it's threatening marine life these deep sea coral reefs are like a block of towers we're removing the bricks from the bottom of these ecosystems and putting human livelihoods in Peril by having more carbon dioxide in the water it's slowly killing the ocean but it's not climate change it's being dubbed climate changes evil twin ocean acidification the point at which we could have avoided the worst of this car crash I'm afraid is over so how serious is this threat bubbling below the surface it's a rush against time to stop this and what can be done to tackle it [Music] [Music] Vanessa O'Brien is an explorer who has been to space and the summit of Mount Everest in 2020 she set out to become the first woman to reach both the highest point on Earth and the deepest part of the ocean I was going to the most extreme environment on the planet in reuseful submersible the longer we're down the more likely things go wrong what motivates me personally to be part of something bigger than myself to contribute to wider knowledge more inspiring than one person after four hours Vanessa successfully reached the very bottom of the Pacific Ocean an area called the Challenger Deep nearly 11 000 meters below the surface part of her mission was to collect samples to allow scientists to do further research into a problem many people have never heard of but which Vanessa had read about ocean acidification I chose to give my water samples to the Natural History Museum because it was their article on ocean simplification that inspired me in 2020 scientists at London's Natural History Museum published a paper on the rising acidification of the ocean since the Industrial Revolution and the impact of this on marine life they studied shelled creatures collected from the Pacific Ocean in 1875 by a ship named HMS Challenger then the scientists compared these historical samples to Modern versions of the same organisms collected nearly 150 years later in the same area what we've seen is that some of these organisms their shells have been up to 76 thinner in the modern day than they were at the time of the Challenger so our conclusion was that the thing of these shelves over 150 years was an example of one of the products of ocean acidification so what exactly is ocean acidification and how worrying is it the best place to start is Washington state in the early 2000s when oyster farmers were mysteriously losing huge amounts of stock from their hatcheries over three quarters of our Oyster Bar we died it was a big big impact for us and the impact is being felt by the local economy that depends on their business this High rate of mortality at first was a mystery could it be pollution could it be climate change then scientists discovered the cause the changing chemistry of the ocean was preventing baby oysters from making shells it was the first time ocean acidification was identified as a threat to marine life Washington state where I live has the dubious distinction of being Ground Zero for ocean acidification ocean acidification has literally changed the chemistry of our oceans what's happening now is at a scale and at a speed which is just unprecedented and it means that we're living in the first ocean acidification experiment at this speed which is truly terrifying ocean acidification is alarming but it's not exactly what it sounds like acidity is measured by the pH scale in the middle is neutral seven anything lower is acidic anything higher is the opposite alkaline the ocean's pH level is around eight meaning it's actually alkaline not acidic since the Industrial Revolution the ocean's pH level has decreased from 8.2 to around 8.05 this drop may sound small but it has a vast reach it equates to an increase in acidity of around 40 percent shown on this map as a shift from Blue to Yellow and by the end of this Century the ocean is predicted to be a hundred and fifty percent more acidic Small Wonder scientists are concerned I have two children I would love for them to know about the oceans in their science and geography lessons but if we keep on going the way we're going with oceanification climate change then my fear is that they will end up having to learn about these things in history lessons so what's driving this there's a familiar culprit the carbon dioxide created by burning fossil fuels as the amount of CO2 in our atmosphere increases the ocean's pH level decreases this chemical change in the ocean makes life much harder for many marine animals carbon dioxide is such an important player in many of the key processes that just a small change in Ocean chemistry can have huge implications for the health of individual organisms and for whole ecosystems Dr Sebastian Henninger is a leading Global expert on ocean acidification and studies its impact on Coral across the world his research suggests ocean acidification is the prime suspect in the destruction of deep cold water Coral which is essential to the Marine ecosystem one of the main reasons they're important is that they support just a huge amount of biodiversity and without those there just would be less life in those areas and less life which then feeds up into the different food chains as well if the coral collapses homes for other animals are lost and ecosystems threatened to really see how complex the framework is here his forensic investigations suggest ocean acidification is the cause of a threatening condition called Coral porosis osteoporosis in humans is when we start getting more holes in our bones we call this Coral porosis because this is porosis or dissolution of the coral itself in California Coral porosis has caused these corals to collapse and crumble the disease first attacks the dead coral skeletons on which the living Coral is anchored these reefs are built up mostly dead coral skeleton with a live Coral continuously growing upwards a tower up to tens of meters high so these deep sea coral ecosystems are really cities of the deep they're supporting all sorts of other life if that dead part starts to dissolve then that whole ecosystem starts to collapse Sebastian says studying California's collapsed reefs could give clues about the fate of deep sea coral in other parts of the ocean we're very interested in looking at the Californian Coral systems because it is a window into our future another challenge for scientists is understanding how the threat of ocean acidification is combining with climate change if you can check the pH from these samples today so now at his lab in Scotland Sebastian is exposing deep sea coral to more acidified warmer Waters and decreased oxygen with results expected in Autumn 2023 we can put these Corals in these tanks and simulate future ocean conditions and by doing that we can see the time scales that we'll see the collapses of ecosystems as a whole with marine ecosystems they're going to come hotter they're going to become more sour as we increase the CO2 and they're going to become breathless as we decrease the oxygen which is available to marine life this threat to marine ecosystems also poses a threat to human livelihoods across the world from scallop fishermen in Peru to the indigenous people of Alaska who rely on salmon I've always been taught that when the tide is out the table is set Raven Cunningham is a sixth generation commercial fisherman who has noticed a worrying change we would go out and harvest shellfish we would be able to go get a five gallon bucket in a couple hours just the spring I went out for half the day and only got a quarter of a bucket Raven is an IAC chugak Alaska native the IAC indigenous Community have been living in southern Alaska for over 3 000 years the sea has always been Central to their way of life but more recently both have been severely threatened devastating environmental and economic effects of this spill going to be here for many years in 1989 the Exxon Valdez tanker spilled over 41 million liters of crude oil and the impact continues to be felt now ocean acidification is another less conspicuous but increasingly serious threat to Raven and her community my community is very dependent on the ocean not only for economic benefits but for subsistence everybody in our community subsists in one way or another the EAC depend on salmon especially much like the rest of Alaska where salmon accounts for more than a third of its Seafood industry worth over five billion dollars it's now feared ocean acidification is contributing to declines in both the numbers and size of salmon our Copper River King Salmon would come around 50 to 100 pounds now we're lucky if we catch 30 to 50 pound salmon ocean acidification could be one of the causes of this decline because it is killing the food source salmon rely on these small creatures called pteropods pteropods are the original poster child of ocean acidification their tiny planktonic snails that literally everybody loves to eat these protein-packed power bars are known as the potato chips of the sea found all over the world they're eaten by everything from salmon to seabirds so these tiny creatures can have a huge impact not just on ocean life but on the entire food chain we quite often call them sea butterflies because they kind of have this flying wing movement they're very beautiful creatures looks nice and healthy it's obviously very active it's moving around but not we can't keep the camera on it but now the shells of this vital species are dissolving in waters all over the world and with around 40 of the global population relying on Seafood as a significant source of protein there are concerns about the impact on the world's food supply chain you can see all around the edges here there's cracking and a great big hole here therapods are now being found around the oceans around different locations around the world in different states of this sort of dissolution and these are indicators that oceanification is happening out there in the real world so what can be done to tackle ocean acidification well the most effective answer is one you've probably heard many times before reduce our carbon dioxide emissions reduce reduce we need to stop putting carbon dioxide into the atmosphere reducing fossil fuel consumption Remains the single most important measure but there are other things which can help deal with the carbon dissolved in the ocean growing plants like seagrass or kelp under the water is one they are very effective at absorbing carbon seagrass captures carbon 35 times faster than tropical rainforests but there are clear limitations to really mitigate today's carbon dioxide emissions you'd have to carpet a fair portion of the world's oceans with seaweed Farms others such as this company in West London are putting their faith in technology we just came back from Hawaii where we've built the world's first ocean-sistered direct diet carbon capture plant that's capturing on 37 tons of CO2 per year at a levelized cost of 475 dollars per ton capturing carbon dioxide from the air is a well-established idea but hindal's technology is novel capturing it from the sea the company is targeting the ocean because it contains more carbon dioxide in the atmosphere we use the ocean as our intermediary in order to capture CO2 because the ocean has 150 times more CO2 in it by volume than the atmosphere does hindel has some fairly lofty Ambitions remember the ocean's pH levels from the 1870s when the ship HMS Challenger collected samples hindel is hoping to bring those levels back we are restoring the BH back to the level that it was pre-industrial Revolution we are going to restore life back to our oceans and the company says its system designed to sit inside a standard container is scalable it will need to be even once these containers are finalized to capture just one year's worth of global CO2 emissions at current rates would take around 36 million units from new technology to growing plants underwater these proposed measures to tackle ocean acidification are hampered By An Inconvenient Truth reducing the volume of carbon in the ocean will have limited impact without reducing the volume in the atmosphere you can't get away from the fact that like climate change ocean acidification is the result of carbon emissions and it's just one more reason to tackle what many regard as the world's most pressing problem the point at which we could have avoided the worst of this car crash I'm afraid is over we need to actually start applying the brakes the big question is how do we make this crash survivable one that we can walk away from look