When will the next ice age happen? – Lorraine Lisiecki

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Twenty thousand years ago, the Earth was a frigid landscape where
woolly mammoths roamed. Huge ice sheets,
several thousand meters thick, encased parts of North America,
Asia, and Europe. We commonly know it as the “Ice Age.” But geologists call it
the Last Glacial Maximum. That’s because it’s the most recent
time that ice reached such a huge extent, and “ice age” is an informal term
without a single agreed-upon definition. Over the last million years, there have actually been
about 10 different glacial maxima. Throughout Earth’s history,
climate has varied greatly. For hundreds of millions of years, the planet had no polar ice caps. Without this ice,
the sea level was 70 meters higher. At the other extreme,
about 700 million years ago, Earth became almost
entirely covered in ice during an event known
as “Snowball Earth.” So what causes these massive swings
in the planet’s climate? One of the main drivers
is atmospheric carbon dioxide, a greenhouse gas that traps heat. Natural processes, such as volcanism, chemical weathering of rocks, and the burial of organic matter, can cause huge changes in carbon dioxide
when they continue for millions of years. Over the past million years,
carbon dioxide has been relatively low, and repeated glacial maxima have been caused by cycles
in Earth’s movement around the sun. As Earth rotates, it wobbles on its axis
and its tilt changes, altering the amount of sunlight that
strikes different parts of its surface. These wobbles, combined
with the planet’s elliptical orbit, cause summer temperatures to vary depending on whether the summer solstice
happens when Earth is closer or farther from the sun. Approximately every 100,000 years, these factors align to create dramatically
colder conditions that last for millennia. Cool summers that aren’t warm enough
to melt the preceding winter’s snow allow ice to accumulate year after year. These ice sheets produce
additional cooling by reflecting more solar energy
back into space. Simultaneously, cooler conditions
transfer carbon dioxide from the atmosphere into the ocean, causing even more cooling
and glacier expansion. About 20,000 years ago, these trends reversed when changes
in Earth’s orbit increased summer sunshine over the giant ice sheets,
and they began to melt. The sea level rose 130 meters and carbon dioxide was released
from the ocean back into the atmosphere. By analyzing pollen and marine fossils, geologists can tell that temperatures
peaked about 6,000 years ago, before another shift in Earth’s orbit
caused renewed cooling. So what’s coming next? Based on the repeated natural cycle seen
in the climate record, we’d normally expect the Earth
to continue a trend of gradual cooling for the next few thousand years. However, this cooling abruptly
reversed about 150 years ago. Why? Carbon dioxide levels in the atmosphere
have been rising since the 19th century, when fossil fuel use increased. We know that from studying air bubbles
trapped in Antarctic ice. This surge in carbon dioxide
also coincides with a global temperature increase
of nearly one degree Celsius. Ice cores
and atmospheric monitoring stations show us that carbon dioxide levels
are rising faster, and to higher levels, than at any point
in the last 800,000 years. Computer models forecast another one to
four degrees Celsius of warming by 2100, depending on how much
additional fossil fuel we burn. What does that mean for the ice currently
on Greenland and Antarctica? Past climate changes suggest that even
a small warming shift can begin a process of ice melt
that continues for thousands of years. By the end of this century, ice melt is expected to raise
the sea level by 30 to 100 centimeters, enough to impact many coastal cities
and island nations. If a four-degree Celsius warming persisted
for several millennia, the sea level could rise
by as much as 10 meters. By studying past climates, scientists learn more about what drives
the shifts in ice that have shaped our planet
for millions of years. Research suggests that
by taking action now to reduce carbon dioxide
emissions quickly, we still have the opportunity to curb
ice loss and save our coastal communities.

100 COMMENTS

  1. We want to help students develop and share their big ideas with the world. Check out our student voice program and get involved: http://bit.ly/2KSa1vJ
    Maybe your big idea is the one the world is waiting for.

  2. LIE NUMBER ONE: CO2 doesn't cause warming, despite what the cartoon says. Every REAL scientist knows CO2 is a TRAILING indicator, not a LEADING indicator or cause. This video is false and misleading.

  3. Funny how they don't mention the medieval warm period 1,000 years ago was warmer than today. http://www.climatedepot.com/2017/08/22/new-study-multiple-lines-of-evidence-show-medieval-warm-period-was-warmer-than-today/

  4. Who ever did the animation of the earth rotating clockwise around the sun,northern hemisphere perspective, which direction is sunrise?

  5. If anyone want another video on this topic if you find this difficult, check this.
    https://youtu.be/I_qX35oZOx4
    Better for small kids. We need to educate our small kids also about this global threat,right?
    https://youtu.be/I_qX35oZOx4

  6. Along with spreading awareness it is better to evolve new ways of reducing carbon emissions as well as from atmosphere.
    Awareness as a single effort will never work

  7. Don't believe anything that is pushed by progressives. You're never too young to follow this 100% reliable rule of thumb!

  8. So that’s so good we reverted the cooling period that was coming!
    Congrats to man kind! Or else we all be starving and living in igloos!

  9. We are in an ice age, we are just on a peak of the Milankovich cycles atm. How can you be engaged in something like this without even mentioning this?

    https://www.google.com/imgres?imgurl=https%3A%2F%2Fqph.fs.quoracdn.net%2Fmain-qimg-3dc324a0a8db39ff8f9a13d517f9baa7&imgrefurl=https%3A%2F%2Fwww.quora.com%2FWhat-is-the-percentage-of-CO2-in-the-atmosphere&docid=bq8Emh6UN0ZC5M&tbnid=zeYlYZ5K6W2eoM%3A&vet=10ahUKEwjmsoDAkYDiAhWRY1AKHfulBQ0QMwiuAShgMGA..i&w=602&h=345&client=firefox-b-d&bih=1005&biw=1920&q=atmosphere%20history&ved=0ahUKEwjmsoDAkYDiAhWRY1AKHfulBQ0QMwiuAShgMGA&iact=mrc&uact=8

  10. Your topic argues against reducing carbon emissions. Earth's most Recent Ice Age lasted for over 103,000 YEARS.
    Burn Fossil Fuels Faster! https://en.wikipedia.org/wiki/Last_Glacial_Period
    Ice Ages are something best to be avoided.

    Of course you also do not want Planet Earth to over heat, but if the price of saving the main continents from being covered in massive sheets of Ice several kilometers thick is losing coastlines and island nations, then the main land continents should offer island nations and coastal cities the opportunity to relocate their entire population into suitable, safer locations deep inland at higher elevations.

    Snowball Earth is a no win situation for humans. Even with nuclear powered survival domes, it is unlikely humanity could survive Earth being completely froze for a 100,000 years or longer… https://youtu.be/P8q13Fqj6MA

  11. Probably know if global warming happens, but if it gets hotter then your runaway greenhouse gas affect.

  12. Given all that's said in this video, might a little, controlled global warming be considered partialy a good thing if it holds off the ice age?
    I'm not for it of course, I've seen Waterworld, but the ice age isn't good either.

  13. Great video, but it's still a common misconception that melting sea ice causes all of the sea level rise while in fact thermal expansion is an equal contributor.

  14. Why is it that instead of saying "affecting our wildlife and ecosystem" she says "coastal communities?" We need a population controller more powerful than the government without its biases and something that can monitor it without taking our freedom away. That would be nature. Also, if we keep focusing on humans, then we will see that all productions that are occurring need to be cut and stopped. We will not focus on nature but instead humans and what is in it for us in the moment so nature will take us out.

  15. why not say 90 millennia , rather than a few? For the last million years 90% of the time has been glaciation  10% warm period.This  is just brainwashing kids . Why not give the full story, it clearly shows there is no anthraprogrogenic   global warming

  16. Lmao we are much closer to extinction levels of Co2 then not…. We are in a warming period. technically we are still coming out of the last ice age and we should be warming not cooling. You're a tool and a fake scientist

  17. We definitely should not be in a cooling period….liar!!!!!!! We are still coming out of the last ice age!!! Learn plz or quit blatantly lying

  18. For the kids out there thinking we just need to plant more trees to lower CO2 levels? We would have to plant the land mass of 2 Earths full of trees to absorb the excess CO2 already in the atmosphere. So we have to rely on future tech eg carbon capture, CO2 Fuel or bioengineering plants to absorb more CO2 or FUSION ENERGY. So hit them books and learn all you can because today's technology just won't cut it!!

  19. 1:16
    And humans burning those buried fossils as fuel
    But the catch is that all 3 others take millions of years but humans can do such a dramatic thing in a thousand years or so 😢

  20. This is so cool, china actually released a movie kind of like the "second ice age" not too long ago, saying we had to steer our earth away from the solar system because the sun would explode

  21. The Earth Temperature RISES AND DROPS NORMALLY PEOPLE.
    It has done that ALL THE BLEEPIN TIME just like the video said.
    Here is the graph of temperatures going UP and DOWN:
    https://www.geocraft.com/WVFossils/Carboniferous_climate.html
    https://www.iceagenow.info/anyone-says-enduring-unprecedented-global-warming-lying-woefully-misinformed/
    https://www.cnsnews.com/news/article/barbara-hollingsworth/climate-scientist-who-got-it-right-predicts-20-more-years-global
    https://youtu.be/ICGal_8qI8c

  22. Grand Solar Minimum has begun. Watch out for weather that is colder than normal. Global warming has reached its peak and will turn to Global cooling. Grand Solar Minimum may bring new little ice age, which May leed to new ice age. Don't watch only the Global Warming theories, watch the Global Cooling theories too. Then compare with the weather changes around you! Sun has always and is presently, NOW, governing the weather and the climate changes. Does anyone seriously believe that man's influence on climate could EVER be stronger than the Sun's influences???

  23. As a science student i can say that yellow stone volcano is a major threat to the humanity,,,,,,,,,,,,,,

  24. Lame. Graphics were abstract when they couldve been literal and more educational. Clearly targeting college or high school aged kids with "cute" graphics. Dangerously oversimplified science with no references. Dont believe everything you see on the internet kids.

  25. We are in the middle of an ice age actually, called quaternary glaciation, and it didn't end 10k years ago as You said, but it's ongoing. What happened 10k years ago was the beginning of an interglacial period within the ice age (i.e. A period of warmer climate usually lasting 10k to 50k years within an ice age)…
    If the ice age actually finished 10k years ago the earth would be ice free and average temperatures would be closer to 20c…..

  26. The earth will never get better and we will never be able to save our planet unless goverments helps us they could put new world laws in place to try and lower the about of bad gasses and green house gasses in our atmosphere or put a ban to fosile power for good and just use sola energy.

    Go back to your childhood winter was cooler and summer was just right now look at summer you can tell it is hotter then when your were a kid and statistics show that we are getting colder winters and warmer summers

  27. By the time those children get to my age there will be 15 billion human beings on this Earth something you should think about

  28. School : pay me 1000 dollars and I will give your child all the basic information
    Ted Ed : here is a free video where you can learn almost everything with inter active learning and mind blowing animations

  29. 3:33 Computer calculations made by climate alarmists and people who believe in anthropogenic global warming
    4:40 and i see they are brainwashing children into little climatewarriors, hmmm… what could go wrong?!

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