Vital Ozone Graphics: Resource Kit for Journalists

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OZONE DEPLETION AND CLIMATE CHANGE

OZONE DEPLETION AND CLIMATE CHANGE

Changes in albedo (less reflecting surfaces)

5

Changes in global atmospheric circulation

decrease human vulnerability to..

Cooling stratospheric temperatues

Changes in precipitations

Changes in global ocean circulation

Ice melting

enhance..

Changes in snow cover

4

At the poles: seasonal formation of polar stratospheric clouds

Changes in cloud cover

Increased UV-B radiation on Earth

Ozone “holes” above the Antarctic (and, to a lesser extent, above the Arctic)

Average temperature rise (”Global warming”)

Global Ozone Depletion

Climate Change

Chemical destruction of stratospheric ozone

Enhanced Greenhouse Effect

enhance..

reduce..

3

Chlorine and bromine atoms released

All Ozone Depletion processes are in blue; all Climate Change processes are in orange.

Solar UV rays

GREENHOUSE GASES

OZONE DEPLETING SUBSTANCES (Halogen gases)

CO 2

N 2 O

CFC-113

Carbon tetrachloride (CCl 4 )

CFC-11

CH 4

H-1211

H-1301

CFCs

CFC-12

Halons

Methyl chloride (CH 3 Cl)

2

HFC-23

HFCs

HCFCs

HFC-134a HFC-125

Methyl bromide (CH 3 Br)

Methyl Chloroform (CH 3 CCl 3)

HUMAN ACTIVITY

1

c UNEP/GRID-Arendal.

Ozone depletion and climate change are two distinct problems but as they both modify global cycles, they cannot be totally separated. There are still many uncertainties concerning the relations between the two processes. Several links have been identified, in particular: 1 Both processes are due to human-induced emissions. 2 Many ozone depleting substances are also greenhouse gases, like CFC-11 and CFC12. HFCs, promoted to substitute CFCs, are sometimes stronger greenhouse gases than the CFCs they are replacing, but do not deplete the ozone layer. This fact is taken into account in the negociations and decisions in both the Montreal and the Kyoto Protocol. 3 Ozone itself is a greenhouse gas. Therefore, its destruction in the stratosphere indirectly helps to cool the climate, but only to a small extent. 4 The global change in atmospheric circulation could be the cause of the recently observed cooling of stratospheric temperature. These low temperatures drive the formation of polar stratospheric clouds above the poles in the winter, greatly enhancing chemical ozone destruction and the formation of the “hole”. 5 Human vulnerability to UV-B radiation is related to the albedo.The global warming context reduces white surfaces that are more likely to harm us.