that works like this. a frame made of recycled material becomes a platform for the seaweed to grow on. it sits just below the surface and sinks lower as the seaweed grows and gets heavier. a pump powered simply by the rise and fall of the ocean, brings the cold, nutrient-laden waters from below and disperses them over the seaweed in the upper warmer layer. the seaweed can be regularly harvested and used for a range of purposes. seaweed is good for food, animal feed, fertiliser, fibre and biofuel. there's so much we can do with seaweeds. so, we're cruising along in this very low-carbon vessel, following brian, who's swum down to get the seaweed

in one of his testing sites here. except he's gone, and he's been underwater for about two minutes and, um... brian! brian?! - brian: i found it. - you found it. - yeah. - alright, we'll come to you. the permaculture tests that brian and his team have conducted in the south pacific have seen marine life return, and the seaweed transform the quality of the water itself. brian: seaweeds actually draw down carbon dioxide from the ocean waters. and they restore the alkalinity of the ocean. that enables shellfish and other creatures to thrive. damon, i thought we'd try some seaweed salad today. oh.

well, the little bursts of gas are good. yeah. like little poppers. ok. that's actually pretty good. seaweed salad. so, what kind of... we're getting omega 3s in here. - what kind of... - oh, yeah. what's our source? epa, dha, antioxidants, phytonutrients, omega nutrients. damon: but this humble weed has one more heroic trait to offer. it could play a profound role in drawing down carbon. well, this is an example of brown seaweed. the fastest brown seaweeds will grow half a metre per day. hang on. half a metre a day? half a metre a day. and they'll grow over 50m long. is that one of the fastest growing plants in the world? it is the fastest-growing tree on the planet. wow. ok. so that's why the understanding of... ..that it's going to be pulling carbon out of the atmosphere very quickly, because it grows so fast. thousands of tonnes of carbon per square kilometre per year.

wow. ok. win! it's not a weed at all. it's food, it's habitat for fish, it gives back to the fish ecosystems, and we balance carbon. we measure the carbon export. the testing of large-scale marine permaculture is yet to be done. but the stakes couldn't be any higher for getting them underway. this is all about restoring the foundation of our civilisation, because with climate disruption, we'll deplete the soils, we'll deplete the oceans. there will be no civilisation left because any time you lose that foundation of food and the soils and the seas, you lose civilisation as well.

damon: so, velvet, because the warming will increase over the next two decades, and sea levels will continue to rise... ..some countries will need to adapt in new and creative ways. but if predictions of severe droughts are realised that see shortages of food, the potential for unprecedented numbers of refugees and civil unrest around the world... ..is enormous.

just imagine large-scale marine permaculture, helping to mitigate the severity of such a crisis. it could provide an alternative food source to the damaged land crops... ..that is rich in protein and other nutrients. kate: instead of having governments that are reacting to disaster, we need governments and communities and businesses that proactively set a new vision that prevents these disasters, that actually takes us off in a different direction. investment in marine permaculture around the world could generate countless jobs and help us reduce our meat consumption, while sequestering staggering amounts of carbon. imagine decommissioned oil rigs converted to house the workers and becoming exciting tourist destinations

for those keen to explore marine life. the seaweed could be particularly valuable in climate vulnerable areas like the bay of bengal, where it could provide food, fertiliser and biofuel. along the coast of africa, it could provide similar benefits, contributing to a thriving local economy. paul: with mechanisms, simple ones, you are in fact regenerating the oceans. you could feed 10 billion people with the protein from marine permaculture alone.

at this point of the trip, i felt for the first time like we genuinely have a chance at a better future... ..if we choose to take it. but before heading home, there was another subject to address. well, i wish they'd stop killing off animals and, well, forests and whatnot. that'd be cool. probably for people to acknowledge that, like, the factories we build and, like, they hurt nature sometimes. like, the things that we produce, it can, like, hurt the wildlife and it's not good. but people just ignore it right now.

i would like to see everyone using the three rs - reduce, reuse and recycle. many people know about it, but don't practice it today. kate: today's economy, right? it gets bigger faster and faster. so the economy is doubling in size nearly every 20 years. we take earth's materials, turn them into stuff we want, we use it for a while and then throw it away. yep. and that take, make, use, lose - it cuts against the living cycles of the planet, causing climate change, causing pollution. so we're kicking ourselves out of planetary balance. it is difficult to see the impacts of our individual resource use on the broader environment.

but our survival could depend on us making that connection. for greater than 99.9% of our evolution, human beings lived in this very intimate association with the natural world. the decisions we made on a daily basis as individuals within the context of communities, they were informed by this immediate feedback we got from the world around us. from the sun, from the water that was falling on us. and you fast forward to this little blip of time that we're in right now, and, you know, we're completely and totally alienated from nature. we've lost that connection. i've come to the town of oberlin in ohio, where john and his team have come up with a quite brilliant way to raise awareness of their community's resource use. the environmental dashboard

was really kind of built around the science and putting people and humans in connection with how they're using their natural resources. and so what this does is it gives a visual representation of the usage. and they put it into the schools and so it's really gotten a lot more into the community. and the teachers are utilising it in their lessons. i want you to pay close attention to the squirrel on the right side. and watch what happens. as it goes down, he gets sadder and sadder and starts to cry. teacher: why do you think the squirrel got happier or sadder? i noticed that too. well, probably because we're using a lot of electricity at that point. more than we regularly used. john: we did a controlled study where we have another school system very similar to oberlin's school systems in a different area of ohio. they've got the same curriculum as we do, but they don't have dashboard. we found as a result of exposure, if you ask them about electricity use, they start talking about emotions.

and when you compare students in our school with this other school, they also have more of a community response when they talk about what needs to be done about energy use. they use the word 'we'. and in the other school system, they use the word 'i'. so we've seen real change as a result of this technology in the school. damon: what is most exciting about this idea is that the dashboards could reconnect us to a range of resources... ..and influence our behaviour. sharon: it's a way to really engage the community in this discussion, regardless of what race, what education, economic level, in this discussion on sustainability and the environment. but awareness of our resource use is just one piece of a complicated puzzle.

another solution that could have a huge impact on our dilemma caught me completely off-guard. paul: probably our biggest surprise was educating girls and family planning. you combine these two together, the number one solution to reversing global warming is the empowerment of girls and women. damon: wow. damon: so, our daughter starts school next year and as an australian, i completely take for granted that she will get to complete her education. and what i'm just learning here is that there are 65 million girls around the world that don't get that opportunity. and there's a host of reasons for that. some are put to work to support families

or they're married off. but on average, those girls will have five or more children. woman: so we found that across the board, and this isn't just countries where there might be high rates of poverty. even wealthier countries, we know that when girls stay in school for longer and they have access to good reproductive health services, as well as decent work opportunities, that women will tend to delay having children until they're ready, and then they choose to have fewer children from then on. so, what this does as a collective, is it slows down the population growth rate, which means that there's less pressure and competition for access to a whole range of resources, whether it's food or water or land. their children tend to stay in school longer as well and, over time, they break that cycle of poverty. so it's a form of family planning, but it's not coercive. it's not control. it's just empowering girls to be who they want to be

and you have these incredible benefits. one child, one teacher, one book and one pen can change the world. (applause) (laughter, indistinct chatter) damon: so this could be a pleasant afternoon in a standard city of 2040. freed-up space has encouraged a range of new outdoor activities.

imagine, velvet, you and your cool group of friends have met for a picnic. although it is unlikely that princess elsa will still be part of your crew. my hope is that we are all using resources more wisely and some of the clever innovations that exist today... man: selfie! ..except for this drone phone that i did make up to obliterate selfie sticks... man: home! ..have been widely adopted. some materials are grown or made from organic matter. while other materials have been recycled or break down rapidly. and wouldn't it be terrific if we have not only implemented the smart ways to deal with the billions of coffee cups

we send to landfill each year... ..but each city of the world has followed the lead of stockholm, who collect their residents' food waste... ..extract the methane to power their local vehicles... ..and give the leftovers to farmers to use as a natural fertiliser for their soils. well played, sweden. well played. these behaviour changes in our resource use could be reflected on dashboards throughout our cities, where there used to be ads. even encouraging some healthy competition. but in this 2040, my greatest hope is that girls across the globe now have access to the same educational opportunities

as you and your friends. the cascading benefits of this could be greater than anything else i have discovered.

so, velvet, this was my story of a future i hope you get to experience. your story and the one that transpires may be completely different. but what i now understand is that not only are there so many people who want to take part in telling a new story... ..but we have everything we need right now to make it happen. helena: when you go beyond the dominant media discourse

and get closer to the ground, you will see, everywhere you look, incredible reasons for hope. over the next few years, you may notice less red meat for dinner... ..more trips to the compost bin... ..better search engines... ..and potentially a new dashboard in your classroom. if enough of us make these sorts of small changes, when combined, they will make a difference. big banks continue to take a hit as the public shifts its money away from organisations that support fossil fuels.

but of equal importance is strong leadership. wouldn't it be terrific if new leaders emerge who can navigate us to a better 2040? and just imagine if they used the doughnut framework to create the new story... ..coupled with more and more people finding a defining role within it. what we can do is see where you get lit up and maybe it's girls' education - "wow. i had no idea!" or it can be food or it can be farming or it could be energy, it could be housing, transport. i mean, there's so many areas where you actually probably do have influence where you are working, where you can affect change in a way that actually is demonstrable and meaningful to you and others.

and it just unleashes the power of innovation and imagination and creativity that's within all people. damon: my hope for you, darling, is that sometime in 2040 there's a day when the greenhouse gases in our atmosphere stop increasing and begin to come down. and the solutions that achieve this benefit a wide range of people. to celebrate, there are parties across the globe for you and your generation. the regeneration.

when i grow up, i want homeless people to have their own homes with their own money to buy their own food and have their own jobs. well, i'd like it to be human instinct to just look after the world and to care for the world. i would like to see everybody have equal rights and the same living opportunities. i just want the future to be good.

dadda! damon: so... ..what's your 2040? (inspirational music plays)