Friday, December 17, 2021

Scientists discover ‘surprising’ cause of Europe’s little ice age in late medieval era

An amusing article from a skeptical viewpoint below. Just a few centuries ago, a warm period was followed by a bitterly cold period. Might that not happen to us? There are clearly large forces at work that are way beyond our control.

And what was the big influence involved? Solar output, not atmospheric CO2

Following an era known as the medieval warm period, temperatures in Europe in the early 15th century fell sharply in what has become known as the little ice age.

This remarkable cold period brought increased glaciation in mountains, expansion of some areas of sea ice, crop failures, famines and disease across Europe.

Undependable summers were followed by harsh winters, during which rivers and canals routinely froze over. In the UK, the first River Thames “frost fair” was held in 1608, and was an almost annual occurrence until the last one in 1814.

The little ice age was not believed to have been due to a global period of glaciation, but its exact cause has remained uncertain.

There are numerous explanations, including heightened levels of volcanic activity, reduced solar activity, the impact of the black death reducing the human population, and the impact of European diseases on South American populations, which in turn affected deforestation and reforestation rates.

But scientists at the University of Massachusetts now believe they have found a new key factor in why temperatures plunged to their coldest in 10,000 years.

“Surprisingly, the cooling appears to have been triggered by an unusually warm episode,” the researchers said.

The discovery came after Lead author Francois Lapointe, a postdoctoral researcher and lecturer in geosciences at the University of Massachusetts, and Raymond Bradley, distinguished professor in geosciences, also at the University of Massachusetts, came across new data suggesting a rapid change in sea temperatures.

Their previous work, which built a 3,000-year reconstruction of North Atlantic sea surface temperatures, revealed a sudden change from very warm conditions in the late 1300s to unprecedented cold conditions in the early 1400s, only 20 years later.

Using various sources to obtain detailed marine records, Dr Lapointe and Professor Bradley discovered there had been an abnormally strong northward transfer of warm water in the late 1300s which peaked around 1380.

As a result, the waters south of Greenland and the Nordic Seas became much warmer than usual. “No one has recognised this before,” said Dr Lapointe.

The researchers said that usually there is always a transfer of warm water from the tropics to the arctic.

It’s a well-recognised process called the Atlantic Meridional Overturning Circulation (AMOC), which is like a planetary conveyor belt.

When it is functioning normally, warm water from the tropics flows north along the coast of Northern Europe, and when it reaches higher latitudes and meets colder arctic waters, it loses heat and becomes denser, causing the water to sink at the bottom of the ocean.

This deep-water formation then flows south along the coast of North America and continues on to circulate around the world.

But in the late 1300s, the AMOC strengthened significantly, which meant that far more warm water than usual was moving north, which in turn caused rapid arctic ice loss.

Over the course of a few decades in the late 1300s and 1400s, vast amounts of ice were flushed out into the North Atlantic. This additional ice not only cooled the North Atlantic waters, but also diluted their saltiness, ultimately causing AMOC to collapse. It is this collapse of the conveyor belt which triggered substantial cooling, the researchers said.

Furthermore, a similar process could now be underway.

Between the 1960s and 1980s, we have also seen a rapid strengthening of AMOC, which has been linked with persistently high pressure in the atmosphere over Greenland.

Dr Lapointe and Professor Bradley believe the same atmospheric situation occurred just prior to the little ice age – but what could have set off that persistent high-pressure event in the 1380s? The answer, Dr Lapointe suggested, can be found in trees.

The researchers compared their findings to a new record of solar activity revealed by radiocarbon isotopes preserved in tree rings, and discovered that unusually high solar activity was recorded in the late 1300s.

They said such solar activity tends to lead to high atmospheric pressure over Greenland.

At the same time, fewer volcanic eruptions were happening on earth, which means that there was less ash in the air. A “cleaner” atmosphere meant that the planet was more responsive to changes in solar output.

“Hence the effect of high solar activity on the atmospheric circulation in the North-Atlantic was particularly strong,” said Dr Lapointe.

On the question of whether a second little ice age could now emerge, Dr Lapointe and Professor Bradley said there is now much less arctic sea ice due to the climate crisis, so an event like that in the early 1400s, involving sea ice transport, is unlikely.

“However, we do have to keep an eye on the build-up of freshwater in the Beaufort Sea (north of Alaska) which has increased by 40 per cent in the past two decades,“ said Dr Lapointe.

”Its export to the subpolar North Atlantic could have a strong impact on oceanic circulation. Also, persistent periods of high pressure over Greenland in summer have been much more frequent over the past decade and are linked with record-breaking ice melt.

“Climate models do not capture these events reliably and so we may be underestimating future ice loss from the ice sheet, with more freshwater entering the North Atlantic, potentially leading to a weakening or collapse of the AMOC.”


Tesla defends Model 3 taxi after fatal accident in Paris

This COULD be a driver error but the French obviously suspect not. There have been problems with Tesla's autopilot facility

Paris taxi company G7 suspended the use of the 37 Model 3 cars in its fleet after the accident on Saturday evening, which involved one of its drivers.

One person was killed in the crash and 20 injured, three of them seriously.

"We have been in contact, of course, with Tesla's management and they tell us that there is no technical problem to flag on their vehicles," government spokesman Gabriel Attal told reporters on Wednesday.

He added that the government was waiting for the outcome of the ongoing judicial investigation.

Still in shock four days after the accident, witnesses said the car ploughed through metal posts, a row of pay-to-ride bicycles, a recycling bin full of glass and hit pedestrians and a van before finally coming to a halt.

"I thought it was an attack. There was glass, dust … it was as if there had been a blast," said Tillard Diomande, who was serving clients from behind his bar in a nearby restaurant.

The vehicle, which had stopped at a red traffic light, suddenly sped forward, hitting and dragging with it a cyclist who later died, a police source said, citing the driver's own version of events, witnesses and video surveillance.

The driver tested negative in an alcohol test, the police source said.

It was not clear whether the car was operating in Tesla's autopilot mode, which handles some driving tasks.

Transport Minister Jean-Baptiste Djebbari told RMC radio that he had spoken with the chief executive of Tesla Europe, who told him there had been no safety alerts about the Model 3.

Mr Musk has repeatedly defended autopilot and in April tweeted that "Tesla with autopilot engaged now approaching 10 times lower chance of accident than average vehicle".

Tesla advises drivers they must keep their hands on the steering wheel and pay attention while using the autopilot function.

G7 Deputy Chief Executive Yann Ricordel told Reuters the accident occurred while an off-duty taxi driver was taking his family to a restaurant.

The driver tried to brake but the car accelerated instead, Mr Ricordel said.


UK: Plug-in Car Grant for electric cars cut AGAIN

The Plug-in Car Grant to help make electric cars more affordable has been cut by further £1,000 in a surprise announcement that will infuriate electric car buyers and manufacturers alike.

Previously £2,500, the Plug-in Car Grant is now just £1,500 as of 7am today (15 December 2021).

What’s more, the qualifying maximum price of an electric car has been reduced, from under £35,000 down to less than £32,000.

Both cuts are effective immediately.

The government argues that its approach to Plug-in Car Grant cuts “is clearly working – whilst the grant has slowly reduced over time, the sales of electric vehicles has soared”.

Transport minister Trudy Harrison said the government is “refocusing our vehicle grants on the most affordable vehicles and reducing grant rates to allow more people to benefit, and enable taxpayers’ money to go further”.

Any motorists who placed orders between 8 December and 14 December will still qualify for the old £2,500 grant, on cars costing up to £35,000.

The Plug-in Van Grant has also dropped, to £2,500 for vans under 2.5 tonnes and £5,000 for vans between 2.5 tonnes and 5.0 tonnes.

The Plug-in Car Grant was previously cut in March 2021, from £3,000 to £2,500.

A larger reduction in the maximum qualifying price of vehicles, from £50,000 to £35,000 was also announced – and immediately criticised by car manufacturers.

At the time, the government argued the changes were made to ensure the funding lasts longer.

With the recent acceleration in electric car sales – last month, they comprised almost 1 in 5 new car sales – it is likely to make the same arguments again.

‘Counterintuitive’ and ‘disappointing’

RAC head of roads policy Nicholas Lyes said “this disappointing cut means that only around 20 EV models are now eligible for the grant, which doesn’t leave a great deal of choice for consumers.

He pointed to research that showed motorists already feel that new electric cars are too expensive. “This has to be seen as a step in the wrong direction.


Just two in 10 Australian motorists plan to buy electric vehicles

Australia’s efforts to reduce transport emissions are in jeopardy, as new data reveals just 16 per cent of motorists intend to make their next car purchase an electric vehicle.

Despite earlier research finding Australia must phase out petrol cars by 2035 to achieve net-zero emissions by 2050, a new survey by Compare The Market finds more than half of motorists may buy another one.

The comparison firm asked 1000 Australians when they plan to replace their current vehicle and found 70 per cent will be in the market for a new car by 2025.

But fewer than two in 10 said they would buy an EV, and a further 49 per cent said they were still undecided.

Those findings are ominous because new cars last 14 years on average, meaning the vehicles motorists buy today will affect Australia’s carbon budget as the nation moves towards net-zero emissions by 2050.

That was a major conclusion from a Grattan Institute report earlier this year, which said Australia must make EVs cheaper to speed up the transition away from petrol and diesel cars.

“Electric vehicles will become more accessible to more people in the future, but with many Australians planning their next car purchase during the next few years, we might not see improved prices in time,” Compare The Market’s Stephen Zeller said of the new survey data on Wednesday.

“It would seem that for the majority of Australians, an electric vehicle might still be one more car purchase away, but their next petrol car might well be their last.”

Worryingly, more than a third of survey respondents in New South Wales and Victoria (Australia’s largest states) said their next purchase will not be an electric vehicle. That’s more than twice the number who said they would buy an EV.

Jake Whitehead, research fellow at the University of Queensland and an expert on EV policies, said he was unsurprised by the survey’s findings. Dr Whitehead said inadequate government policies mean EVs are still too expensive in Australia to entice more buyers to make the switch.

“We shouldn’t read too much into just one survey, but the undecided group is a big opportunity,” he told The New Daily.

Dr Whitehead said his research shows the majority of Australians are interested in buying an EV. But a lack of choice is discouraging many from making the leap.

“The policy settings aren’t in place to encourage that undecided group to definitively purchase an electric vehicle,” he said.

Though growing quickly, electric vehicle sales accounted for less than 2 per cent of total light vehicle sales in the first half of 2021, according to data from the Electric Vehicle Council.

The global average is 4.2 per cent, while other comparable economies like the UK have achieved rates above 10 per cent in the past year.

One reason for that is choice. Australians can choose between just over 30 EV models right now, but Britons can choose between more than 130.

Dr Whitehead said Australia needs a national EV sales target to encourage manufacturers to sell more models Down Under.

He said the current patchwork of state government policies isn’t enough to bridge the gap and ensure Australia sells its last petrol car by 2035.

“It’s a major risk for all states as well as the country in achieving [emissions] reduction targets,” he said. “We need a major transition and the longer you delay, the more disruptive it becomes.”




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