"In
the past, the cycle of ice ages and periods of warming were caused
mainly by shifts in the earth's orbit around the sun, but now, humans
seem to be driving these changes. Since the Industrial Revolution, our
burning of fossil fuels has ratcheted up the output of greenhouse gases
like carbon dioxide, which trap heat in the atmosphere. Temperatures are
climbing, and the ice is melting faster than ever......"
"At
the National Ice Core Lab, in Lakewood, Colorado, a giant freezer
stores over 45,000 feet of ice, drilled from 34 sites around the
cryosphere. Dating back hundreds of thousands of years, these ice cores
are time capsules that allow us to peer deep into the history of
ice......
is
interesting, 'cause it has a couple of things you can see, right away.
One is there are bubbles throughout here. These bubbles are little
packets of air. It's these bubbles we can take out and measure CO2 and methane and nitrous oxide. It's the only medium that really collects the atmosphere itself.
The
other thing you can see in here, quite clearly, is you can see the
layers, and the thickness is going to tell you how much snow fell that
year, so you get a couple of pieces of climate information and a dating
scale, just out of visually looking at this ice core."
"Most
importantly, scientists have identified a direct historical link
between increases in greenhouse gases, like carbon dioxide, and steep
rises in global temperatures.
At every peak, big rises in sea level
followed as Greenland's ice sheet shrank.
The
ice core records also reveal a particularly telling moment in
Greenland's history. Roughly 125,000 years ago, temperatures rose by
about seven degrees Fahrenheit; the entire southern portion of the ice
sheet melted, and global sea levels rose by over 10 feet.
It
was caused by a change in the earth's orbit around the sun, which
increased temperatures and released carbon dioxide from the oceans.
The
more recent ice core record shows the potential for a similar meltdown.
Right now, greenhouse gas levels in the atmosphere are even higher than
they were 125,000 years ago, higher than they've ever been in the last
half-million years. Temperatures are already following suit."
The best and best explanation is the burning of fossil fuels.
http://www.pbslearningmedia.org/resource/nvei.sci.earth.climate/ice-core-record-of-climate/
Worthy Videos About Climate Change and Global Warming
“4.6 Billion Years of Earth’s Climate History: The Role of CO2” (24 min.):
https://youtu.be/ujkcTZZlikg
For more, search “Richard Alley”.
http://www.pbslearningmedia.org/resource/nvei.sci.earth.climate/ice-core-record-of-climate/
Worthy Videos About Climate Change and Global Warming
“4.6 Billion Years of Earth’s Climate History: The Role of CO2” (24 min.):
https://youtu.be/ujkcTZZlikg
For more, search “Richard Alley”.
