of low pressure pushing in from the atlantic. it'll bring some rain, some of it heavy, across south—west england and wales, with rumbles of thunder into the midlands and the north of england as we go through the day. it should stay dry and warm for scotland, cooler and fresher behind. and that marks the change as we go into thursday. for the end of the week, it's cooler and showery, back to where we should be.

hello, this is bbc news. the headlines... sri lankan authorities blame a local islamist extremist group for the series of co—ordinated bomb attacks that killed 290 people, including eight britons. it's confirmed that british mother anita nicholson and her two children are among those killed. her husband ben paid tribute to his "perfect wife" and "wonderful children". dozens of firefighters are trying to control a moorland fire at marsden in west yorkshire. it's thought the blaze, which broke out last night and extends to over a square mile, was started by a barbecue. police say more than 1,000 people have been arrested after seven days of climate change protests.

now on bbc news, it's time for the easter edition of weather world. from the effect on plants and trees to bird migration patterns, nick miller and sarah keith—lucas look at how our changing climate is affecting life around us. this time on weather world, we are looking at the impact our warming world is having on the environment around us. i will be discovering the challenges facing migrating birds as the seasons follow increasingly unfamiliar patterns. and i'm investigating how our changing climate is affecting plants and trees. and finding out why saving seeds is the insurance policy covering whatever direction our future climate takes. i think people are much more aware now of the world around them and how things are changing and the need for places like this to actually keep these things for the future. also on weather world, the wildest

weather of the year so far — astonishing video featuring those caught up in it and those who only narrowly escape it. and how all of that pales in comparison to one of the deadliest tropical cyclones africa has ever seen. this is weather world. i have come to the rspb‘s pulborough brooks nature reserve in west sussex and it is an exciting time of year. the spring migrating birds are starting to arrive back but it is the timing of their arrival and the weather that they face that is really crucial to their prospects of success. this vast reserve, with a mixture of farm and wetland, covers more than 400 acres. it is home to native birds that

are here all year round, but in spring, many more birds arrive here to breed and it is those we are looking out for today. you feel like the birds are ready to get on the nests. julianne evans is the senior site manager here. the nature reserve here at pulborough brooks is very varied so why is it such an important site for nature and wildlife? pulborough brooks is an internationally important wetland. it has the highest legal protection you can get. it is a special area of conservation, it is a special protection area, and it is a site of special scientific interest. in terms of the migrating birds that are alljust starting to arrive at this time of year, how have you seen things changing over recent years? are there changes in the pattern and timing of migration? they are leaving based on day length from their wintering grounds and they are arriving back to the uk where the temperature has risen by probably about a quarter of a degree since 1960. and what that has done is then advance all the vegetation growth and all the insect abundance,

so they are arriving back at the same time, but they have kind of missed the boat in terms of food abundance. they will start nesting and then the peak in insect abundance will have changed and they will not be able to feed their chicks. so, looking ahead, what are the potential implications in the future for bird population numbers, for instance, with climate change and also habitat loss as well? well, if birds cannot adapt, and they don't evolve to arrive on that earlier date, then, potentially, obviously, that could cause significant declines in population. there is some evidence to suggest that they are evolving to arrive earlier. however, they are not evolving fast enough to keep up with the changes that are happening both in vegetation and insect abundance. so, in the end, what we might end up with is fewer specialists, so, fewer migrant birds, and more generalists. thanks, julianne. a little bit later in the programme, we will be back here at pulborough brooks taking a look at some specific examples of some

early arriving birds this spring. but first, we start our look at the wildest weather of the year so far in indonesia, injanuary. as this long house is swept away in flash floods on the island of sulawesi, many people have to be rescued, but dozens of people die here as the flooding continues into march. but it's in march the world bears witness to a weather disaster on a scale rarely seen. southern africa and flooding from cyclone idai indundates mozambique, zimbabwe and malawi. the united nations calls it one of the worst weather disasters ever to hit the southern hemisphere. in the immediate aftermath, a rescue effort finds people stranded on rooftops and clinging to trees, but the death toll rises rapidly, reaching over 700, and still people are dying as diseases such as cholera increase

across the affected areas. the track of idai gives clues as to why the flooding here was so bad. it was a double hit. the scale of the devastation here led many to ask about the role of climate change. in fact, the frequency of tropical cyclones in this area has decreased slightly in recent decades, but the evidence shows that more of those that do form are becoming stronger. now, to europe. this bridge on the greek island of crete has survived a lot of severe weather in its iii—year history, but the force of this flood in february was just too much. australia, in february, and it's supposed to rain in queensland during monsoon season, but the rains here this year are exceptional. the city of townsville is hardest hit, with prolonged rainfall shattering records going back

to the 19th century. flooding hits iran, too. dozens of people are killed in storms that last from march into april. the record rainfall follows a prolonged drought, and the floods strike with astonishing force. the scale of flooding here is thought to have been made worse by decades of deforestation. in the usa, tornado season gets off to a deadly start. this is alabama, in march, where the storms leave a path of destruction half a mile wide and a mile long. 23 people are killed here — that's more than double the number of people killed in tornadoes in the usa in the whole of last year. in the uk, in march, an amazing escape. one moment, you're strolling along the street, then this happens. strong winds cause part of a building to collapse, and one lucky pedestrian misses it by seconds. and here's something you don't see very often,

a tornado hitting a busy airport. antalya airport in turkey injanuary. some planes were damaged and some passengers injured as they waited to board. while sarah's away with the birds at pulborough, i'm down the road here at wakehurst and i'm looking at how the changing seasons are affecting our plants and trees, because there is a huge variety of them here across this 500—acre site. this national trust land is managed by royal botanic gardens kew and it's home to different habitats, allowing plants and tree species from around the world to thrive. what you see today has come a long way since the devastation wrought by the great storm of 1987, which destroyed more than 20,000 trees here. i'm with ed ikin, head of landscapes and horticulture here at wakehurst, and, ed, this is an exciting time. spring growth at last. there's a sense of energy across the landscape, you know? mild days, but more importantly, mild nights. everything is flowering in this incredible kind of concerted

display at the moment. in your time here, do you recognise earlier growing seasons, things coming up earlier than they used to? yeah, the key thing really is, do you have a concerted winter, you know, extended periods of frost that basically kind of sustains dormancy in plants? and if that isn't there, then spring can really start at any point from mid—february onwards. i know you've got some examples of that, maybe some winners and losers that we can take a look at. yeah, let's do that. 0k. ed, you've taken me deeper into the woods here to see this beech tree which, it's fair to say, has perhaps had happier times. yeah. so, you talked about winners and losers, wakehurst has a framework of native trees — beech, oak, pine — all of which are now under considerable stress. so, we talk about biotic and abiotic factors. abiotic, effectively, a more stressful environment. in the case of a beech tree, they don't like mild, very wet winters, very, very hot summers, you know?

a lot of temperatures over 30 degrees. it puts this tree under pressure. and then the biotic factors — the tree diseases — have an upper hand and start to put a really intolerable strain upon this tree. so, an example of something which is suffering, something which is arriving earlier than perhaps we'd normally expect? i know you've got an example of that, let's go and take a look at that. 0k, great. ed, wakehurst is a place actually famous for its bluebell displays. not necessarily as early as these have appeared. they're out about three weeks early and, again, a complete absence of frost since january has meant they have just grown and grown and grown and they're flowering. so, yeah, they're really quite early this year. so, they're pretty to look at, and that's a positive, but is there anything negative from their early appearance? yeah. so, in terms of sort of an ecosystem, it's like, well, who can react quickly? so, the bluebells have responded to an environmental sort of cue, if you like, but can everything else follow? all of the pollinating insects that sort of depend on bluebells for their nectar, can they respond quickly? and then the birds that perhaps depend on the grubs of those

insects, are they around hunting for those grubs at this time? if there's not a nice kind of regular dose of flower, pollen, insects, then things can get out of kilter quite fast and you almost have kind of hungry gaps, where there is no flowers or food available. a very good example of something linking back to the birds we were hearing about earlier in the programme. it's been fascinating to talk to you. thanks for showing us around wa kehurst. and we haven't finished here yet, we are back later on looking at a very special project to protect the future of plants and trees whatever the weather does. now, the earth's warming may be reaching new levels. the uk met office says the world is in the middle of what's likely to be the warmest ten years since records began in 1850, as rebecca morelle reports. a temperature rise of 1.5 celsius above preindustrial levels is set as a threshold by un scientists. anything more could lead to dangerous global impacts. have a look at this graph. the red area shows the predictions the met office has made over

the years and the black lines show the actual temperatures they recorded. there is a close match. the last four years were the hottest on record. this blue area is their forecast for the next five years. it suggests the warming trend will continue, with a small chance temperatures could temporarily exceed 1.5 degrees. the main driver for all this is the greenhouse gas emissions we are producing. we're still too reliant on fossil fuels like coal, and globally levels of carbon dioxide are at a record high. we've got to reduce our emissions of greenhouse gases. we've got to reduce the concentrations because, if we don't, we are looking at really big changes in the climate. we're going into territory that we have never been in before. we haven't experienced this, so we don't know precisely what is going to happen. now, some of your weather watcher pictures showing the early blooming flora and thriving fauna taken during the warmest winter the uk has ever recorded.

in late february, temperatures shattered previous records by soaring above 20 celsius for the first time in winter, peaking at 21.2 degrees in london. show us the weather where you are by becoming a bbc weather watcher. sign up online at bbc. co. uk/weatherwatchers. still to come on weather world... carbon capture — how rising sea levels caused by climate change could bring us unexpected benefits. and i'll be deep inside the vaults of a bank. there is no money here, but what there is could prove priceless for the natural world. this time on weather world, we're looking at our changing climate and the impact of the environment around us. i'm back at the pulborough brooks rspb nature reserve and i'm with julianne, the senior site manager here. now, julianne, you've taken me to a part of the reserve which is a perfect habitat for the chiffchaff. so, tell me about the chiffchaff.

is that one of the earliest birds that arrive back here on our shores? yes, it is, alongside blackcaps, another early arrival. and what's been happening over the years, chiffchaff have been starting to spend the winter here, which is a new development, and we think is a result of climate change. i'm sure they face a lot of challenges with our unpredictable british weather. if we get a harsh winter, it is not great for their numbers. definitely not, that would cause a decline, and other species are very sensitive to harsh weather. in terms of some recent studies and our understanding of bird migration, how has technology changed ? the step change in technology has been amazing and caused a massive increase in knowledge of migration routes, factors affecting birds on migration. it is possible to put geolocators on really quite small birds like nightingales and wood warblers. it is showing us that they are migrating through different routes,

how long they spend at different stopover sites and where they spend the winter. it is notjust to do with changing weather and climate here, but along their routes and in their wintering grounds. yes, climate change is an international problem, if birds are starting off and reaching what was formerly a stopover site which has been impacted by climate change, they cannot refuel and move on, so it might impact not just when they arrive but in what condition they arrive and therefore their breeding success. thank you so much, julianne. just as wildlife has to cope with temperature extremes, so do humans, with varying degrees of success. in a moment, extreme heat. but first, the bitterly, bitterly cold. january in the usa and the polar vortex is back. described as a once—in—a—generation blast of arctic air,

temperatures across parts of the usa and canada fall to record lows and it feels even colder in the wind, with wind chills of —50 celsius. it does not get much worse than here in chicago, the windy city becoming the wind—chill city. you can see frost on your eyelashes. what does it feel like? it is a little cold, they have frozen closed a couple of times. anything and everything is done to keep things moving — ships break up the ice on the river and train tracks are set on fire, not as crazy as it sounds, it is a built—in system of gas heaters used in extreme conditions to prevent tracks and junctions from freezing. is it going to come down here? yes. as winter turns into spring, the freeze—thaw pattern of the weather can lead to avalanches. colorado in march and one crashes

down a major highway, filmed by a father and son on a ski trip. thankfully, nobody was reported hurt. the austrian alps in march. there is an avalanche engulfing a group of skiers. amazingly, nobody is injured, but some skiers had to be rescued. january was europe's coldest month, with widespread heavy snow. some parts of austria measured more snow than on records going back over 90 years, leaving ski resorts and alpine villages cut off. that does not stop everyone trying to make it through seemingly insurmountable snowdrifts. the uk winter had its moments, including a snowstorm in cornwall at the end of january. a picturesque blanket of white, perhaps, but try telling that to the drivers of up to 100 vehicles stranded in freezing conditions. but at least this winter failed to deliver a repeat of the beast from the east which paralysed much

of the uk one year earlier. but for some people, winter holds no fear. this is moldovan athlete dmitri voloshin running 50km for charity at the coldest place in the northern hemisphere — the so—called pole of cold in siberia. the thermometer shows a wind—chill of over —60 celsius. he finished in six hours, a new record at such low temperatures. and from one extreme to the other. the australian summer shatters temperature records. it is the hottest summer here, with peaks of near 50 celsius. there are wildfires, too, including these which destroyed homes in victoria in march. the australian bureau of meteorology says the warming trend in the country is consistent with warming across the globe.

this looks like a summer fire, but this is winter in the uk after the record february heat and a long dry spell. this fire broke out on moorland in yorkshire. warmer spells of weather happening earlier in the year are expected to make fires like this more common. i am still at wakehurst, but i have come inside to a very special place, the millennium seed bank. it is where they collect billions of seeds from varieties across the world. it is a huge project. janet terry is the seed collections manager. why collect so many seeds? we are the world's largest seed bank for wild species and it is our insurance policy against what is happening in the world around us. what is happening? climate change, plants becoming extinct all the time, notjust from the natural climate, but the pressure from people, plants from places like islands

which are very vulnerable to rising sea level, alpine species which are very vulnerable to climate change, they can't go any higher, there's nowhere to go. and when the seeds arrive, it starts here? yes, this crate has come from namibia, one of our partners in africa. these bags contain samples of wild species they have sent to us for safekeeping. this room is at very low humidity. the seeds will dry slowly, so it does not damage them, and we can put them into our —20 cold store where they live for hundreds, possibly thousands of years. let's look at that final storage place. let's visit the world's biggest biodiversity hotspot. who could refuse an offer like that! we have come to the storage area and there is a reason why we have this look going on — the temperature is —20 celsius, why? it is the internationally recognised

standard for long—term storage of seed collections. you can hear the freezers really going at it. when you come in, you just think, "wow, there are so many seeds in so manyjars." you have been here long enough to know what some of them are. for security reasons, they are only labelled with computer reference numbers and the location within the room, but i can see that is an ash collection. ash is threatened in the uk with ash dieback, a really good reason. this is a species of acacia, probably from africa, extremely useful for livestock fodder, shade, timber, everything you can think of, some medicines. since the project began, have some of the reasons for it become even more prominent? definitely, i think people are more aware of the world around them and how things are changing

and the need for places like this to keep these things for the future. it has been an honour to see inside. thank you for showing us around, janet. it is a pleasure to show you. of course, to really know how our climate is changing, you have to measure it, which is what billy barr has been doing for nearly 50 winters, deep in the rocky mountains in colorado. every year, he measures the snow and has seen dramatic changes in the climate surrounding him. february used to be a very winter cold month and it's almost become mild. long—term, what i have learned, just simplified a bit, there is an obvious change in temperature. he knows this because for nearly half a century, he has kept a weather diary and it is a rich source of climate cataloguing for scientists. but could one result of climate change mitigate some of its effects?

rising sea levels are forecast to flood more land near our coasts, but wetlands suck in and store the atmospheric carbon that is warming the planet, as victoria gill reports. you can see plants starting to come back into the restored salt marsh, but when they die, rather than lying and decomposing, these layers of sediment essentially lock that material away in the mud, so the carbon in the plant material is stored in the layers of mud in this marsh. by drilling into the mud, these us scientists are taking part in a global effort to gather evidence of how much carbon—rich plant matter is locked into the layers. by comparing different wetlands around the world, they found that as sea levels rise and wash in more sediment on the tides, even more carbon is buried. they say future sea—level rise could cause marshes on the coast of australia, china and south america to lock away an additional 5 million tonnes

of carbon every year, equivalent to taking 1 million cars off the roads. the whole cycle of plant growth and carbon burial depends on the tides. solid sea walls and flood defences cut wetlands off and shut the system down, so conservationists are calling for the protection and regeneration of wetlands around the world to help fight climate change by ensuring that more carbon remains stuck in the mud. and finally, back to the usa winter and a wildlife rescue with a difference. in michigan, this bald eagle was weighed down by a block of ice which formed on its tail. it is captured, the ice is slowly melted and, after a spell of rehabilitation, a large crowd gathers to watch its happy release back into the wild.

and that's it for this time on weather world. so, it's goodbye from me and the birds at pulborough. and from me at wakehurst, home of the millennium seed bank. for highlights of our previous programmes, go to bbc.co.uk/weatherworld, and watch out for more weather world later in the year. and, for now, keep checking the forecast. good evening.

for most of us, it has been the perfect easter holiday, hasn't it, really? lots of blue sky and sunshine. yesterday was a little bit disappointing in the far north—west of scotland, not so on bank holiday monday, hardly a cloud in the sky. a few subtle differences though, a veil of high cloud arrived in the afternoon, it turned misty and murky as you can see across the south coast in falmouth. it was still dry and you were able to get on the beach. this high cloud will continue to spill its way steadily north and west overnight tonight and we run the risk of a few isolated showers across the channel isles into cornwall and maybe through south wales as well. so cloud and showers an issue overnight, that will prevent temperatures from falling too low. elsewhere we will see clearer skies, temperatures down perhaps 6—8 celsius. we start off tomorrow morning again on a dry, chilly note, a little more cloud and double digits in the south west, and that high cloud could be more of an issue tomorrow. again, a good deal of dry weather with a few isolated showers fading away in the south—west,

but with the sunshine turning increasingly hazy, a bit more of a breeze picking up. it won't be quite as warm. we will see temperatures perhaps peaking at around 22 degrees, always a risk of a bit cooler and fresher, particularly on exposed coasts. as we move out of tuesday into wednesday, that is when the real change is set to arrive, with this area of low pressure gathering out in the atlantic and this weather front will bring some rain into the south—west, to start off with. first thing on wednesday morning, there will be some heavy rain across cornwall, across parts of south wales and stretching up across that south coast. so as we go through the morning, that rain will continue to drift its way steadily northwards. we will see the potential for some thundery downpours across the midlands and into the north of england. it should stay dry throughout the day across parts of scotland. here temperatures peaking at around 18 degrees but a noticeable difference with the feel of the weather, particularly once that front goes through. it will clear and dry up but only highs of around 13—15 celsius.

and the wind direction will change, driving in this moist air off the atlantic and cooler air with it as well. so it stays showery for the end of the week and into the weekend and, more importantly, noticeably cooler for all.

hello, i'm ros atkins, this is 0utside source. sri lanka is in mourning after easter sunday's devastating bombings. the walls were full of blood spread everywhere. the whole church was blood. it is a bad situation. almost 300 people were killed. the government is blaming a small islamist group with international connections. volodymyr zelensk wins the ukraine election, in a landslide victory. the comedian is a political newcomer, but he has played and he has not given much detail about what he plans to do. and we'll hear from barbara, at the state department in washington, as the us threatens sanctions on any