this is bbc news, the headlines: revellers around the globe have rung in the start of a new decade, with fireworks displays held in london and other major cities. in rio dejaniero more than a million people gathered on the copacabana beach to celebrate the new year. the united states is to send more troops to protect its embassy in baghdad, which has been attacked by thousands of protestors, angry at american air strikes. president trump has blamed the attack on iran. the authorities in lebanon say the former nissan boss, carlos ghosn, entered the country legally. mr ghosn was on bail injapan, awaiting trial on financial misconduct charges. reports in lebanon suggest a group of musicians, who played at his house in tokyo, smuggled him out, in an instrument case. now, pallab ghosh looks back on how the frontiers of science and space were pushed in 2019, a year shaped by the impact of deforestation and climate change, in review 2019: the year in science. this is the year we saw the first ever picture of a black hole and we celebrated one of humanity's greatest achievements. it's one small step for man, one giant leap for mankind. there was a new treatment for parkinson's disease. it enabled this woman to walk again. there were also fires raging in australia. you'll need rescueing, won't you? we saw the hottest summers on record across the globe. and climate change activist greta thunberg had this message for world leaders. how dare you! you have stolen my dreams and my childhood with your empty words. what a year it's been. welcome to a year in science, where we'll be looking at the biggest stories of 2019. there was, of course, one issue that dominated. that was climate change. not so long ago, people thought of it as a theoretical issue. but this year, we began to see the impact of a threat that's all too real. australia is enduring a bushfire crisis that has destroyed many homes, killing several people. bushfires happen here regularly. he'll need rescuing, won't he? blazes in new south wales and queensland have never occurred on such a scale and so early in the fire season. it's led many to ask how closely the fires can be linked to climate change. in venice, the problem was flooding. it left much of the italian city underwater. many of the ancient city's historic landmarks were damaged and there are also fears of structural damage to its famous cathedral, st mark's basilica. the city's mayor said he believes that the flooding is a direct result of climate change. there was a similar concern with the recent floods in the uk, in south yorkshire. there were scorching heatwaves across europe with unusually high temperatures in the arctic circle as well. 0ne researcher told us he was concerned about the trend of increasingly hotter summers. this is worrying because this is a new level of temperature extreme, and the regional impacts of that are likely to be unprecedented in some regions. so we are likely to see things that we have not seen in over the hundred years of observational records. there was another threat to our climate from the most unlikely of places — bizarrely, from the sources that are supposed to be helping to save the planet — renewables. these, like all electricity networks, use a gas called sf6 in their switches and relays for safety reasons. this is what would happen if they didn't. but the gas that keeps us safe is harming the climate. it's much more damaging than carbon dioxide and it's leaking out into the atmosphere. matt mcgrath discovered that the problem is getting much worse because of the increased use of sf6 in the growing number of renewable energy electricity networks. this new wind farm, being built off the coast of east anglia, is one of the first and largest in the world constructed without sf6. however, there are limitations. the turbines here are connected to this substation and that still relies on the gas. but engineers are working to find alternatives to the use of sf6. in one of the world's last pristine environments, the arctic, researchers discovered that the snow is contaminated with plastic and rubber and clothing fibres. they're microscopic, so you can't see them. but as roger harrabin discovered, the snow is infused with them — more than 10,000 particles in each litre. given the amount of pollution in the atmosphere, it's perhaps hardly surprising that we're finding microplastics in snow. but we have such a strong belief in the essential purity of this stuff that some people will find this news rather shocking. it's both surprising and upsetting that such a desolate location is so polluted. researchers believe that the particles have been blown here from populated areas in europe and north america. up here, you look around you every day and you see something that you think is the pristine arctic, as it's called, and it's not anymore. and we see it every day and it's really, really sad. there were also fires in the amazon forest in the summer. brazil's space agency said that there was an 85% increase in fires in 2019, the worst in brazilian amazon history since 2010. some thought it to be deliberate in order to create more farmland. the fires have made the problem of the rapid deforestation much worse, as my colleague david shukman reported when he travelled there. it's hard to believe, but an area the size of a football pitch is being cleared every single minute. what that means is that forest that could cover more than 2,000 pitches is just vanishing every day. and all the signs are that this rate of devastation will accelerate. air travel has one of the most damaging impacts on the climate, and so there were calls for us to reduce the number of flights we take. among the protesters was greta thunberg, who, to make the point, travelled to climate conferences by boat. she departed from plymouth on a racing yacht built for speed, as justin rowlatt discovered. the malizia is all about speed. look at her! she's just a giant sail attached to a super light carbon fibre hull. she basically bounces through the waves, sometimes dives right through them. it is...whoa! it is a very rough ride. it's a very wet ride. and to be honest, i'm not sure... whoa! ..that i could take two weeks of this. look, if we're honest, one person giving up flying doesn't make any difference in a world of 8 billion people, so what is the point? i mean, the point, ithink, is to sort of create an opinion. by stop flying, you don't only reduce your own carbon footprint, but also, that sends a signal to other people around you that, i mean, the climate crisis is a real thing, and that also pushes a political movement. when she arrived at the un conference on climate change, she found new yorkers sweltering in the unseasonable september sunshine. inside, world leaders gathered to discuss action on climate change. she had this angry message for them. you all come to us young people for hope. how dare you! you have stolen my dreams and my childhood with your empty words. you are failing us. reporter: mr president! and she had a scowl for president trump. he once described climate change as a hoax, and he's withdrawing the us from the paris climate accord, which is an international agreement to reduce damaging greenhouse gas emissions. greta thunberg has inspired children across the world to put climate before classroom, calling school strikes in protest at what they feel to be a lack of action to tackle climate change. in the low—lying south pacific island of vanuatu, protests from those most at risk from rising sea levels. in india, schoolchildren made themselves heard. chanting. and it was a similar story in australia. well, the younger a person is, the more that the change in climate will impact them as they grow and the less of a voice they're given today. considering we have such a short amount of time to turn this issue around, it's vital that young people are at the forefront of this conversation because they will be impacted more than anyone else. and there was the emergence of a new environmental campaign group, extinction rebellion. among the protesters was the actress dame emma thompson, who was criticised for her own jetsetting lifestyle. u nfortu nately, sometimes i have to fly. but i don't fly nearly as much as i did because of my carbon footprint and i plant a lot of trees. i bloody don't, no! it's always turned back on the individual. "you're the one who flies, you're the one who's using it, you're the one..." the fact of the matter is everyone has been asking for clean energy for decades. if i could fly cleanly, i would! this vast room is the herbarium at kew gardens. it's essentially a library of more than 7 million plant specimens. this one was discovered by charles darwin himself in 1835. a lot of them are now extinct and many more of them are on their way out because of climate change. but it's not all doom and gloom. scientists are beginning to develop solutions to what many are calling the climate crisis. but they say we have to act soon because time is running out. the atmosphere is already so full of c02 that some scientists worry that even sharp reductions in emissions won't, on their own, be enough to halt irreversible damage. so researchers here at cambridge university are looking at ideas, however crazy, to try and take global warming gases out of the atmosphere and to actually repair the earth's climate. with trillions of tonnes of ice gone from both the earth's poles, the new centre will look at ways of refreezing them. one idea is to have boats spray sea water up into the clouds above the ice to reflect sunlight away from them. another is to develop forests of artificial trees to absorb carbon dioxide — just like real forests do, only better. and some even think releasing tiny discs into space might act as a parasol, reflecting sunlight and cooling the planet. it's all the idea of a former government chief scientific adviser. we are looking for processes that are scalable, by which i mean processes that can take out billions of tonnes of greenhouse gases each year. although our planet and the climate dominated the agenda, there are plenty of other inspirational science stories. the exhibits here at the science museum's wonderlab are literally out of this world, and that's where we'll be going for the next part of our review of the year. this is a first ever picture of a black hole. it's more than 3 million times the size of the earth. this is one of the telescopes that captured the image, on top of a mountain in southern spain, seemingly touching the clouds. the instrument is one of a global network of dishes from across the world which will link together. no single telescope is powerful enough to see the black hole, but by adding together the information from each of them, the image gradually becomes sharper. you can actually see black holes! you know, that's crazy! i always thought this is just way beyond what we can be doing. this is a super heavyweight champion among the black holes in the universe. this image will help astronomers learn more about space, time and our own existence. researchers also began the most ambitious study of the universe ever undertaken. they did so in order to learn about a mysterious substance called dark energy. what we see here on earth in the stars and galaxies are made of atoms. that accounts for just 5% of the universe. the rest is mostly dark energy. in order to understand what this force is, we've got to go back all the way to the beginning of the universe. after the big bang, according to the current theory, the expansion of the universe ought to be slowing down and eventually collapsing back in on itself under the pressure of gravity. but instead, the galaxies are flying apart faster than ever. scientists call the force behind this expansion dark energy, but they haven't got a clue what it is. they plan to find out using this telescope. it will track the position and acceleration of 35 million galaxies. we also celebrated what's arguably humanity's greatest achievement. this is one of the capsules used in nasa's moon programme. 50 years ago, the world watched in awe as the first people set foot on the lunar surface. in the dawn‘s early light, the saturn 5 rocket shimmers on the launch pad. three astronauts get ready for a mission that will propel them, and the rest of humanity, into a new era. now departing on the start of its eight—mile trip to launchpad a here at complex 39. commander neil armstrong leads edwin ‘buzz‘ aldrin and mike collins into the spacecraft. here, they're in the suit—up room. you really do look a lot like him, dad. yeah, thanks. mark armstrong was just six at the time. now he's reliving it with his daughter carly. aw, dad! cute as a button! we have lift—off. neil armstrong reporting the roll and pitch programme, which puts apollo 11 on a proper heading. a few days later, the spacecraft approaches the lunar surface. tranquility base here. the eagle has landed. roger, tranquility. we copy you on the ground. you got a bunch of guys about to turn blue. we're breathing again. thanks a lot. i'm going to step off now. it's one small step for man, one giant leap for mankind. good job, grandpa. it's very pretty out here. through neil armstrong's eyes, they saw what he saw. in 1969, he was looking back at the earth and seeing it as a fragile resource. i wasn't alive, of course, for it, and so getting to relive it in my own generation is really, really special. since those heady days, 90% of astronauts have been men. but in 2019, the space age took another small step into the modern age. flight engineers christina koch and jessica meir made history as they stepped out of the international space station. their mission involved routine maintenance but there was nothing routine about it, as they became the first all—female spacewalking team in more than half a century of space travel. we hope that we can provide an inspiration to everybody, not only women, but to everybody that has a dream, that has a big dream and that is willing to work hard to make that dream come true. but 2019 wasn't all about space. there was a breakthrough in the treatment of parkinson's disease, the eradication of a deadly virus from the face of the earth and one of my personal favourites, the researchers who are tackling malaria by learning how to speak to mosquitoes. for us, the sound is annoying. but for the mosquito, it's a love song. the buzz is made by the wing beats. it helps the insects find mates and to reproduce. so what if we could learn how to talk mosquito and sabotage their mating cycle, to stop the spread of deadly diseases? the mosquito's buzz is created by the insect‘s wings. this is a sound of the female on the left. look closely and you can see that her wing beat is slower than the males, here on the right, and that is why her tone is slightly different. joerg albert is studying how to turn the mosquito's buzz against them. we could simulate these sounds, use them for new technological devices to perform attraction of mosquitoes, to lure them away from sites where they can transmit disease — for example, from populations, from households — or also to catch them, kill them. so catch—and—kill devices could be designed. this is the rinderpest virus, relentlessly destroying the cells of a cow. more than 100 years ago, it killed nearly 90% of the cattle in sub—saharan africa, and with that came famine and mass starvation. millions died. it was eradicated in the wild in 2011, but thousands of samples of the virus remained in labs across the world. in 2019, the very last batch was sent to a high—pressure oven to be superheated and destroyed. three, two, one! there was also a big medical breakthrough. this is the first time gail has walked with her husband, stan, for two years. she has parkinson's disease — and it's meant that, until now, she would freeze while she was walking and fall down. an experimental electrical implant around her spine has restored her movement. the sensors on her suit and socks monitor her improvements. i can walk better. i have more confidence. and overall health, it feels better. i used to fall at least two times a day, sometimes. but now i haven't fallen in over two months. normal walking involves the brain sending instructions to the legs to move. it then receives signals back when the movement has been completed and then sends instructions for the next step. the researchers believe that parkinson's disease reduces the signals coming back. the implant boosts that signal and so prevents freezing. what's really surprised the researchers is that the treatment is long—lasting and works even when the implant is turned off. scientists discovered a treasure trove of dinosaur remains. this place is where the giant lizards came to die. from the fossils, researchers have reconstructed what life was once like here. it was home to a fearsome carnivorous allosaurus, eight metres long and weighing two and a half tonnes. and herds of plant—eating diplodocus also grazed on this landscape. before that, this place was a vast inland sea where marine reptiles called ichthyosaurs were abundant. rebecca morelle joined the dinosaur dig in northern wyoming. standing here, you really get a sense of the size of this creature. it's a type of sauropod, which, from nose to tail, measured 30 metres long. and scientists think it might even be a species that's new to science. these critically endangered young black rhinos were all born in european zoos. they're descendants of animals that were taken decades ago from africa. now, they're about to go home. victoria gill went to meet them at a safari park in the czech republic, before they set off on theirjourney to rwanda and were released into the wild. they are looking pretty content, munching on their breakfast. and these are three of the five animals that are going to be taken to rwanda for the reintroduction. and they're from all over europe. they represent all the countries these animals come from, from denmark, the uk and the czech republic. also in 2019, we discovered this rarest and oddest of all living sharks, living somewhere unexpected. scientists thought that the angel shark could only been found in the waters of the canary islands, but the discovery of a hundred—year—old book has changed that view, as helen briggs discovered. this is the book that started the search. evidence shows sharks like this are still living off the coast of wales. the question is, how many and where? staying under the sea, this sub has gone where no sub has gone before — to the very bottom of the sea, the pacific 0cean's mariana trench. adventurer victor vescovo set a new record for the deepest ever dive, seven miles down. he lands with a thump. at bottom! it seemed a bit like being on the moon, but a wet version of it. there were small craters here and there. there were slight undulations. there weren't rocks until you got to the southern or northern portions of the mariana trench. it had some variety, but it was quiet. it was peaceful. in the midst of the festive season, our thoughts turn to the year ahead, where climate will continue to dominate the agenda. the onus will be on the uk to help find a political solution as it hosts the next major climate conference in glasgow. but there will be plenty of space stories, too, with four missions to mars, three rovers roaming, two orbiters orbiting... # ..and a landing on the martian surface! what a year for science it's going to be. merry christmas! hello. we've ended 2019 on a fairly quiet note. the best of the sunshine through new year's eve was across northern and eastern england, parts of scotland we saw some spectacular sunsets to end the year and the decade. and this quieter theme continues through new year's eve underneath this area of high pressure. but notice that the isobars are closer together across northern ireland and scotland, so, a windier day here. and also, a cloudier day across the uk to start 2020. that cloud could be thick enough for the odd patch of drizzle. for most it's mainly dry through daylight hours with some brightness or sunshine across eastern counties of scotland, north—east england, perhaps north wales for a time and maybe into east anglia, too. light or gentle winds for most away from the western and northern isles of scotland, where the winds will be strengthening through the day, perhaps gusts of 40—50 miles an hour. still, quite a cool feel to the day across the uk, 5—9 celsius, the top temperature, perhaps 10—11 for northern scotland and south—west england. cloud cover stays with us through the evening and overnight. again we could see some patchy drizzle. for most it's dry, although rain will start to approach the far north—west of scotland and the west of northern ireland as we head but underneath the cloud cover, temperatures are going to stay above freezing. and actually, as we go through thursday, it is a milder day. these yellow, and in places orange, colours just indicating the milder air flooding across the uk. but with it comes a set of fronts, and that's going to bring some wetter, windier weather initially across scotland and northern ireland, and slowly it slides its way south and eastwards through the day, but weakening as it does. but potentially some very heavy rain across the highlands of scotland, maybe 40—50 millimetres here, gusty winds as well. this front then slides its way south and eastwards, getting into northern england, parts of wales, south—west england, driest the further south and east you are, but some gusty winds, perhaps 50—60 miles an hour for northern and western scotland and 30—110 miles an hour quite widely. so it's a wet, blustery day across northern and western parts of the uk, but mild for most, it will be in double figures. doesn't last long as those fronts push their way south and eastwards, behind it we start to see the blue colours returning. so, we're back in the colder air as we go into friday. but what that also means is clearer conditions, much more in the way of sunshine. cloud and rain clearing away from south—east england, some showers peppering the north of scotland, perhaps wintry in nature, but for much of the uk, on friday we'll end the week dry with much more sunshine. but it will be feeling a little bit colder again. as for the weekend, it's looking mainly dry. there'll be some spells of sunshine, little bit milder but potentially turning wetter and windier into next week. this is bbc news: welcome if you're watching here in the uk, on pbs in america or around the globe. i'm reged ahmad. our top stories: big ben strikes the hour fireworks displays have lit up the skies around the globe as people celebrate the start of the new decade. the us is sending reinforcements to help defend its embassy in baghdad, having repelled an attack by protesters angry about american airstrikes. bushfires continue to rage across wide areas of australia. emergency workers are assessing the damage while still battling to rescue those cut off by the flames. and lebanon says it had no warning that the fugitive ex—nissan boss carlos ghosn was fleeing japan, for beirut.