This is all just a part of a natural cycle, right?


– All this worry about
warming, when it’s just a natural cycle. Climate’s always changed, and
today’s no different, right? (bell dings) If we wanna understand
why the earth is warming, it just makes sense to start
by taking a closer look at all the natural
factors that have caused climate to change in the past. Are they to blame for the current warming, or did these natural suspects
have an alibi this time? Let’s start with the sun. We get nearly all our energy
from our nearest star, and we know that the sun’s
energy tends to fluctuate a bit over time, because
the sun is actually a variable star. When its energy goes up,
the earth gets a bit warmer. When the sun’s energy
goes down, the earth gets a bit cooler. What do we see then when we
track how the sun’s energy has changed over time? Observations show a
repeating 11-year cycle that’s correlated with sun
spots and solar activity. But observations also show
a small, long-term increase in the sun’s energy
through the last century, that is, until we hit the 1970s. Since then, the sun’s energy
has been going down, not up. So over the first part of
the 1900s, increasing energy from the sun did contribute
to some of the warming of the planet, though not much,
but over the last 40 years or more, the opposite has been happening. If the earth’s temperature
were controlled primarily by changes in the sun’s energy,
we would’ve been cooling, not warming. So the sun can’t be
causing us to warm now, it has a perfect alibi. What about volcanoes? Volcanoes can affect climate in two ways: first of all, when they
erupt, they can spew enormous amounts of soot and dust and ash into the atmosphere. If the volcano’s powerful
enough, that dust and ash can reach all the way
up into the stratosphere where the particles can
circle the globe for months and even years. But volcanic ash and dust
doesn’t warm the earth. Instead, it acts like a giant
umbrella, reflecting the sun’s energy back to space,
making the earth cooler. So clearly volcanic eruptions
can’t be responsible for the warming. What’s the second way that
volcanoes can affect climate? Well, in geologically
active areas like Sicily or Yellowstone National Park,
powerful heat-trapping gases like carbon dioxide and
methane can seep out from deep inside the earth’s crust. This can occur during volcanic eruptions, but the majority of it actually happens through what they call mud
volcanoes or mud domes. We know that these gases
are an important part of the earth’s natural
blanket that keeps us nearly 60 degrees Fahrenheit
or over 30 degrees Celsius warmer than we would be otherwise. So are the heat-trapping
gases that are seeping out of the ground in these
areas responsible for our current warming? Well, no. Turns out, regular
volcanoes, little mud domes and other geologic activity
produce around one percent of the carbon dioxide and
less than 15% of the methane that we humans produce every year. So while it’s true that
long-term geologic activity can warm the planet, its
contribution over the past hundred years is pretty much
minimal compared to how much of those same gases are
being produced by humans. So if it can’t be the
sun, it’s not volcanoes, what about natural cycles? Could they be causing our current warming? Natural cycles like El Nino
and other lesser known cycles like the Atlantic Multidecadal
Oscillation are all part of the variability that’s
built into the climate system. Because these cycles are
internal to the climate system, they can’t spontaneously generate heat. That would violate the
fundamental physical law of conservation of energy. Rather, these cycles affect
the earth’s temperature by redistributing heat around the world, usually by altering the
balance of heat stored in the atmosphere versus the ocean. During a La Nina episode, for example, more heat is transferred
from the atmosphere into the ocean so global
average temperature tends to dip a little below average. In contrast, during an El Nino year, more heat is relocated from the ocean into the atmosphere so global temperature tends to tick up, and El Nino
years like 2016 tend to be a little warmer than average. If natural cycles have been
causing the atmosphere to warm, they could only be doing
this by moving heat from the ocean into the atmosphere. Over the last century
then, if the heat content of the atmosphere has increased
due to natural cycles, then the heat content of the
ocean should have decreased to balance out the total
heat in the system. So is this happening? No, it isn’t. The heat content of both
the ocean and the atmosphere is going up. Not only that, but the increase
in the ocean heat content is 20 times greater than the
increase in the atmosphere and the land and the ice all put together. If the entire climate system
is warming, natural cycles inside the system can’t
be causing it to warm, because all they do is move heat around. So the warming must be
coming from somewhere else, and that leads us to our
last natural suspect: orbital cycles. Over time, the earth’s
orbit around the sun becomes more circular
and then more elliptical. The earth’s axes of
rotation also precesses just like a top when you spin it. These slow, periodic,
and most importantly, predictable changes affect how
sunlight falls on the earth, which in turn, affects
the earth’s temperature. We’ve known for almost a
hundred years that these orbital cycles are
responsible for the ice ages, and the warm periods in
between like the one we’re in right now. So it just makes sense to
ask: are we still coming out of the last ice age? Well, no. If we look at the earth’s
history, we see that warming after the last ice age peaked
about six to 8,000 years ago. Since then the earth’s
temperature has been very gradually, slowly
decreasing on a long slide into the next ice age. We can even calculate
where we are in these orbital cycles and when we
do, it explains what we see in the observations. The next thing on our
geologic calendar, some time in the next few thousand
years, was another ice age. Was, that is, until that long,
slow cooling trend stopped and then abruptly reversed
just about 200 years ago. The sun, volcanoes, and
natural cycles, they all have an alibi. Now it’s time to look for a new factor that might be causing the planet to warm, and it turns out that
scientists have known about such a factor for over 150 years. The heat-trapping gases we
produce whenever we burn coal or gas or oil, as well
as from deforestation, land use change and agriculture,
these gases are wrapping an extra blanket around our planet. This blanket is trapping heat
inside the climate system that would otherwise escape to space. That’s why we’re warming
for the first time in the history of the planet, it’s us. (bell dings) Thank you for watching “Global Weirding.” Be sure to check out
globalweirdingseries.com every other Wednesday for a new episode. Don’t forget to subscribe
to our YouTube page, like us on Facebook, and
follow me on Twitter. Have a question about climate change, we wanna hear it! We’ll have a live Q&A on our Facebook page every other Thursday at 7:00 P.M. Central. See you next time!

Comments 41

  • Always enjoy your videos Katharine. Good timing on this one.

  • Thanks for bringing back some sanity to my life.

  • thank you, now lets focus on social and then technical solutions!

  • I learn so much from Katharine Hayhoe and these graphics help with understanding . This is a perfect video to share with others of any age or education level. Thank you so much.

  • Especially important to make videos like this now. Thank you for shedding more light on the subject 🙂

  • U don't mention the amount of the suns energy change, it is 0.001% per 11 year cycle……….

  • Cow flatulence

  • Knowing all of the earths warming/cooling is something for a God. If you know it, explain why the climate models run hot.

  • Weird why some people make climate change so difficult, while in reality it's very simple!

  • One of the best of the series! Thanks! Keep up the good work.

  • I've only watched this one video, but this looks like a cool channel. You should cite sources so a "skeptic" viewer can't simply state what you're saying isn't true.

  • Considering our species has more than doubled in a mere 40 years……………..3.5 billion in the mid-70's, and we are quickly approaching 8 billion! Everything we purchase is produced from fossil fuel. Our food is encased in plastic, our gizmos are made of plastic & rare earth metals, we wear fossil fuel produced, synthetic clothing. The oceans currently have 6 lbs of plastic floating in them, for every ONE (1) POUND of ZOOPLANKTON!! Hell, we even place our plastic garbage in trash liners made of plastic! The bottom line is, it's ALL about selfish human convenience! We are the ONLY species which defecates where we eat.

  • Another outstanding cogent presentation. The evidence for human-induced climate change has, over the decades, expanded to the extent that an entire study could be made of the people who aren't persuaded — by reality.

    “It is difficult to get a man to understand something, when his salary depends on his not understanding it.” — Upton Sinclair

  • I see no practical point whatsoever in these types of videos if they are about getting agreement on burning less carbon because ~50% of humans appear to be coal/oil shills and they have absolutely no interest whatsoever (they have only the personal wealth interest that we all have). To everybody who isn't a coal/oil shill (apparently, ~50% of humans) this is all patently obvious anyway. Keep making the child-like videos anyway though because the quiet talking relaxes and energizes me in preparation for the daily grind of turning out reports that earns me a living. Thanks.

  • Here's an interesting little tidbit. It is virtually certain that the combined amount and rate of warming of Earth's ecosphere 1970-2450 A.D. (or whatever humans choose) will be entirely or almost unparalled in the last 3,800,000,000 years since the oceans formed and Earth became the water world it's been ever since. That's because there are only 2 things that could do it on this planet that could possibly have happened in the last 3,800,000,000 years, which are (1) ice thawing from the tropical ocean surface at the end of a Snowball Earth (2) injection of GHGs in Earth's atmosphere. Certainly, there's nothing matching this in the 500,000,000-year record, not even anything close to the +1.06 degrees that the global mean surface temperature (GMST) of the thin surface/air has increased over the last 130 years. The PETM at 56,030,000 years to 55,760,000 years ago had GMST increase +4 to +8 degrees over 35,000 years, likely caused by a large methane release. The deglacation warmings that take ~10,000 years for a GMST increase +5 to +6 degrees are the only ones that even come close to the vast warming of the ecosphere that started 50 years ago and will run for centuries. No person can produce any science for anything else that's a practical possibility that could cause such a warming at such a speed or that would even come close, because any other means is physically impossible (I'm making an invitation of course, give it your best shot). Interesting times are on the way.

  • Just because they happened in the past doesn't mean that it isn't caused by something different dipshits. We know exactly why it's happened but it just can't be proven because people rely on only the past not the fact a lot has changed since before the climate began to change… around the industrial revolutions :/

  • Allow me to mention some nitpicks about this video.

    In showing the Earth's orbit as elliptical, the Sun is put in the center of the ellipse. This is wrong. The Sun should be at one of the foci.

    Volcanoes can indeed warm the Earth in the short term. If there is a steady stream of volcanoes erupting then the Earth will be kept at a cool temperature. If there is a lull in the eruptions then the Earth will warm. Not that this is happening, but just ignoring the possibility doesn't make it go away.

  • LoL – I don't buy it. CO2 going to 400 ppm causing global warming? In years to come, when the Grand Solar Minimum kicks in, people will be looking for so-called climate scientists to lynch them

  • Oh what a wonderful presentation! Clear and concise. This video should be shown in every classroom in every school in the world.

  • Hey, I just found another really good you tube channel.  Better demonetize it.  This is the kind of confusing information we don't need.

  • Parabéns dra. Katharine!

  • How many edits for such 'simple' science?

  • Fun fact: Animal agriculture is producing more greenhouse gasses than the entire transportation system. You want to prevent our planet (and us) from destruction? Watch Cowspiracy.

  • ilove this video.. please mam put button for the transcript

  • Dont buy the antics, ok so the planet does warm up what's a consequence more evaporation what does that do produces more clouds what does that do well produces more precipitation what happens you get more growth for vegetation therefore more grass more trees grow temperate zones moveabout and next thing you get less reflection into space because there's more Greening so therefore you get a cooling effect so I would say that it would end up into a situation where the earth would control it own temperature, to try and say that man is going to make that much of a change in a huge planet that's been around possibly before mankind is silly. Scientists can't predicted weather let alone predict how a colourless odourless gas can keep heat in, ridiculous

  • Sure let's say you are correct man caused all of the warm we see today. Well how much has the temperature increase since the 1970s? From what I could find online the answer is about .2 degrees, which really isn't much. The second question would be is increasing temperature really a bad thing? Historically the climate has been much warmer and was associated with a more productive planet.

  • I LIKE CHICKEN!!!!!!!1

  • i like pizza

  • I'm glad you made this video, thanks 🙂 I do have one question though, you mentioned we've essentially reversed an oncoming ice age, if we are causing global warming isn't that a good thing? Or is it just inconvenient having to get billions of people to co-operate to survive such an event?

  • THANK YOU!!!! THANK YOU!!!! THANK YOU!!!! THANK YOU!!!! THANK YOU!!!!
    THANK YOU!!!! THANK YOU!!!! THANK YOU!!!! THANK YOU!!!! THANK YOU!!!!
    THANK YOU!!!! THANK YOU!!!! THANK YOU!!!! THANK YOU!!!! THANK YOU!!!!

    OMG, THANK YOU!!!!

    This was all clear to me after reading a great book back in 1991 (forgot the name) — and I was a ####-up back then!

    I just can't get enough "THANK YOU!!!"s out of me!!!

  • Thank you for creating these! Great for anyone who's not a climate scientist!

  • You ignored that NASA adjusted the data. Coolng the past and warming the present. You also ignored climategate and how to "hide the decline" because temperatures are declining regardless of NASA forgeries and propaganda. We are in for a grand solar minimum and further cooling. Do more research before making a video.

  • Natural cycles such as ENSO/El Nino are driven by lunisolar forcing, as described in the book Mathematical GeoEnergy.

  • Great. Can I have some solid prooflinks for all of this?

  • This is an amazing, if not the best summary of climate change

  • I love how global alarmists only go back 100 years. Research the Milankovitch cycles which go back 800,000 years.

  • This was a great video! It taught me a lot and will help with my school projects! 🙂

  • If CO2 is causing warming, then why has the temperature gone down through the holocene periode, when CO2 has gone up?

  • So we would all be sliding into the next ice age if it weren’t for the warming that started about 200 years ago? Is that what you’re saying? Ice age = everybody’s dead. Warming = more herbaceous plants to eat. I don’t get it.

  • Not a mention about the Milankovic cycles ?

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