13 Misconceptions About Global Warming

[Applause] let's talk about the science of climate change don't you mean global warming how'd you get in here I'm the Internet I never left now why did you change the name global warming wasn't happening so you have to call it climate change well the overall average temperature of the planet is increasing so global warming is technically correct but that doesn't mean it's going to be warmer everywhere all the time and that leads to some confusion like on a cold winter's day you might say so much for global warming exactly so the term climate change indicates that the problem is more intense storms droughts and floods ocean acidification not just that the globe is warming but it's not what the globe's not warming since when 1995 that's not how you draw a trendline through data if the slope is nil the climates chill you know 13 of the 14 years occurred this century and the graph you're using is old it doesn't include satellite data if you take that into account the trend is obviously continuing upwards oh so now you say it's warming in the past scientists told us it was cooling why can't they just admit that they have no idea what's going on it's true in the 1970s there were some papers published predicting cooling but over that same time period there were six times as many papers predicting warming so scientists really haven't changed their tune well just judging by temperatures I say they're wrong the earth is cooling but you don't just have to go by the temperatures there are plenty of other signs that the globe is warming like sea levels are rising three millimeters a year that's an indication that the oceans are getting warmer and so expanding ice on Antarctica and Greenland is melting at unprecedented rates and Arctic sea ice continues to decline nah-uh Arctic sea ice increased 40% in the last two years that last little uptick that's what you focus on what about the general downward trend that could mean anything you know if the earth is warming the most likely source of the problem is the Sun the Sun is getting brighter did you ever think of that the Sun was getting brighter in the 1930s and it probably contributed to some warming then but since the 50s the Sun has been getting dimmer and temperatures continue to rise Oh see you automatically assume it's man-made co2 you know humans only emit a tiny fraction of the co2 released into the atmosphere every year that's true people emit about 30 Giga tons compared with 780 Giga tons from natural land and ocean processes so you admit it humans aren't the problem no before us the system was in balance with the land and oceans absorbing that same amount 780 Giga tons a year this balance kept carbon dioxide levels in the atmosphere between 180 and 280 parts per million for 800,000 years now it's at 400 parts per million and still rising but our small contribution couldn't have caused that well the amount of co2 in the atmosphere is increasing by about 15 Giga tons or 2 parts per million every year but how do you know that's man-made co2 because the isotope carbon 13 is less common in fossil fuels than it is naturally in the atmosphere and over time we're seeing the concentrations of carbon 13 are decreasing but volcanoes emit way more co2 than humans no they don't they emit about 0.25 Giga tons annually that's less than 1% as much as human ok well even if we are responsible for the rise in co2 it doesn't matter because water is by far the most potent greenhouse gas yes it is I win no you don't water in the atmosphere is increasing as well but that can't be due to human activity the only way for the atmosphere to hold more water vapor is if it gets warmer so hang on you're not saying yes it all comes back to co2 a doubling of co2 on its own would increase the temperature of the globe by about 1 degree Celsius but that warming means there'll be more water vapor in the atmosphere and ice will melt reducing the reflectivity of Earth's surface so it's a positive feedback loop which a bunch of different sources of evidence all indicate will lead to about a 3 degrees Celsius rise in temperature but if this is true why have all the predictions failed in actuality most of the predictions show remarkable agreement with observations but you're probably thinking of the model from 19 88 back when we thought climate sensitivity was higher if you rerun that model with three degrees of warming for every doubling of co2 the predictions match exactly the warming that we've observed but the earth has warmed and cooled in the past so who is releasing co2 back then aliens we understand that past changes in the climate were triggered at regular intervals by Milankovitch cycles that is the periodic oscillation of the earth's tilt precession of the tilt and stretching and squashing of Earth's elliptical orbit during every warming cycle co2 and temperature rise together ah but if you look closely at that graph you'll see that co2 lags behind the temperature rise so it can't be causing the warming the co2 doesn't cause the first warming the Milankovitch cycles changed the way the sunlight hits the earth and that causes a little bit of warming decreasing the solubility of co2 in the oceans so some of that co2 is released and that is a positive feedback loop which amplifies the warming in fact over 90% of the temperature increase happens after the co2 starts to rise let's say you're right and the co2 we're releasing is warming the planet what's so bad about that planet gets a little warmer big deal I'm not claiming it's gonna be some sort of crazy catastrophe but we are gonna get more intense storms more droughts and floods the oceans will become more acidic sea levels will rise and my point is it would be better for all species on this planet and probably cheaper for us if we just started reducing emissions now than if we wait and pay the consequences later no thanks why are you wearing sunglasses [Music] global warming this episode of veritasium was supported by audible.com a leading provider of audiobooks with over 150,000 titles in all areas of literature including fiction nonfiction and periodicals this week I wanted to recommend the book merchants of doubt' which is about scientists who have spread misinformation about certain topics like how cigarettes cause lung cancer or how CFCs caused the ozone hole or now how co2 is causing the planet to warm so if you want to find out more about that you can download this book by going to audible.com/veritasium or you can pick any other book of your choosing for a one-month free trial so I want to thank audible for supporting me and I want to thank you for watching

Channel: Veritasium

Views: 4,233,164

Rating: 4.7088227 out of 5

Keywords: veritasium, science, physics

Id: OWXoRSIxyIU

Length: 6min 50sec (410 seconds)

Published: Mon Sep 22 2014

Reddit Comments

[u/Xerozoza]

I'd like to add that potholer54's entire series of climate denial (and sensationalism) rebuttals are much more comprehensive and well-sourced. Everyone with doubts on climate change should check them out.

[u/Goatmo]

If I showed this video to be dad, he would still take the side of the YouTube comment guy.