Northern hemisphere. And that means its cold and theres snow in many parts lots and lots of it. In europe its been a good season for skiing. And at lower elevations as well people have been rumbling in the snow. Many just love the stuff. Out. There and i get up and look out the window and everything suddenly white. It just looks so beautiful thats not such a great feeling in your tummy i cant describe it its wonderful. I did a mish million yet to meet a child that doesnt love the snow we always loved it but it was great to just mess around in the snow much. That sneak. If we just love the first snow of the year if it transforms the forests and makes everything sparkle and we can see all kinds of tracks of a few animals initially hide because everything so bright and so that is my four years and so i hadnt. But when they come out you often see the younger ones playing my doll the place to just like the children. But i really like this now. Thats a really funny things can happen. One time i was ten and a rabbit suddenly came out of nowhere. He just appeared out of the snow. It was really cool this young boy. Might not miss my name is mohammed. I come from eritrea ive been living in germany for four years now. My Refugee Status has now been approved ive been working full time for the past year. When the snow comes people are so friendly i built a snowman together with my instructor we used to carry it for the nose. So now i can do it by myself i know what to do. Had a snowball fight it was great. Isnt there to entertain. A real and important physical role. Without the world would be a very different case. We still get snow. For some its fun for others plain bothersome. But its essential for life on earth. When winter g. Sends on the Northern Hemisphere snow covers fifty percent of the landmass within a few weeks. Its so heavy it even slows the earths rotation. And its so white but when seen from space the earth even changes color with the seasons. The snow cover also affects global temperatures. It reflects ninety percent of solar radiation straight back into space. And it cools the air above it. That affects weather patterns. When russia gets a lot of snow temperatures there drop dramatically a High Pressure zone develops which channels dry icy air towards western europe and germany where it then also gets very cold. Albeit dry and sunny as well. But even though the air mass above the snow is ice cold its warmer below a deep blanket of snow insulates and prevents things underneath from freezing. Plants can survive the winter because the water they need remains liquid. And people. A billion of us are dependent on melt water. So what if we suddenly had no more snow. In a World Without snow northern temperatures would jump by five degrees celsius. Weather patterns would change. Warm humid air would flow from the atlantic to germany bringing miserable rainy weather. Even though its comparatively warmer the ground begins to freeze permafrost spreads. Without its insulating snow cover the ground temperatures fall so low in winter the soil can never quite thought out in summer plants and animals die. Forests disappear from large swathes of the Northern Hemisphere leaving only sure obes moss and lichen. Further south melt Water Supplies fail wide expanses of arable land in age or in north america become barren. Drinking water become scarce. Lack of moisture turns the remaining forests into tender boxes. The world becomes a parched husk. A World Without snow would be a nightmare. Its time for this weeks viewer question. And it is particularly relevant when its cold and rainy outside. Shyam sunder like a saffron register down in india wants to know. Why do we catch so many colds in winter. If. Its winter is indeed the season for colds everyone seems to be sneezing and coughing. I was. But is it really the cold that makes us sick. No say researches at least not directly. Beth theyre a chilly weather weakens our immune systems slow circulation and our blood vessels constrict. But its viruses that are the real culprits they take advantage of the situation. I mean because membranes in our mouth and nose unable to ward off the invaders. Whats more cold viruses are constantly mutating there are more than two hundred different kinds. Having had one cold doesnt mean you wont get another. Theres another possible reason for the phenomenon in winter where often huddled together indoors in heated poorly ad rooms. The dry air makes our mucous membranes vulnerable and theres always someone who has a cold. So getting really cold having wets half or cold feet doesnt lead to a cold for say. Some even claim exposure toughens you up. But dressing more is never a bad idea. If you have a question about signs you can submit. It on the. D. V. D. Featuring a good look at albert einsteins most famous theories. The most important thing is to never stop asking questions. Human kind is pretty much at the mercy of the weather. But if we can make it behave the way we want it to. Researchers are making some headway there new insights dont always come in a flash. Leap. Lightning is one of natures most inspiring phenomena and can also be a highly destructive one two million lightning bolts are recorded in germany every year. Researching the enormous power and Energy Behind trees discharges of static electricity is anything but easy. Scientist Christiane Pollard is determined to find out more. He traps lightning as a profession luring it to a t. V. Tower on top of a one thousand meter high peak in the various alpine foothills. Of the tower is one hundred fifty meters tall. At the top of attached an aluminum ring and weve positioned a roughly four meter tall aluminum pole in the center of that in order to attract Lightning Strikes. Were talking here of an average of around ten thousand amps by comparison a standard household electrical socket delivers a maximum of about sixteen apps that gives you an impression of the power behind it. The facility here on the pipes and back is unique in germany full of sophisticate. The technology its designed to expose the very essence of Lightning Strike a strike a remnant of one of the polish lightning traps shows the forces hes dealing with. And looking at this all conduct iraq from the previous unit you can see all the scorch marks the base point of the lightnings path where the strike discharges. You can see that the tip of this conductor used to be round and now up here its got some really lovely melted patches you can see it here as well. Inside the t. V. Tower instruments record the power and dynamics of each strike. Paul has also installed a high speed camera which captures the chaotic and varied nature of each hit. Normally an electrical storm develops from cloud to ground. Electrical tension in the cloud has built up enough an electrically conductive channel will suddenly extend towards the ground and the current will discharge repeatedly. At the price and bear tower here we can see something very typical for tall structures. We can see an upward lightning discharge building up from the top of the tower towards the sky when we see a very powerful current carrying over twenty thousand amps. It causes a very bright flash in instantly heats the plasma to over thirty thousand degrees celcius that causes the adjacent air to expand explosively at almost the speed of sound and thats what you hear is thunder. Like snowflakes no two strikes are alike each discharge reveals something new to christiane powell. And while hes trying to understand the secrets of lightning jumpy a lot of Geneva University is using mobile lasers to manipulate the path like name takes its quite a daring concept. What were trying to do is to guide the lightnings by shooting with a laser in the clouds. And so for instance protecting sensitive sites like airports or industrial plants. In a basement laboratory at the University Shows us how it works. Is operators generate static charges all he needs is two metal switches and. Enough electrical tension between them one hundred thousand volts worth. Compared to a natural lightning discharge of several hundred million volts that sounds paltry but the mechanisms which lead to the discharges are identical theer to the high voltage ionizers the air molecules creating channels that are conductive theft alone the resulting discharge is flashed around in chaotic zigzag paths for now the scientists in geneva want to guide the lightning to where they wanted to go through what is really amazing with these new laser is that the intensity is very high so when you travel through the year. The air molecules and you get a lot of electric charge a little bit like a wire electric wire and so you get this wire if you connect with the earth it will channel the electricity through it and then you can really guide. And experiment shows what happens for without a laser the static discharge is chaotic when a laser beam touches the spheres the discharge follows it. Far off five on guided lightning. Coincidentally the research is also found but the laser can be used to make clouds if the beam goes through a chamber of humid air it generates wisps of condensation the chamber is soon full of clouds. Vats all confined to the laboratory but soon it might be possible to even manipulate the weather. Around the world people are searching for alternatives to fossil fuels cleaning sources of energy. For many the answer is electricity from renewable sources electricity its hoped will also be the key to environmentally friendly liquidity and. Electric cars are often touted as the answer but are they really as green as they seem. Combustion engines are out electric motors the future mine is in congo provide the cobalt needed for lithium ion rechargeable batteries lithium graphite rare earths theyre all needed for the batteries that drive socalled environmentally friendly electro mobility. Electrodes and i compared to conventional cars building the electric car is more complex and the Environmental Impact is greater around sixty percent greater in terms of the manufacturing process them special roberta graph this research an ecological engineering study showed that compared to a conventional. Our providing the Raw Materials for an electric car and manufacturing it generate two and a half tons more c o two and the electric car has to be driven a long long way to offset those extra emissions. After thousand kilometer after about eighty thousand kilometers electric cars come into their own thats when their advantages kick in and when they prove more environmentally friendly than conventional cars and. The environmental footprint of an electric car needs to be shrunk a lot of r. And d. Is going into batteries to reduce their consumption of Raw Materials and to boost performance to increase the range of electric cars new batteries need to hold more charge on their manufacture needs to be more environmentally friendly but this research wont bear fruit overnight by mining whats the standard pace of innovation is such that it can easily take ten or fifteen years or even longer to bring such a system to market. Says the recently green mobility requires green power that makes electric cars much more environmentally friendly in germany the share of Renewable Power is growing about three Percentage Points a year given Current Technology to power all road transport in the country with renewables would require additional Solar Systems covering well over two thousand square kilometers. Theres even a minister there were not be one massive plant but lots of small ones were raised on roofs throughout the country would together constitute what we call virtual power plants and output would be sold and sent to where its needed. And when most i mean the switch to environmentally friendly transportation requires of course to switch to environmentally friendly sources of energy and that is on the way. Its going to be a long and bumpy road to we get. That cars are not the only way to get around we asked our viewers to tell us their favorite means of transport. Chris wright says hed like even when he lives in the provinces a bunk is the best way to avoid bad traffic jams. Brian de gette also says the bike is his favorite means of travel for short distances but for longer trips he takes public transport. And rubbish kamar points out that we can expect new environmental problems to arise as we develop new means of transport and theyll need to be studied to. You dont have to come up with a new technology to make a difference a tried and tested means of transport can also improve peoples lives. For example from the ski slopes to a bustling city in south america. As the seat of bolivias government is a traffic nightmare two Million People now live in the metropolitan area up to now public transport has consisted mainly of many buses but the roads are far too narrow getting to work on time is the exception here everyone is fed up with the congestion. Glides effortlessly above the chaos below. Oh yes were in the cable car. Cables up to eight thousand meters in length extend over the sea of houses cable cars are a perfect solution and steve regions where subways are out of the question. From the telephone everything on the ground looks small and insignificant. Is on her way to the market. And shes got a push cart stored here. Shes a single mother and has four children to feed. In a daily battle to keep her head over water every minute counts in the captivity thanks to the telephone records i can spend more time in the market whereas you need at least an hour in the bus to get here the cable car takes just twenty minutes. It has really changed my life. The cable car connects the Satellite Town of ill talk with the center of. Five lines already in operation with six more under construction the existing one thousand kilometer network is already the most dense urban cable car system in the world. That connects very different worlds rich and poor. This is where western meets indigenous culture. The Austrian Company began building the cable car system in twenty fourteen. Project manager at austin and has been part of the team from the outset business. Is good enough to start soldier today varies in the city by up to a thousand meters there are very narrow alleyways hatin bandits gridlocked roads the cable car takes advantage of the capacity in the skies above. Each car can carry ten passengers every line can take three thousand people an hour in each direction. The technology can even adapt to rush hour demand. Can go a little faster reducing the distance between the cars and increasing capacity from three thousand to four thousand people. Here has made enough money and can go home or ticket costs are the equivalent of thirty five euro cents a reasonable price. But. I really like writing the cable car. The views are great its clean and quiet very different from the bus while so crammed. Shops for lunch tossed in boiling and stuck in a traffic jam that. Was theres no cable car where hes heading. Erecting sixty five meter tall mast in a city is a major challenge they have to be carefully planned so that they dont end up in the middle of a road say or require demolition work. Compounds are extremely heavy so construction is very difficult usually helicopters are deployed but here thats not possible. Most troops here are made of corrugated iron. The updraft from a Helicopter Rotor blades would lift the roofs off. Them all over. The impossible. Instead the work is done with a crane especially imported for the task from europe this kind of technology doesnt exist in. Major components are also manufactured in austria to be assembled here. Its one thing coming up with Technical Solutions its quite another getting people to accept and use the new technology at first many were afraid of being so high up. Its like flying in a plane my level. Riding cable car has become the most popular way of getting about town the network carries almost one hundred thousand passengers a day. The telephone has transformed life in the past and has become a landmark its residents are proud of. Stories from the world of science. And try to. Yes on twitter and facebook we love to hear from you and bowl. Thats a live for today and im coming so we get it if its to develop an unsufficient hot to fit inside the body. All that and more next time on tomorrow today until then good bye. The fire. The be. The big. Movement. The the. Climate change the beast the book. Says. Isnt it time for. Eco africa people and projects that are changing our farm and for the good its up to us to make a difference lets try the b. B. Q. Of the barman magazine the big. Value. Of freedom of expression. Of value that always has to be defended and new. All over the world. Are to a Freedom Freedom of art. A multimedia project about artists and their right to express their views freely. D w dot com or the freedom. Are you up to speed on the latest technology. Know when it may be time for an upgrade. Become part of the future become a cyborg i am a safeword so i have created a new sense and a new organ and design my perception of reality implants that make every day life easier. I use my implants on a daily basis that optimize the shoeman body and connect people more effectively. I hope that this will make us more ethical persons if we have a greater understanding for each other. What would life be like as a cyborg how far would people in upgrade i think its only the beginning of this. Side force shimon machines starting february first on d w. Odd. I am. I am. Sure this is you know we news live from berlin more carnage in caldwell another terrorist attack rocks the Afghan Capital latest you know wave of attacks at least eleven soldiers are killed as suicide bombers and gunmen strike a military academy in kabul the socalled Islamic State claims responsibility but also coming up. A shocking report reveals that german automakers funded diesel emissions tests exposing people and monkeys to do small fumes or raises more disturbing questions about the countrys