Climate Change Will Happen to You - Stolen Future, Broken Present: The Human Significance of Climate Change - page 5

climate severely. We are already seeing what might be the beginnings of
that event, in which case it is making itself felt at temperatures far lower
than we expected, and several decades earlier as well.
There is yet another worrisome instance looming not far from the arc-
tic region. One of the most pressing instances of a possible tipping point
is the melting permafrost throughout the far North—in Siberia, Alaska,
and northern Canada. When it melts, it releases immense volumes of car-
bon dioxide and methane. Once the release of these gases hits a certain
point, it will cause so much further warming—and further melting of the
permafrost—that the results will be irreversible.
The tipping point for the permafrost is not far away. One study that
appeared in January 2011 strikingly predicts that the feedback loop in
the far North will cause the arctic permafrost to become a net source
(not sink) of carbon and methane after the mid-2020s and will be strong
enough to cancel between 42 and 88 percent of the planet's land-based
capacity to absorb those emissions. 19
These examples may imply that only the feedback loops of the far
North—the Arctic ice, the clathrates, the permafrost—are of concern.
But consider what is transpiring in the Amazon region. Rising tempera-
tures and an associated decline in rainfall have led to the drying of the
Amazon rainforest, causing trees there to grow less and making them
more vulnerable to decay and to wildfires, as well as to the very serious
droughts of 2005 and 2010. 20 This process has gone so far by now that by
some estimates this ecosystem now releases more carbon dioxide into the
atmosphere than it absorbs . 21 Think about it: the Amazon, once famous for
being one of the Earth's best ecosystems for soaking up immense quanti-
ties of carbon dioxide—and for pumping huge quantities of oxygen into
the atmosphere—may already be helping to drive global warming rather
than alleviate it, and if not, is likely to do so very soon. Once we cross that
tipping point for good, an entire array of planetary systems that dominate
not far from the Equator will be transformed as well. That example sug-
gests that the Earth's systems in every region are vulnerable to severe disar-
ray; no area of the biosphere is safe.
As realities like this suggest, if we ignore the causes that set these
vicious circles into motion, we will face an impossible challenge, for in
the following years, the results could wipe out any gains we might make