Melting of Greenland ice exacerbates rate of global sea level rise by 50 per cent

By summing up all sea-level contributions— from ocean warming to melting glaciers, a recent study has found that the rate of global sea-level rise has increased by 50 per cent over the past two decades.

Scientists estimate that sea-levels will continue to rise if the effects of climate change are not mitigated. 



The study was conducted by researchers from the CSIRO, the University of New South Wales, the University of Tasmania, as well the Ocean University of China.

Curiously, despite indications that the melting of glaciers and ice sheets were contributing to sea-level rises, there had been no reported increases in sea level observations by satellite altimery (an instrument for measuring height or altitude). 

When comparing and carefully analysing satellite and coastal measurements of sea level, they revealed a small but significant bias in satellite measurements between 1993 and 2003.

Biases ranged from conflicts owing to the differing observational techniques and different data quality control procedures and mapping methods.

In comparing the corrected satellite data from 1993 to 2014 with the contributing factors to sea-level rises over these two decades including ocean warming, the melting of glaciers and ice sheets and the amount of water stored on land, it became clear that there was an increased rate of sea level rise over the entire two decades. 

Based on corrected satellite altimetry, the rate of sea level rise went from 2.4 mm per year in 1993 to 2.9 mm per year in 2014, meaning there was a steady increase of about 0.5 mm per year from 1993 to 2014.

Ocean expansion as a result of ocean warming was pinpointed as the number one factor behind the sea-level rises, while glaciers and ice sheets were the second largest contributor. 

"Strikingly, the largest increase came from the Greenland ice sheet, as a result of both increased surface melting and increased flow of ice into the ocean," the scientists told The Conversation

Greenland's contribution to the sea-level rises increased from 5 per cent in 1993, to 25 per cent in 2014. 

"While the rate of ocean thermal expansion has remained steady since 1993, the contributions from glaciers and ice sheets have increased markedly," they said. 

The research points to the need for correction of biases in earlier data to understand the rapid rate of sea-level rises, while also demonstrating the need for effective climate change protocols. 

"If the global community fails to move toward zero greenhouse gas emissions very soon then the planet will see something like 1 metre of sea level rise by 2100," Matt King, a professor in Surveying & Spatial Sciences who was involved in the study, told Australian Geographic. 

"Recent studies have suggested Antarctica could contribute more than previously thought – if this occurs, then sea levels will rise by more than 1 metre by 2100. We can limit the damage but we can also make it worse. This rise will affect coastlines but more than that will have effects on human migration and, potentially, national security."

Matt explains that considering $250 billion of Australian infrastructure sits within 1.1 metre of sea level, building new flood defences may help in some locations, however these are expensive.

"For many locations, planned retreat from vulnerable coastlines needs to be considered well in advance – this will affect private landowners, businesses and governments."

The research was published in the journal Nature Climate Change.

Source: Australian Geographic.

Why the world needs meteorologists?

The Mid-Atlantic Ridge

The mid ocean ridge systems are the largest geological features on the planet. The Mid-Atlantic Ridge (MAR) is a mostly underwater mountain range in the Atlantic Ocean that runs from 87°N -about 333km south of the North Pole- to subantarctic Bourvet island at 54°S.

The MAR is about 3 km in height above the ocean floor and 1000 to 1500 km wide, has numerous transform faults and an axial rift valley along its length.

Scientists discover how world's biggest volcanoes formed

A study led by ANU has solved the 168-year-old mystery of how the world's biggest and most active volcanoes formed in Hawaii.



The study found that the volcanoes formed along twin tracks due to a shift in the Pacific plate's direction three million years ago.

Lead researcher Tim Jones from ANU said scientists had known of the existence of the twin volcanic tracks since 1849, but the cause of them had remained a mystery until now.

"The discovery helps to better reconstruct Earth's history and understand part of the world that has captivated people's imagination," said Mr Jones, a PhD student from the ANU Research School of Earth Sciences (RSES).

"The analysis we did on past Pacific plate motions is the first to reveal that there was a substantial change in motion 3 million years ago. It helps to explain the origin of Hawaii, Earth's biggest volcanic hotspot and one of the most popular tourist destinations in the world."

Twin volcanic tracks exist in other parts of the Pacific, including Samoa, and the study found that these also emerged three million years ago.

Mr Jones said this kind of volcanic activity was surprising because it occurred away from tectonic plate boundaries, where most volcanoes are found.

"Heat from the Earth's core causes hot columns of rock, called mantle plumes, to rise under tectonic plates and produce volcanic activity on the surface," he said.

"Mantle plumes have played a role in mass extinctions, the creation of diamonds and the breaking up of continents."

Co-researcher Dr Rhodri Davies from RSES said the twin volcanic tracks emerged because the mantle plume was out of alignment with the direction of the plate motion.

"Our hypothesis predicts that the plate and the plume will realign again at some stage in the future, and the two tracks will merge to form a single track once again," Dr Davies said.

"Plate shifts have been occurring constantly, but irregularly, throughout Earth's history. Looking further back in time we find that double tracks are not unique to young Hawaiian volcanism - indeed, they coincide with other past changes in plate motion."

Hawaii sits at the south-eastern limit of a chain of volcanoes and submerged seamounts which get progressively older towards the north west.

The researchers worked with the National Computational Infrastructure at ANU to model the Pacific plate's change in direction and formation of the twin volcanic tracks through Hawaii.

The study titled 'The concurrent emergence and causes of double volcanic hotspot tracks on the Pacific plate' is published in Nature.

The Predator Dinogorgon

A quarter of a billion years ago, long before dinosaurs or mammals evolved, the 10-foot (3-meter) predator Dinogorgon, whose skull is shown here, hunted floodplains in the heart of today's South Africa. 
In less than a million years Dinogorgon vanished in the greatest mass extinction ever (the End-Permian Extinction, a/k/a "The Great Dying"), along with about nine of every ten plant and animal species on the planet.

This Literature Map of the World Shows You Every Country's Favourite Book

Luke Abrahams - Everyone loves a good book right? Well, guess what. A savvy reddit user has put together this awesome literary map of the world that shows what everyone's mad for reading.

Bored of Harry Potter, tired of the Millennium trilogy, can’t be bothered to finish War and Peace? Well this map will make your morning commute that little more interesting.

Thanks to reddit user Backforward24, you can now see what the entire world’s favourite books are.

Each book represented in the map is marked by that country’s most famous or important novel.

Obviously the map is going to cause quite the stir. For Russia, for example, Backforward24 went with Leo Tolstoy’s War and Peace, but we’re sure many of you will make a case for one, if not several of Dostoevsky’s works.

The UK has Pride and Prejudice, Spain – Shadow in the Wind, Iran – Persepolis and Ireland – Ulysses. The USA? To Kill a Mockingbird, of course and Canada – Anne of Green Gables, but it should really have been Atwood’s Handmaid’s Tale
What is amazing though, is when you scroll over places like Africa and Asia.

We’re all down on our classics (those lovely books we all had to read at school), but have you ever picked up a copy of Sony Labou Tansi’s The Antipeople?

Thought not. Off to the bookshop wethinks!

This Man is Planting a Forest to Save His Island

See how one man is single-handedly planting a forest to save his river island in India.

Since 1979, Jadav Payeng has been planting hundreds of trees on an Indian island threatened by erosion. In this film, photographer Jitu Kalita traverses Payeng’s home—the largest river island in the world—and reveals the touching story of how this modern-day Johnny Appleseed turned an eroding desert into a wondrous oasis. Funded in part by Kickstarter, "Forest Man" was directed by William Douglas McMaster and won Best Documentary for the American Pavilion Emerging Filmmaker Showcase at the Cannes Film Festival in 2014.

Making North America: Origins

Experience the colossal geologic forces that shaped our continent over 3 billion years.