Q&AJESSICA HOWARD, INVERNESSWHAT WOULD
HAVE HAPPENED IF
WE’D CARRIED ON
USING CFCs?
In the late 1970s, scientists noticed
levels of ozone gas (O 3 ) dropping in
the ozone layer, a region of the
stratosphere some 15 to 30km
above our heads. The ozone here
absorbs most of the Sun’s damaging
ultraviolet (UV) radiation, shielding
us from UVB and UVC rays. The
culprit for the disappearing ozone?
Chloro uorocarbons (CFCs), which
were used in fridges, aerosols and
air conditioners. As CFCs entered the
atmosphere, they released chlorine
atoms which broke down ozone and
allowed more UV radiation through.
As rates of ozone depletion
accelerated, the internationalcommunity sprang into action.
E ective from 1989 and signed by 197
countries, the Montreal Protocol has
now phased out 99 per cent of CFCs
and other ozone-depleting chemicals,
with ozone levels predicted to make a
full recovery by the 2050s. Without
this treaty, CFCs would have
continued to rise, with disastrous
consequences for life on our planet.
In humans, heightened exposure to
UVB radiation would have triggered a
surge in incidences of skin cancer and
cataracts. According to one estimate,
there would have been an extra two
million cases of skin cancer worldwide
by 2030. By 2065, UV radiation at the
planet’s surface would have reached
three times its current strength,
making any Sun exposure dangerous.
Overexposure to UVB radiation
stunts the growth of many plants,
and the resulting decline in
agricultural productivity could have
triggered food shortages. The
radiation harms phytoplankton, too- the tiny organisms that form the
basis of marine food webs – with
untold consequences for wider
ecosystems. CFCs are powerful
greenhouse gases, and US researchers
have calculated that there would have
been an additional 2°C of global
warming by 2070 if CFCs had been le
unchecked. This would have fuelled
extreme weather such as oods,
droughts, hurricanes and heatwaves.
Fortunately, this disaster scenario
was averted, and today the Montreal
Protocol is o en heralded as the most
successful piece of environmental
legislation in history. AFC
HENRY BUTLER, CANTERBURYWHY DO
MILLIPEDE S HAVE
SO MANY LEGS?
Though no known
millipede species has
1,000 legs, common
species of this burrowing
arthropod have between
40 and 400 legs – more
than enough to move the
millipede forwards with
impressive he. Like an
army of tiny soldiers
running a giant baering
ram into a wall, this
adaptation allows the
millipede’s head to be
forced into the cracks
between lumps of soil
where the most delicious
leaf maer oen resides.
These crevices also oer
excellent protection
from predators. JHEDWARD SEYMOUR, HOVEARE HUMAN AND ANIMAL
BONES THE SAME?
Humans and other mammals share the same
distant ancestors, so our bones are almost
identical to theirs in form and function. The
bones in your hand have the same layout as those
in bat wings and in the fins of whales, for
instance. What diers most between species,
however, is the thickness, size and density of
minerals that provide strength to bones. This is
what scientists are most interested in when
trying to determine the origin of mysterious
bones. Even today, mistaken identifications of
human bones from animal remains can occur. To
the untrained eye, the bones within the paw of a
bear, for instance, look very similar to the bones
within the human hand. JHHuman Cat Whale BatHumerusRadiusCarpals
Metacarpals
PhalangesUlnaQ&AJESSICA HOWARD, INVERNESS
WHAT WOULD
HAVE HAPPENED IF
WE’D CARRIED ON
USING CFCs?
In the late 1970s, scientists noticed
levels of ozone gas (O 3 ) dropping in
the ozone layer, a region of the
stratosphere some 15 to 30km
above our heads. The ozone here
absorbs most of the Sun’s damaging
ultraviolet (UV) radiation, shielding
us from UVB and UVC rays. The
culprit for the disappearing ozone?
Chloro uorocarbons (CFCs), which
were used in fridges, aerosols and
air conditioners. As CFCs entered the
atmosphere, they released chlorine
atoms which broke down ozone and
allowed more UV radiation through.
As rates of ozone depletion
accelerated, the internationalcommunity sprang into action.
E ective from 1989 and signed by 197
countries, the Montreal Protocol has
now phased out 99 per cent of CFCs
and other ozone-depleting chemicals,
with ozone levels predicted to make a
full recovery by the 2050s. Without
this treaty, CFCs would have
continued to rise, with disastrous
consequences for life on our planet.
In humans, heightened exposure to
UVB radiation would have triggered a
surge in incidences of skin cancer and
cataracts. According to one estimate,
there would have been an extra two
million cases of skin cancer worldwide
by 2030. By 2065, UV radiation at the
planet’s surface would have reached
three times its current strength,
making any Sun exposure dangerous.
Overexposure to UVB radiation
stunts the growth of many plants,
and the resulting decline in
agricultural productivity could have
triggered food shortages. The
radiation harms phytoplankton, too- the tiny organisms that form the
basis of marine food webs – with
untold consequences for wider
ecosystems. CFCs are powerful
greenhouse gases, and US researchers
have calculated that there would have
been an additional 2°C of global
warming by 2070 if CFCs had been le
unchecked. This would have fuelled
extreme weather such as oods,
droughts, hurricanes and heatwaves.
Fortunately, this disaster scenario
was averted, and today the Montreal
Protocol is o en heralded as the most
successful piece of environmental
legislation in history.AFC
HENRY BUTLER, CANTERBURYWHY DO
MILLIPEDE S HAVE
SO MANY LEGS?
Though no known
millipede species has
1,000 legs, common
species of this burrowing
arthropod have between
40 and 400 legs – more
than enough to move the
millipede forwards with
impressive he. Like an
army of tiny soldiers
running a giant baering
ram into a wall, this
adaptation allows the
millipede’s head to be
forced into the cracks
between lumps of soil
where the most delicious
leaf maer oen resides.
These crevices also oer
excellent protection
from predators. JHEDWARD SEYMOUR, HOVEARE HUMAN AND ANIMAL
BONES THE SAME?
Humans and other mammals share the same
distant ancestors, so our bones are almost
identical to theirs in form and function. The
bones in your hand have the same layout as those
in bat wings and in the fins of whales, for
instance. What diers most between species,
however, is the thickness, size and density of
minerals that provide strength to bones. This is
what scientists are most interested in when
trying to determine the origin of mysterious
bones. Even today, mistaken identifications of
human bones from animal remains can occur. To
the untrained eye, the bones within the paw of a
bear, for instance, look very similar to the bones
within the human hand. JHHuman Cat Whale BatHumerusRadiusCarpals
Metacarpals
PhalangesUlna