CHANGING THE EARTH
31, May 2019
Prelims level : Science and Tech Mains level : GS-III Technology, Economic Development, Environment
Why in News:
- A 34-member panel of the Anthropocene Working Group (AWG) voted 29-4 in favour of designating a new geological epoch — the Anthropocene.
- The current epoch is the Holocene.
- It is about 11,700 years of stable climate since the last ice age during which all human civilisation developed.
- As Earth entered a warming trend, the glaciers of the late Paleolithic retreated. Tundra gave way to forest.
- As the climate changed, the very large mammals that had adapted to extreme cold, like mammoth and wooly rhinoceros, became extinct.
- Humans, once dependent on these “mega mammals” for much of their food, switched to smaller game and increased their gathering of plant materials to supplement their diet.
- Evidence indicates that about 10,800 years ago, the climate underwent a sharp cold turn lasting for several years.
- As temperatures began to rebound, human population began to increase and we began inventing the processes that would change the planet forever.
- The Holocene and the preceding Pleistocene together form the Quaternary period.
- The term ‘Anthropocene’ was coined in 2000 by Nobel Laureate Paul Crutzen and Eugene Stoermer to denote the present geological time interval in which human activity has profoundly altered many conditions and processes on Earth.
- According to the AWG, the phenomena associated with the Anthropocene include
- An order-of-magnitude increase in erosion and sediment transport associated with urbanisation and agriculture. Marked and abrupt anthropogenic perturbations of the cycles of elements such as carbon. Environmental changes generated by these perturbations including global warming, sea-level rise, and ocean acidification. Rapid changes in the biosphere.
- Proliferation and global dispersion of many new minerals, rocks including concrete, fly ash, plastics, and the myriad ‘technofossils’ produced from these materials. The most recent period of the Anthropocene has been referred to by several authors as the Great Acceleration during which the socioeconomic and earth system trends are increasing dramatically, especially after the Second World War. For instance, the Geological Society termed the year 1945 as The Great Acceleration.
- The panel plans to submit a formal proposal for the new epoch by 2021 to the International Commission on Stratigraphy. The International Commission on Stratigraphy is responsible for deciding and defining the divisions of geological time.
- The focus is now on identifying a definitive geologic marker or golden spike (technically called Global boundary Stratotype Section and Point) to signal the beginning of the Anthropocene Epoch.
- The golden spike must be present globally and should be a part of deposits for geological record. Many in the AWG believe that artificial radionuclides spread across the world by atomic bomb tests from the early 1950s would serve as the golden spike. The radionuclides are present almost everywhere from marine sediments to ice layers and even stalagmites and stalactites.
- Once a formal proposal is made by the AWG, it will be considered by several more groups of the International Commission on Stratigraphy.
- The final ratification will be made by the executive committee of the International Union of Geological Sciences.