Subtitles section Play video Print subtitles What if a dramatic surge of climate change melted all the Earth's ice overnight? Would you wake up to find yourself drowning under water? Would most of your country be submerged? How would you enjoy slowly choking to death? This is WHAT IF, and here's what would happen if all the world's ice melted. Ever watched an ice cube melt in a glass of water that's filled to the brim? How does it change the water level? The truth is, it doesn't. Above or below the water line, a melted ice cube replaces exactly the same volume of water. Now let's add salt to the mix. In the case of a 1-cubic-inch ice cube, the water level in the glass will rise by 0.03 cubic inches. That rise is displaced salt water. It's an increase in volume of nearly 3%. Fairly small amount, isn't it? But what if you apply this to glaciers and floating sea ice? 5.8 million square miles of our planet is covered with ice. If all of it were to melt overnight, the global sea level would rise approximately 230 feet. That's enough to cover London's Tower Bridge. All seven continents would be partially underwater. There would be no Miami and no London. The coast of Australia would be washed out, together with 80% of its residents. So would Venice and the Netherlands. Things wouldn't be that bad for Africa. But with the extreme heat waves that followed, most of the continent would be uninhabitable. Think floods would wash out humanity entirely? Well, not all of it. But whoever is left will have plenty of dangers to deal with. All that melted ice would release carbon dioxide into the air. Ice needs high CO2 concentrations to melt in the first place. Given that oxygen content in the atmosphere would remain the same, you would slowly start to choke from breathing the air. You'd have very little time to acclimatize to the new world. Ocean currents would change their direction, affecting sea life. With no time to evolve to such extreme changes, sea creatures and polar animals would face massive extinction. The ones still alive would have to leave their homes and find a better place to live. This would result in a decrease of human food supply. A change in sea current would also mean dramatic weather changes. Heavy rains would hit the desert, and areas with a significant rainfall would dry out. This would devastate agriculture and cause a global famine. Wind patterns would change, too. With no ice to reflect the sun's rays, the sun would draw more moisture from the oceans, making more clouds in the sky. The clouds would gather first near the mountain areas, and eventually rainfall would flood them. Oceanic hurricanes would occur more often, causing even more floods. Even the smallest earthquake off the coast could devastate nearby regions with a massive tsunami. All of this would force a global migration that governments would not be able to deal with. The world as we know it would collapse. Luckily, all the ice can't melt overnight. But it is melting. Even the oldest ice core that has been storing information about Earth's climate for 1.5 million years. If we keep adding fuel to the climate change fire, in 5,000 years, the Earth will be ice-free.