GS Paper: GS1

Tropical cyclones remain the deadliest natural climate hazard that causes an unacceptably high loss of life, property and infrastructure.  Global warming has already resulted in a detectable increase in the number of higher intensity cyclones as well as their intensification.

Also read:

[Burning Issue] Tropical Cyclones and India

Try this question:

Q. The Marsupial Theory often seen in news is related to which of the climatic phenomena?

a) Heatwaves b) Monsoon Variability c) Formation of Cyclones d) Thunderstorms

What is Rapid Intensification of Cyclones?

• RI is defined as an increase in maximum sustained winds by at least 55 km/hour in a 24-hour period.
• Such acceleration can only come with a rapid drop in the pressure in the eye of the cyclone.
• Rapid intensification (RI) is making cyclone forecasts harder and intense cyclones with RI are expected to grow in number.
• The lack of understanding of the transition from a seedling of a cyclone, like a low-pressure system to a tropical storm, limits extending the forecast lead times.

Factors causing RI

The most important environmental factors for cyclone genesis are-

• the rotation or vorticity of a low-pressure system at the surface;
• sea surface temperatures or the volume of warm water available;
• the vertical motion of air in this low-pressure system;
• the amount of humidity available in the middle atmosphere and
• the vertical shear or the change in winds from the surface to the upper atmosphere.

MJO and Cyclones

• Madden-Julian Oscillations as they are known, dominate the tropics during October-April by propagating from the western Indian Ocean into the eastern Indian Ocean, across the Indonesian seas into the Pacific Ocean.
• Referred to as MJOs, these Madden-Julian Oscillations throw seeds of rotational low-pressure systems over the Indian and the Pacific Oceans.
• And thus, MJOs show a strong association with cyclogenesis, especially for the post-monsoon season.

Impacts of MISO

• Monsoon Intraseasonal Oscillations (MISO) are alternating periods of heavy and minimal rainfall, each lasting for about a month or so and tending to follow a cyclical, northward shifting pattern from the equator to southern Asia.
• While the strong vertical shear suppresses cyclones during the monsoon season, MISOs influence cyclone genesis during the pre-monsoon season.

Other factors

• At longer timescales, phenomena like the El Niño and La Niña influence not only the number of cyclone seeds but also the location and the expanse of warm water.
• For example, during the pre-monsoon season of La Niña year, the region of warm water over the Bay of Bengal increases. This leads cyclones to travel longer and grow stronger than during an El Niño year.
• Over the Pacific Ocean, on the other hand, it is the El Niño that provides a larger swath of warm water and more intense cyclones.
• West Africa produces waves called easterly waves that propagate west from land onto the tropical Atlantic Ocean and sow the seeds for most hurricanes.
• Extensive analysis has produced theories that are evocatively called the Marsupial Theory — a wave pouch that allows cyclones to grow, or waves interacting to produce a Kelvin cat’s eye, which is a ‘sweet-spot’ for the birth of a cyclone.

A new map has revealed the lost continent of Zealandia.

The ocean relief can be divided into various parts such as Continental Shelf, Continental Slope, Continental Rise or Foot, Deep Ocean basins, Abyssal plains & Abyssal Hills, Oceanic Trenches, Seamounts and Guyots.

Revise these ocean bottom relief features from your basic references.

Also revise India’s Deep Ocean Mission.

About Zealandia

• Zealandia — or Te Riu-a-Māui, as it’s referred to in the indigenous Māori language — is a 2 million-square-mile (5 million square kilometres) continent east of Australia, beneath modern-day New Zealand.
• Scientists discovered the sprawling underwater mass in the 1990s, then gave it formal continent status in 2017.
• Still, the “lost continent” remains largely unknown and poorly studied due to its Atlantean geography.

Its formation

• It is a group of submerged pieces of crust that separated from the ancient supercontinent Gondwana about 85 million years ago.
• Gondwana was formed when Earth’s ancient supercontinent, Pangea, split into two fragments.
• Laurasia was transformed into North America, Asia, and Europe, while Gondwana became Africa, South America, Australia, and Antarctica.
• But land masses continued to be rearranged afterwards, with Zealandia breaking off Gondwana.

Data revealed by the new map

• The new maps reveal Zealandia’s bathymetry (the shape of the ocean floor) as well as its tectonic history, showing how volcanism and tectonic motion have shaped the continent over millions of years.
• Data for the bathymetric map was provided by the Seabed2030 project — a global effort to map the entire ocean floor by 2030.

Why call it a continent?

• Zealandia was classified as a “microcontinent,” as the island of Madagascar, until 2017.
• But according to Mortimer, it has all the requirements to be classified as a continent.
• It has defined boundaries; it occupies an area of over one million square kilometres and is elected above the ocean crust.

Also read: https://www.civilsdaily.com/news/seabed-2030-project/

Researchers in the UK are set to study the “Anthropause”, a term they have coined to refer to the coronavirus-induced lockdown period and its impact on other species.

Practice question for mains:

Q. What is the significance of declaring Anthropocene epoch? Discuss how it is different from any geological events. Discuss the Anthropause Period.

Anthropause Period

• Researchers have suggested the lockdown period, which is also being referred to as the “Great Pause”, be referred to with a more precise term.
• It is referred specifically to a considerable global slowing of modern human activities, notably travel.
• The unprecedented curbs imposed on millions of people around the world, mainly due to restrictions in travel, led to reports of unusual animal behaviour.
• For instance, there were pumas sighted in Chile’s Santiago, jackals in the parks of Tel Aviv in Israel, dolphins in the waters of Italy and even a monkey fight on the streets of Thailand.
• The researchers believe studying this period will provide valuable insights into the relationship between human-wildlife interactions in the 21st century.

What do the researchers hope to find?

• As a result of the lockdown, nature appears to have changed, especially in urban environments, since not only are there now more animals, but also some “unexpected visitors.”
• In their outline, researchers mention how the scientific community can use these “extraordinary circumstance” provided by global lockdowns to understand how human activity affects wildlife.
• On the other hand, there are some animals for which the lockdown may have made things more challenging.
• For instance, for various urban-dwelling animals, such as rats, gulls and monkeys who depend on food provided or discarded by humans, the lockdown would have made life more difficult.

Why is studying the lockdown important?

• Expanding human populations continue to transform their environments at unprecedented rates.
• Further, because the reduction in human activity during the lockdown on both land and sea has been “unparalleled” in recent history, the effects have been “drastic, sudden and widespread”.
• Essentially, this gives them a chance to study the extent to which modern human mobility affects wildlife.
• The study can be linked can help provide insights that may be useful in preserving global biodiversity, maintaining the integrity of ecosystems and predicting global zoonoses and environmental changes.

Back2Basics

https://www.civilsdaily.com/news/anthropocene-as-earths-new-epoch/

The Seabed 2030 Project has finished mapping nearly one-fifth of the world’s ocean floor.

The ocean relief can be divided into various parts such as Continental Shelf, Continental Slope, Continental Rise or Foot, Deep Ocean basins, Abyssal plains & Abyssal Hills, Oceanic Trenches, Seamounts and Guyots.

Revise these ocean bottom relief features from your basic references.

Also revise India’s Deep Ocean Mission.

The Seabed 2030 Project

• The global initiative is a collaboration between Japan’s non-profit Nippon Foundation and the General Bathymetric Chart of the Oceans (GEBCO).
• It is the only intergovernmental organisation with a mandate to map the entire ocean floor and traces its origins to the GEBCO chart series initiated in 1903 by Prince Albert I of Monaco.
• The project was launched at the UN Ocean Conference in 2017, and coordinates and oversees the sourcing and compilation of bathymetric data from different parts of the world’s ocean.

What’s so special about this project?

• In the past, satellites and planes carrying altimeter instruments have been able to provide large swathes of data about the ocean floor.
• The Seabed 2030 Project, however, aims to obtain higher quality information that has a minimum resolution of 100 m at all spots.
• It is using equipment such as deepwater hull-mounted sonar systems, and more advanced options such as Underwater Vehicles (AUVs).
• For this, the project aims to rope in governments, private companies, and international organisations to acquire data.

Progress of the project

• Since the launch of the project in 2017, the surveying of the ocean bed as per modern standards has gone up from around 6 per cent to 19 per cent.
• The project has added 1.45 crore square kilometres of new bathymetric data to its latest grid.

Why is the study of the ocean floor important?

• Ocean topography: The knowledge of bathymetry — the measurement of the shape and depth of the ocean floor, is instrumental in understanding several natural phenomena, including ocean circulation, tides, and biological hotspots.
• Navigation: It also provides key inputs for navigation, forecasting tsunamis, exploration for oil and gas projects, building offshore wind turbines, fishing resources, and for laying cables and pipelines. This data becomes highly valuable during disaster situations.
• Climate Change study: Importantly, the maps would also ensure a better understanding of climate change, since floor features including canyons and underwater volcanoes influence phenomena ocean currents. These ocean currents act as conveyor belts of warm and cold water, thus influencing the weather and climate.
• Marine conservation: A map of the entire global ocean floor would also help further achieve the United Nations Sustainable Development Goal to conserve and sustainably use oceans, seas and marine resources.

Try this PYQ from CSP 2012:

Q.Consider the following factors:

1. Rotation of the Earth
2. Air pressure and wind
3. Density of ocean water
4. Revolution of the Earth

Which of the above factors influence the ocean currents?

(a) 1 and 2 only

(b) 1, 2 and 3

(c) 1 and 4

(d) 2, 3 and 4