Enacting and developing international environmental law - Introduction to International Environmental Law - page 70

The Arctic coastal states now have wider rights to regulate and control the
movements of vessels in their ice-covered sea areas. The situation, however,
is altering, as climate change is causing the ice of the Arctic Ocean to melt at
an accelerating rate: as states' exclusive economic zones in the Arctic Ocean
gradually become ice-free, the application of Article 234 will be increasingly
questioned.
Interplay between customary international law and
international treaties
Even when an international convention expresses a valid rule of customary
international law, as Article 234 does, the two sources of law should be consid-
ered distinctly. Customary international law is binding across the entire world,
whereas a convention is only binding for the parties to it.
Today, the development of customary international law is different, not least
because of the speed at which the international community has evolved since the
Second World War and the Cold War. Now, the main focus is on the content
of an agreement. If states negotiate a global convention that is legally binding,
they are in fact signalling their willingness to be bound by certain rules. Within
international organizations and in other forums, states are constantly expressing
their opinions of how other states should behave. How states 'talk' and the formal
commitments that they make are increasingly important to the development of
customary international law. International rules are being created at an accelerat-
ing pace, both by treaties and via other international instruments.
The principle of no-harm provides a good example. There is not enough
evidence that states in practice - in a uniform manner and all over the world -
pay attention to the potential impact in the environment of other states of
their own planned projects. Nevertheless, this principle is included in nearly
all globally binding international environmental conventions. Since expressed
willingness to apply this principle has been expressed in treaty form, it is inad-
equate and simply wrong to consider it as merely a treaty rule. If a state has
already, through committing to several conventions, signalled that a principle
is legally binding, is this not a suffi cient indication that the principle has devel-
oped into a norm of customary international law? It has become diffi cult to
know why states behave according to the principle of no-harm, as it is not easy
to say whether a state is observing a convention it has ratifi ed (and the princi-
ple of no-harm recorded in it) or the principle of no-harm in customary
international law.
International environmental conventions regulate almost all aspects of
contemporary environmental law, while customary law plays a supplementary
role. The principle of no-harm, for example, applies as a general principle in
contamination cases where international environmental conventions do not
necessarily apply: most international environmental conventions apply to
certain defi ned cases or actions, excluding other cases outside their scope.