Arctic environmental security and abrupt climate change - Environmental and Human Security in the Arctic - page 100

climate change impacts without the inevitable contradictions that state-level
security would bring to analyses.
Despite popular intuition that climate change issues affect human and
international security, it remains difficult to conceptualize what these con-
nections may be, particularly for a global process so rife with uncertainty.
Without a useable framework for analysis, policy action and discussion will
remain difficult, and a form of policy paralysis may result (Barnett 2003). The
following sections explain briefly the non-intuitive ways that climate systems
act and how such complex networks also relate to alternative definitions of
vulnerability and risk assessment.
Systems theory
In contrast to the linear systems assumed in the environmental security lit-
erature of the 1990s, ecological systems (including the global climate) are
better understood as complex emergent systems. The units of environmental
systems, however defined, are not nearly as important as the relationships
and networks among a system's components. Properties of the system can-
not be determined simply by reference to its components, nor can the future
state of a system be understood in reductionist terms. Change can occur while
maintaining the integrity of the system, but the system may shift to multiple
points of stability. Such shifts, as with eutrophication of lakes (when nitrogen
added to water, often from fertilizers, results in sudden algae blooms), may
occur quite suddenly and with little indication that conditions may suddenly
'worsen' (Walker and Salt 2006). Likewise, palaeo-climatological studies have
indicated that atmospheric temperatures can shift very suddenly, perhaps as
much as 10-20 degrees Celsius within a few years. Sudden temperature shifts
similarly occurred 11,500 years ago at the end of the Younger Dryas Period,
when temperatures in Greenland dropped 19 degrees Celsius in less than 20
years (National Research Council 2002; Alley et al . 2009).
What are less well understood are the 'tipping points' in such systems, tech-
nically known as catastrophe sets . How far can a system be pushed before it shifts
to a new level of stability? What are the most relevant relationships? In climate
terms, the most pressing question is concerned with what amount of green-
house gases (GHGs) the global climate system can absorb before a large-scale
shift in climate stability occurs (Lenton 2011). Atmospheric temperatures may
rise gradually over the years, as per the standard Intergovernmental Panel on
Climate Change (IPCC) projections, but then suddenly rise (or fall) precipi-
tously. The National Research Council's (2002) report on abrupt climate change
described several qualities of a system that creates 'abruptness'. First, the system
is non-linear, and shifts from one condition (often measured as temperature) to
another occur rapidly, perhaps within a number of years. Second, this change
is irreversible, as measured by human time scales, a condition made even more
likely by the increases in atmospheric irradiance caused by GHG emissions and