As a girl, I walked along the shores of Lake Chad, one of the largest lakes in Africa. It went on forever, touching four countries: Chad, Niger, Cameroon and my own country, Nigeria. It seemed like an ocean to me at the time, with 30 million people relying on its bounty. Sadly, today, as you fly over Lake Chad, you won't see much. It's a fraction of its original size. Ninety percent of this fresh water basin has dried up, and with it, millions and millions of livelihoods, farmers, fisherfolk and our market women. Climate change takes yet another victim. Now, add another extreme weather event the Harmattan. What was once a short three-month season of dust and wind, one farmer told me the dust storms are coming earlier and bigger every year. A single storm can wipe out an entire year's crop overnight. The human and ecological cost? More jobs lost. Hunger. Families displaced. A perfect storm for crushing poverty. And even more, sadly, violence. And so it may be a challenge to grow food today in the Lake Chad basin, but it has also become a fertile ground for extremists to take root, wreaking havoc on peace. Sadly, touch down anywhere in the world, and you'll hear more tragic stories of climate devastation. Droughts. Floods, wildfires. Lives and livelihoods in jeopardy, tipping towards catastrophe. And yet, despite it all, I still have hope in our human family. And you might ask why. It's our capacity for human endeavor to survive against all odds. One that created the extraordinary promise of the UN Paris Agreement and its power to drive the 17 Sustainable Development Goals for people and for planet. We know that the promise of Paris aims to limit global heating to 1.5 degrees to ensure that we survive as a human family. To get there, we know exactly what we must do. We must decarbonise the global economy by 2050 by way of halving the emissions in this decade. We must make coal history, with coal phased out in rich countries by 2030 and in other countries by 2040. The G20 produces 80 percent of all greenhouse gas pollution, and so they too must, these 20 global leaders, take responsibility and lead. We must stop spending trillions subsidizing fossil fuels, clogging the lungs of our people and destroying forests and oceans. And we must provide the resources that are needed for a just green and blue transition. We know that these are all essential ingredients to fulfill the Paris Agreement. Now, try to re-imagine with me what this journey to net-zero emissions could look like through another lens. One that puts our focus on investing in people to reach their potentials while protecting our home, planet Earth. Decarbonization, a powerful vehicle for climate action but also for delivering on the 17 Sustainable Development Goals. Let me give you an example of what this looks like. The Great Green Wall, an idea born in Africa over a decade ago at the edge of the Sahara. It aims to stop desertification and restore 100 million hectares of degraded lands from Senegal in the West to Djibouti in the Horn of Africa. It's an ambitious plan to plant 100 million trees, improve water harvesting and the use of land. Clearly, the climate benefits will be enormous, but it's about much more than keeping dust in the desert. It's about creating a green economic corridor for more than half a billion people. Men, women, children. One that builds local value chains, strengthens economies and fosters a young, fast-growing workforce. And as an economic opportunity grows, hope for the future becomes a reality in millions of lives. And the space for terrorism, extremism, recedes. The Great Green Wall inspires me because it is a journey of the human potential. Potential to amplify the deep knowledge of indigenous people who survive and thrive in harmony with nature. Potential to harness technology, to connect and to bridge the renewable energy divide, especially for women and for girls. The potential to transform food systems in ways which make people and planet healthier. So what's holding us back? What will it take for this potential to become a shared, lived reality? It would be easy for me to say money. So let me say it. Money, more money. (Laughter) It's a big part of the solution. We need to make good now on the handshake that we had at Paris of 100 billion dollars. And that was promised annually. Rich countries, let me say here and now, we are looking at you for the unfinished business. You must step up, and you must do it urgently. The other ingredient we need is solidarity. Sometimes that seems to be in fairly short supply. But we do know it exists. After all, it's solidarity that forged the Paris Agreement. It's solidarity that got us the Montreal Protocol. And there you see that the ozone layer is saved and our world is healing. But we need to rekindle that spirit and we need to do that now. It's not too late, but the window of opportunity is closing. Which brings me back to you. You're the reason that I have hope. Time and time again, we've seen that when people raise their voices, that chorus becomes too urgent and too loud for leaders to ignore. That chorus for bold climate action is growing, but it's in fits and starts. Climate change doesn't pause, and neither must we. Now, last I checked, every single person in this room and all those watching online, teachers, presidents, shareholders, chief executives, scientists, employees, mums and dads, everyone on Earth is a citizen on this planet. So now's the time to stand up. With the courage of your convictions, raise your voices yet again and demand our leaders to take action on the promise of a 1.5 degree world. Friends, it's time to make some serious noise to transform our world. Right now, there's another young girl, maybe it's Kolu, maybe it's Aisha, maybe it's Fatima, walking on the shores of Lake Chad. She's looking out and wondering what her future may hold. Will it be an ocean of opportunity? It could be. Or will it be a wasteland of dust as far as the eyes can see? She's asking that question of all leaders who hold her future in their hands, and she's also asking it of all of us here today and around the world. The time for real action has come. The choice is ours. Individually, collectively. What will you do? Thank you. (Applause)