How Biodiversity and Climate Change Impact Each Other

Biodiversity and climate change are not separate problems – they are deeply intertwined crises that amplify each other. A warming planet threatens species and ecosystems, but the loss of those very ecosystems in turn accelerates climate change. Understanding how these two forces interact is essential for anyone working in environmental science, conservation, or climate policy. This post breaks down the relationship clearly: how biodiversity shapes the climate, how climate change reshapes biodiversity, and what real-world examples tell us about where we are headed.

The interdependent relationship between biodiversity and climate 🔗

The connection between biodiversity and climate is a two-way street. Ecosystems rich in biological diversity regulate the climate by absorbing greenhouse gases, cycling nutrients, and stabilizing temperatures. At the same time, a changing climate restructures those very ecosystems – altering which species survive, where they live, and what ecological functions they perform.

According to the United Nations, land and ocean ecosystems absorb more than half of all carbon emissions produced by human activity. These ecosystems – and the biodiversity they contain – are natural carbon sinks that underpin climate stability. When biodiversity is lost, this carbon absorption capacity diminishes, releasing stored carbon back into the atmosphere and intensifying warming further.

This creates what scientists call a positive feedback loop: climate change drives biodiversity loss, which reduces carbon storage, which produces more emissions, which drives more climate change. Research published in Nature Communications found that plant biodiversity loss from climate and land-use change could lead to a global carbon loss of between 7.44 and 145.95 petagrams of carbon – losses that could rival emissions from land-use change itself.

Biodiversity also influences climate regulation through subtler ecosystem feedbacks. A study in PNAS found that plant species richness positively affects soil organic carbon storage across forest, shrubland, and grassland biomes, because diverse plant communities produce varied root structures and litter inputs that support richer microbial communities and more efficient carbon stabilization in soils. More simply: the more diverse the plant life, the more carbon gets stored underground.

How ecosystem feedbacks work 🔗

Feedback loops in ecology can be negative (stabilizing) or positive (destabilizing). Plant diversity, for example, can create a negative feedback where higher biodiversity enhances carbon sequestration, which supports more plant growth, which sustains diversity – a self-reinforcing cycle of stability. But climate change can flip this into a positive feedback: warming temperatures shift species distributions, alter the timing of biological events, and increase disturbances like wildfires. These changes reduce an ecosystem’s capacity to sequester carbon, and may convert formerly productive carbon sinks into net carbon sources. The Amazon rainforest – historically one of the world’s most important carbon sinks – is already emitting more carbon than it absorbs in some heavily deforested areas, according to the UN.

How climate change intensifies ecosystem stressors 🔗

Climate change does not act in isolation. It compounds existing threats to biodiversity – including habitat loss, pollution, overexploitation, and the spread of invasive species. The result is that many ecosystems are being hit from multiple directions simultaneously, making recovery far more difficult.

Habitat fragmentation is one of the most damaging outcomes. As temperatures shift, species need to move to find suitable conditions – but fragmented landscapes, divided by roads, farms, and urban areas, block those movements. Climate Signals notes that while many species are being forced uphill and poleward, manmade obstacles frequently cut off their paths, leaving populations isolated and more vulnerable to local extinction.

Rising temperatures are also changing when biological events occur – a phenomenon called phenological mismatch. When flowering plants bloom earlier due to warming springs but the pollinators that depend on them haven’t adjusted their schedules, the timing breaks down. Food webs that evolved over millennia around synchronized seasonal cues begin to unravel. The compounding effect of habitat fragmentation, phenological mismatch, and direct heat stress makes species increasingly unlikely to adapt quickly enough.

Species loss itself then becomes an additional stressor. When a keystone species disappears – a top predator, a dominant tree, a key pollinator – the ripple effects can destabilize entire food webs, reduce overall ecosystem productivity, and ultimately lower the system’s capacity to regulate climate. A review in the Philosophical Transactions of the Royal Society B argues that rather than viewing biodiversity only as a victim of climate change, it should be seen as a key ally in managing it – but only if ecosystems remain intact enough to function.

The role of ecosystems in climate regulation 🔗

Terrestrial and marine ecosystems store enormous quantities of carbon, and their degradation has direct consequences for atmospheric greenhouse gas concentrations.

Terrestrial carbon stores 🔗

Forests are among the most important land-based carbon reservoirs. Research published in Premier Science indicates that tropical forests alone store approximately 450 billion tons of carbon. Peatlands – wetland ecosystems covering only 3% of the world’s land – store twice as much carbon as all the world’s forests combined, according to the UN. Yet both face accelerating threats. Under hotter and drier conditions, forests become more prone to wildfires. Amazon fire activity in 2021 increased by 30% over the previous year, directly affecting biodiversity and forest carbon capacity. When peatlands are drained or degraded, the carbon they hold oxidizes and releases into the atmosphere, accelerating the very warming that threatens them.

The diversity of a forest’s plant community also matters for how much carbon it stores. Evidence from large-scale studies shows that species richness and biomass diversity consistently and positively influence soil organic carbon storage – suggesting that protecting biodiversity and protecting carbon stocks are not just compatible goals, but the same goal.

Marine carbon stores and blue carbon 🔗

Ocean ecosystems are equally critical. Mangroves, seagrasses, and salt marshes – collectively called blue carbon ecosystems – can sequester carbon dioxide at rates up to four times higher than terrestrial forests, according to the UN. They also protect coastlines from storm surges and provide nursery habitats for commercially important fish. Yet 85% of the world’s wetlands have already disappeared, removing both their carbon storage function and the biodiversity they supported.

Marine biodiversity loss also disrupts ocean nutrient cycles in ways that affect carbon sequestration at large scales. Research highlighted in the Philosophical Transactions of the Royal Society B points to the role of marine megafauna – including cetaceans – in enhancing vertical nutrient transfer through deep feeding and surface defecation, which modifies ocean fertility and carbon uptake. As these populations decline, so does the ocean’s capacity to process and store carbon.

Real-world examples of biodiversity and climate change interactions 🔗

Coral bleaching: a system under collapse 🔗

Coral reefs are one of the clearest and most alarming examples of climate change acting directly on biodiversity. Corals host tiny photosynthetic algae in their tissues. When ocean temperatures rise beyond a threshold – even by 1-2°C for extended periods – corals expel those algae, turning bone white in what is known as bleaching. Without the algae, corals lose their primary energy source and eventually die.

UNEP confirms that scientists recorded bleaching in 53 countries between February 2023 and April 2024 – the fourth global mass bleaching event in 25 years. The Great Barrier Reef experienced its fifth extensive bleaching event since 2016. An updated IUCN Red List assessment released at COP29 in 2024 found that 44% of all coral species are now threatened with extinction – a sharp rise from the third threatened just 16 years earlier.

The stakes extend far beyond aesthetics. Scientists estimate that a quarter of all marine species depend on coral reefs. The loss of these ecosystems would cascade through marine food webs, affecting fisheries that hundreds of millions of people rely on for food and livelihoods. NOAA’s Coral Reef Watch projects that even conservative warming estimates could cause mass bleaching on the majority of reefs worldwide by 2050.

Species range shifts: moving targets in a warming world 🔗

As temperatures change, species are being forced to move – tracking the climate zones they evolved in. A major synthesis published in Environmental Evidence found statistically significant poleward latitudinal shifts averaging about 18 kilometers per decade and upslope elevational shifts of approximately 6 meters per decade across multiple taxonomic groups including birds, insects, fish, and crustaceans.

But these shifts are not straightforward. Habitat fragmentation blocks many species from tracking their shifting climate niches. When the landscape between a species’ current location and a suitable destination is dominated by farmland, cities, or roads, individuals may not be able to make the journey at all. Research in Trends in Ecology & Evolution warns that in the face of rapid climate disruption and widespread habitat loss, species may need to move faster than at any point in evolutionary history, while their movements are more impeded than ever before.

Tropical species face a particularly acute version of this problem. Many lowland tropical taxa have very narrow thermal tolerances and cannot relocate – there is nowhere cooler to go at the same latitude. Island endemics and cold-restricted mountain species face similar dead ends. If range contractions dominate over range shifts or expansions, global biodiversity could decline sharply, particularly in the tropical lowlands that contain the highest concentrations of species on Earth.

Permafrost thaw and feedback acceleration 🔗

In the Arctic, climate change is triggering a particularly dangerous ecosystem feedback. As permafrost – frozen ground that has stored organic matter for thousands of years – thaws, it releases carbon dioxide and methane. Projections suggest permafrost thaw through 2100 could release up to 240 billion metric tons of carbon, generating a powerful positive feedback that accelerates warming, which in turn causes more thaw, more emissions, and further disruption of Arctic biodiversity including mosses, lichens, caribou, and migratory birds that depend on timed seasonal cycles.

Why this matters for conservation 🔗

The interactions between biodiversity and climate change make a strong case for an integrated approach to both challenges. Protecting and restoring biodiverse ecosystems is not just a conservation goal – it is a climate mitigation strategy. The Kunming-Montreal Global Biodiversity Framework, adopted in 2022, commits countries to conserving 30% of the Earth’s land and oceans by 2030, a target explicitly designed to serve both biodiversity and climate goals simultaneously.

Conservation strategies that focus purely on expanding ecosystem area – planting more trees, protecting more land – without considering species diversity may miss much of the benefit. As Nature Communications research shows, biodiversity declines reduce the carbon storage potential of ecosystems even when their physical extent is maintained. A plantation of one tree species sequesters far less carbon than a native forest with dozens. Restoration must prioritize composition and diversity, not just coverage.

What do you think? Given that biodiversity loss and climate change reinforce each other in feedback loops, should conservation policy and climate policy be formally integrated into a single framework – and what barriers might exist to making that happen? And considering that tropical regions hold the highest concentrations of biodiversity but face the greatest constraints on species movement, how should global climate funding prioritize the protection of these areas?

References

1. https://www.un.org/en/climatechange/science/climate-issues/biodiversity
2. https://www.nature.com/articles/s41467-024-47872-7
3. https://www.pnas.org/doi/10.1073/pnas.1700298114
4. https://www.climatesignals.org/climate-signals/habitat-shift-or-decline
5. https://royalsocietypublishing.org/rstb/article/375/1794/20190104/30552/Climate-change-and-ecosystems-threats
6. https://premierscience.com/pjes-24-520/
7. https://www.unep.org/news-and-stories/story/worlds-corals-are-bleaching-heres-why-and-what-it-means-oceans-future
8. https://www.nhm.ac.uk/discover/news/2024/november/climate-change-threatens-nearly-half-corals-with-extinction.html
9. https://www.npr.org/2024/04/17/1245085914/coral-reefs-bleaching-climate-change-algae
10. https://coralreefwatch.noaa.gov/satellite/research/coral_bleaching_report.php
11. https://link.springer.com/article/10.1186/s13750-023-00296-0
12. https://www.sciencedirect.com/science/article/abs/pii/S0169534725000291
13. https://climatechange.academy/impacts-of-climate-change/biodiversity-climate-change-influence/