Climate101: Sea Level Rise

CLIMATE 101: WHAT IS SEA-LEVEL RISE? THE BASICS Absolute sea-level rise is the increase in the average sea level across the globe. And it’s a fact: Around the Earth, oceans are climbing higher and higher up our coasts and it’s happening faster and faster So what’s to blame? As humans burn more and more fossil fuels, Earth’s climate is changing and the world is getting warmer. The result: glaciers and icebergs are melting. Oceans are expanding – and our seas are rising. QUICK FACTS • According to NASA’s satellites and buoy data, seas around the world have risen an average of nearly 3 inches (7.6 cm) since 1992, with some locations rising more than 9 inches (22.9 cm). • The longer it takes us to reduce emissions, the higher our seas will become. Scientists at NASA say what we can expect depends on how quickly we cut emissions. • Researchers at Cornell University estimate that by the year 2100, 2 billion people – about one-fifth of the world’s population – could become climate refugees due to rising ocean levels WHAT’S CAUSING SEAS TO RISE? The short answer? Sea-level rise is driven by climate change. Ever heard of the greenhouse effect? When humans burn fossil fuels for energy, we release carbon dioxide (CO ) and other greenhouse gases into the 2 atmosphere. These gases act like a blanket (or a greenhouse) of sorts over our atmosphere, absorbing heat radiation from the sun and preventing a significant amount of it from escaping into space. Burning fossil fuels means we’re putting more greenhouse gases into the atmosphere and trapping more heat than the Earth can safely handle. Which means the Earth (including its atmosphere, surface, and seas) is getting warmer. Learn more at climaterealityproject.org Last updated August 2018

HOW IS ADDED HEAT IS CONTRIBUTING TO SEA-LEVEL RISE? 1. MELTING GLACIERS AND ICE SHEETS AT THE POLES It’s simple physics: heat melts ice. When air and ocean temperatures rise, glaciers and ice sheets melt. The melted ice becomes water that flows into the ocean, either directly or running over land first. All that extra water then causes sea levels to rise. 2. THERMAL EXPANSION Water expands as it warms. Imagine a pot of water heating on the stove. The volume of that water in the pot expands as it heats up. Now imagine the entire ocean doing that. Scientists estimate that