Holyrood 350 — H35O

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