Down To Earth is a fortnightly magazine focusing on politics of environment and development, published in New Delhi, India.
UPSC Previous years’ questions on Development, Environment, Health and Disaster Management give us a clear idea about the increased importance of DTE magazine.
DTE Magazine is one of the most important and indispensable source for UPSC Civil Services Exam Preparation. Keeping this in mind, here, we come with ”Gist Of Down To Earth Magazine” which covers important environmental current affairs articles in smooth pointed form, keeping in mind the demand of UPSC aspirants.
What is the Era of Great Dying?
- The Permian era (298.9 million to 252.2 million years ago) was a time before the dinosaurs ruled the planet.
- The oceans were 10o C warmer than they are now, and oxygen levels were 80 per cent lower.
- During the period, land masses collided to form the arid supercontinent Pangaea.
- The massive Panthalassic Ocean, which covered much of the Earth, was home to many sponge and coral species, ammonites (tiny shelled organisms), brachiopods (invertebrate animals closely related to starfish), and fusulinid foraminifera (single-celled organisms closely associated with modern amoebas).
- Reptiles began to flourish, and Sharks and bony fish thrived.
- Towards the end of the era, a series of volcanic eruptions in the present-day central Siberia region injected massive amounts of greenhouse gases (GHGs) into the atmosphere. Then the uncontrolled GHG emissions triggered climatic changes.
- This sounded the death knell for the flourishing and diverse life forms. Roughly 96 per cent of marine species and 70 per cent of land species went extinct. Thus, scientists refer to this period as the “Great Dying”.
- Climate change that happened at the end of the Permian era is similar to the one that is unfolding now.
How Oceans are the planet’s largest ecosystem?
- Oceans are the planet’s largest ecosystem, accounting for 95 per cent of all space available for life and hosting 90 per cent of the planet’s total species.
- Beneath the oceans lies a world that is vast, diverse and elusive. Mountain ranges, hydrothermal vents that resemble terrestrial hot springs, and volcanoes rise from the seafloor.
- The landscape is dotted with trenches, which go as deep as 11,000 metres (m).
- The oceans are home to organisms of all sizes and shapes: from microorganisms to the blue whale.
- The average depth of the oceans is 3,700 m, and 80 per cent of the areas have not been explored at all.
- The exact number of species that live in the ocean is unknown; 91 per cent of the species have yet to be classified. As it is popularly said, we know more about the moon and Mars surfaces than the sea surface.
- What we know with certainty is that the oceans modulate the global climate and control the planetary temperature, and thus the weather events like rain, storms, cyclones, floods and droughts.
- Human lives are intimately tied to the oceans. About 50-80 per cent of the oxygen produced on Earth can be traced back to the sea.
- These saltwater bodies support the livelihoods of 3 billion people, according to the United Nations (UN).
- Also, ocean currents—the continuous movement of water—have an essential role. Acting as conveyor belts, they transport warm water from the equators to the pole and cooler waters from the poles to the equators.
- Upwelling currents allow the vertical movement of water, pushing cold, nutrient-rich water from the ocean depths to the surface, which is critical for fisheries.
- But the most important role the oceans play is that of a carbon sink: four-fifths of the global carbon cycle is circulated through them.
- According to the 5th Assessment Report published by the UN Intergovernmental Panel on Climate Change (ipcc) in 2014, the oceans have absorbed more than 90 per cent of the global warming created by humans since the 1970s.
- To make sense of this, without the oceans, the global average temperatures would have jumped by almost 56o C.
- The atmosphere has a low heat capacity compared to the ocean water, which can accommodate 1,000 times more heat. So, most of it is moving into the ocean.