Sixth Mass Extinction

Context: Recently a new study led by the University of Hawaii claimed that Earth is witnessing its sixth mass extinction event.

Highlights of the study:

• Studies show that loss of species is taking place across all ecosystems — from land to oceans, from the sea surface to the yet-to-be-fully-explored seafloors, from forests to desert, and from swamps to rivers. This proves that a mass extinction event is taking place.
• The Living Planet Report by WWF: According to the report, there has been a 69 per cent decline in the wildlife populations of mammals, birds, amphibians, reptiles and fish, across the globe in the last 50 years.
• Marine species: Scientists have also warned of an imminent mass annihilation of marine species similar to one 250 million years ago that wiped out most lives in oceans.
• Migratory fish species: Habitat loss and barriers to migration routes were responsible for about half of the threats to monitored migratory fish species.
• Human induced: Humans have annihilated 83 per cent of all wild mammals and half of all plants, according to a census of the biomass on Earth.

About Mass Extinction:

• A mass extinction is a short period of geological time in which a high percentage of biodiversity, or distinct species—bacteria, fungi, plants, mammals, birds, reptiles, amphibians, fish, invertebrates—dies out.
• In this definition, it’s important to note that, in geological time, a ‘short’ period can span thousands or even millions of years.
• The planet has experienced five previous mass extinction events, the last one occurring 65.5 million years ago which wiped out the dinosaurs from existence.
• Experts now believe we’re in the midst of a sixth mass extinction.

Causes of mass extinction:

• The “Living Planet Report 2020” points out five major reasons behind the biodiversity loss across the planet:
  • Changes in land and sea use (habitat loss and degradation),
  • Overexploitation of species,
  • Invasive species and disease,
  • Pollution and
  • Climate change.
• Pollution and Climate Change: In the Asia Pacific region, including India which is experiencing a loss of species higher than the global average, habitat degradation is the biggest trigger, followed by species overexploitation and invasive species and disease. The role of pollution and climate change was proportionately higher at 16 per cent.
• Invasive alien species: Invasive alien species have spread across and populated faster.
  • They have been regarded as the most serious drivers of biodiversity loss across the Asia-Pacific region.
• Overexploitation of species: In just the last three centuries, global forest areas have shrunk by 40 per cent.
  • Every year, to meet the timber needs from natural sources, the Earth is stripped of 100 million trees.
  • They store 50 per cent of the world’s terrestrial carbon and provide a buffer from extreme weather, such as hurricanes and tsunamis.
• Human induced: The current rate and scale of extinction is unprecedented and is being caused majorly by humans.
  • From greenhouse gas emissions and ozone depletion to deforestation, plastic pile-up and the illegal animal trade, humans have actively stripped the world of some species and threatened many more.
• Change in ocean circulation pattern and climate cooling: Cooling climate likely changed the ocean circulation pattern. This caused a disruption in the flow of oxygen-rich water from the shallow seas to deeper oceans, leading to a mass extinction of marine creatures.

Consequences of mass extinction:

• Interdependent ecology: Losing species at a such an alarming rate has a far-reaching consequence on the landmass.
  • Each and every being is part of the complex ecosystem of Earth, where every existence has a reason and is rational.
• Each has an ecosystem service for the other that has evolved with them over billions of years, as they carved out their own society or ecological niche. If one fails, the other stutters.
• Moving towards poles: The IPCC report cites that half of all species are moving towards the poles or to a higher elevation to adapt to the new planetary climate.
  • At the sea, due to the warming, species have travelled pole-ward at the rate of 59 km per decade on average.
• Missing SDG targets: The world may miss the UN Sustainable Development Goals (SDG) targets by a wide margin if human civilisation does not pull up its socks and promptly acts to protect the natural order.

Suggestions measures:

• Regulating wildlife markets: In the wake of the current pandemic, wildlife markets have been thrust into the spotlight as not only being environmentally irresponsible, but potentially dangerous to human health through zoonotic diseases that jump from animals to humans such as COVID-19.
  • These markets, trading live exotic animals or products derived from them, are found worldwide.
• Treating them as one: Biodiversity loss and climate crisis should be dealt with as one instead of two different issues as they are intertwined.
• Monitoring species population: One of the best ways to help prevent species from becoming extinct is to monitor their populations and identify any problems before it’s too late to help.
  • Currently camera traps and surveys conducted on foot or from aircraft are the main method of data collection.
• 30X30: Our leaders can support the America the Beautiful initiative to conserve 30% of US lands and waters by 2030.
• UN Biodiversity Summit: US leadership can play a critical role beside 195 other countries and agree to new ambitious global goals on biodiversity and how they can be financed and implemented.
• Institutional efforts: From tackling global pollution emissions in the 2016 Paris Agreement to the U.K.’s Global Resource Initiative that combats deforestation, legislation will always be at the forefront of the fight against mass extinction.

Source: DownToEarth

Previous Year Question

Q.1) The term “sixth mass extinction/sixth extinction” is often mentioned in the news in the context of the discussion of   (2018)

1. Widespread monoculture Practices agriculture and large-scale commercial farming with indiscriminate use of chemicals in many parts of the world that may result in the loss of good native ecosystems.
2. Fears of a possible collision of a meteorite with the Earth in the near future in the manner it happened 65million years ago that caused the mass extinction of many species including those of dinosaurs.
3. Large scale cultivation of genetically modified crops in many parts of the world and promoting their cultivation in other Parts of the world which may cause the disappearance of good native crop plants and the loss of food biodiversity.
4. Mankind’s over-exploitation/misuse of natural resources, fragmentation/loss, natural habitats, destruction of ecosystems, pollution and global climate change.