Connect with us

Foreign News

Monster iceberg ‘A23a’ just shy of a trillion tonnes

Published

on

Scientists now have good numbers to describe the true scale of the world’s biggest iceberg, A23a.

Satellite measurements show the frozen block has a total average thickness of just over 280m (920ft).

Combined with its known area of 3,900 sq km (1,500 sq miles), this gives a volume of roughly 1,100 cubic km and a mass just below a trillion tonnes.

The iceberg, which calved from the Antarctic coast in 1986, is about to drift beyond the White Continent. It has reached a critical point in its journey, researchers say, with the next few weeks likely to decide its future trajectory through the Southern Ocean.

A23a viewed from Royal Research Ship Sir David Attenborough
As far as the eye can see: A23a is more than twice the area of Greater London (pic BBC)

To put the new thickness data in some context, London skyscraper 22 Bishopsgate is 278m tall – bettered, in the UK, by only the 310m Shard tower.

But A23a is also more than twice the area of Greater London, giving it an overall profile much like that of a credit card.

TwentyTwo
22 Bishopsgate is the UK’s second-tallest skyscraper (pic BBC)

The measurements of A23a come from the European Space Agency’s CryoSat-2 mission. This veteran spacecraft carries a radar altimeter able to sense how much of a berg’s bulk is above the waterline.

Using information about the density of ice, it is then possible to determine how much must be submerged.

“Altimetry satellites like CryoSat-2, which measure the distance to the iceberg surface and to the sea surface, allow us to monitor iceberg thickness from space,” Dr Anne Braakmann-Folgmann, from the University of Tromsø – The Arctic University of Norway, told BBC News.

“They also enable us to watch the iceberg thinning as it gets exposed to warmer ocean waters. “And together with knowledge of the sea-floor topography, we know where an iceberg will ground or when it has thinned enough to be released again.”

Lost thickness over time

When the berg started moving, after 2020, it became increasingly difficult to obtain broad thickness measurements. But assuming an area of 3,900 sq km and an average total thickness of 285m, then A23a has a volume of 1,113 cubic km and a mass of 950 billion tonnes.

Presentational grey line

Born in a mass breakout of bergs from the Filchner Ice Shelf, in the southern Weddell Sea, A23a was almost immediately stuck in shallow bottom muds to become an “ice island” for more than three decades. And the CryoSat data can now explain why.

The berg is not a uniform block – some parts are thicker than others.

CryoSat indicates one section in particular has a very deep keel, which in 2018, had a draft – the submerged portion of an iceberg – of almost 350m and it is this section that anchored A23a for so long.

Satellite images show crevasses directly above the keel.

“This is likely the surface expression of the damage that was caused when A23a hit the seabed,” Prof Andrew Shepherd, from Northumbria University and the Natural Environment Research Council Centre for Polar Observation and Modelling (CPOM), said.

Edge of A23a
A23a: Most of an iceberg’s bulk sits below the waterline (pic BBC)

And in the years that followed, A23a gradually lost mass to eventually free itself and start moving.

“Over the last decade, we have seen a steady 2.5m per year decrease in thickness, which is what you would expect given the water temperatures in the Weddell Sea,” Dr Andy Ridout, a CPOM senior research fellow from University College London, explained.

A23a has now reached the tip of the Antarctic Peninsula, where there is a convergence of various streams of fast-moving water that turn clockwise around the continent.

How it interacts with these and the westerly winds that dominate in that part of the world will control where the behemoth goes next.

But it is expected take a track called “iceberg alley” that points in the direction of the British overseas territory of South Georgia.

Iceberg comparison

Scientists will follow its progress with interest.

Bergs this big have a profound influence on their environment. “They’re responsible for very deep mixing of seawater,” Prof Mike Meredith, from the British Antarctic Survey, told BBC News. “They churn ocean waters, bringing nutrients up to the surface, and, of course, they also drop a lot of dust.

“All this will fertilise the ocean – you’ll often see phytoplankton blooms in their wake.”

(BBC)



Continue Reading
Click to comment

Leave a Reply

Your email address will not be published. Required fields are marked *

Foreign News

Pakistan’s election chaos casts shadow on next IMF deal

Published

on

By

Supporters of former Prime Minister Imran Khan's party, the Pakistan Tehreek-e-Insaf, demand free and fair results of the elections outside the provincial election commission office in Karachi on February 17, 2024 (Aljazeera)

As Pakistan grapples with the aftermath of controversial elections, political chaos is threatening to cloud its $3bn deal with the International Monetary Fund (IMF), which analysts say is key to the country’s economic stability.

On Thursday, the global lender said Pakistan’s interim government had “maintained” economic stability. The IMF’s communications chief, Julie Kozack, said the interim government had managed to achieve fiscal targets while also “protecting” the social safety net. “We look forward to working with the new government on policies to ensure macroeconomic stability and prosperity for all of Pakistan’s citizens,” Kozack said.

But the comments from the IMF come at a time when Pakistan is about to swear in a new government after this month’s general election, which has been marred by widespread allegations of rigging and manipulation.

Former Prime Minister Imran Khan  the founder of his Pakistan Tehreek-e-Insaf (PTI) party, drew a link between these allegations and the IMF loan in a statement from prison, asking the international body to carry out an audit of the elections before proceeding with the deal.

“Imran Khan will issue a letter to IMF. The charter of IMF, EU and other organisations stipulates that they can function or provide loan to a country only if there’s good governance,” Khan’s lawyer and Senator Ali Zafar told journalists after meeting the ex-premier at Rawalpindi’s Adiala Jail on Thursday. Khan is in jail over a series of convictions in cases involving a range of charges — from corruption to leaking secret documents.

Pakistan signed a nine-month standby agreement with the IMF last year. It will expire early next month, and securing another long-term plan is seen as a priority for the next government.

The February 8 elections in Pakistan saw a split mandate with PTI-backed candidates winning 93 seats in the National Assembly while the party’s main rivals, the Pakistan Muslim League-Nawaz (PMLN) and Pakistan Peoples Party (PPP)  secured 75 and 54 seats, respectively.

The PMLN, PPP and smaller allies have agreed to form a coalition government, whose members are expected to take oaths next week.

The PTI was denied its electoral symbol — a cricket bat — weeks before the elections and was forced to field candidates as independents. The party also faced a nationwide crackdown that impeded its campaign but still beat the odds when its candidates won the highest number of seats. Khan was removed from office in 2022 after a no-confidence motion. Many analysts believe he came to power in 2018 with the support of Pakistan’s powerful military establishment, but they eventually fell out.

The PTI has alleged widespread manipulation in the counting and results and has said it will continue both street protests and legal cases to reclaim what it insists is a stolen mandate.

Lahore-based economist Hina Shaikh, however, said this political uncertainty wouldn’t affect the IMF’s approach. With the IMF already signalling its willingness to work with the new government, “any effort by Khan would not bear any fruit,” she said.

“Firstly, it would have no official ramifications, and secondly, it would not be in the interest of Pakistan nor IMF to end financial support. Pakistan has several payments due in the next two months and needs IMF support to stay afloat and continue leveraging other sources of revenue,” the economist told Al Jazeera.

Extending the IMF deal is critical for Pakistan, economists said. A failure on the part of the government to tackle the country’s massive economic challenges could send the nation of 241 million people into a default.

Pakistan’s foreign reserves currently stand at about $8bn, just enough to cover eight weeks of imports. The Pakistani rupee has lost more than 50 percent of its value against the US dollar over the past two years.

Inflation, which hit a record high of almost 38 percent last year, is currently nearly 30 percent, and high tariffs for electricity and gas along with other essential commodities are draining household incomes.

The looming debt obligations mean that Pakistan must be able to negotiate a new plan with the IMF as soon as the new government comes in. A recent report by Tabadlab, an Islamabad-based think tank, called Pakistan’s debt obligations “unsustainable”, saying its total external and internal debt totals up to $271bn.

A United States Institute of Peace report from last year concluded that the country needs to “repay $77.5 billion in external debt” by June 2026. “For a $350 billion economy, this is a hefty burden,” the report stated.

Pakistan’s central bank says it needs more than $6bn to service its debt obligations by June 30, the end of current fiscal year.

Emphasizing the need for a continuation of the IMF loan programme, Uzair Younus, principal at the US-based advisory firm The Asia Group, said Pakistan’s economy cannot afford politics when it comes to the next IMF deal.  “Any delays due to politics or a staring contest between the next finance minister and the IMF is likely to rapidly fuel economic uncertainty, pressure on the currency and heightened default risk,” he told Al Jazeera.

(Aljazeera)

Continue Reading

Foreign News

Senegal’s President Sall agrees to step down in April but sets no poll date

Published

on

By

People nationwide gathered to watch President Sall being interviewed on Thursday evening (BBC)

Senegal’s President Macky Sall has said he will leave office when his term comes to an end on 2 April, but tensions remain over an election date.

His recent decision to delay the vote, originally scheduled for Sunday, to mid-December sparked deadly protests. In a televised interview, Mr Sall said an election date would now be decided in political talks to start on Monday.

But the opposition has refused to take part in the proposed dialogue dashing hopes of resolving the turmoil.

Sixteen of the 19 presidential hopefuls have said they will not be turning up for what the president has termed a “national dialogue”. A number of civil society organisations have also declined to take part in the exercise.

Mr Sall, who is on his way to the Nigerian capital, Abuja, for an extraordinary summit of the regional bloc Ecowas, has been under pressure to announce a new date since Senegal’s highest court declared last week that the postponement of the poll was illegal.

His original decree to delay the vote received strong condemnation from the international community. Many feared the postponement would lead to President Sall’s remaining leader of the country indefinitely in a region plagued by coups and military governments.

Speaking on national television on Thursday evening, Mr Sall said he felt there was not enough time to vote in a new president by the time he steps down on 2 April. He said that the dialogue forum would decide what should happen if this was the case.

In a show of good faith, the president said he was prepared to release the popular opposition politician, Ousmane Sonko, from prison. His arrest sparked nationwide protests last year. Dozens of the president’s opponents have already been set free since Senegal’s Constitutional Council ruled that his decision to postpone the election was illegal.

But the fact that the president did not set a new election date has further fuelled suspicions by his critics that this is just another stalling tactic.

President Sall has served two terms as Senegal’s leader and when he was first elected in 2012 he promised he would not overstay.

His televised interview has not yet restored his country’s reputation as a bastion of democracy in an increasingly totalitarian region.

(BBC)

Continue Reading

Foreign News

Root’s assured century helps England recover well

Published

on

By

Joe Root toiled away to ensure England didn't crumble (Cricinfo)

A stirring century from Joe Root tempered Akash Deep’s dream debut and pulled England out of trouble on an enthralling first day of what is a must-win fourth Test for the touring side in Ranchi.

Root, who had copped criticism for what was seen as some ill-timed innovation in the first innings of England’s 434-run loss in Rajkot, reverted to a more classical Root innings on Friday and it paid big dividends – his first century of the series (in fact, his first score above 29) and 10th against India in Tests. In doing so, he carried England to a healthy 302 for 7 at the close after they had slumped to 57 for 3 and, later, 112 for 5 with Akash claiming his first three wickets in Test cricket inside two overs.

Akash, the 27-year-old right-arm quick called up to replace a resting Jasprit Bumrah, opened the bowling with Mohammed Siraj and caused England problems almost from the outset, hitting an impeccable length and finding subtle movement on a dry pitch already displaying some cracks which the seamers were able to exploit for extra bounce on occasion. His 11th ball was a gem which nipped back into Zak Crawley and stayed a little low to sneak through the gate and send off stump cartwheeling but he and an ecstatic crowd were muted by the no-ball siren signalling he had over-stepped.

Crawley settled and helped himself to 18 of the 19 runs Siraj conceded off his fourth over with three fours in a row followed by a lofted six over mid-on.

England lurched into danger though, as Akash snared two wickets in three balls and then a third to all but erase his earlier disappointment. First, he had opener Ben Duckett caught behind off a length ball which pitched just outside off stump and jagged away slightly to kiss the outside edge, the bowler fiercely and repeatedly thumping the badge on his chest in celebration. Ollie Pope followed for a duck, lbw after India reviewed and replays showed Akash hitting the top of leg stump with a ball that seamed in to beat the inside edge and strike the pad right on the knee roll. Pope was down the wicket but it didn’t really help his cause in the end.

In his next over, the 12th of the match, Akash overcame Crawley’s pulled four off another no-ball with a perfect-length delivery outside off which seamed back in and pinged the top of off stump to remove the opener for a run-a-ball 42.

Jonny Bairstow staged a 52-run stand with Root but fell lbw attempting to sweep R Ashwin after a punchy 38 off 35 balls – and after India overturned Rod Tucker’s on-field decision. Then Ben Stokes was left dumbfounded by a full Ravindra Jadeja delivery that kept unbelievably low and skidded into the front pad at ankle-height on the stroke of lunch.

But then Root and Ben Foakes combined for a 113-run sixth-wicket stand which steadied the tourists through a middle session in which India went wicketless for the first time this series.

Brief scores:
England 302 for 7 in 90 overs  (Zak Crawley 42, Joe Root 106*, Jonny Bairstow 38,  Ben Foakes 47, Ollie  Robinson 31*; Akash Deep  3-70, Mohammed Siraj 2-60) vs India

(Cricinfo)

Continue Reading

Trending