president biden has announced his administration's first measures to limit gun violence in the united states after describing the situation as an international embarrassment. his executive orders include the tightening of regulations for guns that can't be traced by the authorities, because they're assembled at home. the uk and irish governments have condemned ongoing violence in northern ireland following the eighth night of unrest in belfast. police faced more assaults from, petrol—bombs, fireworks, and stones after protestors gathered on both sides of large gates separating loyalist and nationalist areas. the trial of the former minneapolis police officer derek chauvin has been told by a medical expert that george floyd floyd died from a lack of oxygen after officers held him down, in a vice hold, for more than nine minutes. mr chauvin denies a charge of murder.

now on bbc news — weather world. this time on weather world, spring is in the air here in the uk. after a winter which delivered something increasingly rare — proper cold. the uk records its lowest february temperature in over 60 years. and texas, colder than alaska, we look at the science behind winter's big freeze. also on weather world... oh, my goodness. washed away, the shift in global weather patterns that have turned parts of australia wetter and wetter. plus, carbon crisis — as levels of atmospheric carbon dioxide reach record post—industrial levels. it was only a matter of time. i'm not surprised. it's very sad, it's very. disappointing, but it's, you know, unless we do something about it, - it is inevitable. and from the skies to the stars — what the rest of the year has

in store for us astronomically. whether it's a solar eclipse or a shower of meteors, i will be letting you know when to look out for this year's celestial highlights. welcome to the latest weather world. our regular look at the stories and the science behind the weather that's been making the news. now, this time, nick and i are in london's regent's park where all around us, there are signs that spring is about to break forth. and it's all very welcome to see, but it comes after a northern hemisphere winter which has at times delivered some extreme, and what is nowadays extremely unusual, cold weather. not possible, not a chance. that's ridiculous. february, and more than 30cm of snow fell across parts of eastern england in the wake of storm darcy. the most significant snow here since 2018's infamous

beast from the east. in scotland, the highland village of braemar is the joint holder of the uk's lowest temperature ever recorded, —27.2 celsius. in february, it dropped to —23 here. not a record, but still the uk's lowest february temperature since 1955. spells of extreme cold like this are becoming less frequent. the uk met office says in the 30—year period up to 1990, 14 years recorded a temperature below —20 celsius. since 1990, it's only happened in four years. severe cold and heavy snow swept across the usa too, and it's hard to believe this is texas. this is no longerjust an emergency, it's clear that it is a disaster. at one stage, the entire state

was under a winter storm warning, and houston suffered its first—ever wind chill warning. dozens of people died, whilst power cuts and food shortages affected millions. i barely found bread, so everybody is getting stocked up. the shelves are getting empty. in all, around 20% of observing sites across the usa logged all—time record minimum temperatures. but even though the country had its coldest february in more than 30 years, the winter as a whole was still warmer than average. this outbreak of severe cold across parts of north america and europe is linked to a natural phenomenon first discovered in the 1950s — sudden stratospheric warming. up in the stratosphere, way above where our everyday weather happens, very cold air forms above the arctic during the winter months.

strong westerly winds develop as the temperature difference between the air here and the equator increases. this is the polar vortex. but sometimes this pattern can break down, the winds can slow, even become easterly, and the air here can warm very rapidly, and the effects of that can then move down through the atmosphere, eventually impacting our weather. what you tend to get is a disruption in the wind pattern in the stratosphere, which then filters downwards and can affect the jet stream, particularly in the mid—latitudes, and the wind directions here can become easterly. so often, we can get winds coming from siberia and the continent. so a famous example from two or three years ago is the beast from the east, as it was known, where very cold winds from siberia came across the continent, picked a bit of moisture off the north sea and created quite a heavy snowfall in the eastern side of the uk. dr hall says it's unclear whether sudden stratospheric warming events and their subsequent cold—weather outbreaks will become more or less frequent in the future due to climate change.

but extreme warmth in the arctic region last summer may have played a role in this latest example of it. there were fires in siberia, it was very, very warm in the sea ice was very low on that side of the arctic ocean. it took a long time to recover, so you had a warm anomaly over there. it is possible that that could be linked with the sudden stratospheric warming, although, you know, the analysis has yet to be done on that. as global warming heats the arctic more quickly than at the equator, that could be having an impact on the jet stream. it could, at times weaken, with some scientists saying it's more likely to wobble or meander, at times, taking cold air unusually far south, but further along its meandering path, take warm air unusually far north. as the usa froze, parts of europe had exceptional warmth, with several countries logging their highest february temperatures on record. but assessing how weather patterns that would naturally bring us spells of very cold weather are being affected by climate change is far from clear and still very much a work in progress. but no matter how hard the freeze, the thaw will come. that's something these skaters

will remember from now on. the dutch capital, amsterdam, in february, and after the ice broke beneath them, bystanders offer rope, even hockey sticks to help them to safety. many of us noticed during the coronavirus pandemic that with reduced traffic levels, the air became a bit clearer, with less pollution, and indeed, emissions of carbon dioxide, a key greenhouse gas, did drop. but c02 levels are still rising in the atmosphere, and so far this year, the mauna loa observatory in hawaii recorded daily levels of over 419ppm, which might not sound like a lot, but that is in fact the highest reading ever recorded. the uk met office suggests that average c02 levels are now

reaching 50% higher than they were before humans embarked on the industrial revolution. we have measurements of carbon dioxide from ice cores which go back 800,000 years. we have a record of how much c02 was in the atmosphere. we can see that we have more than 30% more carbon dioxide in the atmosphere nowadays than we have had at any time in the previous 800,000 years, which is nearly the entire human history. so we are well, well out of sync with the natural system. and the earth's extremes, the poles, are bearing the brunt of the global temperature rise that scientists say is largely due to increased concentrations of greenhouse gases in our atmosphere. we have satellite measurements that go back to 1979, and there is this very, very fast decline in the extent of the sea ice in the arctic. and even now in the antarctic, we are starting to see the effects.

we are seeing the west antarctic ice sheet areas thin where the ice is losing mass. it's actually being eroded from underneath by the warm ocean currents. so we are now seeing the effects of climate change basically in both polar regions. but of course, after that dip during the pandemic, carbon emissions are now rising again, as some of the hardest—hit parts of the world start to relax restrictions and open up again. and now more than a year in, what more do we know about how the virus may be affected by weather and climate? that's a question i put to dr rachel lowe from the london school of hygiene and tropical medicines. well, there have been some studies to suggest some modest associations between temperature and humidity and transmission. a lot of those studies didn't account for confounding factors such as government interventions and socioeconomic differences. and the consensus to date is that the transmission has been very much driven by government interventions and human behaviour,

and so we can't base any decisions about relaxing interventions on climate itself. dr lowe says the spread of the virus in warm humid weather in brazil is proof that these conditions aren't significantly hindering it, and weather factors can only become more important when there is better global vaccine coverage and immunity, and covid—19 could settle into a seasonal pattern. now, more of the weather that's been making news recently, starting with more snow. and this is spain injanuary as the capital, madrid, had its coldest weather in decades with record snowfall measuring more than 50cm. in february, unusually heavy snow hit greece too, blanketing some of athens' famous landmarks. temperatures in the northwest of the country fell to —19 c. in africa injanuary, flooding in mozambique�*s second—largest city, beira, hit by cyclone eloise, the second of three consecutive cyclones to impact the country in recent months.

elsewhere in east africa, swarms of locusts are back with fears above average rainfall in late 2020's rainy season has produced good breeding conditions for the insects once again. to the wind now, and the chinese capital, beijing, in march, covered in thick dust in what the weather bureau called the worst sandstorm in a decade, leading to a spike in air pollution with levels in some areas hitting 160 times the recommended limit. caught in a tornado — the terrifying moment these people drive into a storm in alabama in march. they escape 0k as parts of the usa are hit by several rounds of severe storms bringing significant damage and destruction. and could the most expensive gust of wind in history be responsible for this? a container ship blown off course and blocking the suez canal in march.

12% of global trade is supposed to pass through here every day. now to this stunning frozen view from highland scotland injanuary, which was chosen as the bbc weather watcher pic of the winter season. to mark the fifth anniversary of weather watchers, the bbc in the east midlands invited viewers to say what being a weather watcher means to them. i do like weather watchers because it's interesting to see other people's photographs. you wake up in the morning, open the curtains, i've got a camera beside the bed, you take a photograph, you go to the supermarket, you take a photograph on the way. you stop and capture the clouds, the sky. it gives you an excuse to sit down as well, . take it in. i mean, there's nothing like sitting down in-

the derbyshire peaksjust- looking out over the landscape. it's just really nice i to do, and relaxing. i mean, it's obviously- emphasis on the weather. the light particularly- in landscape photography is essential. a good landscape photographl nearly always has a really nice light. probably some good - clouds, maybe even rain. you think, the forecast is good, you know what you're to expect, you know where to go and you go for it. and when you've got that shot, you're just chuffed. and you can sign up to be a weather watcher by going to bbc. co. uk/weatherwatchers. yes, maybe your photo can be the next pic of the season. still to come on weather world... six years on from the historic paris climate accord, we look at what's next as the uk prepares to host a major international climate conference. 2020 was another hot year, with nasa ranking it as the joint hottest on record along with 2016. and the uk met office

calculating it as the second hottest. either way, all worrying enough in itself, but this heat came despite a global weather pattern that usually has a cooling influence. so what's going on? late 2020 saw the development of la nina in the tropical pacific ocean, a natural weather pattern with stronger easterly trade winds bringing cooler than average sea surface temperatures. the opposite to el nino, la nina can have a cooling effect across the globe, but it came too late this year to have much of an impact. since the start of this year, its effects have become much more noticeable, especially here in australia, where in march, water cascades off this historic landmark, uluru. a massive deluge gives what the australian weather service describes as "phenomenal amounts of rain". oh, my goodness. in new south wales, the owners of this property should have

been celebrating their wedding day. instead, they watched their home being washed away. even where they are used to floods at this time of year, they haven't seen things so bad. it's very shocking because i haven't seen it like this before. in 1990 was the last time i remember having a really big flood. we've had some where the bridges have gone under before, but not like this. la nina did what it normally does — bring cooler, wetter weather to eastern australia. a huge change from the last few hot summers here. last summer, when smoke j was blanketing entire cities like canberra and sydney, no one could breathe, - no one could do anything, but at least this summer. we had that oxygen. so we knew coming out of winter and going into spring _ that we were going to l have a la nina summer. we didn't know how strong iti would be, we didn't know how strong the impacts would be, but we knew that we would . have a wetter and coolerl summer, at least relative to the summers we've had over the last 9—10 years. _ but even though la nina is a natural cooling weather

pattern, dr perkins kirkpatrick says evidence of climate change�*s warming influence can be found in this too. la ninas we're now experiencing are actually a lot warmer - than they would've been without climate change. | and on top of that, mostl of the la ninas that we've experienced are warmer than the hot pattern - which is the el nino pattern, and that's the brother to lai nina. so, if we experienced la nina before the industrial- revolution, it would've beenl a lot colder and perhaps even a lot wetter than what we actually experienced - this summer. la nina means 2021 is not predicted to be a record hot year globally, but the uk met office still expects it to be the seventh year in succession where temperatures have exceeded or been close to one degree celsius above pre—industrial levels. weather world is now in its seventh year, and this is our 18th programme. and i can count onjust one hand how often we have been filming and it's dry, let alone sunny, so this really

is a collectors' item. what isn't so rare is how often we say on this programme, "a warmer world doesn't necessarily mean a drier one." january, and the uk endures another round of winter flooding. this time, parts of greater manchester and cheshire are hardest hit as storm christoph sweeps through. my living room floor literally looks like a water bed because the water's gone straight under it. i've had to turn off all the electricity, all the gas, everything. it was another wetter than average winter in the uk, and as the climate warms, our atmosphere is being loaded to produce higher rainfall amounts. scientists say for every one celsius of warming, the air can hold 7% more moisture. the fact that we're increasing moisture also means that moisture is moving more effectively from the regions where it's evaporating to the regions where it's coming down as rain or snow, so this movement of moisture is actually making the water cycle not only more intense, but also more variable.

in the drier regions, the atmosphere is almost becoming more thirsty, because it can hold more water, it's more greedy for that water and it's sucking it up more effectively, and moving that into a storm system, into monsoons, into the high latitudes where it can fall as heavy rain, so in some senses, the warming of climate because of increasing greenhouse gases, is causing very dry events to become more dry as well as making very wet events become more wet. last october, the uk had its wettest day ever recorded. the uk met office says such a deluge without human—induced climate change should happen once every 300 years but by the end of this century under a medium greenhouse gas emissions scenario, it could happen every 30 years. later this year, leaders from around the world will gather here in the uk

for the latest united nations climate change summit, cop26. having been postponed from last year due to the pandemic and with pressure growing to further cut carbon emissions to limit global warming, it promises to be the most important meeting since the paris climate accord was signed in 2015. speaks french cheering and applause that landmark deal brought a commitment to pursue efforts to limit the global temperature increase to 1.5 celsius above pre—industrial levels. since then, the usa under donald trump became the first nation to withdraw from that agreement. we don't want other leaders and other countries laughing at us any more. and they won't be. but now, with president biden in charge, the country has rejoined. and appointed one of its most senior politicians, john kerry, as its climate envoy. glasgow will be extremely important. in fact, i would say that in myjudgement,

it is the last best chance the world has to come together in order to do the things we need to do to avoid the worst consequences of the climate crisis. in the run—up to the glasgow conference in november, we've asked some delegates from around the world to give us their thoughts on what they want it to achieve. for us in the caribbean, climate change is an existential threat. what it does, it threatens the very survival of people within this region. we are hoping that cop26 will not only be a cop of climate ambition to reduce greenhouse gases, but it will be a cop with greater ambition where there is greater recognition that the current system of providing climate finance to developing countries, particularly in the caribbean, is not working. africa has only 4% of the world's emissions but 17% of the world's population.

so in some ways, africa is already net positive in relation to climate emissions, but i think you will see that african leaders will come with a more nuanced argument. they will emphasise that green recovery, that investing in renewable energy, investing in sustainable, investing in recognising the real value of natural capital, those elements are actually better for growth anyway than fossil fuels. mexico is one of five mega - diverse countries in the world. last year, the pandemic impacted the world. - in a single year, we were able to change a lot of things - that we never thought - to change in that short time. maybe we can, at this point, use that experience to really craft some policies| for climate change. pulling together everything on everyone�*s wish list to produce realistic achievable policy will be the glasgow conference's biggest challenge as the bbc�*s environment correspondent,

justin rowlatt told us. so as you can see, everyone coming to this conference in glasgow in november this year has a slightly different agenda. think of it like trying to get your family to agree to a programme of action. so the host, the uk government, has come up with a series of key priorities it wants from the conference — it would like every country in the world to make a commitment to going net zero by 2050. it wants to up the pace of carbon cuts and would like to see greenhouse gas emissions halved by 2030. it also wants countries to say how they are going to adapt to the consequences of climate change. and it wants richer countries to come up with £100 billion a year to help poorer countries adapt and make the transition to a lower—carbon economy. now, that's a lot of cash and it is an ambitious agenda, and just like with your family, it's very hard to get everyone to agree, but that is the challenge for this conference in glasgow

in november this year. now, lockdown during the pandemic has given some of us a renewed interest in the natural world around us, perhaps because we've had no choice but to spend more time in our garden or local park. and less pollution, clear skies permitting, has made it easierfor us to spot notable events in the night sky. now, last year's highlight was in december, the great conjunction, the closest jupiter and saturn have appeared in the night sky in 800 years. so we thought we'd have a look at what's coming up this year, and joining me is bbc weather presenter, elizabeth rizzini, who also provides forecasts for the bbc sky at night programme. lizzie, wow us with all things celestial in 2021. there are some really good conjunctions coming up this year. conjunctions, of course, vary year on year because everything is moving in space.

so it will always appear to look a little bit different. conjunction, of course, is when two or more celestial objects appear to be close together in the night sky. so look out for, on the morning of the sixth and seventh of aprilfor saturn and the thin crescent moon. if that's a bit too early for you, venus becomes an evening planet and we will see that in conjunction with mercury and, again, with the moon on the night of the 12th and 13th of may. what about an eclipse? everyone likes those, any of those coming up this year? well, we're due to see the biggest solar eclipse, actually in the uk, since 2015, the most spectacular. it will be a partial solar eclipse here, so the shadow of the moon won't completely cover the sun. towards parts of the arctic, it will be an annular solar eclipse, which means ring of fire, as the moon's disc won't completely cover the sun. meteor showers, what are the highlights with those this year? well, we see the same ones every year, but this year, three of them coincide

with the new moon. in october, the draconid and another in november, and most importantly, the very high meteor rate at around 160 metres per hour possible to spot in clear skies and stay away from the city lights, of course. fingers crossed for conditions like this, obviously, it will need to be dark, but clear, you know what i mean. lizzie, thank you. and finally, proving that it's notjust humans who get excited about snow — an acrobatic performance from a giant panda in washington, dc in february. next up, the olympics. that's all we have time for for this edition of weather world. you can watch clips from some of our previous programmes at bbc website. yes, you can watch when we went whiskey tasting in scotland. that was a good one. i'm sure there is a link to weather and climate in there somewhere. we're back later in the year, but until then, you can never get enough of pandas in the snow. so here are some more. see you next time.

goodbye! hello. although thursday was a little less claude for many, friday plunges us back into the arctic air. in fact, we will stay with the colder air again into the weekend for many. there is certainly a chance of those snow showers and possibly wet and windy weather in the south, we will come to that in a moment. this is the weather front ushering that cold air southwards and that will push to most parts by the end of the day today. with it the brisk wind which has reached severe gale

force in the north, slowly easing away, but cold air means widespread frost first thing and a risk of ice because here the showers have been coming through notjust for scotland but for northern ireland, some northern fringes of england and wales as well. that weather front south is a slow—moving affair. slow—moving although they ease off, the great risk of snow piling up as northern scotland but the showers will come through thick and fast during the day. they could fall as rain, sleet, snow, hail, rumbles of thunder. further south we will have a weather front coming slow—moving. could be sleety on high ground as the cold air digs in but we will see crisp sunshine across the northern half of the uk through the day ahead and brightness and sunshine to the south of the weather front affording us perhaps 11 or 12 degrees but if you are under the cloud all day, seven and eight is more likely. a transition day one that

feels wintry for many. the big question for the weekend is this area of cloud and rain, possible hill snow and a brisk and north—easterly wind during the course of saturday and into sunday. there is still quite a bit of uncertainty as to how far north that will come but as i say it could be a spell of wet weather. a brisk north—east wind makes it feel cold and that could turn to snow over the hills. further north again the crisp sunshine continues but even with the sunshine it will be cold with the risk of sleet and snow showers just about anywhere because we are into the arctic air. the same is true through saturday night and sunday that slowly works out of the way but that we have arctic air right across the uk and perhaps something more organised coming into the north—west later on sunday. plenty of detail to fill in and if you have plans stay tuned to the forecast. as ever, the forecast and the warnings are online.

this is bbc news. i'm lewis vaughanjones with the latest headlines for viewers in the uk and around the world. president biden outlines gun control measures as a first step towards curbing mass shootings in the united states. gun violence in this country is an epidemic. let me say it again — gun violence in this country is an epidemic and it's an international embarrassment. violence flares again in northern ireland for a sixth consecutive night a medical witness says george floyd died from a lack of oxygen after being pinned down by the former policeman derek chauvin — not drugs as the defence claimed. archaeologists unearth an ancient egyptian pompeii close to some of the world's best known monuments.