Global Geological And Climatic Events

Aug, 31, 2019

When did the Anthropocene Epoch begin on Earth?


News

  • A committee of geologists has now proposed to mark the start of the Anthropocene in the mid-20th century, based on a striking indicator: the widely scattered radioactive dust from nuclear bomb tests in the early 1950s.

A new human age

  • Human impacts are everywhere. Our societies have changed Earth so much that it’s impossible to reverse many of these effects.
  • Examples of how human societies are changing the planet abound — from building roads and houses, clearing forests for agriculture , to shrinking the ozone layer, driving species extinct, changing the climate and acidifying the oceans.etc.
  • Some researchers believe these changes are so big that they mark the beginning of a new “human age” of Earth history, the Anthropocene epoch.

When to mark as beginning?

  • Researchers debate the utility of picking a single time line in Earth’s geological record to mark the start of human impacts in the geological record.
  • Maybe the Anthropocene began at different times in different parts of the world.
  • For example, the first instances of agriculture emerged at different places at different times, and resulted in huge impacts on the environment, through land clearing, habitat losses, extinctions, erosion etc.
  • There are multiple beginnings, scientists need to answer more complicated questions — like when did agriculture begin to transform landscapes in different parts of the world?
  • This is a tough question because archaeologists tend to focus their research on a limited number of sites and regions and to prioritize locations where agriculture is believed to have appeared earliest.
  • To date, it has proved nearly impossible for archaeologists to put together a global picture of land use changes throughout time.

Global answers from local experts

  • To tackle these questions, collaboration was held among archaeologists, anthropologists and geographers to survey archaeological knowledge on land use across the planet.
  • They mapped the current state of archaeological knowledge on land use across the planet, including parts of the world that have rarely been considered in previous studies.

With onset of agriculture

  • Archaeologists reported that nearly half (42 per cent) of the regions had some form of agriculture by 6,000 years ago, highlighting the prevalence of agricultural economies across the globe.
  • Moreover, these results indicate that the onset of agriculture was earlier and more widespread than suggested in the most common global reconstruction of land-use history, the History Database of the Global Environment.
  • This is important because climate scientists often use this database of past conditions to estimate future climate change; according to our research it may be underestimating land-use-associated climate effects.
  • Hunting and foraging was generally replaced by pastoralism (raising animals such as cows and sheep for food and other resources) and agriculture in most places, though there were exceptions.
  • In a few areas, reversals occurred and agriculture did not simply replace foraging but merged with it and coexisted side by side for some time.

More deeper roots

  • Global archaeological data show that human transformation of environments began at different times in different regions and accelerated with the emergence of agriculture.
  • Nevertheless, by 3,000 years ago, most of the planet was already transformed by hunter-gatherers, farmers and pastoralists.
  • To guide this planet toward a better future, we need to understand how we got here.
  • The message from archaeology is clear. It took thousands of years for the pristine planet of long ago to become the human planet of today.
  • To build a more robust Earth science in the Anthropocene, the human sciences must play as central a role as the natural sciences do today.

Back2Basics

Anthropocene as Earth’s new epoch

Aug, 30, 2019

Hurricane Dorian


News

  • The hurricane Dorian is to hit the east coast of Florida as a “major” hurricane, in Category 3 or possibly Category 4.

What do the categories mean?

  • Powerful winds are what define a hurricane, so they are named and classified based on how hard their winds are blowing.
  • To qualify as a hurricane, a storm must have sustained winds of 74 mph or more.
  • All hurricanes are dangerous, but some pack more punch than others.
  • So meteorologists try to quantify each storm’s destructive power by using the Saffir-Simpson scale placing it in one of five categories based on sustained wind speed:

Saffir-Simpson scale

Category 1, 74 to 95 mph:

  • These storms’ winds may knock down some trees and power lines and do a bit of damage to buildings.

Category 2, 96 to 110 mph:

  • These storms are likely to uproot many trees, disrupt electric power over wide areas and do significant roof and siding damage.

Category 3, 111 to 129 mph:

  • These are major storms that can take roofs off even well-constructed houses and knock out electric and water systems for days or weeks.
  • Roads will be blocked by falling trees and poles. Dorian is forecast to be at least this strong when it makes landfall.

Category 4, 130 to 156 mph:

  • These major storms do catastrophic damage, felling most trees and power poles and wrecking some buildings.
  • Affected areas may be uninhabitable for days or weeks afterward.

Category 5, 157 mph or more:

  • Storms this powerful are rare, and when they strike, they are immensely destructive.
  • Few structures will come through a direct hit unscathed, and a large percentage of frame buildings will be destroyed. Recovery may take weeks or months.

Back2Basics

What is the difference between a hurricane, a cyclone, and a typhoon?

  • The only difference between a hurricane, a cyclone, and a typhoon is the location where the storm occurs.
  • In the Atlantic and Northeast Pacific, the term “hurricane” is used.
  • The same type of disturbance in the Northwest Pacific is called a “typhoon” and “cyclones” occur in the South Pacific and Indian Ocean.
  • A tropical cyclone is a generic term used by meteorologists to describe a rotating, organized system of clouds and thunderstorms that originates over tropical or subtropical waters and has closed, low-level circulation.
Aug, 23, 2019

Adratiklit boulahfa


News

Adratiklit boulahfa

  • Scientists have described a new species of stegosaurus and dated it to 168 million years ago, which makes it the oldest known member of that group of dinosaurs ever known.
  • Named Adratiklit boulahfa, it is also the first stegosaurus to be found in North Africa.
  • Its remains were discovered in the Middle Atlas Mountains of Morocco.
  • The scientists believe it is not only a new species but also belongs to a new genus.
  • The name is derived from the words used by the Berber (an ethnic group indigenous to North Africa) for mountains (Adras), lizard (tiklit) and and the area where the specimen was found. (Boulahfa).

What makes it special?

  • The Adratiklit was armoured and herbivorous, and lived on the ancient supercontinent of Gondwana, which later split into Africa, South America, Australia and Antarctica.
  • Most stegosaurus remains so far have been found in the northern hemisphere.
  • However, this may not mean that stegosaurs were uncommon in Gondwana.
  • It may be due to the fact that Gondwana rock formations have been subject to far fewer excavations and detailed studies.
Aug, 13, 2019

Perseid Meteor Shower


News

What is Meteoric Shower?

  • On its journey around the Sun, the Earth passes through large swathes of cosmic debris.
  • The debris is essentially the remnants of comets — great frigid chunks of matter that leave behind dirty trails of rocks and ice that linger long after the comets themselves have passed.
  • As the Earth wades through this cloud of comet waste, the bits of debris create what appears from the ground to be a fireworks display in the sky — known as a meteor shower.

When does Perseid Meteor Shower occur?

  • Several meteor showers can be seen around the year.
  • Among the brightest and best known of them is the Perseid Meteor Shower, which has been active from July 17 onward, and can be seen until August 26.
  • The showers peaked on the night of Monday-Tuesday.
  • The Perseids occur as the Earth runs into pieces of cosmic debris left behind by the comet Swift-Tuttle.
  • The cloud of debris is about 27 km wide — and at the peak of the display, between 160 and 200 meteors streak through the Earth’s atmosphere every hour as the pieces of debris, travelling at some 2.14 lakh kph.

When to see them?

  • Meteors are best seen on a cloudless night, when the entire sky is visible, and when the Moon is not extremely bright.
  • Chances of a successful viewing are higher from locations far away from the lights of cities. Pollution and monsoon clouds make the Perseids difficult to view from India.
  • The showers peak when the Earth passes through the most dense part of the debris cloud.
  • Peaks can last for a few hours or several nights. They tend to be most visible after midnight and before dawn.
  • The showers should be seen with naked eyes; binoculars and telescopes narrow the field of vision.

The Swift-Tuttle Comet

  • The Perseids currently visible in the night sky are not due to the debris left behind by the comet Swift-Tuttle during its most recent pass, which happened in 1992.
  • This particular comet goes around the Sun once in 133 years, and the meteors now visible were left behind by the pass before the last one — or perhaps even earlier.
Jul, 26, 2019

Milky Way’s violent birth decoded


News

  • The Milky Way, home to our sun and billions of other stars, merged with another smaller galaxy in a colossal cosmic collision roughly 10 billion years ago, scientists said based on data from the Gaia space observatory.

What is Milky Way?

  • The Milky Way is the galaxy that contains the Solar System, with the name describing the galaxy’s appearance from Earth.
  • It resembles to a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye.
  • Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610.

Its formation

  • The union of the Milky Way and the so-called dwarf galaxy Gaia-Enceladus increased our galaxy’s mass by about a quarter and triggered a period of accelerated star formation lasting about 2 to 4 billion years.
  • Galaxies of all types, including the Milky Way, began to form relatively soon after the Big Bang explosion that marked the beginning of the universe some 13.8 billion years ago.
  • But they were generally smaller than those seen today and were forming stars at a rapid rate.
  • Subsequent galactic mergers were instrumental in configuring galaxies existing now.

How was that verified?

  • A high-precision measurement of the position, brightness and distance of around a million stars within 6,500 light years of the sun was obtained by the Gaia space telescope.
  • It helped pinpoint stars present before the merger and those that formed afterward.
  • Certain stars with higher content of elements other than hydrogen or helium arose in the Milky Way and others with lower such content originated in Gaia-Enceladus owing to its smaller mass.
  • While the merger was dramatic and helped shape the Milky Way, it was not a star-destroying calamity.
  • This crash was big in cosmic terms, but if it was happening now, we could probably not even notice at a human or solar system level.
Jul, 25, 2019

Explained: How lightning strikes, and why it kills

News

  • Twenty-nine people have been killed by lightning over the past 36 hours in Bihar.

Deaths by Lightening

  • Lightning is the biggest contributor to accidental deaths due to natural causes.
  • A few years ago, over 300 people were reported killed by lightning in just three days — a number that surprised officials and scientists.
  • And yet, lightning remains among the least studied atmospheric phenomena in the country.
  • Just one group of scientists, at the Indian Institute of Tropical Management (IITM) in Pune, works full-time on thunderstorms and lightning.

What is lightning?

  • Lightning is a very rapid — and massive — discharge of electricity in the atmosphere, some of which is directed towards the Earth’s surface.
  • These discharges are generated in giant moisture-bearing clouds that are 10-12 km tall.
  • The base of these clouds typically lies within 1-2 km of the Earth’s surface, while their top is 12-13 km away.
  • Temperatures towards the top of these clouds are in the range of minus 35 to minus 45 degrees Celsius.

How does it strike?

  • As water vapour moves upward in the cloud, the falling temperature causes it to condense. Heat is generated in the process, which pushes the molecules of water further up.
  • As they move to temperatures below zero degrees celsius, the water droplets change into small ice crystals.They continue to move up, gathering mass — until they are so heavy that they start to fall to Earth.
  • This leads to a system in which, simultaneously, smaller ice crystals are moving up and bigger crystals are coming down.
  • Collisions follow, and trigger the release of electrons — a process that is very similar to the generation of sparks of electricity.
  • As the moving free electrons cause more collisions and more electrons, a chain reaction ensues.
  • This process results in a situation in which the top layer of the cloud gets positively charged, while the middle layer is negatively charged.
  • The electrical potential difference between the two layers is huge — of the order of a billion to 10 billion volts.
  • In very little time, a massive current, of the order of 100,000 to a million amperes, starts to flow between the layers.
  • An enormous amount of heat is produced, and this leads to the heating of the air column between the two layers of the cloud.
  • This heat gives the air column a reddish appearance during lightning. As the heated air column expands, it produces shock waves that result in thunder.

How does this current reach the Earth from the cloud?

  • While the Earth is a good conductor of electricity, it is electrically neutral.
  • However, in comparison to the middle layer of the cloud, it becomes positively charged.
  • As a result, about 15%-20% of the current gets directed towards the Earth as well.
  • It is this flow of current that results in damage to life and property on Earth.
  • There is a greater probability of lightning striking tall objects such as trees, towers or buildings.
  • This happens because air is a poor conductor of electricity, and electrons that are travelling through air seek both a better conductor and the shortest route to the relatively positively charged Earth’s surface.

When does lightening hit people?

  • Lightning rarely hits people directly — but such strikes are almost always fatal.
  • People are most commonly struck by what are called “ground currents”.
  • The electrical energy, after hitting a large object (such as a tree) on Earth, spreads laterally on the ground for some distance, and people in this area receive electrical shocks.
  • It becomes more dangerous if the ground is wet (which it frequently is because of the accompanying rain), or if there is metal or other conducting material on it.
  • Water is a conductor, and many people are struck by lightning while standing in flooded paddy fields.

How uncertain is its prediction?

  • Predicting a thunderstorm over a pinpointed location is not possible.
  • Nor is it possible to predict the exact time of a likely lightning strike.

Precautions to be taken

  • For reasons given above, taking shelter under a tree is dangerous.
  • Lying flat on the ground too, can increase risks.
  • People should move indoors in a storm; however, even indoors, they should avoid touching electrical fittings, wires, metal, and water.
Jun, 11, 2019

Arabian Sea Cyclones

News

  • Just over a month after the powerful cyclone Fani devastated large areas of Odisha, another cyclone is headed towards India, this time towards the Gujarat coast.

Arabian Sea cyclones

  • Though cyclones are common in the June, very few of them originate in the Arabian Sea. Most of them are found in the Bay of Bengal.
  • In the last 120 years for which records are available, just about 14% of all cyclonic storms, and 23% of severe cyclones, around India have occurred in the Arabian Sea.
  • Arabian Sea cyclones are also relatively weak compared to those emerging in the Bay of Bengal.
  • This, along with the fact that the Gujarat coastline, which is where most of the cyclones emerging in the Arabian Sea are headed, is not very densely populated.
  • This ensures that the damage potential of the cyclones on the western coast is comparatively low.

About Cyclone Vayu

  • Cyclone Vayu is a deep depression positioned around 250 km northwest of Aminidivi island in Lakshadweep and about 750 km southwest of Mumbai.
  • It is likely to generate winds of speed 110-120 km per hour. In contrast, winds associated with Fani had speeds of about 220 km per hour.
  • Vayu at its most powerful stage would only be categorised as a “severe cyclonic storm”, while Fani was an “extremely severe cyclonic storm”
  • It has almost satisfied the conditions for classification as a “super cyclone”.

Major Impact: It halts Monsoon

  • Cyclones are sustained by very strong low-pressure areas at their core. Winds in surrounding areas are forced to rush towards these low-pressure areas.
  • Vayu is likely to halt the northward progression of the monsoon for a few days.
  • The cyclone is expected to interfere with normal progression, by sucking all the moisture from the monsoon winds towards itself.
  • Similar low-pressure areas, when they develop near or over land, are instrumental in pulling the monsoon winds over the country as well.
  • But right now, the low-pressure area at the centre of the cyclone is far more powerful than any local system that can pull the monsoon winds moving northeast.

Implications

  • What this means is that the places where the monsoon has already reached would continue to get rain, mainly along the western coastline, but other areas would have to wait a little longer.
May, 27, 2019

Seawater from Ice Age tucked in rocks discovered in Indian Ocean

News

Seawater from Ice Age

  • Scientists have discovered the remnants of seawater dating back to the Ice Age, tucked inside rock formations in the middle of the Indian Ocean.
  • Researchers from the University of Chicago in the U.S. made the discovery during a months-long scientific mission exploring the limestone deposits that form the Maldives.
  • The ship, the JOIDES Resolution, is specifically built for ocean science and is equipped with a drill that can extract cores of rock over a mile long from up to three miles beneath the seafloor.
  • The water in actual specimen was found to be 20,000-year-old as it was much saltier than normal seawater.

Importance of the study

  • Scientists are interested in reconstructing the last Ice Age because the patterns that drove its circulation, climate and weather were very different.
  • Understanding these patterns could shed light on how the planet’s climate will react in the future.
May, 24, 2019

Anthropocene as Earth’s new epoch


News

  • Rising global temperatures, sea levels, depleting ozone layer and acidifying oceans are the result of human activity that has “distinctively” altered our planet.
  • Now, a team of scientists have voted to declare “Anthropocene” as a new chapter in the Earth’s geological history.

Anthropocene Epoch

  • Coined by Paul Crutzen and Eugene Stoermer in 2000 to denote the present geological time interval, Anthropocene has been used to describe humanity’s large impact on the environment.
  • The scientific community have intensely debated in the past the idea to formally define it as a geological unit within the Geological Time Scale.
  • Recently the 34-member Anthropocene Working Group (AWG), voted in favour of starting the new epoch.
  • The result builds on an informal vote taken at the 2016 International Geological Congress in Cape Town, and lays the groundwork for a formal proposal by 2021 to the International Commission on Stratigraphy.
  • The move signals the end of the Holocene epoch, which began 12,000 to 11,600 years ago.
  • The International Union of Geological Sciences needs to ratify the AWG formal proposal, before the new epoch can formally be recognised.

Global boundary Stratotype Section and Point

  • To show a clear transition from the Holocene, the scientists plan to identify a definitive geologic marker or ‘golden spike’.
  • It would be technically called a Global boundary Stratotype Section and Point (GSSP).
  • For this, the group will search for the marker from around the globe, including a cave in northern Italy, corals in the Great Barrier Reef and a lake in China.

Demarcation of an epoch is not so easy

  • To demonstrate a sedimentary record representing the start of the epoch, the researchers are likely to choose the radionuclides that came from atomic-bomb detonations from 1945 until the Limited Nuclear Test Ban Treaty of 1963.
  • The stratigraphic evidence indicates a time-transgressive Anthropocene with multiple beginnings rather than a single moment of origin.
  • Declaring a new epoch on the basis of the radionuclide signal alone impedes rather than facilitates scientific understanding of human involvement in Earth system change.
May, 03, 2019

Explained: Naming of cyclones

News

Context

  • The newest cyclone to emerge out of the Bay of Bengal has been named Fani.
  • Before that, there were cyclones Hudhud in 2014, Ockhi in 2017 and Titli and Gaja in 2018.
  • Each Tropical Cyclone basin in the world has its own rotating list of names.
  • For cyclones in the Bay of Bengal and Arabian Sea, the naming system was agreed by eight member countries of a group called WMO/ESCAP and took effect in 2004.

Naming a Cyclone

  • There are five tropical cyclone regional bodies, i.e. ESCAP/WMO Typhoon Committee, WMO/ESCAP Panel on Tropical Cyclones, RA-I Tropical Cyclone Committee, RA-IV Hurricane Committee, and RA-V Tropical Cyclone Committee.
  • In general, tropical cyclones are named according to the rules at a regional level.
  • The WMO/ESCAP Panel on Tropical Cyclones at its twenty-seventh Session held in 2000 in Muscat, Oman agreed in principal to assign names to the tropical cyclones in the Bay of Bengal and Arabian Sea.
  • After long deliberations among the member countries, the naming of the tropical cyclones over north Indian Ocean commenced from September 2004.
  • Eight countries — India, Pakistan, Bangladesh, Maldives, Myanmar, Oman, Sri Lanka and Thailand participated in the panel and came up with a list of 64 names.
  • If public wants to suggest the name of a cyclone to be included in the list, the proposed name must meet some fundamental criteria, the RSMC website says.
  • The name should be short and readily understood when broadcast.
  • Further, the names must not be culturally sensitive and should not convey any unintended and potentially inflammatory meaning.

How naming takes place?

  • These countries submitted eight names each, which are arranged in an 8×8 table.
  • The first cyclone after the list was adopted was given the name in the first row of the first column — Onil, proposed by Bangladesh.
  • Subsequent cyclones are being named sequentially, column-wise, with each cyclone given the name immediately below that of the previous cyclone.
  • Once the bottom of the column is reached, the sequence moves to the top of the next column.
  • So far, the first seven columns have been exhausted, and Fani (again proposed by Bangladesh) is the top name in the last column.
  • The next cyclone will be named Vayu. The lists will wind up with Cyclone Amphan, whenever it comes.

When the lists end

  • After the 64 names are exhausted, the eight countries will propose fresh lists of names.
  • The lists for storms in the Atlantic and Eastern Pacific basins are, however, rotated.
  • Exception are, however, made in certain cases — if a storm causes excessive death and destruction, its name is considered for retirement and is not repeated; it is replaced with another name.

Why name cyclones?

  • It is generally agreed that appending names to cyclones makes it easier for the media to report on these cyclones, heightens interest in warnings, and increases community preparedness.
  • Names are presumed to be easier to remember than numbers and technical terms.
  • The practice of naming a storm/tropical cyclone would help identify each individual tropical cyclone.
  • The purpose of the move was also to make it easier for people to easily understand and remember the tropical cyclone/hurricane in a region, thus to facilitate disaster risk awareness, preparedness, management and reduction.
  • It does not confuse the public when there is more than one tropical cyclone in the same area.
  • Many agree that appending names to storms makes it easier for the media to report on tropical cyclones, heightens interest in warnings and increases community preparedness.
  • It’s easier and less confusing to say “Cyclone Titli” than remember the storm’s number or its longitude and latitude.
Apr, 30, 2019

Indian subcontinent’s collision with Asia boosted oxygen in world’s oceans

News

  • When the landmass that is now the Indian subcontinent slammed into Asia about 50 million years ago, the oxygen in the world’s oceans increased, altering the conditions for life.

Impact of Indian Plate

  • The collision was already known to have changed the configuration of the continents, the landscape, global climate and more.
  • Researchers used microscopic seashells to create a record of ocean nitrogen over a period from 70 million years ago – shortly before the extinction of the dinosaurs – until 30 million years ago.

Nitrogen dating to find Oxygen level

  • Every organism on Earth requires “fixed” nitrogen – sometimes called “biologically available nitrogen.”
  • Nitrogen has two stable isotopes: 15N and 14N. In oxygen-poor waters, decomposition uses up “fixed” nitrogen.
  • This occurs with a slight preference for the lighter nitrogen isotope, 14N, so the ocean’s 15N-to-14N ratio reflects its oxygen levels.
  • That ratio is incorporated into tiny sea creatures called foraminifera during their lives, and then preserved in their shells when they die.
  • By analysing their fossils researchers were able to reconstruct the 15N-to-14N ratio of the ancient ocean, and therefore identify past changes in oxygen levels.

Why study oxygen?

  • Oxygen controls the distribution of marine organisms, with oxygen-poor waters being bad for most ocean life.
  • Many past climate warming events caused decrease in ocean oxygen that limited the habitats of sea creatures, from microscopic plankton to the fish and whales that feed on them.
  • Scientists trying to predict the impact of current and future global warming have warned that low levels of ocean oxygen could decimate marine ecosystems, including important fish populations.
  • The researchers found that in the 10 million years after dinosaurs went extinct, the 15N-to-14N ratio was high, suggesting that ocean oxygen levels were low.
  • They first thought that the warm climate of the time was responsible, as oxygen is less soluble in warmer water.
  • Global climate was not the primary cause of this change in ocean oxygen and nitrogen cycling.

Back2Basics

Movement of Indian Plate

  • Until roughly 140 million years ago, the Indian Plate formed part of the supercontinent Gondwana. It was a large island situated off the Australian coast, in a vast ocean.
  • The Tethys Sea separated it from the Asian continent till about 225 million years ago.
  • India is supposed to have started her northward journey about 200 million years ago at the time when Pangaea
  • India collided with Asia about 40-50 million years ago causing rapid uplift of the Himalayas.
  • The positions of India since about 71 million years till the present are shown in the Figure. It also shows the position of the Indian subcontinent and the Eurasian plate.
  • About 140 million years before the present, the subcontinent was located as south as 50◦ S. latitude. The two major plates were separated by the Tethys Sea and the Tibetan block was closer to the Asiatic landmass.
  • During the movement of the Indian plate towards the Asiatic plate, a major event that occurred was the outpouring of lava and formation of the Deccan Traps. This started somewhere around 60 million years ago and continued for a long period of time.
  • Note that the subcontinent was still close to the equator. From 40 million years ago and thereafter, the event of formation of the Himalayas took place.
Apr, 22, 2019

A new landscape on the horizon

News

  • The recent scientific evidence has given a glimpse of the Earth’s changing contours—the African continent is splitting into two.

Africa is splitting

  • A place near Nairobi, Kenya had a large crack on the ground that appeared during an intense spell of rain and flooding.
  • The crack is 57 km long which is a locus of a future ocean formation.
  • Such an event happened 138 million years ago when the South American and African continents separated to give rise to the current South Atlantic Ocean.
  • All such signs on Earth’s surface point to a totally new landscape, which resembled how it looked like when it was formed 4.5 billion years ago one huge continent.
  • The farthest scientists can predict is that 250 million years from now all continents will unite again in one supercontinent and then will break apart again along the future rift systems.

Why such cracks?

  • At first, geologists thought the crack in Kenya was formed due to “erosion of soft soils infilling an old rift-related fault.
  • They later revealed that the crack had existed for quite some time, but was filled with ash from Mount Longmont, a volcano nearby.
  • The rain had washed away the ash to expose the crack. This triggered a debate whether the crack was a part of the East African Rift system.

Rift in systems

  • Rifts are the regions of extension of the crust and the lithosphere.
  • Continental changes take place at the boundaries of tectonic plates which are divisions of the uppermost layer of the Earth and swim around on the fluid mantle layer below it.
  • The extension may develop to a stage when two plates split apart, like in the example of the Red Sea and the Gulf of Aden. So continental rifts are potential places where new oceans are expected to form.
  • These plates periodically crash into each other, giving rise to earthquakes and volcanic eruptions when the intensity is less over short periods of time.
  • Over longer periods of time, they create all the geological and geographical features that we find on Earth like mountains, valleys and oceans.

Intra-continental drifting

  • One of these processes is an intra-continental rift system which acts between tectonic plates and can give rise to rift valleys or even new oceans.
  • The African Rift Valley, which is between Ethiopia and Kenya, is a classical example of this geodynamic process.
  • There, volcanism, earth-quakes and fracturing of the Earth’s surface result from the enormous forces that tear the eastern portion of the African continent apart.

 East African rift system

  • The East African rift system is more active in terms of volcanism and it is connected to the global ocean rift (ridge) system through the Afar-Red Sea—Gulf of Aden triple junction.
  • The Red Sea and the Gulf of Aden are the rifts along which two continents break apart and new oceanic flow is formed.
  • There are numerous rift systems around the world but the most active ones are the East African rift, Baikal rift, West Antarctic rift, Rio Grande rift, the Rhine Graben rift system in Europe and Shanxi rift system in China.
  • When such geographical features become prominent enough they reshape the way the planet looks.
  • The rifts undergo massive geological changes—shoulders of rifts grow and get eroded by rain and melting snow.
  • At the same time, the axial parts of rifts subside and get filled with sediments, which gets eroded from the shoulders.
Apr, 01, 2019

Malham Caves

Note4students

Mains Paper 1: Geography | Geographical features & their location

From UPSC perspective, the following things are important:

Prelims level: Malham Cave

Mains level: Features of the cave


News

  • Israel unveils world’s longest salt cave.

Malham Caves

  • Malham is one of 150 caves in Mount Sodom, at the southern part of the Dead Sea, that are made of pure salt.
  • Mount Sedom sits near the Dead Sea, a shrinking salt lake (and lowest point on Earth) that extends into Jordan, Israel and the occupied West Bank.
  • A large part of the cave’s interior is covered by a fine dust that blows in from the desert.
  • Massive slabs of salt, some amber-colored from dust and minerals, stick out in dramatic formations.
  • A thin slab appearing to have been sliced out is nicknamed “The Guillotine,” while twin slabs that look like a pair of tablets in a different hall have earned the title of “The Ten Commandments.”
  • Israeli researchers say they have discovered the world’s longest salt cave near the desert site where, according to the Bible, Lot’s wife was turned into a pillar of salt.

How old is it?

  • Radiocarbon dating suggests it’s about 7,000 years old, its many passages carved by the very occasional rain storms that pass through the region.
  • Even now, Malham continues to grow when water flows in and dissolves more of the salt.
Mar, 18, 2019

Solar tsunami can trigger the sunspot cycle

Note4students

Mains Paper 1: Geography | Salient features of World’s Physical Geography

From UPSC perspective, the following things are important:

Prelims level: Sunspots, Solar Tsunami

Mains level: Impact of Sunspots on mankind as a whole


News

  • A group of solar physicists suggests that a “solar tsunami” is at work that triggers the new sunspot cycle, after the old one ends.

Solar Dynamo

  • It is believed that the “solar dynamo” a naturally occurring generator which produces electric and magnetic fields in the sun is linked to the production of sunspots.
  • What kick-starts the 11-year sunspot cycle is not known.
  • The extreme temperature and pressure conditions that prevail some 20,000 km below the sun’s surface cause its material to form plasma consisting primarily of hydrogen and helium in a highly ionised state.
  • The plasma is confined with huge magnetic fields inside the sun.

What is Solar Tsunami?

  • The sun’s magnetic field, from which sunspots get generated, wraps around the sun in the east-west direction.
  • These magnetic fields behave like rubber bands on a polished sphere. They tend to slip towards the poles.
  • Holding these fields in their place requires that there is extra mass (plasma mass) pushing at the bands from higher latitudes.
  • Thus, a magnetic dam is formed which is storing a big mass of plasma.
  • At the end of a solar cycle, this magnetic dam can break, releasing huge amounts of plasma cascading like a tsunami towards the poles.
  • These tsunami waves travel at high speeds of about 1,000 km per hour carrying excess plasma to the mid-latitudes.
  • There they give rise to magnetic flux eruptions.
  • These are seen as the bright patches that signal the start of the next cycle of sunspots.

What are Sunspots?

  1. Sunspots are temporary phenomena on the Sun’s photosphere that appear as spots darker than the surrounding areas.
  2. They are regions of reduced surface temperature caused by concentrations of magnetic field flux that inhibit convection.
  3. Sunspots usually appear in pairs of opposite magnetic polarity.

 Why study them?

  • The solar cycle and sunspot activity are intimately connected with space weather.
  • The model provides a sound physical mechanism supporting why we should expect the next sunspot cycle 25 to begin in the year 2020.
  • This is again followed by a strong increase in space weather shortly after the trigger of a series of new sunspots in that year.
Feb, 18, 2019

Scientists discover massive mountains under Earth’s crust

Note4students

Mains Paper 1: Geography | Changes in critical geographical features

From the UPSC perspective, the following things are important:

Prelims level: Interior of Earth

Mains level: Structure and feature of Earth’s interior


News

  • Scientists have discovered massive mountains in the Earth’s mantle, an advance that may change our understanding of how the planet was formed.

Earth’s Interior is different

  1. We often learn that the Earth has three layers: a crust, mantle and core, which is subdivided into an inner and outer core.
  2. While that is not wrong, it does leave out several other layers that scientists have identified within the Earth.

Earthquake data helps study

  1. In a study published in the journal, scientists used data from an enormous earthquake in Bolivia to find mountains and other topography on a layer located 660 km straight down, which separates the upper and lower mantle.
  2. Lacking a formal name for this layer, the researchers simply call it “the 660-km boundary.”
  3. Data from earthquakes that are magnitude 7.0 or higher sends shockwaves in all directions that can travel through the core to the other side of the planet — and back again.

The transition zone

  1. The key data came from waves picked up after a magnitude 8.2 earthquake — the second-largest deep earthquake ever recorded — that shook Bolivia in 1994.
  2. The researchers examined a layer 410 km down, at the top of the mid-mantle “transition zone,” and they did not find similar roughness.
  3. The presence of roughness on the 660-km boundary has significant implications for understanding how our planet formed and evolved.
Jan, 14, 2019

Shifting north magnetic pole forces urgent navigation fix

Note4students

Mains Paper 1: Geography | Changes in critical geographical features

From the UPSC perspective, the following things are important:

Prelims level: World Magnetic Model

Mains level: Magnetic Pole Drifting


News

  • Rapid shifts in the Earth’s north magnetic pole are forcing researchers to make an early update to a model that helps navigation by ships, planes and submarines in the Arctic.

Shifting Magnetic North Pole

  1. Magnetic North Pole wanders, and every few hundred thousand years, the polarity flips so that a compass would point south instead of north.
  2. Liquid churning in Earth’s core generates most of the magnetic field, which varies over time as the deep flows change.
  3. However, the magnetic field has been changing so quickly and erratically that while conducting a routine check in early 2018, British and US researchers realized drastic steps were needed.
  4. The shift they observed was so large it was on the verge of exceeding the acceptable limit for navigation errors.
  5. Scientists must periodically update the World Magnetic Model to map this process, and the most recent version – produced in 2015 – was intended to last until 2020.

Tracking the movement

  1. The wandering pole is driven by unpredictable changes in liquid iron deep inside the Earth.
  2. It’s moving at about 50 km (30 miles) a year.
  3. It didn’t move much between 1900 and 1980 but it’s really accelerated in the past 40 years.
  4. On the contrary, the South magnetic pole drift is very slow (less than 10 km per year).
  5. It has not changed much over the past few decades, and hence provided a much smaller contribution to the overall model declination error.

Why Drift?

  1. The Earth’s magnetic field is in a permanent state of change.
  2. Magnetic north drifts around and every few hundred thousand years the polarity flips so a compass would point south instead of north.
  3. The strength of the magnetic field also constantly changes and currently it is showing signs of significant weakening.

Effect on Life

  1. Life has existed on the Earth for billions of years, during which there have been many reversals.
  2. There is no obvious correlation between animal extinctions and those reversals. Likewise, reversal patterns do not have any correlation with human development and evolution.
  3. It appears that some animals, such as whales and some birds use Earth’s magnetic field for migration and direction finding.
  4. Since geomagnetic reversal takes a number of thousands of years, they could well adapt to the changing magnetic environment or develop different methods of navigation.

Effect on Climate

  1. Earth’s magnetic field, which has existed for at least 3.45 billion years, provides a shield from the direct impact of solar radiation.
  2. Even with Earth’s strong magnetic field today, we’re still susceptible to solar storms that can damage our electricity-based society.
  3. The fluctuations in the number of cosmic rays hitting the atmosphere directly alter the amount of cloud covering the planet.

Back2Basics

World Magnetic Model

  1. The World Magnetic Model (WMM) is a large spatial-scale representation of the Earth’s magnetic field.
  2. It consists of a degree and order 12 spherical harmonic expansion of the magnetic potential of the geomagnetic main field generated in the Earth’s core.
  3. The charts are used to convert between compass measurements of magnetic north and true north.
  4. It can be found in the navigation systems of ships and airplanes as well as geological applications (such as drilling and mining).
  5. Researchers from the U.S.’s National Oceanic and Atmospheric Administration (NOAA) maintain the WMM.
  6. The charts, known as the World Magnetic Model (WMM), are used to convert between compass measurements of magnetic north and true north
  7. The WMM is also part of map applications in smartphones, including the Google Maps App.
Dec, 19, 2018

Volcano erupts in Indonesia

Note4students

Mains Paper 1: Geography | Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc

From the UPSC perspective, the following things are important:

Prelims level: Mount Soputan

Mains level: Volcanic eruptions and Plate Tectonics Theory


News

Mount Soputan erupts

  1. A volcano, Mount Soputan has erupted in Indonesia’s North Sulawesi province spewing a column of ash measuring 7.5 km to the sky.
  2. Soputan is a small stratovolcano that rises to an elevation of 1,784m (5,853 ft).
  3. The cone is made of andesite and basalt rock.
  4. The volcano is one of Sulawesi’s most active, with 39 confirmed eruptions in the last 600 years.
  5. It is one of 129 active volcanoes in Indonesia which lies on a vulnerable quake-hit zone called “the Pacific Ring of Fire”.

Pacific Ring of Fire

  1. The Ring of Fire is a major area in the basin of the Pacific Ocean where many earthquakes and volcanic eruptions occur.
  2. In a large 40,000 km horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and plate movements.
  3. It has 452 volcanoes (more than 75% of the world’s active and dormant volcanoes).
  4. About 90% of the world’s earthquakes and 81% of the world’s largest earthquakes occur along the Ring of Fire.
  5. The Ring of Fire is a direct result of plate tectonics: the movement and collisions of lithospheric plates, especially subduction in the northern portion.
Nov, 30, 2018

[op-ed snap] Cool it: on labour loss due to heatwave

Note4students

Mains Paper 1: Geography | changes in critical geographical features (including waterbodies & ice-caps) & in flora & fauna & the effects of such changes

From the UPSC perspective, the following things are important:

Prelims level: UNFCCC, Heatwaves

Mains level: Impact of climate change on various weather events


Context

Loss of crucial labour hours due to heat waves

  1. The staggering loss of an estimated 153 billion hours of labour during 2017 due to rising temperatures around the globe is a reminder to governments that they are not doing enough to dramatically curb greenhouse gas emissions
  2. The Lancet countdown on health and climate has reported that India was particularly affected by the rising frequency of heatwave events and lost about 75 billion hours of work, a significant part of it in the agricultural sector

Impact on India

  1. This has worrying implications for rural employment and the well-being of a large section of the population that depends on farming
  2. At stake for all countries in the developing world is the health of millions, many of them already vulnerable to extreme weather events
  3. From a public health perspective, the report sounds a warning that rising temperatures will enable the dengue virus and malaria to spread farther and faster
  4. This is also true of some other infections

Measures that need to be taken by India

  1. It is vital that India gets more ambitious about cutting back on carbon emissions, even as it presses for the fulfilment of the climate finance obligations of developed countries under the Paris Agreement of the UN Framework Convention on Climate Change
  2. A further reduction in the share of coal in the energy mix through sustained support for renewable energy, particularly solar photovoltaics, must form the cornerstone of national policy
  3. This must be matched by a shift away from the use of fossil fuels for transport, and the induction of more electric vehicles
  4. Such a policy would yield the parallel benefit of improving air quality
  5. Ambient air pollution led to the premature death of an estimated half a million people in India in 2015

Garnering international consensus for changing climate fund usage

  1. The consensus on climate change is that it has begun to affect the intensity and frequency of extreme weather events
  2. India’s approach to adaptation should, therefore, prepare for catastrophes with a well-considered plan to provide relief and rehabilitation
  3. If the Centre and State governments can arrive at a consensus on the strong climate link to the excessive rain in Kerala and Cyclone Gaja in Tamil Nadu, for instance, a case could be made for climate funds under the Paris Agreement
  4. Such a claim has to be supported by a perspective plan that identifies vulnerable regions and communities and incorporates transparent systems for funds utilisation

Way forward

  1. The aggravated impact of climate change on health is a serious issue for policymakers to consider
  2. The importance of funds for adaptation is underscored by Lancet’s finding that 99% of losses from climate-related events in low-income countries were not insured
  3. Increased exposure to heatwaves needs a policy response, nationally and globally
Oct, 25, 2018

Indian monsoons influence Atlantic hurricanes: study

An Indian monsoon steers tropical cyclones across the Atlantic

Note4students

Mains Paper 1: Geography | Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc.

From UPSC perspective, the following things are important:

Prelims level: Indian, Atlantic Ocean (Features & location), Indian monsoon, El Nino, La Nina, Hurricanes

Mains level: Indian monsoon impact on various other geographical features


News

Indian monsoon impact

  1. Strong monsoons in the Indian Ocean can induce easterly winds that push Atlantic Ocean hurricanes westward, increasing the likelihood they will make landfall in the Americas
  2. The newly-discovered relationship could help scientists better predict the path of oncoming hurricanes, especially in late summer months like September, when Atlantic hurricane activity peaks
  3. As the climate continues to warm, the monsoon could have an increasing influence on the paths of Atlantic hurricanes

How the phenomenon works

  1. In years where summer rainstorms in India are stronger, Atlantic hurricanes move further westward towards land
  2. In years where the rains are not as strong, hurricanes tend to curve northward earlier and fizzle out in the North Atlantic Ocean
  3. Strong monsoons influence hurricane steering by enhancing the effects of the North Atlantic subtropical high, a centre of high atmospheric pressure in the Atlantic Ocean
  4. When the subtropical high increases, stronger winds come from the east and push hurricanes westward

Effect of El Nino & La Nina

  1. Previous research has attributed changes in hurricane steering to El Nino-Southern Oscillation (ENSO), a periodic fluctuation in sea surface temperature and air pressure in the equatorial Pacific Ocean
  2. Scientists have traditionally relied on the La Nina cool phase of ENSO to make predictions about how strong a particular Atlantic hurricane season will be, but have trouble forecasting the paths of individual hurricanes
  3. La Nina and the Indian monsoon are correlated, but the strength of the monsoon influences the steering of hurricanes independently of La Nina fluctuations, which are responsible for changes in hurricane frequency
  4. La Nina fluctuations may result in more Atlantic hurricanes, but strong Indian monsoons steer them further westward, making it more likely they will make landfall in the Americas
Jul, 19, 2018

Newest phase in Earth's history named after Meghalaya rock

Image result for A layer (marked in pic) in this stalagmite from Meghalaya he

Note4students

Mains Paper 1: Geography | Salient features of world’s physical geography

From UPSC perspective, the following things are important:

Prelims level: Meghalayan age, Holocene Epoch, International Union of Geological Sciences (IUGS), International Commission on Stratigraphy

Mains level: Geological era’s of Earth and their important features


News

Meghalayan Age

  1. Scientists have created a new phase in Earth’s geological history and named it Meghalayan, after a stalagmite from a cave in the Indian state of Meghalaya
  2. The stalagmite helped define climatic events 4,200 years ago, marking the beginning of the phase that continues till today

The beginning of a new age

  1. The Meghalayan Age began with a mega global drought that devastated ancient agricultural civilisations from Egypt to China
  2. It is part of a longer period known as the Holocene Epoch, which reflects everything that has happened over the past 11,700 years

Uniqueness of this age

  1. The Meghalayan is unique because it is the first interval in Earth’s geological history that coincided with a major cultural event, as agricultural societies struggled to recover from the shift in climate
  2. The droughts over a 200-year period resulted in human migrations in Egypt, Greece, Syria, Palestine, Mesopotamia, the Indus valley and the Yangtze river valley
  3. The change in global climate was likely triggered by shifts in ocean and atmospheric circulation

IUGS findings

  1. This discovery was done by the International Commission on Stratigraphy of the International Union of Geological Sciences (IUGS)
  2. The commission then forwarded these proposals to its parent body, the IUGS, for consideration, and the executive committee of IUGS voted unanimously to ratify them
  3. Two other ages — the Middle Holocene Northgrippian Age and the Early Holocene Greenlandian Age — with beginnings defined at climatic events that happened about 8,300 years and 11,700 years ago, respectively, were also approved by the International Commission on Stratigraphy, which is responsible for standardising the geologic time scale

Distinct periods of Earth’s geology

  1. Geologists divide the 4.6-billion-year existence of Earth into distinct periods
  2. Each period corresponds to significant events such as the break-up of continents, shifts in climate, and the emergence of particular types of animals and plant life
  3. These units of the geologic time scale are based on sedimentary strata that have accumulated over time and contain within them sediment types, fossils and chemical isotopes that record the passage of time as well as the physical and biological events that produced them

Back2Basics

International Union of Geological Sciences (IUGS)

  1. The IUGS is an international non-governmental organization devoted to international cooperation in the field of geology
  2. It is a Scientific Union member of the International Council for Science (ICSU), which it recognizes as the coordinating body for the international organization of science
  3. Currently, geologists from 121 countries (and regions) are represented in IUGS through a 121 Adhering Organization
  4. IUGS promotes and encourages the study of geological problems, especially those of worldwide significance, and supports and facilitates international and interdisciplinary cooperation in the earth sciences
  5. The Union’s Secretariat is currently located at the Chinese Academy of Geological Sciences in Beijing, China
  6. The Union is the main scientific sponsor of the International Geological Congress (IGC), which takes place every four years
  7. IUGS is a joint partner with UNESCO for the International Geoscience Programme (IGCP) and they also participate in the Global Network of National Geoparks (GGN)
  8. The Geological Society of London oversees the production and distribution of IUGS Publications
  9. As of 2016 IUGS runs Seven international commissions covering the following topics:
  • Commission for the Management and Application of Geoscience Information (CGI)
  • Geoscience Education, Training and Technology Transfer (COGE)
  • Geoscience for Environmental Management(GEM)
  • International Commission on Stratigraphy (ICS)
  • International Commission on the History of Geological Sciences (INHIGEO)
  • Commission on Tectonics and Structural Geology (TECTASK)
  • Commission on Global Geochemical Baselines
Apr, 27, 2018

Strong winds in Atlantic create high waves off Indian coasts over 10,000 km away

Image source

Note4students

Mains Paper 1: Geography | Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc.

From UPSC perspective, the following things are important:

Prelims level: INCOIS, Swell waves, IMD colour codes

Mains level: India’s vulnerability to sea level changes and measures that can be taken to avoid major casualties


News

High energy waves hit Indian coasts

  1. Strong winds in the Atlantic Ocean, more than 10,000 kms from the Indian coasts, have given rise to high energy waves in the Arabian Sea and the Bay of Bengal
  2. These high period waves can travel long distances and become more strong as they reach the coast

Waves Forecast

  1. The Indian National Centre for Ocean Information Services (INCOIS), a unit of the Ministry of Earth Sciences, issued ‘swells’ alerts to states
  2. After the devastating tsunami of 2004, India developed the necessary infrastructure to issue alerts in case of any abnormal wave activity in the seas

Colour codes for the forecast

  1. The IMD has four colour codes to denote the levels of caution
  2. The Red alert is considered serious and demands action by government agencies
  3. The Orange denotes an alert to be prepared for any extreme weather event
  4. The Yellow indicates that the authorities must keep a watch on the natural calamity
  5. The Green denotes that no action should be taken and that situation is normal

Back2Basics

Indian National Centre for Ocean Information Services (INCOIS)

  1. INCOIS is an autonomous organization of the Government of India, under the Ministry of Earth Sciences
  2. ESSO-INCOIS is a unit of the Earth System Science Organization (ESSO)
  3. ESSO- INCOIS is mandated to provide the best possible ocean information and advisory services to society, industry, government agencies and the scientific community through sustained ocean observations and constant improvements through systematic and focused research
Apr, 21, 2018

Swell waves forecast along India’s coasts

Image source

Note4students

Mains Paper 1: Geography | Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc.

From UPSC perspective, the following things are important:

Prelims level: Swell waves, NDMA, INCOIS

Mains level: Impact of sea level changes on India


News

High energy swell waves forecasted

  1. India’s coasts will be lashed by ‘high energy swell waves’ according to an alert from the National Disaster Management Agency (NDMA)
  2. This is based on a forecast from the Hyderabad-based Indian National Centre for Ocean Information Services (INCOIS), which is charged with issuing tsunami alerts
  3. The low-lying coasts of Kerala and West Bengal are particularly vulnerable

Back2Basics

Swell Waves

  1. ‘Swell waves’ are massive ripples that form on the sea due to winds coming from as far away as Madagascar
  2. Swells are collections of waves produced by storm winds raging hundreds of miles out to sea, rather than the product of local winds along beaches
  3. They are often referred to as surface gravity waves
  4. Swell continues to move under winds and waves that have long since changed direction, it can even head in the opposite direction as the wind and waves
  5. They might appear to be tsunami-like waves but have completely different characteristics
  6. They can have heights between 2 m and 3 m and periods between 17-22 seconds
Mar, 14, 2018

Rare meteorite may hold clue to life’s origin

Image source

Note4students

Mains Paper 3: Science & Technology | Awareness in the fields of IT, Space, Computers, robotics, nano-technology, bio-technology

From UPSC perspective, the following things are important:

Prelims level: Meteorites, Geological Survey of India (GSI)

Mains level: Studies related to the origin of life


News

Evidence of origins of life

  1. A study of two meteorites by the Geological Survey of India (GSI) has concluded that they may contain significant clues to the origins of life
  2. These meteorites fell in Assam and Rajasthan over a span of 13 hours in 2017

Material dates back to the pre-sun era

  1. The Mukundpura (Rajasthan) meteorite is a carbonaceous meteorite, one of the most primitive types
  2. They contain grains of calcium and iron which date to a time before the sun came into existence
  3. They may contain clues to the formation of early life

Back2Basics

Meteorites

  1. A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon
  2. When the object enters the atmosphere, various factors like friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate that energy
  3. It then becomes a meteor and forms a fireball, also known as a shooting star or falling star
  4. Meteorites have traditionally been divided into three broad categories: stony meteorites are rocks, mainly composed of silicate minerals; iron meteorites that are largely composed of metallic iron-nickel; and, stony-iron meteorites that contain large amounts of both metallic and rocky material
  5. Meteorites mostly originate from the asteroid belt between Mars and Jupiter
  6. Meteorites are always named for the places they were found usually a nearby town or geographic feature
  7. In cases where many meteorites were found in one place, the name may be followed by a number or letter
Feb, 21, 2018

Global temperature in January 2018 fifth highest for the month since 1880: report

Note4students

Mains Paper 1: Geography | changes in critical geographical features (including waterbodies & ice-caps) & in flora & fauna & the effects of such changes.

From UPSC perspective, the following things are important:

Prelims level: Global warming, Arctic sea

Mains level: Effects of global warming


News

Fifth warmest month since 1880

  1. Global temperature in January 2018 was the fifth highest for the month since 1880
  2. Another analysis said that earth’s polar regions continue to experience record-low ice conditions
  3. Arctic sea ice extent the smallest for the month in 39 years

Continued warming 

  1. The latest analysis only adds to the long list of records that are being set by global warming in the last few years
  2. Last month, NASA had said that earth’s global surface temperature in 2017 ranked the second warmest since 1880
Jan, 29, 2018

Rare ‘super blood blue moon’ visible on Jan. 31

Image source

Note4students

Mains Paper 3: Science & Technology | Awareness in the fields of IT, Space, Computers, robotics, nano-technology, bio-technology

From UPSC perspective, the following things are important:

Prelims level: Super blood blue moon, Supermoon, Lunar eclipse

Mains level: Solar and Lunar eclipses and their effects on Earth


News

Astronomical trifecta to appear on January 31

  1. A rare “super blood blue moon” may be glimpsed January 31 in parts of western North America, Asia, the Middle East, Russia and Australia
  2. It combines three unusual lunar events — an extra big super moon, a blue moon and a total lunar eclipse

Blue moon

  1. A blue moon refers to the second full moon in a month
  2. Typically, a blue moon happens every two years and eight months

Supermoon

  1. Supermoons happen when the moon is closest to Earth in its orbit
  2. This point, called the perigee, makes the moon appear 14% larger and 30% brighter
  3. Supermoons can happen four to six times a year

Lunar eclipse

  1. A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra
  2. This can occur only when the Sun, Earth, and Moon are aligned exactly, or very closely so, with the Earth in the middle
  3. Lunar eclipses occur at least twice a year
  4. Lunar eclipses during a supermoon happen regularly
Jan, 27, 2018

Rain in western hemisphere linked to currents in Atlantic Ocean, says study

Image source

Note4students

Mains Paper 1: Geography | Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc.

From UPSC perspective, the following things are important:

Prelims level: Atlantic Ocean

Mains level: Ocean currents, rainfall patterns


News

Study on climate factors affecting rains

  1. Changes in ocean currents in the Atlantic Ocean influence rainfall in the western hemisphere and the two systems have been linked for thousands of years
  2. The Atlantic Ocean surface circulation, and however that changes, has implications for how the rainfall changes on continents

Importance of Atlantic Ocean surface circulation

  1. The Atlantic Ocean surface circulation is an important part of the Earth’s global climate, moving warm water from the tropics towards the poles
  2. The Atlantic Ocean surface currents correlate with rainfall patterns in the western hemisphere
Oct, 05, 2016

Hurricane Matthew pummels Haiti and Cuba, evacuations ordered in U.S.

  1. Hurricane Matthew pummeled Haiti and moved on to Cuba
  2. Impact: Killed 7 people, unleashed floods and forced hundreds of thousands to flee
  3. It is the Caribbean’s worst storm in nearly a decade
  4. Civil protection officials in Haiti are struggling to communicate with the south after Matthew’s furious wind and rain blew down telephone lines
  5. The collapse of a bridge cut off the only road linking Port-au-Prince to the peninsula that makes up southern Haiti

Discuss: Tropical cyclones are largely confined to Bay of Bengal, South China Sea, Gulf of Mexico. Why? [Mains 2014, GS-I]

Sep, 30, 2016

Nearly 400 tourists trapped as Indonesian volcano erupts

  1. A volcano erupted at Mount Rinjani in Lombok, Indonesia
  2. Mount Barujari that forms part of Rinjani was seen emitting a 2,000-metre-high column of smokeRinjani, the second highest volcano in Indonesia stands 3,726 metres high
  3. It attracts thousands of tourists annually for a three-day trek to the mountain top, which has a lake in its boiler
    Indonesia sits on the Pacific Ring of Fire
  4. Ring of Fire: An area of high seismic and volcanic activity which is home to more than 400 volcanoes, including at least 129 that are still active and 65 qualified as dangerous

Discuss: Earthquakes and volcanism are some of the most important topics for Mains & Pre both. Go back to your NCERTs or GC Leong and revise them now!

Mar, 03, 2016

Major quake strikes off Sumatra

sumatara_2759440f


  1. Context: Warning was issued for West Sumatra, North Sumatra and Aceh after the quake of magnitude 7.9
  2. Epicentre: 808 km southwest of Padang and 10 km deep
  3. History: Indonesia, especially Aceh, was badly hit by the Indian Ocean tsunami in 2004
  4. Pacific Ring of Fire: A highly seismically active zone, where different plates on the earth’s crust meet and create a large number of earthquakes and volcanoes
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