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Since
government leaders and environment ministers first met in Kyoto, Japan, in December 1997 to
formulate an agreement to reduce global-warming emissions, the
extraction and combustion of fossil fuels has gone unabated as the
worldwide demands of the capitalist growth economy have risen. As a
result, greenhouse gases belch out at ever-increasing rates from both
developed and developing nations, causing atmospheric carbon dioxide
levels to spike every year. They have gone into deadly overshoot by
having exceeded 350 ppm CO2 and now stand at
390 ppm.
Consequently,
global temperatures continue to rise. The 12 hottest years on record
were from 1995 to 2007—the latter tying with 1998 as the hottest.
Growing
evidence indicates that the pace of climate change is speeding up and
intensifying with an array of positive feedbacks at work that could
force natural systems toward irreversible tipping points and the planet
into a state of climate chaos. How dangerously close we are
getting to this becomes glaringly obvious with the shrinking of Earth’s
ice masses.
• The
Arctic Circle: Arctic sea ice continues to deteriorate, with the
summer minimum extent decreasing and darker open water absorbing more
solar radiation and enhancing warming. With a large ice deficit
at the start of winter, it becomes increasingly difficult for the
northern polar cap to recover. This is because the ice is thinning from
below due to warm sea water. Thicker, older, multi-year ice is being
replaced by thinner one-year ice. The years 2007 and 2008 were the
lowest on record in extent and volume
respectively.
• Greenland
ice sheet: The world is watching as scientists aboard a Greenpeace
ship in the Nares Strait are monitoring the
enormous 16-kilometer crevasse in the Petermann
Glacier, which is scarred by many cracks. With air temperatures in the
50s Fahrenheit, whirlpools of meltwater are
boring full steam ahead down into the ice. Warm seawater is eroding the
Petermann’s tongue from underneath, where the
ocean’s thawing of the glacier is 25 times faster than the surface
melt. The Petermann is only one of many
Greenland glaciers that are racing into the sea. Greenland’s record 2007 ice loss has
since tripled.
• West
Antarctic Peninsula: The finger of land that points up toward the
tip of South America is warming six times faster than the global
average, and at four times the rate of Alaska and Siberia. However, the
real hotspot on the planet is the peninsula’s west coast, which is
heating up at 10 times the global average! The much warmer conditions
have led to the break-up of five major ice shelves. The Wilkins is the
latest to collapse into the sea, with its ice bridge having snapped off
in April this year. The rapid warming on the peninsula has had a
profound effect on the complex marine food web, particularly the Adelie penguins and the krill on which they feed.
• West
Antarctic Ice Sheet: It was previously thought that the rest of Antarctica would not warm as much as
the peninsula. However, a recent study shows that the entire continent
has gradually warmed since 1957. The marine-based West Antarctic Ice
Sheet (WAIS) is known to be inherently unstable because its bedrock
lies below sea level on what is essentially the continental shelf, and
it is lubricated by water-saturated sediments that will speed the ice
streams to the sea once the ice shelves give way to the action of warm
sea water.
• Southern
Ocean: This great body of circumpolar water has warmed 0.3 C on
average over 15 years. It normally accounts for over 15% of annual
ocean uptake of atmospheric carbon dioxide. However, its CO2 absorption
has flattened out since 1975. This has been due to greenhouse gases and
the depletion of stratospheric ozone, which are altering the radiation
balance of Earth’s atmosphere. This in turn has caused a windier
regime, which is stirring ocean currents, bringing carbon-rich
waters up from the deep, saturating the surface water and limiting its
capacity to absorb carbon from the atmosphere.
Warmer
seawater absorbs and retains less carbon dioxide. Consequently, as sea
surface temperatures rise, CO2 degasses like the fizz from a glass of
root beer sitting in the sun. This has caused a drop in Southern Ocean
pH of 0.01 units, with increased acidification putting
carbonate-shelled life at risk. Carbon upwelling and off-gassing is
occurring in the North Atlantic and Western Pacific as
well, indicating that Earth’s liquid sinks are weakening.
• Shrinking
Alpine Glaciers: Mountain ice masses have retreated in all parts of
the world. Most striking is the decline in mass balance of the
equatorial glaciers of the Andean Cordillera Real. Surface measurements
of the 376 glaciers there indicate an overall loss in area of 48%. This
is hugely impacting water supplies. The Himalayas, which feed a dozen
major rivers in Asia, have lost a third of their snow. Montana’s Glacier National Park is expected to become very un-glacial
10 years ahead of previous predictions.
•
Extreme weather conditions: Depending upon what part of the world
one lives in, all one need do is look out the window for evidence of
droughts, heat waves, wildfires, floods, or violent storms and then
compare what is happening to one’s neighbors in the region
nearby. As we follow the news, we find that it can be radically
different from one spot on the globe to the next.
While
not every extreme weather anomaly can be blamed on global warming,
since some are due to natural variation or a combination thereof, we can
detect distinct patterns in which certain phenomena have become
persistent and unusually prolonged. The burning of the American West,
the Southeast Australian drought, the drying of the Sahel, and more intense Pacific
typhoons and Atlantic hurricanes are examples.
• Transformed
Natural regimes: With the alteration of seasonal rhythms and shifts
in climatic zones, hundreds of plant and animal species are struggling to adapt. Some are succeeding
with their survival strategies. Others are failing and passing into the
silence of extinction, which, we must remember, is forever.
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