for great apes, forest elephants, and myriad plant species. Climate models project that the region will warm by 2–3°C by the end of the century, while rainfall patterns become more unpredictable. This could lead to the dieback of some forest types and encroachment of savanna ecosystems. Additionally, increased carbon dioxide levels may alter forest composition, favoring fast-growing species over slow-growing ones, with cascading effects on wildlife that depend on fruit production.

Southeast Asian Rainforests (Indo-Burma and Sundaland)

The rainforests of Southeast Asia, including the Indo-Burma and Sundaland hotspots, are among the most threatened on Earth due to deforestation, illegal wildlife trade, and climate change. Rising sea levels threaten low-lying coastal forests, while increased frequency of droughts and fires has devastated peat swamp forests in Indonesia and Malaysia. The 2019 fires in Sumatra and Borneo released massive amounts of carbon and destroyed habitats for orangutans, tigers, and countless other species. Moreover, cloud forests in the mountains of the region—such as those on Mount Kinabalu—are being squeezed by warming temperatures, forcing unique frog and lizard species to move upward until they run out of space.

Mediterranean Basin

The Mediterranean Basin is a global biodiversity hotspot with over 25,000 plant species, about half of which are endemic. Climate change is intensifying droughts, heatwaves, and wildfires. A 2021 study found that the length of the fire season has expanded by nearly 19% across the region. Many plant species adapted to periodic fires cannot survive the increased frequency, while animal species such as the Iberian lynx face habitat fragmentation and reduced prey availability. Water scarcity is also driving conflicts between human and ecological needs.

Caribbean Islands

The Caribbean Islands hotspot includes exceptional terrestrial and marine biodiversity, with many endemic reptiles, amphibians, and birds. Rising temperatures and ocean acidification threaten coral reefs, which support fisheries and coastal protection. Hurricane intensity has increased, with storms like Hurricane Maria (2017) causing severe damage to forest ecosystems on Puerto Rico and Dominica. The combined effects of warming, storms, and sea level rise could lead to the extirpation of many species, especially those confined to small islands with limited adaptive capacity.

Feedback Loops and Tipping Points

Biodiversity hotspots are not merely passive victims of climate change—they are active components of the Earth system that can amplify or dampen climate impacts. For instance, the Amazon rainforest plays a crucial role in carbon storage and regional rainfall generation. Its destruction releases stored carbon, worsening global warming, which in turn further dries and degrades the forest. This positive feedback loop is a major concern, as it could push the Amazon past a tipping point where it loses its ability to function as a rainforest.

Similarly, the collapse of coral reef ecosystems due to bleaching reduces fish habitat, which in turn diminishes carbon sequestration by fish communities and coastal protection. In the Arctic (not a hotspot, but relevant), melting permafrost releases methane, a potent greenhouse gas. These interconnections mean that protecting biodiversity hotspots is also a climate change mitigation strategy.

Conservation Strategies for Climate-Resilient Hotspots

Reducing Greenhouse Gas Emissions

The only way to limit long-term damage is to rapidly reduce global greenhouse gas emissions. This requires transitioning to renewable energy, enhancing energy efficiency, protecting and restoring carbon-rich ecosystems like forests and peatlands, and implementing policies that price carbon. International agreements such as the Paris Agreement provide a framework, but individual and corporate action is also essential. For example, reducing deforestation in hotspots could contribute up to 30% of the emissions reductions needed to meet the 2°C target.

Protecting and Expanding Protected Areas

Countries are expanding protected area networks to cover 30% of land and sea by 2030 (the 30×30 target). However, protected areas must be designed with climate change in mind—siting them to allow species movement along elevational and latitudinal gradients, and ensuring they are large enough and well-connected. Ecological corridors that link hotspots with cooler refugia can facilitate range shifts. For instance, the Mesoamerican Biological Corridor aims to connect protected areas from Mexico to Panama, enabling species to move as climates change.

Adaptive Management and Restoration

Adaptive management—adjusting conservation actions as conditions change—is vital. This includes restoring degraded habitats to improve resilience, for example by reforestation with climate-adapted native species. In the Cape Floristic Region, managers are using assisted migration of endangered plants to cooler slopes. In the Galápagos Islands, invasive species removal helps native species cope with milder impacts. Restoration of mangroves and seagrasses in coastal hotspots can buffer against sea level rise and provide carbon sinks.

Supporting Indigenous and Local Communities

Indigenous peoples and local communities (IPLCs) manage or have tenure over approximately 25% of global lands, including many biodiversity hotspots. Their traditional knowledge often includes practices that enhance ecosystem resilience, such as rotational farming, fire management, and water conservation. Empowering IPLCs with land rights, resources, and participation in decision-making is not only a matter of justice but also an effective conservation strategy. The Kayapó people in the Amazon, for example, have successfully protected large tracts of forest from deforestation.

Read more about indigenous-led conservation from the Conservation International.

Enhancing Habitat Connectivity

As species shift their ranges, they need corridors of suitable habitat to travel through. In fragmented landscapes, roads, agriculture, and urbanization create barriers. Establishing wildlife crossings (e.g., overpasses, underpasses), restoring riparian buffers, and promoting agroforestry can maintain connectivity. In the Western Ghats, for instance, a network of wildlife corridors has been mapped to allow elephants and tigers to move between protected areas as climate conditions change.

Ex-Situ Conservation

For species that cannot adapt or move fast enough, ex-situ measures like seed banks, captive breeding, and botanical gardens provide insurance against extinction. The Millennium Seed Bank at Kew Gardens stores seeds from thousands of plant species, many from biodiversity hotspots. Zoos and aquariums are increasingly participating in conservation breeding programs for amphibians, birds, and mammals. However, ex-situ conservation is a last resort and should complement, not replace, in-situ habitat protection.

International Cooperation and Policy Frameworks

Because climate change and biodiversity loss are global problems, they require international collaboration. The Convention on Biological Diversity (CBD) and the United Nations Framework Convention on Climate Change (UNFCCC) are the primary multilateral agreements. The post-2020 Global Biodiversity Framework, adopted at COP15 in 2022, includes targets directly relevant to climate–biodiversity linkages, such as restoring 30% of degraded ecosystems and reducing pollution. Similarly, climate negotiations increasingly recognize the role of nature-based solutions. For example, the Intergovernmental Panel on Climate Change (IPCC) has emphasized that protecting and restoring forests, peatlands, and coastal ecosystems can contribute up to 30% of the mitigation needed by 2030.

Funding mechanisms such as the Green Climate Fund and the Global Environment Facility allocate resources to projects that simultaneously address climate change and biodiversity conservation. Debt-for-nature swaps, like those in the Mesoamerican Reef region, allow countries to redirect debt payments toward conservation.

Learn about the IPCC’s latest findings on ecosystems at the IPCC Sixth Assessment Report.

Conclusion

Climate change is no longer a distant threat—it is reshaping biodiversity hotspots today. Rising temperatures, altered rainfall, sea level rise, and extreme events are pushing many species to the brink. Yet, these hotspots are not just victims; they are part of the solution. Conserving and restoring them can sequester carbon, buffer local climates, and provide essential ecosystem services. The window for effective action is closing, but targeted strategies—emissions reductions, protected areas, connectivity, adaptive management, and community engagement—offer hope. By acting decisively, humanity can preserve the rich tapestry of life in these irreplaceable regions for future generations.