Accelerating extinction rate threatens global biodiversity
In honour of this year’s International Day for Biological Diversity (celebrated every 22nd of May), the United Nations University (UNU) has shed light onto the phenomenon known as “co-extinction”.
With nearly 1 million species currently at risk of extinction, this year’s theme for the International Day for Biological Diversity encourages the support of the implementation of the Kunming-Montreal Global Biodiversity Framework (GBF); this plan aims to stop and reverse the loss of nature by 2050. One of the ways this will be achieved is by reducing the rate of extinction of all species tenfold and increasing the populations of wild species to healthy and resilient levels by 2050.
To understand how co-extinction works, we must first understand how ecosystems function. Every organism in an ecosystem is interconnected, with everything existing in a delicate balance. A change to the population of one species can tip this balance, affecting all the other species in the ecosystem as well, similar to a row of dominoes. The extinction of one species can therefore cause other species to go extinct as well. The UNU’s most recent report contains worrying findings on the rate at which extinctions are occurring. According to the report, human activities, namely land-use change, overexploitation of natural resources, climate change, pollution and the introduction of invasive species, have caused the rate of extinctions to accelerate up to tens or even hundreds of times faster than they should be occurring naturally.
Accelerated extinctions are classified as one of the six “risk tipping points” - these are points when the natural systems that humans rely on stop functioning as they should, which will significantly impact our everyday lives and oftentimes cause irreversible damage to that system. In this case, those systems are our ecosystems. Human-induced extinctions can impair ecosystem functions and increase the risk of entire ecosystems collapsing, causing a reduction in global biodiversity.
Overall, the only way to stop the loss of biodiversity is to stop causing more extinctions. Deputy Director of the UNU’s Institute for Environment and Human Security, Zita Sebesvari, remarks that the fate of humanity is “inevitably intertwined with the fate of our natural world”, and that “urgent and decisive action is needed to preserve the resilience of ecosystems and ensure the survival of our planet’s diverse web of life.”
Climate change is causing the oceans to change colour
While not clearly visible to the human eye, recent research has found that the world’s oceans are changing colour, and the main cause of this appears to be human-induced climate change.
Using MODIS (Moderate Resolution Imaging Spectroradiometer) data from NASA’s Aqua satellite, simulations have been created to map the entire spectrum of colour changes in the world’s oceans. One of these simulations was modelled whilst taking climate change into account, which matches the data taken by real-world satellites. This suggests that human activity is the main driver of these changes.
Satellite data has shown that waters near the Equator are becoming more green, while areas of a higher altitude are turning more blue. Up to 56% of the oceans have changed colour. Scientists believe that chlorophyll, which has a greenish hue, could be the cause of these colour changes. A recent study published by the European Union’s Copernicus Climate Service shows that chlorophyll levels in the ocean were 200-500% higher than average in the Norwegian sea and Atlantic Ocean, and 60-80% lower than average in the waters near the Iberian Peninsula.
Scientists believe that this phenomenon could be to do with phytoplankton distribution. Research has shown that ocean temperature records have been broken every day for the past year, which is causing phytoplankton distribution to shift as the oceans continue to warm. Because phytoplankton contain chlorophyll, they impact the ocean’s colour. Greener waters indicate the presence of more phytoplankton, while water that is less green means that there are fewer phytoplankton.
Researchers predict that phytoplankton could shift North as fast as 35 km a decade, which will likely change the global distribution of fish species and marine biodiversity, also resulting in negative repercussions on the entire marine food web.
Technical terms used in this article:
Chlorophyll - a green pigment which allows organisms to absorb sunlight to carry out photosynthesis
Photosynthesis - the process of organisms making their own food using energy from the Sun
Phytoplankton - microscopic animals that are capable of photosynthesising
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