字幕表 動画を再生する 英語字幕をプリント You've likely heard about the effects climate change is having on our planet and specifically in the Arctic which is warming twice as fast. But what would actually happen if all the ice melted on Earth. Bill: I can help with that! When you and I drink water We drink non-salty water, we drink fresh water Of all the water in the world most of it is salty, just 3% is not salty Now of that 3%, you can't get to most of that because 70% of that 3% is FROZEN - thirty million cubic kilometers of frozen water! It's so much frozen water, so much ice that if you put a layer of it a thousand meters thick, it would cover North America That's a lot of frozen water people! On land frozen water forms glaciers, icesheets, permafrost and snow but the Arctic is largely ocean so there it takes the form of floating sea ice like icebergs and because it's in direct contact with warming waters Sea ice will be the first to melt as global temperatures rise In fact this year NASA reported that the extent of Arctic sea ice was the lowest ever recorded for for January, February, April, May and June 2016 Bill: So the world is getting warmer and the ice is melting Pretty soon you'll be able to drive your ship from Europe to Russia, right over the North Pole, with no ice in the way. That's good for certain shipping companies maybe, but for the marine species: the polar bears, the walruses, the seals! They don't have their own habitats. They're all going away, they're melting out from under them. And ocean dwelling animals like bowhead whales and narwhals aren't immune to these changes either. As sea ice melts energy and oil companies are taking it as an opportunity to search further north for untapped resources using a process known as seismic blasting they shoot air explosions into the water in an effort to map the ocean floor and find oil. Of course, this has detrimental effects on the whole ecosystem of the Arctic ocean while also causing physical trauma and habitat relocation in whales. In terms of sea levels, melting sea ice won't have much of an effect. This is because the floating ice already displaces roughly the same amount of water as it would produce when it melts, so that effect would be negligible. Furthermore, of the majority of Earth's ice, more than 95% is land-based and contained mostly in enormous ice sheets that cover Greenland and Antartica where there are entire mountain ranges almost as big as the alps, completely buried in ice So, what if all the ice on land melts? Bill: If all this ice melts, the ocean's gonna have more water in it So the sea levels, as measured from the coasts, is gonna go up. It's gonna go up 70 meters. That's a long way people. Half the world's citizens live on sea coasts. That's where the, uh, commerce action is. So they're gonna have to move! Where are they gonna go? And... who's gonna pay for it? Tokyo, New York, Sao Paulo, Mumbai, Shanghai and Jakarta are all coastal and happen to be some of the world's biggest cities. Even a small sea level rise of only a couple feet could cause up to a trillion dollars worth of flood damage per year. A rise of 10 meters would displace more than 630 million people nearly 10% of the world's population. At 25 meters, 1.4 billion people, roughly 20% of humanity is left homeless and to visualise the full 70 meters, the rising seas would drown out most of the US Eastern seaboard, much of the West coast, the entire state of Florida, huge areas of Asia including Bangladesh and much of Northern China and create a new inland sea in Australia. At the North and South pole of the Earth we have a lot of ice. Ice is white. Ice reflects sunlight into space. But there's a feedback mechanism, one thing leading to another. As the world gets warmer the ice melts. As the ice melts it's reflecting less sunlight into space which lets the world get warmer still. The sunlight is absorbed by the dark , liquid ocean. So as the ice melts the world gets warmer. And the sea gets fresher. Currently the world's oceans are crisscrossed by a set of currents that act as a giant conveyer belt. And these currents are powered in part by the differences in the saltiness between one part of the ocean and another. So, if a melting ice sheet in Greenland dumps a whole bunch of non-salty, fresh water into the North Atlantic it's possible that it could disrupt the currents. Bill: So the conveyer belt takes chemicals, takes nutrients around the world, which feed plankton, which feed fish, which feed us. Half of the oxygen you breathe is made by plants in the ocean. So you don't wanna mess with this. Furthermore, as that sea surface gets warmer, off of Greenland, the Gulf Stream will probably shift a little bit, and if that shifts, what keeps Europe warm right now, May not keep Europe as warm. So the crops are gonna have to be grown elsewhere and who's gonna grow them and who's gonna ship them around and who's gonna feed each other and what's going on?! This is serious business! When you go melting the ice. We actually went up to the Arctic to see the current state of things first hand while documenting it all and were absolutely shocked by what we found. Click here to watch our documentary, The End of the Arctic, where we learn about an Inuit communities fight to defend their human rights against oil companies and the Canadian government all while trying to save the Arctic from the drastic effects of climate change and seismic blasting. You can help spread awareness by sharing the video and signing our petition to put pressure on the governement to prevent seismic blasting in the Arctic which would have detrimental, long-lasting effects on the wildlife and the Inuit people living in Northern Canada. Check out the links in the description and join the movement to stand up for the Arctic, and our Planet. And subscribe for more weekly science videos.
B1 中級 米 もしも地球上のすべての氷が溶けたとしたら?ビル・ナイ (What If All The Ice Melted On Earth? ft. Bill Nye) 12149 1225 韓澐 に公開 2021 年 01 月 14 日 シェア シェア 保存 報告 動画の中の単語