review 2021, the year in science. it was a year shaped by the global fight against the coronavirus pandemic, but with significant developments in climate change and space exploration. 0ur science correspondent pallab ghosh gives his analysis of the year. 2021 was the year that world leaders agreed on a new plan to save the planet. hearing no objections, it is so decided. scientists warned that it was now or never to stop damaging climate change. the difference between 1.5 and 2.4 is really survival of millions and millions of people and species in the planet. environmentalists chopped down trees to save the planet. nasa's perseverance rover landed on mars. and there was a discovery of what might be another fundamental force of nature. welcome to the year in science. the earth's climate dominated this year in science. for a long time, scientists have warned that our current way of life will lead to dangerous and possibly irreversible damage to the earth's ecosystems. world leaders gathered at the un climate change conference were told now is the time to act. ready to start. world leaders gathered in glasgow in november to hammer out a deal to reduce carbon dioxide levels to stop dangerous global warming. and one of the biggest disputes was over the future of coal. for a while, it looked like negotiators couldn't reach a deal. then, the man at the centre of the talks, alok sharma, had to appeal to all the parties to cooperate. this is the moment of truth for our planet, and it's a moment of truth for our children and our grandchildren. it did the trick. an agreement was reached. by the end of 2022, countries will have to update their climate pledges at a faster pace than before. by 2024, a package of long—term financial aid for the poorest nations have to be agreed. and then, by 2030, to avoid the worst of global warming, carbon emissions should be halved. but that will be made harder by china and india's insistence that coal should be phased down rather than phased out. so, as things stand, polar ice will still melt faster than ever, raising sea levels, and, together with heavier rain, threatening millions of people with flooding. we've already warmed by 1.1 degrees since pre—industrial times. world leaders said that limiting the rise to 1.5 was still possible, but projections suggest that we're headed for at least 1.8 — and that's only if every promise is kept. more realistically, we're on course for 2.4 degrees — a really dangerous level. the difference between 1.5 and 2.4 is really the survival of millions and millions of people and species in the planet. this is what is particularly true for the islands. but, according to a government adviser at the heart of the talks, the worst outcomes can be averted. we have kept 1.5 alive, but on the basis of delivering on those commitments, and that'll be our next task for us as the presidency but for all the countries, and it's on us to make sure that this is real in action. and sir david attenborough said the richest nations had a moral responsibility to help the most vulnerable. it would be really catastrophic if the developed nations - of the world, the more powerful. nations of the world simply ignored these, these problems. if we say, "well, it's . nothing to do with us," and cross our arms, we caused it. thousands of men, women and children who have lost everything — _ lost everything — can we just go - by and say it's no business of ours? an assessment by the environment agency said that the uk was not yet ready for the impact of climate change. in october, a street in cardiff became a dangerous river after a massive downpour. there was a similar scene in newcastle after torrential rain there. in america, europe, south america and siberia, there were raging wildfires. the biggest shock came in germany injuly as a surge of water tore through communities. 200 people were killed. the weather events that we saw in europe this summer could happen here in england, and we need to be ready. to save lives. we need to recognise that it's adapt or die. chanting: stop deforestation... young people were involved in protests across the world, as they have the most to lose if we fail to get the impact of climate change under control. they're also the ones that can fix the problem. 5,000 of them were involved in a scheme to understand and help solve the environmental crisis. we want to know how clean the air is in our school. we're measuring plants to see how they're growing outside. we've been learning about worms. this is mustard powder. you're going to mix the mustard powder into the water. this one is about understanding the role of worms. these are babies, 0k? you can hold that. baby worms! these are the scientists of tomorrow. they've got to think about their future and their children's future and it's a long—term game. this is not something for a single generation. we've all got to play our part. other projects involve growing nature—friendly food. it's so important to me. it's a matter of our lives now, and i think it should be important to everyone, and this is why we've started the outdoor learning area so that we can protect the environment and try and combat climate change. the young researchers took what they discovered and presented their work to the politicians at cop26. there was a new award for those trying to save the planet called the earthshot prize. we have lift—off. its name is a reference to america's moonshot — an ambitious programme to get an astronaut on the lunar surface. but, more than 50 years on, prince william told the bbc that saving the earth was an even bigger challenge. we need some of the words greatest brains and minds fixed on trying to repair this planet, not trying to find the next place to go and live. but many space scientists say the choice between earth or space is a false one. the science museum gallery celebrates the heyday of space travel in the 1960s and �*70s when humans went to the moon. and it was that effort, they say, that helped draw attention to the planet's environmental plight. but, for many, it's the beautiful images from space that most inspires — no more so than the pictures from the hubble space telescope. for more than 30 years, it's captured distant galaxies, stars being born and dying. images that have been as uplifting to the soul as they have been to the mind. hubble's successor is nasa's james webb telescope. unlike hubble, the £7.5 billion spacecraft will go beyond earth's orbit — 930,000 miles into deep space. once in space, it unfurls its sunshield and deploys its giant mirror and instruments. the space telescope is much more powerful than hubble. it'll be able to analyse the atmospheres of worlds orbiting distant stars to see if there are signs of life. it'll also be able to witness the birth of the very first stars. this is a simulation of that critical moment. the purple areas are clouds of hydrogen gas becoming ever denser until they form stars, blazing like fireworks. james webb is expected to capture images of this really happening. i'm so excited! why are you so excited? isn't that just fantastic that as humanity, a tiny little civilisation on planet earth, that we can create a telescope that we can send up into space and peer back to the universe as it was just a couple of hundred million years after the big bang? and some incredible views from space were obtained from these aerials planted in a small field in hampshire. these pick up radio waves from distant galaxies. they may not look like much, but astronomers have connected 52 sites just like this one spread all across europe. together, they've captured some of the most detailed pictures from space ever taken. in this image, the galaxy is in the middle. shooting out either side are jets of material across the expanse of space. it's because of a gigantic black hole inside of it. astronomers can now see things they've never been able to see before. this is a picture of a galaxy seen through a normal telescope. and here is a standard radio image of it. although it's a lot brighter, a lot of the detail has been lost. now compare it with one of the new high—definition images, which is much sharper, showing features inside in unprecedented detail. the brightest area at the bottom shows the location of a gigantic black hole inside this galaxy. it's bright because of the energy released as it's sucking in material around it. meanwhile, in the deserts of chile, a telescope was able to see the universe as it really is — filled with a mysterious substance called dark matter. it can't be seen, but this instrument detected dark matter by the way it distorts starlight. this is a map of matter in the universe. astronomers produced this map of how it spread across the cosmos. it permeates space, accounting for most of the mass of the universe. the bright areas are where dark matter is most clumped together. it's here that galaxies form. it's our reality shining like gems on an unseen, tangled cosmic web. but the map is not what astronomers expected. according to einstein's theories, the matter should be slightly more clumped together. instead, it's smoother and more spread out. building on the work of einstein, carlos frank was among the scientists who developed the current theory of cosmology. hearing now that there may be something not quite right with the theory, well, it's very disconcerting, it's very alarming, and, in a way, frightening, to see that maybe my whole life's work might crumble in front of me. but, at the same time, it is immensely exciting. back in our own solar system, nasa's perseverance rover landed on mars. first look at the surface. these pictures are from the spacecraft during the final few minutes of its descent. as it nears the surface, clouds of dust and grit are blown around as its thrusters are fired. and, from another camera angle, we can see the vehicle lowered to the ground. perseverance safely . on the surface of mars! these were the scenes at mission control. shortly after, a thoughtful tweet from the rover — "i'm safe on mars. perseverance will get you anywhere." it's been drilling into the surface and storing some of the rocks for a future mission to bring back. some of the samples may contain fossilised evidence of life. i am not talking about martian little green men. probably not even fish. we're looking for microbial life or maybe microbes that have made a little mat or a slime of sorts that you might find at the bottom of a pond. those are the type of things that are likely to — well, they did exist on earth 3.5 billion years ago. the question is, did they exist on mars at the bottom of lakes? 0n—board is a small helicopter, ingenuity. which carried out the first ever powered flight on another planet. star trek theme plays back on earth, and boldly going where hundreds of people had gone before... william shatner. star trek�*s captain kirk, william shatner, blasted off from a launch site in texas. it was a ten—minute flightjust 60 miles above the earth, but enough time to float in zero gravity. waiting for him on his return, amazon founderjeff bezos, whose company developed the rocket system. what you have given me is the most profound experience i can imagine. i'm so filled with emotion about whatjust happened, ijust... it's extraordinary. at the age of 90, william shatner finally reached the final frontier. in physics, there was what could be one of the biggest steps forward for a generation. scientists believe that there are four fundamental forces of nature. one for gravity, another for electricity, and two nuclear forces which control the behaviour of atoms. together, they explain the way the world works. but, in recent years, astronomers began noticing things in space that can't be explained by the four forces, such as galaxies spinning faster than they should. and they can't explain why the stars and planets and everything on them, including us, exist at all. the new results suggest there might be a fifth force which could explain some of these mysteries. the result was from fermi lab, a particle accelerator just outside chicago. scientists accelerated particles inside this giant ring close to the speed of light. and they found something that can't be explained by the current theory of physics at the subatomic level. i think it's quite mind—boggling, and it has the potential to turn physics on its head. we have a number of mysteries that remain unsolved, and this could give us the key answers to solve those mysteries. you've heard of electrons — well, there are similar particles called muons, which are much heavier and spin like tops. in the experiment, they were made to rotate using magnets. the current theory states that they should rotate at a certain rate. instead, they rotated faster. this might be caused by a mystery force — a fifth force that in turn is created by another, yet to be discovered, particle. in february, a meteorite blazed across the night sky over the rooftops across the uk. a large chunk of it landed in the driveway of the wilcock family living in winchcombe in gloucestershire. i came out, and we looked at this pile of what looked like crushed coal. and so i started even then thinking perhaps it's come down from space. security camera footage captured the flight of the meteorite as it flew over nuneaton, somerset, wigan before it ended up at the natural history museum for study. winchcombe is very special because it is one of the most pristine materials that we have available on earth to study, and the thing that's really good about this particular case is that we saw it fall. and so we can use that fireball to, kind of, track back the trajectory, work out where in the solar system it came from. a study from the natural history museum found that the uk is losing biodiversity so quickly that it's now one of the most nature—depleted places in the world. that's important because there are rare, long—lost species that could be better suited to the extreme conditions caused by global warming. many of the crops we depend on, such as this coffee plant, won't thrive under the increased temperatures predicted by climate change. but these beans from 1873 could provide an answer. they were found in the collection at kew gardens here. not only are they more heat—resistant, but they make an excellent brew, with tones of honey and blackcurrant, apparently. it's just one example of many of how science, rather than taking us away from the natural world, is bringing us closer to solutions for some of humanity's greatest problems. millions of tonnes of sand were shifted to a stretch of coastline in north norfolk to see if a natural barrier could hold back rising sea levels. it seems to have worked. the homes and businesses are on the front line of rising sea levels. the sand barrier idea is cheaper than building a concrete seawall. this more natural solution could be used to protect more coastal communities. in a way that making space for water, so allowing natural processes to come back in places where we can do this, i think that's the attitude we need to have. and that we're not going to be able to keep building sea walls and defend, defend, defend. in 2021, nearly 60 acres of trees were cut down in northumberland — to reduce carbon emissions. it sounds strange, but it was done to save an ancient peat bog, which traps far more carbon than trees ever could. the building blocks of the peatland are the sphagnum mosses which themselves, like this one, are absolutely full of water. they're about 90% water. and that water is why bogs are better at slowing climate change than trees. when plants die in a bog, they don't release all their carbon into the atmosphere because they don't rot completely. which is why this... chainsaw whirrs ..is good for the environment. there's greater diversity among science students than ever before. but an analysis in march by the royal society showed that there was an unacceptably low number of black people among academic staff. 6.3% drop out of their postgraduate studies. that compares with 3.8% of white students. black people account forjust 1.7% of research staff in the uk, whereas they make up 3.5% of the population. and out of 22,745 professors in academia, 155 are black. we know something's happening within the university. it's that culture that can be quite toxic. it's due to racism — all the statistics show that it's not due to class, it's not due to what school they went to. and that environment and that culture is carried on all the way through the student life cycle and into careers as well. in an effort to attract more ethnic minorities, a series of projects were launched across england to encourage them to do phds and to support them throughout their research careers. there was a surprising discovery at canterbury cathedral. inside, its stunning windows depict symbolic religious scenes. this series was thought to have been made in the 13th century. but researchers discovered that some of the panels, including this one of the prophet nathan, were made much earlier. it's only come to light now because of this device, called a windolyser. it may not look like much, but it was developed by scientists to be used on location without damaging the glass. it shines a beam onto the surface, which causes material inside to radiate. this radiation contains a chemicalfingerprint from which the researchers worked out their age. we've been working on this detective story for some time, putting all the pieces in place, and then we finally get an answer, something new that brings together science and art into one story. it's fantastic. these are all stories that were recorded at the time they happened here. the discovery astonished leonie seliger, who looks after the stained glass windows here. she believes the redated panels could go back to the mid—1100s and were in place during the great historical events at the cathedral, including the assassination of the then—archbishop thomas becket, who features in many of the windows. they would have witnessed the murder of thomas becket. henry ii come on his knees begging for forgiveness. they would have witnessed the conflagration of the fire that devoured the cathedral in 1174. and then they would have witnessed all of british history. there's a lot more in store next year in science. the large hadron collider will restart at its highest power ever. the james webb telescope will send back its first data, which may include pictures of the first starlight in the universe. and europe and russia will send a rover to the martian surface to search for signs of life. but it's the earth we'll need to focus on. its changing climate means that the planet's fate hangs in the balance, but science can provide some of the solutions and give us hope for the future. hello, merry christmas. if you have plans today to get out for a boxing day walk, the weather looks really mixed out there. we have a bit of everything thrown into the forecast. some rain and sleet and hill snow around but it should ease later on. and there will be some sunshine for those lucky few across south—west england, wales and perhaps northern ireland. for the bulk of the uk, though, it is quite cloudy. we have a couple of weather fronts pushing northwards. as milder air pushes into that cold air that's still in place across the north—east of the uk, that's where we see that mix of rain, sleet and hill snow. there's been quite heavy snow for the pennines and the southern uplands as well. as we move into the afternoon, most of this snow in the north will tend to ease a little bit. but we will still see quite a lot of wet weather across parts of eastern england, some low cloud, some murkiness around, too. some brighter skies for parts of northern ireland and wales and the south west but still a few showers working in, and it will feel quite breezy, too — average winds around 14 mph in the east but we could see gusts of up to about 40 mph. it's not going to feel particularly warm — four or five degrees across scotland and northern england, particularly where you've got lying snow around into the afternoon. a bit milder towards the south and south—west. through this evening and overnight, we'll see some drier weather developing, but also some quite extensive mist and fog as well — quite a murky night for many of us. temperatures holding on into mid single figures for most places, but we'll see a touch of frost for parts of northern england and scotland under some clearer spells with lying snow around in places still. heading on into monday, the next area of low pressure arrives from the south—west bringing potentially wet and quite windy weather for the likes of the channel islands, south—west england into wales through the course of the morning. pushing slowly north and east, so much of wales and the southern half of england seeing blustery and wet weather. but further north for northern england, northern ireland and scotland, an improved day on monday with some sunshine coming through — six or seven in the north and 11 or 12 so, quite a contrast in temperature at the moment, but we have got very mild air working in through the course of this week across all of the uk, dragging in that breeze from the south—west. so, it looks fairly unsettled for the final week of 2021, but temperatures certainly very mild, 16 or 17 degrees through the middle of the week. an unsettled end, though, for 2021. bye— bye. it this is bbc news broadcasting in the uk and around the globe. i'm ben brown. our top stories: tributes are pouring in for archbisop desmond tutu — nobel laureate and veteran of south africa's struggle against apartheid — who has died at the age of 90. was extraordinary that you also knew that to his dying day he was constantly focused on jesus christ and that was where he got his sense of integrity and truth from. new coronavirus restrictions come into force in scotland, wales and northern ireland — as the uk's devolved nations try to limit the spread of the 0micron variant. with the two metre rule we have unfortunately lost about