6min 25sec @TheEconomist clip - #Wooden #skyscrapers could be the future for cities

Text from youtube "

Wooden skyscrapers are an ambitious and innovative solution to the problems posed by urbanisation. Not only are they faster to build, they have smaller carbon footprints than high-rises made of concrete and steel. 

By 2050 the world’s population is expected to soar to almost 10 billion people and two-thirds of us will live in cities. Space will be at a premium. High-rise offers a solution.

But concrete and steel – the materials we currently use to build high – have a large carbon footprint. An answer might lie in a natural material we’ve used for millennia.

Throughout history buildings have been made of wood. But it has one major drawback. It acts as kindling. Fire destroyed large swathes of some of the world’s great cities.

But by the early twentieth century, the era of modern steelmaking had arrived. Steel was strong, could be moulded into any shape and used to reinforce concrete.

It allowed architects to build higher than ever before. So why, after more than a century of concrete and steel, are some architects proposing a return to wood? Concrete and steel are costly to produce and heavy to transport.

Wood however can be grown sustainably and it’s lighter than concrete. And crucially, as trees grow, they absorb carbon dioxide from the air, locking it into the timber.

One study showed that using wood to construct a 125-metre skyscraper could reduce a building’s carbon footprint by up to 75%

Regular timber isn’t malleable like steel or concrete, and isn’t strong enough to build high. But engineers have come up with a solution. It’s called cross-laminated timber, or CLT for short. CLT is light and it’s comparable in strength to concrete and steel. 

But how does it cope when burnt with a high heat source? London architects Waugh Thistleton are already designing buildings with this new kind of timber. Andrew and his colleagues designed Britain’s first high-rise wooden apartment block and have recently completed the world’s largest timber-based building.

Behind these bricks is a timber core, made from more than 2000 trees, sourced from sustainable forests.

And this London practice is not alone in advocating the use of CLT. Ambitious wooden high-rise buildings are also being constructed in Scandinavia, central Europe and North America. As yet, nobody has used CLT to build beyond 55 metres.

But Michael Ramage’s research centre in Cambridge, working with another London practice, has proposed a concept design of a 300-metre tower, that could be built on top of one of London’s most iconic concrete structures – the Barbican.

Making that jump in height will be a difficult sell. The cost of building wooden skyscrapers is largely unknown, but those costs could be reduced by prefabricating large sections of buildings in factories.

And city-dwellers will need to be persuaded that CLT does not burn like ordinary wood.

As an attractive, natural material, wood is already popular for use in low buildings. If planners approve, it could rise to new heights.

3min 15sec @theeconomist clip: #Obesity: not just a #rich-world problem

Text from you tube " Obesity is a global problem, but more people are getting fatter in developing countries than anywhere else. If current trends continue, obese children will soon outnumber those who are undernourished.

People are fatter than ever. Obesity has more than doubled since 1980. But the biggest rise is in the developing world. Anyone with a body mass index, or BMI, over 30 is considered obese. The higher your BMI, the greater your risk of developing weight-related diseases like diabetes and heart disease.

Nearly half of the world’s overweight and obese children under five years old, live in Asia.

And in Africa, the number of overweight children under five has increased by nearly 50% since 2000. Hunger still blights many parts of the world. But the share of people who do not have enough to eat is in decline.

Globally one in nine people in the world suffer from chronic undernourishment. One in ten are obese. If current trends continue, the share of obese children in the world will surpass the number of undernourished by 2022.

Africa has the fastest-growing middle class in the world. A move from traditional foods to high-calorie fast food and a more sedentary lifestyle is driving the rise in obesity. Fast food outlets like KFC and McDonalds have seen rapid growth on the continent.

Women appear to be most affected.

More than half of women in Botswana are overweight. Ethiopia known for its terrible famine, has seen obesity rates in women rise by 600% since 1984. Health systems in Africa, more focused on treating malnourishment and diseases like malaria and HIV, are ill equipped to deal with obesity-related illnesses like heart disease and diabetes.

Pacific islands have the highest obesity rates in the world, thanks to the spread of western fast food. Diets which a generation ago consisted of fish and coconuts are now dominated by processed meat.

Nauru is top of the list. 61% of the population are obese, making this tiny paradise island the world’s fattest nation. Cook Islands take second place, with an obesity rate of 56% and Marshall Islands come in third, with 53%.

The Middle East is also in the grip of an obesity crisis. In the Saudi Arabia and Qatar and Kuwait more than a third of the population is obese.

Obesity is already a global epidemic and is rapidly spreading from the rich world to the poor. "

3min 20sec @theeconomist clip - How free #electricity would change the world

 

Text from youtube "Imagine if heating and powering homes became free in the next decade. What would that mean for the world? "

2min @TheEconomist clip - #foreign #aid - who gives the most?