Holyrood 350 — H35O

4 Action Points For Holyrood To Avert Climate Chaos

“A safe operating space for humanity”

October 6th, 2009 · No Comments

Just in case you haven’t seen this arti­cle. It helps to estab­lish just
what are the “Lim­its to Growth” — includ­ing the oth­er lim­its besides
cli­mate change:

Fea­ture: “A safe oper­at­ing space for human­i­ty”
Nature 461, 472–475 (24 Sep­tem­ber 2009) | doi:10.1038/461472a;
Pub­lished online 23 Sep­tem­ber 2009

“Iden­ti­fy­ing and quan­ti­fy­ing plan­e­tary bound­aries that must not be
trans­gressed could help pre­vent human activ­i­ties from caus­ing
unac­cept­able envi­ron­men­tal change, argue Johan Rock­ström and
col­leagues.”

“We have tried to iden­ti­fy the Earth-sys­tem process­es and asso­ci­at­ed
thresh­olds which, if crossed, could gen­er­ate unac­cept­able
envi­ron­men­tal change. We have found nine such process­es for which we
believe it is nec­es­sary to define plan­e­tary bound­aries: cli­mate
change; rate of bio­di­ver­si­ty loss (ter­res­tri­al and marine);
inter­fer­ence with the nitro­gen and phos­pho­rus cycles; stratos­pher­ic
ozone deple­tion; ocean acid­i­fi­ca­tion; glob­al fresh­wa­ter use; change in
land use; chem­i­cal pol­lu­tion; and atmos­pher­ic aerosol load­ing”

“In gen­er­al, plan­e­tary bound­aries are val­ues for con­trol vari­ables
that are either at a ‘safe’ dis­tance from thresh­olds — for process­es
with evi­dence of thresh­old behav­iour — or at dan­ger­ous lev­els — for
process­es with­out evi­dence of thresh­olds. Deter­min­ing a safe dis­tance
involves nor­ma­tive judge­ments of how soci­eties choose to deal with
risk and uncer­tain­ty. We have tak­en a con­ser­v­a­tive, risk-averse
approach to quan­ti­fy­ing our plan­e­tary bound­aries, tak­ing into account
the large uncer­tain­ties that sur­round the true posi­tion of many
thresh­olds.”

“Human­i­ty may soon be approach­ing the bound­aries for glob­al fresh­wa­ter
use, change in land use, ocean acid­i­fi­ca­tion and inter­fer­ence with the
glob­al phos­pho­rous cycle (see Fig. 1). Our analy­sis sug­gests that
three of the Earth-sys­tem process­es — cli­mate change, rate of
bio­di­ver­si­ty loss and inter­fer­ence with the nitro­gen cycle — have
already trans­gressed their bound­aries. For the lat­ter two of these,
the con­trol vari­ables are the rate of species loss and the rate at
which N2 is removed from the atmos­phere and con­vert­ed to reac­tive
nitro­gen for human use, respec­tive­ly. These are rates of change that
can­not con­tin­ue with­out sig­nif­i­cant­ly erod­ing the resilience of major
com­po­nents of Earth-sys­tem func­tion­ing.””

Graph­ic at  http://www.nature.com/nature/journal/v461/n7263/fig_tab/461472a_F1.html

Fig­ures for Plan­e­tary Bound­raries at
http://www.nature.com/nature/journal/v461/n7263/fig_tab/461472a_T1.html#figure-title

Whole arti­cle at

http://www.nature.com/nature/journal/v461/n7263/full/461472a.html

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