Imagine this! Our Earth, but not as we know it. The forests, once full of life and sound, are now quiet. The big ice caps at the poles have melted because it’s too warm, making the sea levels go up and cover the places near the coast. Many animals and plants that used to be everywhere are now gone. The butterflies don’t flutter around anymore, and the coral reefs under the sea, which used to be full of color and life, are now empty and white. This is what could happen to our world because of climate change, showing us how important it is to take care of all living things.
What is biodiversity?
Biodiversity is, in essence, the variety of life on our planet. The UN Convention on Biological Diversity (CBD) defines it as “the diversity within species, between species and of ecosystems, including plants, animals, bacteria, and fungi”. These three aspects interact to create the complex web of life we see on Earth.
Figure 1. Biodiversity on Earth (Source: The Guardian)
The rich variety of life we see today is the outcome of 4.5 billion years of evolution. This intricate web of life is crucial for our survival and well-being, providing us with essentials like food, water, medicine, and a stable climate, and contributing to economic growth. Nature plays a significant role in our economy, with over half of the global GDP being nature-dependent. Forests, in particular, are a source of livelihood for more than a billion people. Additionally, land and oceans play a critical role in climate regulation by absorbing more than half of all carbon emissions.
However, nature is under threat. An alarming number of species, up to a million, face the risk of extinction, many within a few decades. Vital ecosystems, such as sections of the Amazon rainforest, are shifting from carbon sinks to carbon sources due to deforestation. Moreover, we’ve lost 85 percent of our wetlands, like salt marshes and mangrove swamps, which are known for their high carbon absorption capacity.
How is climate change affecting biodiversity?
Climate change has already led to the extinction of certain species and is projected to push many more towards the same fate. While species extinction is a natural part of Earth’s history, human activities have significantly sped up this process. It’s estimated that humans have caused the extinction of about 10% of species in the last 10,000 years, a rate that’s approximately 1,000 times faster than the natural rate. Recent studies suggest that if climate change continues at its current pace, around one-third of all plant and animal species could be at high risk of extinction by 2070.
Figure 2. Potential impact of climate change on mammals (Source: United Nations)
Following are some ways climate change can impact biodiversity:
1. Adaptation and Extinction
As our climate undergoes changes, some species will adjust by altering their behavior, physical traits, or bodily functions. However, not all species will be capable of such adaptation. Consequently, climate change could lead to the expansion, reduction, or even extinction of certain populations. These shifts can, in turn, impact the overall biodiversity of an area. Take the Arctic, for instance. The sea ice there is melting, and unless significant reductions in greenhouse gas emissions are made, it’s likely to vanish during summers within this century. This implies that animals that have adapted to life on sea ice, such as polar bears and certain seals, may face extinction shortly after the ice disappears.
Figure 3. On Isle Royale, an island in Lake Superior, warming has reduced wolves’ ability to survive, which has led to an increase in moose populations (Source: US EPA)
2. Natural signals
Numerous plants and animals depend on natural signals, such as temperature and water conditions, to initiate various stages of their life cycles. However, as the climate changes, these signals can shift at varying rates, or perhaps not at all. This could lead to a mismatch in timing between species that rely on each other at specific times of the year. For instance, plankton, a crucial food source for juvenile fish, tend to respond to temperature changes more rapidly than the fish. This could result in a scarcity of plankton when the growing fish need them the most. Similarly, a bird that migrates annually might arrive at its destination only to discover that its primary food source has already bloomed too early due to changing temperatures and is no longer available.
3. Invasive species
Climate change is altering the interactions between species and their environment, as well as their interactions with each other. These effects can ripple through entire ecosystems. For instance, climate change is facilitating the spread of invasive species in certain regions. These invasive species can outcompete local flora and fauna, introduce new diseases, and cause various other issues. Such changes can lead to substantial environmental damage and economic losses. As sea temperatures rise, invasive fish like the tropical lionfish are predicted to migrate northward along the Atlantic coast, posing a threat to indigenous species. This could also pose a risk to humans, given that lionfish are venomous and their stings can harm people.
Figure 4. Lionfish are an invasive species to the Atlantic Ocean. A warming ocean could encourage this fish to expand its range closer to the southeast coast of the United States (Source: US EPA)
4. Impact on food web
Climate change has the potential to disrupt food webs. Any climatic influence on a single element of a food web can have repercussions on the entire system and even spill over into other ecosystems. For example, if young fish in estuaries struggle to find adequate nourishment due to climate changes, it could impact their oceanic predators as well.
5. Extreme events
One significant effect of climate change on biodiversity is the heightened intensity and frequency of fires, storms, and droughts. For instance, in late 2019 and early 2020 in Australia, severe fires exacerbated by climate change devastated approximately 97,000 square kilometers of forest and nearby habitats. It’s estimated that these fires may have led to a 14% increase in the number of species at risk in the affected areas.
6. Coral bleaching
Increasing ocean temperatures have a significant impact on marine life. Corals are especially susceptible to these temperature rises. Additionally, ocean acidification, another consequence of climate change, can pose challenges for shellfish and corals living in the upper ocean layers. It can make the process of forming shells and rigid skeletons more difficult for these organisms. This is because the increased acidity can dissolve the calcium carbonate, a key component of their shells and skeletons.
Figure 5. Potential impact of climate change on coral reefs (Source: United Nations)
7. Salinity intrusion
Another key aspect is the sea level rise where saline water intrusion in the coastal land areas will have serious consequences on the fresh water species as well as vegetation.
Our planet’s biodiversity faces unprecedented challenges due to climate change. As temperatures rise, ecosystems shift, and species struggle to adapt. Yet, within this delicate balance lies hope. By preserving diverse habitats, promoting sustainable practices, and fostering global cooperation, we can safeguard our shared future.
Reference
Convention on Biological Diversity. (2023, February 14). Introduction. Secretariat of the Convention on Biological Diversity. https://www.cbd.int/climate/intro.shtml
IPCC. (2022). Terrestrial and freshwater ecosystems and their services. In Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press.
Royal Society. How does climate change affect biodiversity? | Royal Society. Retrieved April 10, 2024, from https://royalsociety.org/news-resources/projects/biodiversity/climate-change-and-biodiversity/
United Nations. Biodiversity—Our strongest natural defense against climate change. United Nations; United Nations. Retrieved April 10, 2024, from https://www.un.org/en/climatechange/science/climate-issues/biodiversity
US EPA. (2022, October 18). Climate Change Impacts on Ecosystems [Overviews and Factsheets]. https://www.epa.gov/climateimpacts/climate-change-impacts-ecosystems
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