are many ways to tell the Earth’s temperature. One is by measuring
how warm the atmosphere is near the surface. Another is to track the
heat content of the world’s oceans. Still another is by taking
account of melting glaciers and comparing thaw lines with times in
the geological past.
satellite shot of
the last melting remnant of the Laurentide Ice sheet on August 30 of
2016. Want to see a time lapse of Barnes Ice Cap melt from 1984 to
a look at this GoogleEarth time lapse,
zoom in on Baffin Island, find the ice cap, and watch the edge lines
retreat. It’s a bit uncanny..)
the past 2.5 million years, the Laurentide Ice Sheet has swelled and
shrunken as cold ice ages were followed by warm interglacials. During
the height of each ice age, the glaciers of Laurentide expanded to
cover most of present day Canada and parts of the Northern United
States. And during warmer interglacials, the ice sheet retreated to
its final stronghold of the Barnes Ice Cap on Baffin Island.
decline of the Laurentide Ice Sheet during the end of the last ice
age to 1,000 years before present. Soon, this once great mass of ice
will be completely lost. Yet one more casualty of human fossil fuel
that happens, the Laurentide Ice Sheet will be gone. And
this will be the first time such a thing has happened in 2.5 million
study authors further note that even if fossil fuel burning were to
stop now, that the total loss of this ice would still occur. What
this means is that some parts of the Arctic are now likely as hot or
hotter than they were at any time in the last 2.5 million years.
the World Meteorological Organization noted so cogently this week, it
also means that we’re heading deeper and deeper into uncharted
territory when it comes to climate.