The earth’s biodiversity is dependent on the climate. But anthropogenic actions resulting in changes in climate cause a major global threat to biodiversity and natural ecosystems. The various elements of climate change affect all levels of biodiversity, and its impacts are expected to increase over the next century, resulting in biodiversity loss.
The Convention of Biological Diversity (CBD) defines “biodiversity loss” as “the long-term or permanent qualitative or quantitative reduction in components of biodiversity and their potential to provide goods and services, to be measured at global, regional and national levels”.
The biodiversity is now under threat from increasing land and ocean temperatures and changing weather patterns. According to the data from the United Kingdom’s Met Office, the rise in global average temperature in 2015 and 2016 had breached 1°C above pre-industrial levels (1850-1900 reference period). In a business-as-usual scenario, global warming could reach up to 4°C by 2050, leading towards more frequent extreme weather-related disturbances.
Climate change has caused dramatic shifts in the geographical distributions of species and ecosystems. The changes in hydrologic cycles (evaporation and precipitation) and an increase in magnitude and extent of extreme weather events and frequent fires can affect biodiversity in many ways, including altering life cycles, shifting habitat ranges and species distribution, changes in abundance, changes in migration patterns, and changes in the frequency and severity of pest and disease outbreaks.
Phenological shifts. The seasonal timing of life events has been observed in response to variations in climate. A change in the intensity or duration of the rainy or drought seasons could cause changes in leaf growth, flowering and blooming in plants, and shifts in the timing of spawning, reproduction, and migrations in animals, even relative breeding rates and genetic structures.
Forest fires. As global warming increases, wildfires are likely to get more intense and extensive and may result in significant ecosystem changes that would affect biodiversity through species loss or changes in species composition.
Sea-level rise. An increase in sea level could threaten many coastal ecosystems. Also at risk are mangrove forests and low-lying freshwater wetlands.
Coral Bleaching and Ocean Acidification. Warmer sea surface temperatures are also blamed for a phenomenon called coral bleaching, wherein corals expel their zooxanthellae, a symbiotic photosynthesizing algae that lives within the coral tissues and provides it with essential nutrients. Ocean acidification poses another challenge for corals and other marine life. A lot of carbon dioxide that has been emitted into the atmosphere has been absorbed by the oceans. This has resulted in a decrease in the ocean’s pH, which in turn affects the rate at which many marine organisms build skeletons.
Migration. The current rates of migration of species have much higher rates than during post glacial periods for them to adapt to the changing climate. As the climate warms, some species are physiologically vulnerable to temperature rise and can no longer survive in their current locations. They tend to migrate to cooler environments. Marine species will also need to adapt to warmer ocean temperatures. However, there are some cases that migration might not be possible because of unfavorable environmental parameters, geographical or human-made barriers and competition from species already in an area. In general, those species with limited ability to migrate are most likely to suffer in the face of rapid climate change.
Extinction. Studies revealed that climate change could result in the extinction of more than a million terrestrial species in the next 50 years. The International Union for Conservation of Nature Red List of Threatened Species predicted that 4161 species are being threatened by climate change, 33% are at the risk from climate change-induced habitat shifts and alteration, 29% are due to temperature extremes, and 28% are due to drought. It is also found that 19 species have already been extinct due to climate change.
Deforestation and disease regulation. Loss of biodiversity linked to deforestation and forest degradation could further diminish the ability of forests to do carbon sequestration. Deforestation also further affects the animals’ natural habitat. Without a home, more and more wild animals, which may have carried diseases without effect for years, are coming into contact with humans. Humans can contract the disease by eating or handling an infected animal. According to the United States Agency for International Development, nearly 75 percent of all new, emerging, or re-emerging diseases affecting humans at the beginning of the 21st century are zoonotic — meaning they originate in animals. Scientists have also found that climate variability and extreme weather events, such as high temperatures and intense rainfall events, are critical factors in high numbers of malaria cases and other insect-related epidemics.
Some species might be able to adapt to changing conditions or evolve in response to climate change. But for many, global warming could pose an insurmountable challenge.
Further attention and action are urgently needed. The changing climate has complex consequences disrupting biodiversity and ecosystem services. This is most significant for countries like the Philippines because the majority of our local livelihoods depend on goods and services provided by natural ecosystems.
The integration of biodiversity-related policies, strategies and programs at the international, national, and local levels must be functional. Future initiatives must start to overcome the lack of connections between the relevant sectors.
Everyone must be able to adapt in an appropriate way toward increasing knowledge and raising public awareness on the effects of climate change on biodiversity, knowing responsibility on biodiversity management, and developing practical ways of mitigating such effects or limiting the damage.