When I was a kid growing up in the Mediterranean, I was fascinated by the underwater world that Jacques Cousteau showed us on TV. When he started filming in the mid-1940s, the Mediterranean shores were still full of large fish. But when I went to the sea to swim in the '70s, I saw none of that. There were sea urchins on a barren bottom, but I never saw a large fish. The industrialization of fishing after the World War II put the latest nail in the coffin of Mediterranean marine life. I thought nature was lost. Until I started scuba diving in the Medes Islands marine reserve in Spain. One square kilometer fully protected from fishing and other damaging activities. I still remember that first dive in the reserve. As soon as I put my head underwater, I felt like diving into one of Cousteau's films. What was missing from the sea of my childhood was there. Groupers, sea bass, octopus, scorpion fish, seaweed forests. Just a few years of protection had allowed the sea to bounce back. I have seen this miracle happen in other areas across the ocean, like in Cabo Pulmo, Mexico, where local fishermen were so upset with not having enough fish to catch, that in the mid-'90s, they asked the Mexican government to create a no-take area. A national park in the sea. We surveyed the marine environment then, and the place was an underwater desert. When we returned a decade later, everything had changed. What had been a barren sea was now a kaleidoscope of life and color. We saw it come back to pristine in only 10 years, including the return of the large fish like groupers, jacks and sharks. And those visionary fishermen are better off now. From diving tourism inside the reserve and better fishing around it. But today, globally, only seven percent of the ocean and less than a fifth of our land have been protected. That means that we have converted most of our planet into a tame environment, where 96 percent of the mass of the mammals is us and our domesticated livestock. Only four percent is everything else, from pandas to tigers to elephants. And we have removed over 90 percent of the large fish in the ocean in the last century alone. On top of the loss of nature, we have global warming. The summer of 2021 has seen some of the hottest temperatures in human history, in places that one would expect to be cool, like Canada, Finland and Siberia. This extreme heat kills hundreds of thousands of people. It fuels raging wildfires, turning towns, forests and grasslands into ashes, also killing billions of individual animals and trees and many coral reefs around the world. No place is safe anymore unless we rewild our planet. If we are to prevent a global disaster, we need to do two things. As we know, we need to reduce emissions of greenhouse gases to almost zero. But we also need to draw down the excess carbon pollution in the atmosphere and in the ocean. How can we do that? To capture the excess of greenhouse gases, we need nature's help. Because trees, grasslands, peatlands, mangroves, kelp forests and healthy oceans are the best and most efficient technologies to remove carbon from the atmosphere, and they already exist. As long as we protect them, they do the removal for free. The more biodiversity there is, the more carbon pollution it can absorb, the more it can help stabilize the climate. And biodiversity also gives us clean air and water, food and protection from floods, storms and even wildfires. The problem is that nature cannot keep up with us. The biodiversity that is left today is not enough to absorb our impacts any longer. That's why in 2018, I put together a team of top scientists and economists to answer the question of which areas in the ocean we must protect first. And how much of the ocean do we need to protect? We decided to focus on three objectives: biodiversity, food and carbon storage to help mitigate climate change. If we think of each objective in isolation, there are tradeoffs. Protecting the top areas for biodiversity could result in a loss of fishing catch, for example. To solve that problem, we developed a new framework to optimize multiple benefits. Picking which areas to protect depends on how much we value the different objectives. We found that if we gave the same weight to each biodiversity, food and carbon, we would want to protect the right 45 percent of the ocean to maximize the three benefits. We also found that even if we didn't value biodiversity, the minimum amount of ocean we would protect would be 30 percent. So 30 percent of the ocean is the floor, the minimum area that we need to protect if we want to preserve marine life and all the benefits it provides for people. Similar analysis has been done for the land, also showing 30 percent as a minimum. Armed with this research, we at National Geographic partnered with the Wyss Campaign for Nature, and launched a campaign for "30 by 30," meaning at least 30 percent of the planet, land and sea, protected by 2030. Working with the governments of Costa Rica, France and the United Kingdom, we built the High Ambition Coalition for Nature and People, which now has 66 countries in it and growing, all supporting "30 by 30" as a main target for a global deal on nature. Thirty percent of our planet by 2030. Only that amount of wild nature, together with a massive reduction in carbon emissions, will be able to get us back on track. And of course, we need to manage our activities more responsibly everywhere else. "30 by 30" will involve a combination of strategies. From national parks and marine protected areas, to lands managed by Indigenous peoples and local communities, which have been effective in preventing habitat loss, often more effectively than conventional conservation methods. Expanding recognition of the land rights of Indigenous peoples is an effective and moral solution for protecting our world. And protecting the land can be done only together with the people living on it, like Canada is doing with its Indigenous, Protected and Conserved Areas. Some will say, however, that we cannot afford to protect our natural world. Well, let's look at the numbers. A study has put the cost of protecting 30 percent of the planet at about 140 billion dollars a year. That's only a fraction of the money that governments use to subsidize industries that pollute our air, waste our soil and empty our ocean. We need to reverse the flow of that money from funding the destruction of our life support system to preserving it. The solution to the problem we have created has been here all along. I understand that the idea of protecting a third of our land and ocean may feel threatening to those who see only the short-term profits of their destruction. But I am hopeful because I have seen with my own eyes how nature can recover in those marine reserves. And I have seen how the return of nature has helped people thrive and build a better life. We just need to give nature the space it needs so she can continue providing for us. Thank you.