1.6 Biophysical Limits
1.6
Biophysical
Limits
“We are
modifying
physical,
chemical
and
biological
systems
in
new
ways,
at
faster
rates,
and
over
larger
spatial
scales
than
ever
recorded
on
Earth.
Humans
have
unwittingly
embarked
upon
a
grand
experiment
with
our
planet.
The
outcome
is
unknown,
but
has
profound
implications
for
all
of
life.”
Figure 1.6.1 The Earth viewed from the Moon
(Picture source: MIT OpenCourseware [see reference 13])
Figure 1.6.1 sourced
from MIT Open Courseware under a Creative
Commons Attribution-NonCommercial-ShareAlike
3.0 United States
http://ocw.mit.edu/courses/science-technology-and-society/sts-003-the-rise-of-modern-science-fall-2010/
The above picture was taken in 1968 by an Apollo 8 crew member. For the first time humanity could see the Earth from a distance. It illuminated an understanding that the planet is a finite space on which we all need to live. It clearly demonstrated that, and that there are certain limits to our growth on our small planet.
In 1972 the book “Limits to Growth” was published [see reference 12] which made an assessment of humanity's impact on the world, followed this with predictions of future trends based on at the time current consumption patterns, and calculated what levels we could approach without causing irreversible implications by crossing them.
The following are categories of the limits, otherwise known as planetary boundaries:
Assimilative
capacity
of
the
atmosphere
to
hold
Carbon
Dioxide
Loss
of
biodiversity
Human
interference
with
nitrogen/phosphorous
cycles
stratospheric
ozone
depletion
Ocean
acidification
Global
scarcity
of
fresh
water
Adverse
changes
in
land
use
Chemical
pollution
Atmospheric aerosol loading
Figure
1.6.2
Graphical
Representation
of
the
planetary
boundaries,
and
current
situation
(Source: Stockholme resilience [see reference 14])
Figure
1.6.2 sourced from Stockholme Resilience (Stockholme University) with permission
http://www.stockholmresilience.org/research/researchnews/tippingtowardstheunknown/quantitativeevolutionofboundaries.4.7cf9c5aa121e17bab42800043444.html
Figure
1.6.2
graphically
represents
the
9
planetary
boundaries. The green areas
are the
estimated
safe
limits
within
these
boundaries,
and
the
red
areas
are
our
current
measured
levels
within
the
boundaries. Limits to
the
graph
are
that
some
of
the
boundaries
have
no
data,
and
it
does
not
show
at
what
rate
these
levels
have
changed
over
time.
The
graph
shows
that
in
some
case
(such
as
loss
of
biodiversity
and
CO2
emissions)
we
have
already
crossed
the
boundaries. In other cases
there
is
still
room
for
growth,
but
levels
are
increasing
rapidly as
explained
earlier.
Many
of
these
biophysical
limits
to
growth
can
be
observed
as
measures
of
unsustainability
rather
than
a
lack
of
sustainability. There is
an
important
difference: when attempting
to
address
these
problems,
if
we
only
seek
to
find
“quick
fixes”
to
avoid
the
effects
of
unsustainability
then
it
is
likely
that
the
problems
will
reoccur
in
the
future
a
different
form. A key concept is
to
look
at
the
roots
of
unsustainability
and
implement
a
paradigm
shift
to
create
systems
with
a
holistic
view
of
our
relationship
with
the
earth
and
to
each
other
that
will
see
us
not
just
surviving
but
flourishing
into
the
future.
The
underlying theme to
take
from
these
graphs
is
that
exponential
growth
on
a
finite
planet
will eventually fail – the
world
cannot
support
us
if
we
continue
at
the
current
trajectory.
Figure 1.6.3 Timeframes and Possible Future Scenarios
(Source MIT Opencourseware [see reference 15])
Figure 1.6.3 sourced
from MIT Open Courseware under a Creative
Commons Attribution-NonCommercial-ShareAlike
3.0 United States
http://dspace.mit.edu/bitstream/handle/1721.1/39134/1-964Fall-2004/OcwWeb/Civil-and-Environmental-Engineering/1-964Fall-2004/LectureNotes/index.htm
The following is
a
presentation
about
by
Johan
Rockstrom
about
limits
to
growth
http://www.ted.com/talks/lang/en/johan_rockstrom_let_the_environment_guide_our_development.html