 Ocean acidification, known as climate change's evil twin, is a huge time bomb waiting to explode and we still don't know enough about it. These IAEA scientists and their colleagues around the world are working to change that. This acidification has negative effects on a lot of the life in the ocean including shellfish and corals and a lot of fish that we like to eat so aquaculture and fisheries are greatly affected. The ocean absorbs a quarter of all CO2 emissions. This helps mitigate climate change but it also means paying a heavy price. When the carbon dioxide is dissolved in the water there's a chemical reaction that causes the ocean to become more acidic slowly and as we add more and more carbon into the atmosphere the water is getting slowly more and more acidic. The resulting acidification is threatening fragile marine life. Calcifying organisms such as oysters, crabs, sea urchins, lobsters and corals struggle to form their shells and skeletons and studies show that some of these organisms start dissolving in an increasingly acidic marine environment. The organisms in the ocean that will be impacted will be impacted in terms of things like increased mortality, their sizes might change, their ability to deal with threats and predation might be impacted as well. It is not just marine life that is impacted. Over three billion people depend on the ocean for their livelihoods. Ocean acidification is of course a phenomenon that is much harder to portray, harder to see. Yet it is now a reality whose economic consequences are directly perceptible and whose effects could be devastating in the long term for many sectors starting with farming and harvesting of many shellfish and crustaceans already severely impacted. According to the latest report of the UN's intergovernmental panel on climate change scientists predict that by 2100 the ocean could become 150 percent more acidic and affect half of all marine life. There are many challenges to addressing ocean acidification and one of the big ones is that it's a global issue. Our oceans are completely all over the planet and because of different influences from rivers and the ocean chemistry varies a lot regionally that if you measure ocean acidification in one place you can't understand ocean acidification for the whole globe which is why it's really important to have a global monitoring presence throughout the world for ocean acidification. This is why the IAEA runs a center to drive global ocean acidification activities following increasing concern from member states about the issue. At IAEA the ocean acidification international coordination center really focuses on the science of ocean acidification as well as communicating the dangers of this issue and building capacity and really vulnerable developing regions of the world and this is really crucial so that they can understand the chemistry conditions in their waters and then make projections about how this chemistry is changing and how it will impact the industries and seafood species that they really care about. Monitoring is essential to understand the extent of the problem but is there anything that can be done concretely to combat ocean acidification? It's very simple and very difficult to achieve at the same time. The simple solution is avoid emissions and decrease energy consumption. There is no quick fix. Alongside global momentum towards the need to reduce carbon emissions the studies being done in Monaco and at labs around the world are also examining potential solutions to the issue. One of these is alkalinity enrichment to counterbalance acidification. Nuclear science allows researchers to trace key elements like calcium and learn more about coral growth. One possible outcome of this research is finding small-scale solutions to reduce acidification in key shellfish growing regions. Ocean alkalinity enhancement directly adds alkalinity to the seawater in local regions and this combats the acidity locally so this can be a really effective way to improve shellfish aquaculture or coral reef restoration projects. But even more importantly such research gives policymakers the data and insight they need to drive forward climate policy and actions before it is too late.