We’ve all been told that when the Arctic melts sea level rises. But that’s actually only half the story. And hardly anybody is talking about the other half. There are two types of Arctic ice: land ice and sea ice. When land ice melts, it runs into the ocean and causes sea levels to rise But when sea ice melts, the water essentially doesn’t rise at all. It’s already in the water. It’s accounted for. So then there’s no problem, right? Well actually, here’s something very frightening going on. Potentially something catastrophic. And it could affect the entire weather system as we know it. So let’s start at the beginning. Year-round in the Arctic, we have sea ice. In the winter, it’s a lot. But by the end of summer, it is much less. And that sea ice is always doing a job. When the Sun hits white Arctic sea ice it’s heat is reflected back into the atmosphere. That’s called the albedo effect and it’s one of the simplest things ice does to protect our planet. However when sea ice melts more dark ocean is exposed underneath. Now when the Sun hits that dark ocean the heat is absorbed, rather than reflected back to space. It’s the same reason why you feel hotter in the summer when you’re wearing dark clothes. Dark colors absorb the heat. Light colors reflect it. As the ocean gets hotter, it also creates a feedback loop where more sea ice melts and then more dark ocean absorbs even more heat. But it isn’t just the temperature that heats up the Arctic. Pollution from all over the world is mixing in the air and becoming a foul substance called black carbon. That black carbon is then traveling all around the Northern Hemisphere, Gradually being deposited across the Arctic. Because the black carbon is dark and it’s covering the snow and ice, the Albedo effect becomes much weaker. It helps explain why the Arctic is warming at twice the rate as the rest of the planet. Because Arctic sea ice is an important influence on something called the jet stream. Think of the jet stream as a current of fast-moving high altitude wind circulating around our planet. The jet stream is powered by the contrast between cold Arctic air in the north and warm tropical air in the south. The speed and direction of the jet stream help keep the cold air contained in the north and the warm air contained in the south. And by doing that, it creates our weather patterns which generally move from west to east across the country. But as the sea ice melts the Arctic becomes warmer, meaning that there’s less of a temperature difference between the tropics and then now warmer Arctic. And that makes the jet stream weaker and more wobbly. Now a wobbly jet stream allows warm air to make its way further north. And now that we have warm air further north. It makes the situation even worse because the jet stream winds further weaken, meaning that weather patterns can get stuck in place. So we may see heat waves more powerful and longer-lasting than ever before. It could even mean more erratic and slow-moving hurricanes. And, cold snaps and blizzards more likely to hover in one place, freezing one area for days or even weeks at a time. Not to mention that the warm air that is sucked up from the south goes right back into the Arctic making it melt even faster and creating an even more wobbly jet stream. And that could create a scenario so extreme that scientists cannot fully predict what would come next. As scientists, we can predict a lot, but I’m here to tell you right here, right now, that we have never gotten to this point before. We really have no idea what the global repercussions could be Arctic sea ice continues to melt at the current pace This is an existential crisis, the defining challenge of our time and we need to be doing everything, absolutely everything, in our power to stop it in its tracks.