AFP UK

In search of lost time: The leap second will soon become a thing of the past

Scientists and government representatives meeting at a conference in France voted on Friday to scrap leap seconds by 2035, the organisation responsible for global timekeeping said.

Similar to leap years, leap seconds have been periodically added to clocks over the last half century to make up for the difference between exact atomic time and the Earth’s slower rotation.

While leap seconds pass by unnoticed for most people, they can cause problems for a range of systems that require an exact, uninterrupted flow of time, such as satellite navigation, software, telecommunication, trade and even space travel.

It has caused a headache for the International Bureau of Weights and Measures (BIPM), which is responsible for Coordinated Universal Time (UTC) — the internationally agreed standard by which the world sets its clocks.

A resolution to stop adding leap seconds by 2035 was passed by the BIPM’s 59 member states and other parties at the General Conference on Weights and Measures, which is held roughly every four years at the Versailles Palace west of Paris.

The head of BIPM’s time department, Patrizia Tavella, told AFP that the “historic decision” would allow “a continuous flow of seconds without the discontinuities currently caused by irregular leap seconds”.

“The change will be effective by or before 2035,” she said via email. 

She said that Russia voted against the resolution, “not on principle”, but because Moscow wanted to push the date it comes into force until 2040.

Other countries had called for a quicker timeframe such as 2025 or 2030, so the “best compromise” was 2035, she said. 

The United States and France were among the countries leading the way for the change. 

Tavella emphasised that “the connection between UTC and the rotation of the Earth is not lost”.

“Nothing will change” for the public, she added.

– A leap minute? –

Seconds were long measured by astronomers analysing the Earth’s rotation, however the advent of atomic clocks — which use the frequency of atoms as their tick-tock mechanism — ushered in a far more precise era of timekeeping.

But Earth’s slightly slower rotation means the two times are out of sync.

To bridge the gap, leap seconds were introduced in 1972, and 27 have been added at irregular intervals since — the last in 2016.

Under the proposal, leap seconds will continue to be added as normal for the time being.

But by 2035, the difference between atomic and astronomical time will be allowed to grow to a value larger than one second, Judah Levine, a physicist at the US National Institute of Standards and Technology, told AFP.

“The larger value is yet to be determined,” said Levine, who spent years helping draft the resolution alongside Tavella.

Negotiations will be held to find a proposal by 2035 to determine that value and how it will be handled, according to the resolution.

Levine said it was important to protect UTC time because it is run by “a worldwide community effort” in the BIPM.

GPS time, a potential UTC rival governed by atomic clocks, is run by the US military “without worldwide oversight”, Levine said.

A possible solution to the problem could be letting the discrepancy between the Earth’s rotation and atomic time build up to a minute.

It is difficult to say exactly how long that might take, but Levine estimated anywhere between 50 to 100 years.

Instead of then adding on a leap minute to clocks, Levine proposed a “kind of smear”, in which the last minute of the day takes two minutes. 

“The advance of a clock slows, but never stops,” he said.

In search of lost time: The leap second will soon become a thing of the past

Scientists and government representatives meeting at a conference in France voted on Friday to scrap leap seconds by 2035, the organisation responsible for global timekeeping said.

Similar to leap years, leap seconds have been periodically added to clocks over the last half century to make up for the difference between exact atomic time and the Earth’s slower rotation.

While leap seconds pass by unnoticed for most people, they can cause problems for a range of systems that require an exact, uninterrupted flow of time, such as satellite navigation, software, telecommunication, trade and even space travel.

It has caused a headache for the International Bureau of Weights and Measures (BIPM), which is responsible for Coordinated Universal Time (UTC) — the internationally agreed standard by which the world sets its clocks.

A resolution to stop adding leap seconds by 2035 was passed by BIPM members and others at the 27th General Conference on Weights and Measures, which is held roughly every four years at the Versailles Palace west of Paris.

The head of BIPM’s time department, Patrizia Tavella, said the “historic decision” would allow “a continuous flow of seconds without the discontinuities currently caused by irregular leap seconds”.

“The change will be effective by or before 2035,” she told AFP via email. 

“The connection between UTC and the rotation of the Earth is not lost, UTC remains related to Earth,” she said, adding that “nothing will change” for the public.

– A leap minute? –

Seconds were long measured by astronomers analysing the Earth’s rotation, however the advent of atomic clocks — which use the frequency of atoms as their tick-tock mechanism — ushered in a far more precise era of timekeeping.

The problem is that Earth’s slightly slower rotation means the two times are out of sync.

To bridge the gap, leap seconds were introduced in 1972, and 27 have been added at irregular intervals since — the last in 2016.

Under the proposal, leap seconds will continue to be added as normal for the time being.

From around 2035, the difference between atomic and astronomical time will be allowed to grow to a larger value than one second, Judah Levine, a physicist at the US National Institute of Standards and Technology, told AFP.

“The larger value is yet to be determined,” said Levine, who spent years helping draft the resolution alongside Tavella.

Negotiations will be held to find a proposal by 2035 to determine that value and how it will be handled, according to the resolution.

The breakdown of which countries voted for the resolution was not yet known, but the United States and France have been among those leading the way for the change.

Levine said it was important to protect UTC time because it is run by “a worldwide community effort” in the BIPM, which has 59 member states and consults with other nations. 

GPS time, a potential UTC rival governed by atomic clocks, is run by the United States military “without worldwide oversight”, Levine said.

A possible solution to the problem could be letting the discrepancy between the Earth’s rotation and atomic time build up to a minute.

It is difficult to say exactly how often that might be needed, but Levine estimated anywhere between 50 to 100 years.

Instead of then adding on a leap minute to clocks, Levine proposed a “kind of smear”, in which the last minute of the day takes two minutes. 

“The advance of a clock slows, but never stops,” he said.

Award-winning Indian artist Shilo Shiv Suleman painted a mural called "fearless" at the youth pavillon, during the COP27 climate summit in the Red Sea resort of Sharm el-Sheikh

Egyptian artist Bahia Shehab had one goal at the COP27 climate talks in Egypt: to let people experience the “hell” that is global warming. 

At first, she said, she wanted to “hack the rooms” to literally turn up the heat on delegates from nearly 200 countries who have been talking for two weeks about how to drive forward action against worsening climate change. 

With wealthy and developing nations struggling to agree on final deals, talks were extended to Saturday.

“There’s research that said that people who are in a hotter place, in a hotter room, they’re more likely to believe in climate change than those who are not,” Shehab said at Egypt’s Red Sea resort city of Sharm el-Sheikh, which is hosting the talks.

But due to security measures, instead of the “hack”, Shehab set up a public art installation dubbed “Heaven and Hell in the Anthropocene”. 

It features two adjacent rooms, one heated at 45 degrees Celsius (113 Fahrenheit) while the other is air-conditioned. 

“We wanted to come up with a scenario that is accessible to everyone,” she said. 

Campaigners the world over have been pulling public stunts targeting artworks to draw attention to global inaction over climate change.

In Milan on Friday, climate activists threw flour over a car repainted by American artist Andy Warhol.

“Do we really get outraged at the simulation of damage to works of art while the ongoing objective destruction of works of nature, ecosystems and our own lives leaves us indifferent?” the activists from the Last Generation group wrote in a statement.

Activists have also glued themselves to a Francisco Goya painting in Madrid, thrown soup at Vincent van Goghs in London and Rome, and mashed potatoes on a Claude Monet in Germany.

– Triggering questions –

Shehab has taken a more restrained approach with her art and says it works, producing an impact on many. 

“Scary,” a British visitor who gave her name as Jolene said of the “hell” room, in contrast with the “cool, clean, nice” environment she found in heaven.

The artist said she had already seen attitudes change.

“There’s one girl who walked out of ‘hell’ who said: ‘I will never throw trash on the ground ever again,'” she said.

“So to me, it’s not important whether they like it aesthetically or not but it’s really important that it triggers questions and that they reconsider their daily practice.”

Another artist, Rehab el-Sadek, sought to be the voice of indigenous populations across Egypt. She pitched a Bedouin-like tent inscribed with messages in Arabic, English and Spanish. 

“I want climate action to prioritise indigenous and local communities,” one message read. 

Sadek said that, with the COP taking place in the Sinai Peninsula, home to nomadic Bedouin, “we thought that the tent… will make a connection between locals and people around the world.”

Indian artist Shilo Shiv Suleman painted an entire mural at the COP27 complex to send a message “to the leaders of the world who consider the planet as a product”. 

The mural depicting animals in their natural habitat is a reminder “to return to ourselves — the mountains, the stars, the rivers and ways of being that placed us within the empire of the earth, not outside of it,” she said.

But art’s role is not limited to raising awareness, said Marguerite Courtel, a Paris-based expert on environmental transition and culture.

It should also develop techniques to fend off the impact of climate change, and she said a key question remains: Are the works themselves produced with “eco-responsibility”?

Cleaning up "Horse and Rider" in Paris

Environmental activists on Friday dumped orange paint over an outdoor sculpture by the American artist Charles Ray in central Paris, the latest in a string of artwork defacements aimed at spurring greater government efforts to fight climate change.

The lifesize “Horse and Rider” stands in front of the Bourse de Commerce contemporary art museum, which houses part of the collection of French fashion billionaire Francois Pinault.

The action was claimed by Derniere Renovation (“Last Renewal”), which showed two activists kneeling and holding hands in front of the doused sculpture on its website.

They had also put a white T-shift over the rider with the phrase “We have 858 days left”, apparently a reference to studies that say carbon emissions must peak by 2025 if the planet is to have a viable future.

“Eco-vandalism is taken up a notch,” Culture Minister Rima Abdel Malak, who visited the site as workers cleaned up the paint, wrote on Twitter.

“Art and ecology are not incompatible. It’s the opposite, they are common causes,” she said.

The incident came as climate activists targeted an Andy Warhol work in Milan on Friday, covering a car repainted by the American pop artist with flour — two weeks after the same group threw pea soup at a Van Gogh painting in Rome.

Vermeer’s “Girl with a Pearl Earring” in The Hague and Van Gogh’s “Sunflowers” in London have also been targeted, drawing widespread condemnation from officials.

Climate activists protest outside the COP27 climate conference in Egypt

UN climate talks were extended by a day Friday in an effort to break deadlock as nations tussle over funding for developing countries battered by weather disasters and ambition on curbing global warming.

Representatives from nearly 200 countries have gathered at the COP27 in Egypt for two weeks with the aim of driving forward action on climate change as the world faces a worsening onslaught of weather extremes.

But wealthy and developing nations were struggling to find common ground on creating the fund, and on a host of other crucial issues, with only hours before the summit was scheduled to end in the Red Sea resort of Sharm el-Sheikh.

Egyptian Foreign Minister Sameh Shoukry, who chairs the COP27 talks, told delegates that the negotiations would spill into Saturday, a delay not unusual in such sprawling UN climate talks.

“I remain concerned at the number of outstanding issues,” he said.

The daunting list of tasks includes finding agreement on reaffirming a goal to limit average warming to 1.5 degrees Celsius from pre-industrial levels, which scientists say is a safer guardrail to avoid the most dangerous impacts.

Rich countries are also under pressure to finally fulfil promises to provide $100 billion a year to help developing countries green their economies and adapt to future impacts, and to hammer out future finance plans. 

But for many vulnerable countries the defining issues at the conference is money for the “loss and damage” caused by climate change — a controversial issue previously blocked by wealthy countries fearful of open-ended liability.

– ‘Crunch time’ –

A cascade of climate-driven extremes in recent months — from floods in Pakistan and Nigeria to heatwaves and droughts across the world — have shone a spotlight on the ferocious impacts of a warming world for emerging economies as well as small island states threatened by sea level rise.

The G77 and China bloc of 134 developing countries launched an opening gambit this week, a proposal to create a loss and damage fund at COP27, with operational details to be agreed later.

A compromise response from the European Union, proposed late Thursday, suggested a fund specifically for the most vulnerable nations.

The EU proposal indicated that the bloc has “shifted significantly”, said Rachel Cleetus, lead economist at the Union of Concerned Scientists’ climate programme. 

But she said the United States and China, the world’s two biggest polluters, “can really unlock this”, fresh from a thaw in their climate relations after a meeting between Presidents Joe Biden and Xi Jinping earlier this week in Bali. 

“It’s crunch time,” Cleetus told AFP. “There’s no time anymore for the US to sit on the sidelines.” 

Cleetus added that China should also make its position clear, particularly on the issue of whether it would contribute to such a fund and pledge not to draw from it.  

  

– ‘Our final offer’ –

European Commission Vice President Frans Timmermans told reporters on Friday that the EU offer had two “very important” conditions that differ from the G77 proposal.  

It should be for “the most vulnerable” nations, he said, and the money should come from a “broad funder base” — code for countries including China that have become wealthier since they were listed as developing countries in 1992.

“I have to say this is our final offer,” Timmermans said.

Pakistan’s climate minister Sherry Rehman, whose country chairs G77+China, expressed a willingness for “working with each other to find common ground”.

“It is up to all of us to steer a path that sends a powerful message from this COP that the implementation COP actually turned into a historic actionable COP,” she said.

She said the G77 had zeroed in on one of the options put forward in a draft loss and damage text “with a few changes that have been submitted and we are working on with each other”.

Timmermans said he had explained the EU proposal to US delegates who were “very interested in seeing” the 1.5C target reaffirmed.

Vulnerable nations, small island states and many wealthy emitters have stressed the need to maintain the goal of limiting warming to 1.5C, while observers are calling for stronger language in the final COP27 statement on curbing planet-heating fossil fuels. 

Even with new commitments, the world is on track to heat up by about 2.5C by the end of the century — enough, scientists say, to trigger dangerous climate tipping points. 

With tight restrictions on demonstrations, several dozen activists  on Friday protested inside the venue, holding signs demanding rich countries “pay up for loss and damage”. 

Wet pet diets
have a far greater environmental impact that dry ones, the study found

Feeding cats and dogs wet food has a much larger climate impact than dry food, a new study found, suggesting small changes by pet owners can massively reduce their carbon footprint.

The Brazilian study looked at the environmental impact — including greenhouse gas emissions, land use and water usage — of pet food, finding that there was more than a seven-fold increase in CO2 production for a wet diet compared to dry. 

“Wet diets for cats and dogs had the greatest environmental impact, particularly compared to dry diets,” said the study from the University of Sao Paulo published in Scientific Reports. 

The study’s authors examined the environmental impacts of the diets of 618 dogs and 320 cats in Brazil. 

They looked into commercial as well as homemade pet food, both wet and dry, and assessed the nutritional and calorific make-up of the different diets.

They estimated that a 10-kilo dog (22 pounds) consuming an average of 534 calories per day “would be responsible for 828.37 kilograms of CO2 per year when fed a dry diet, compared to 6,541 kilograms of CO2 per year for a wet diet.”

That was 689 percent more for the wet diet. 

“Cat and dog owners could significantly reduce the environmental impact of their pets’ diets by feeding them dry food (consisting of kibble or biscuits) rather than wet food with higher water content,” it said. 

“These results highlight the extensive environmental impacts of pet foods, the need to make them more sustainable and an indication of how this may be achieved.”

According to the PetSecure website, cited by the study, the United States has the world’s biggest dog population with over 69 million and the most cats with more than 74 million. China holds the number two spot for both, followed by Russia.

The Earth's mass can now be expressed as six ronnagrams after scientists voted to add new metric prefixes

Say hello to ronnagrams and quettametres: International scientists gathered in France voted on Friday for new metric prefixes to express the world’s largest and smallest measurements, prompted by an ever-growing amount of data.

It marks the first time in more than three decades that new prefixes have been added to the International System of Units (SI), the agreed global standard for the metric system.

Joining the ranks of well-known prefixes like kilo and milli are ronna and quetta for the largest numbers — and ronto and quecto for the smallest.

The change was voted on by scientists and government representatives from across the world attending the 27th General Conference on Weights and Measures, which governs the SI and meets roughly every four years at Versailles Palace, west of Paris.

The UK’s National Physical Laboratory, which led the push for the new prefixes, confirmed that the resolution had passed in a statement.

The prefixes make it easier to express large amounts — for example, always referring to a kilometre as 1,000 metres or a millimetre as one thousandth of a metre would quickly become cumbersome.

Since the SI was established in 1960, scientific need has led to a growing number of prefixes. The last time was in 1991, when chemists wanting to express vast molecular quantities spurred the addition of zetta and yotta.

A yottametre is a one followed by 24 zeroes. 

But even the mighty yotta is not enough to handle the world’s voracious appetite for data, according to Richard Brown, the head of metrology at the UK’s National Physical Laboratory.

“In terms of expressing data in yottabytes, which is the highest prefix currently, we’re very close to the limit,” Brown told AFP.

“At the bottom end, it makes sense to have a symmetrical expansion, which is useful for quantum science, particle physics — when you’re measuring really, really small things.”

– New weight of the world –

The new prefixes can simplify how we talk about some pretty big objects.

“If we think about mass, instead of distance, the Earth weighs approximately six ronnagrams,” which is a six followed by 27 zeroes, Brown said.

“Jupiter, that’s about two quettagrams,” he added — a two followed by 30 zeros.

Brown said he had the idea for the update when he saw media reports using unsanctioned prefixes for data storage such as brontobytes and hellabytes. Google in particular has been using hella for bytes since 2010.

“Those were terms that were unofficially in circulation, so it was clear that the SI had to do something,” he said.

However metric prefixes need to be shortened to just their first letter — and B and H were already taken, ruling out bronto and hella.

“The only letters that were not used for other units or other symbols were R and Q,” Brown said.

Convention dictates that the larger prefixes end in an A, and the smaller ones in an O.

And “the middle of the words are very, very loosely based on the Greek and Latin for nine and 10,” Brown said.

The new prefixes should “future proof the system” and satisfy the world’s need for higher numbers — at least for the next 20 to 25 years, he added.

Climate-driven extremes have highlighted the costly impacts of a warming world for developing nations

UN climate talks that were supposed to end Friday were extended by a day in an effort to break a deadlock over creating a fund for developing countries devastated by the fallout from global warming.

Representatives from nearly 200 countries have gathered at the COP27 in Egypt for two weeks with the aim of driving forward action on climate change as the world faces a worsening onslaught of extreme floods, heat waves and droughts.

But wealthy and developing nations were still struggling to find common ground on creating the fund and on a host of other crucial issues with only hours before the summit in the Red Sea resort of Sharm el-Sheikh was due to end.

“Today we need to shift gears again, time is not on our side,” Egyptian Foreign Minister Sameh Shoukry, who chairs the COP27 talks, told delegates.

“I remain committed to bringing this conference to a close tomorrow in an orderly manner.”

The daunting list of urgent tasks includes finding agreement — and funds — for the emissions cuts needed to limit average warming to 1.5 degrees Celsius from pre-industrial levels, which scientists say is a safer guardrail to avoid the most dangerous impacts.

For many developing countries — and small island states threatened by sea level rise — the defining issues at the conference is money for the “loss and damage” caused by climate change.

A cascade of climate-driven extremes in recent months — from floods in Pakistan and Nigeria to heatwaves and droughts across the world — have shone a spotlight on the ferocious impacts of a warming world for developing nations that are also struggling with debts and surging inflation.

In a bid to find a compromise, the European Union proposed late Thursday the creation of a fund for the most vulnerable nations but warned it was its final offer.

The EU proposal indicated that the bloc, previously fearful of open-ended climate damages liability, has “shifted significantly”, said Rachel Cleetus, lead economist at the Union of Concerned Scientists’ climate programme. 

But she said all eyes were now on the United States and China, the world’s top two polluters, fresh from a thaw in their climate relations after a meeting between Presidents Joe Biden and Xi Jinping earlier this week in Bali. 

“It’s crunch time,” Cleetus told AFP. “There’s no time anymore for the US to sit on the sidelines. They have to come out with what their position is to show that they’re being constructive.” 

Cleetus added that China should also make its position clear, particularly on the issue of whether it would contribute to such a fund and pledge not to draw from it. 

“We think China and the US can really unlock this in these last 24 hours,” Cleetus said. 

  

– ‘This is our final offer’ –

Earlier in the week, the G77 and China bloc of 134 developing countries proposed creating the loss and damage fund at the COP27 meeting, with other details to be agreed later.

European Commission Vice President Frans Timmermans told reporters on Friday that the EU offer had two “very important” conditions that differ from the G77 proposal.  

He said the fund should be for “the most vulnerable” nations and the money should come from a “broad funder base” — code for countries including China that have become wealthier since they were listed as developing countries in 1992.

“I have to say this is our final offer,” Timmermans said. “This is where the (EU) member states can find an agreement and I have to thank all of them for for the courage to go this far. But this is it.”

Timmermans said he had explained the EU proposal to US delegates who were “very interested in seeing” that reaffirming the need to step up efforts to cut emissions to reach the 1.5C target be reflected in the conclusions.

Pakistan’s climate minister Sherry Rehman, whose country chairs G77+China, expressed a willingness to “working with each other to find common ground”.

“It is up to all of us to steer a path that sends a powerful message from this COP that the implementation COP actually turned into a historic actionable COP,” she said.

She said the G77 had zeroed in on one of the options put forward in a draft loss and damage text “with a few changes that have been submitted and we are working on with each other”.

Developing nations have been relatively united in calling for the loss and damage fund at this COP. Some small island states said they had discussed walking out if they do not see progress. 

But the AOSIS coalition of small island states has also indicated it wants to see China, India and other major polluters contribute.

Glaciers are retreating due to climate change

UN climate talks entered their last day Friday with rich and developing nations deadlocked over creating a fund for countries devastated by the affects of global warming — and the EU warning its offer was final.

Representatives from nearly 200 countries have gathered at the COP27 in Egypt for two weeks with the aim of driving forward action on climate change as the world faces a worsening onslaught of extreme floods, heat waves and droughts.

The daunting list of urgent tasks includes finding agreement — and funds — for the emissions cuts needed to limit average warming to 1.5 degrees Celsius from pre-industrial levels, which scientists say is a safer guardrail to avoid the most dangerous impacts.

For many developing countries — and small island states most threatened by sea level rise — the defining issues at the conference is money for the “loss and damage” caused by climate change.

A cascade of climate-driven extremes in recent months — from floods in Pakistan and Nigeria to heatwaves and droughts across the world — have shone a spotlight on the ferocious impacts of a warming world for developing nations that are also struggling with debts and surging inflation.

The summit in the Red Sea resort of Sharm el-Sheikh went into the final hours of official negotiating time with a range of key issues outstanding. These include funding for countries to prepare for future climate impacts — a priority for African nations.   

With talks expected to spill into overtime, disagreement over creating a specific loss and damage fund has proved critical. 

The European Union proposal outlined late Thursday has indicated that the bloc, previously fearful of open-ended climate damages liability, have “shifted significantly”, said Rachel Cleetus, lead economist at the Union of Concerned Scientists’ climate programme. 

But she said all eyes were now on the United States and China, the world’s top two polluters, fresh from a thaw in their climate relations after a meeting between Presidents Joe Biden and Xi Jinping earlier this week in Bali. 

“It’s crunch time. There’s no time anymore for the US to sit on the sidelines. They have to come out with what their position is to show that they’re being constructive,” she told AFP. 

Cleetus added that China should also make its position clear, particularly on the issue of whether it would contribute to such a fund and pledge not to draw from it. 

“We think China and the US can really unlock this in these last 24 hours,” Cleetus said. 

  

– ‘This is our final offer’ –

Earlier in the week, the “Group of 77,” a bloc of 134 “developing countries” that includes China, proposed creating the loss and damage fund at the COP27 meeting, with other details to be agreed later.

European Commission Vice President Frans Timmermans told reporters on Friday that the EU offer had two “very important” conditions that differ from the G77 proposal.  

He said the fund should be for “the most vulnerable” nations and the money should come from a “broad funder base” — code for countries including China that have become wealthier since they were listed as developing countries in 1992.

“I have to say this is our final offer,” he said.

“This is where the (EU) member states can find an agreement and I have to thank all of them for for the courage to go this far. But this is it.”

Timmermans said he explained the EU proposal to US delegates who were “very interested in seeing” that reaffirming the need to step up efforts to cut emissions to reach the 1.5C target be reflected in the conclusions.

Developing nations have been relatively united in calling for the loss and damage fund at this COP. Some small island states said they had discussed walking out if they do not get progress. 

But the AOSIS coalition of small island states has also indicated it wants to see China, India and other major polluters contribute. 

– ‘Blame game’ –

A draft outline of positions on loss and damage published on the COP27 website late Thursday included some elements of the main proposals, providing a starting point for negotiations to begin in earnest.

But a separate 10-page draft of the COP27 final statement released Friday morning only had a placeholder for a “funding arrangement” — signalling significant work still to be done.

The statement also keeps a line reaffirming the aspirational goal of limiting warming to 1.5C, a key demand from the US and EU.

UN chief Antonio Guterres called for countries to break the deadlock late Thursday, warning that “the blame game is a recipe for mutually assured destruction”. 

Mohenjo Daro was equipped with a primitive drainage system and sewers

One of the world’s first cities came close to being wiped off the map during tragic floods this summer in Pakistan. Though Mohenjo Daro survived, it has become a symbol of the threat global warming poses to humanity’s cultural heritage. 

Built in around 3000 BC by the Indus civilisation in modern-day South Asia, Mohenjo Daro was not swept away by the floods, most likely thanks to the genius of its designers. 

Perched high above the Indus river, the city was equipped with a primitive drainage system and sewers, meaning much of the floodwaters could be evacuated. 

Nearly 1,600 Pakistanis died in the floods and 33 million others were affected in a disaster “probably” made worse by global warming, according to World Weather Attribution, a network of researchers.

The ancient metropolis “could have disappeared with all the archaeological traces” it contains, said Lazare Eloundou Assamo, the director of the World Heritage programme at UN agency UNESCO.

The Pakistani site was “a victim” of climate change and was “very lucky” to still be around, exactly 100 years since it was first discovered in 1922, Assamo said. 

Fortunately, “the situation is not catastrophic” in Mohenjo Daro, said Thierry Joffroy, a specialist in brick architecture who visited the site on behalf of UNESCO.

Despite ground sinking in some areas and water damage to some structures, the site “can be repaired,” Joffroy said.

– ‘Huge impact’ – 

For 50 years, Paris-based UNESCO has compiled a list of World Heritage sites, significant places that are deemed worthy of protection, and is marking the milestone this week in Greece.

“To protect this heritage ourselves… is to confront the consequences of climate disruption and the loss of biodiversity. It’s the main threat… that we assess in a tangible way,” UNESCO director Audrey Azoulay told the conference in Delphi on Thursday.

Of its 1,154 World Heritage sites, “one site in five, and more than a third of natural sites, already see this threat as a reality,” she said.

“We are experiencing many more incidents of floods, hurricanes, cyclones, typhoons,” said Rohit Jigyasu of the International Center for the Study of the Conservation and Restoration of Cultural Property (ICCROM).

“We have these climate-related disasters, which are having a huge impact on sites, for example Mohenjo Daro,” he said.

Huge forest fires have scorched the Rocky Mountains in Canada, which are a world heritage site, and this year flames came within 15 kilometres (nine miles) of Delphi as heatwave intensify the severity of wildfires across the Mediterranean basin.

In Peru, meanwhile, landslides occurred this year at the foot of Machu Picchu in the Andes mountains.

Other less noticeable changes can also have serious consequences. 

In Australia, the protected Great Barrier Reef is experiencing bleaching episodes due to rising water temperatures. 

In Ghana, erosion has washed away part of Fort Prinzenstein, which is conserved as a notable slave trading post. 

– Termites and drought –

“Slow factors” that do not have an immediate impact pose “new kinds of risks in many of these sites,” Jigyasu said.

These include invasions of wood-eating termites in areas that were previously either too dry or too cold for the insects to thrive. 

In other countries, the drying out of soil due to declining rainfall can have a “destabilising” effect on some heritage sites, said Aline Magnien, director of the French state-funded  Laboratory for Research on Historical Monuments. 

Under drought conditions, “the soils contract and… make the foundations move”, then “swell suddenly when it rains”, which causes cracking, she said. 

When parched and hard, they absorb less water, which promotes flooding. 

“We may have certain heritage sites that we will not be able to save, that we will not be able to transmit, which will perhaps be doomed to disappear”, said Ann Bourges, a researcher from the French culture ministry.

“It’s not just the heritage that is affected when you lose part of it, but all the social system around it,” added Bourges, who is also secretary general of the International Council of Monuments and Sites (Icomos), an NGO. 

In Mongolia, archaeological sites have been abandoned then looted because “the population no longer had access to water”, Jigyasu added. 

Expected water shortages in the future could also lead to an increase of conflicts in which important heritage sites might be lost.