this is bbc news, the headlines... russia's self—declared ceasefire in ukraine has come to an end. fighting continued in various locations throughout the 36—hour period. president volodymyr zelensky said moscow's offer of a christmas truce was deceitful. prime minister rishi sunak and the health secretary have been meeting leaders of nhs organisations and medical experts in downing street to try to tackle the ongoing challenges facing the health service in england. the new republican speaker of the us house of representatives, finally elected after 15 rounds of voting, says former president trump helped him get there. kevin mccarthy's repeated attempts to secure the job almost saw fellow republicans come to blows.

iran is facing international condemnation for hanging two more people said to have been involved in nationwide protests. the uk called their executions abhorrent. you are watching bbc news. now it's time for click. as cop27 winds up in egypt, this week we'll look at some of the latest tech that is trying to clean up our planet. we'll muster up a mass of moss that's mopping up the mess in the air. that's easy for you to say! we will find out if hydrogen can do the heavy lifting.

and check out our latest merch. if you don't like the band, don't worry, the logo comes back off. once again, the leaders of the world have been coming together in an effort to fight climate change. as cop27 comes to a close, campaigners are warning that key commitments aimed at securing the future of the planet are at risk. in the year since cop26 happened here in glasgow, there has been a lot of criticism that the event was all talk and not much action. change is not going to come from inside there, that is not leadership. this is leadership. these un climate summits bring together thousands of delegates from governments, science and pressure groups from around the world. the aim is to provide the support for all countries to be able to reduce their carbon emissions and deal with any issues that climate change will inevitably cause. the world is warming

because of emissions produced by burning fossilfuels, like oil, gas and coal. yet global temperatures are heading towards 1.5 celsius above pre—industrial levels, and if they go to 1.8 celsius, scientists warn that half the world's population could be exposed to life—threatening heat and humidity. climate scientists have warned that change needs to come from the top, from governments and companies. but science and innovation will play an important part. so, this week, we're going to look at some of the latest green ideas. and first off, take a deep breath. deep inhalation and exhale. if you live in the green, it's easy to forget what life is like in the grey. the air literally can smell sweeter, and it's definitely cleaner. the world health organization says air pollution poses a major threat to health and climate,

and it kills an estimated seven million people worldwide every year. now, we're not all going to move back to nature — but what if we could bring nature into the cities? just outside berlin, this company is trying to freshen up our urban air. this is a biofilter which is sucking air in through the bottom and pumping it back out through this wall of moss. to illustrate that, we've got a smoke machine from the local discotheque. and if i just show you... there you go. it's going in through the bottom and out through the moss. and what happens to the air as it comes back out through the moss is where the magic happens. moss eats pollution. it sticks to its tiny leaves. it's absorbed, digested, and then is turned into more moss. so, as fans draw dirty air in, the bad stuff is left

on the moss' leaves, leaving cleaner air to flow back out. the idea of using moss' natural filtering properties came to the founder after he went for a jog. so, i was in shanghai and i did a lot of exercise outdoors to get back in shape, so go out for runs. and after i think two or three months, i started to have difficulties breathing and that's when i thought maybe i caught the flu, maybe i caught the cold, and it kept on lasting until the point i really left china, left shanghai and went went back to germany. and only after i came back, i realised, "hey, there's definitely a connection to the air quality in china and my personal health." that's when it clicked and i realised i have to do something about the air quality in cities. for the past eight years, green city solutions have been growing moss up to 15 times faster than in nature.

each moss mat takes just under 12 weeks to grow. and i have to say, there's something very soothing about being in their greenhouse. do you just come in here and stroke the moss? when i'm stressed. cool about moss is that this plant doesn't have roots, so they can capture all nutrients through the walls, leaves or leaves' surface. so, you can imagine, like the normal plants, it takes the nutrients from the earth, but it's moss. it can capture everything. the second thing is, like, every plant, moss can absorb c02 because it needs for photosynthesis, for the energy. but the benefit is the density of the moss is pretty high, so we need this higher leaf—surface ratio to capture as much as possible. so, now we are going to take a sample. you? i can do it? for sure. let's tweeze some moss. got some. perfect. now we can have a look under the microscope.

there we go. and it's in the lab where we'll get to see moss�*s super power. the plant acts a lot like a human lung, whose high surface area can absorb a lot of the air in one go. and just like the lungs of a smoker, which end up getting blackened by tar, moss could act like the lungs of a city, eventually being covered in the stuff that we don't want to breathe. so, this is from our one active products. and the black — the black bits are the... exactly. this is the fine dust or particles from polluted air. and these are the green cells. and it means that the moss is still healthy because it's green. but they are pretty powerful. really good. moss fan. well, yeah — i am, somehow! as well as pulling pollutants out of the air, there's another advantage to these biofilters, too.

here's a piece of moss and here's a thermal—imaging camera, and you can see the temperature is about room temperature. but, look, when i point this at the air that's coming out of the moss, when you switch the ventilation on, look how much cooler it is. so, not only does this clean the air, it cools it too. and of course, pulling pollutants out of the atmosphere could help cool more than just your local surroundings. air pollution and climate change are also directly related. we have pollutants in air pollution — for instance, black carbon, which speed up the heating of the planet. and by binding those pollutants, we also help to decelerate climate change. you'll already see these biofilters in several cities around the world, although you might not have realised that you're sitting in front of a load of moss. and to make sure the moss is as effective and long—lived as possible, the health of each moss

mat can be monitored from hq. an algorithm can control the irrigation, depending on the individual conditions. so, in the future, i would envision that many buildings and the facades of the buildings would be covered in our solutions and, of course, you could also have motorways — large stretches. you could also use our moss filters to clean and cool the air and maybe even protect it from noise. moss on its own won't solve the climate crisis, but in amongst the talk of inventing greener technologies, it may be worth taking a lead from something that's been right under our feet the whole time. after all, nature has been regulating the environment much longer than we've been disrupting it. moss — who'd have thought it could be so useful? the lungs of a city! nature's natural filter. now, as companies try to reduce their carbon footprint and their impact on the climate, there are lots of different things that they could try.

you could change your manufacturing process, how you transport goods or even move factories, but all of these are big things to do, so you really need to know which is going to work best. how do you do it? answer — get yourself a digitaltwin! you make a virtual copy of your entire business and try stuff out in that first. alasdair keane's been to see the makers of dettol, who are trying to assess whether they can make their new products more sustainable or not. we use these kinds of products every day, from cleaning tabletops to personal hygiene and health. these brands are made by one company, called reckitt, and the industry to get them from factories to our homes is fast—moving and comes with a big impact on the planet. not huge, but important that we look at that carbon footprint and think how are we going to reduce it, decarbonise it? the product carbon footprint — that's everything from the raw materials all the way

through to people using products — has to come down by 50% by 2030. that's going to take longer process. that's where we have to think not just about our factories, but the ingredients that we use, the packaging that we use. to work out how they can meet targets, the company is turning to a digital replica of everything they do through a programme called risilience. so, this is it. this is the digital twin. this is risilience. this is risilience�*s version of different companies. we map them as a digital twin. we're looking at the data from a pretend company but the programme is bringing together lots of information, such as the miles that individual ingredients are shipped or how much energy each factory uses. it then runs lots of scenarios over the company to see how sustainable it is now and in the future. we've got a large team of analysts who compile a lot of data forecasts out into the future, looking at how policy's likely to change in different countries of the world and how taxes

are likely to change. the digital twin is also helping firms map the impact climate change is already having on their operations. so, this is an example of its factories in the united states and how they might be subjected to future patterns of hurricane risk. and look at how often it's going to get disrupted, the cost to the business of that particular thing. and then, a company can then start to make changes in the laboratories here. they can work on a new product, put it into the programme and find out if it will make a difference? exactly, yes. so, that's where we're heading next. safety goggles on, as i've been given rare access to the room where the next big thing in cleaning could be on the verge of discovery, and where they're also adjusting existing product lines. we changed one of the ingredients, so it now uses lactic acid, and that's plant—based and it has a lower carbon footprint. and so, we looked at what risilience was telling us about where carbon footprints and maybe carbon tax in the future will affect us and we thought, what are the ingredients

we can change? and by moving to lower carbon ingredients — things like lactic acid, which is developed from fermenting maize — we were able to reduce the carbon footprint and that means it's set up for the future — a low—carbon, low—water economy. reckitt aren't the only ones turning to this tech. there are estimates the market for digital twins could be worth billions of dollars over the next decade. but having all the data on sustainability is one thing. companies need to act on it. i think when a lot of people hear about big companies and sustainability, they probably roll their eyes because big companies are out to make money. what is the balance there between being more sustainable and still bringing pounds in? well, the key here is how we can decarbonise and still grow. so, if we can achieve our ambition to be net zero by 2040, we can grow as well, and that decouples those two — those two topics. it could be years before we know

if the decisions companies are making now will really help the planet. this tech is making that a little bit less of a gamble. that was alasdair. now it is time for a look at this week's tech news. google has agreed to pay $400 billion to settle a privacy case. ——google has agreed to pay $400 million to settle a privacy case. it had been accused by a0 american states of misleading users into believing location tracking was switched off. the search engine it says the claim was based on policies that changed years ago. uber says it expects people to keep using it even as their budgets get squeezed. the firm is branching out to let users book trains and buses in the app but it also told us that more drivers have joined them. potentially we can serve those needs of customers who decide no longer to have their own car but to use us instead and in tough economic times, to me, that make total sense.

food delivery firm deliveroo says it is quitting australia because of tough economic conditions. the country's government has been putting pressure on companies to improve gig workers' conditions. animal crossing's first e—cycling centre! intel has created a land on the game, animal crossing, to help educate us on how to recycle old tech. the firm says electronic waste is rising three times faster than the world's population. the steam train — first built in 180a, it made rail travel cheap and suddenly everything seemed much closer to home. industry rolled on, and by the 1960s electric and diesel trains had replaced steam. today, around the world, most high—speed trains