The Arctic Messenger - The Changing Arctic Environment: The Arctic Messenger - page 19

is much more sensitive to climate change than most other regions. The impact on the Arctic
as we know it will be very substantial indeed. In fact, it has already begun. However, there
is even more significance in Arctic warming because the Arctic is a major link in the global
climate system that redistributes heat around the world. Wherever they live, all people on
Earth should be concerned about how the Arctic is reacting to global warming.
These issues illustrate a historical trend in terms of the relationship between the loca-
tion of the activity that caused concern (source) and the locality of potential environmental
impact (receptor). In the case of Arctic resource development, the two are side by side. If
there is an impact, it is not going to creep up unnoticed, and in theory, the potential for
effective remedial action is always a possibility and could be in the hands of local people.
With acid rain, the source area is geographically separated from the receptor by a distance
of perhaps 1,000 kilometres or more. However, although the areas affected (receptor areas)
can include a number of countries, they are not significantly circumpolar or global and it is
possible to locate the sources.
In the case of radioactivity, there have been only a limited number of global source
localities (weapons test sites or accidents) where anthropogenic radionuclides were re-
leased into the troposphere and stratosphere. Other point sources, mainly on land, have re-
leased soluble radionuclides directly or indirectly (via rivers) to the marine environment. In
both cases, the receptor can extend very far from the source and may even be hemispheric,
if not global. A particularly sensitive receptor element is the Arctic terrestrial environment
that provides habitat and food for caribou and reindeer. With stratospheric ozone depletion,
POPs and mercury, we move to a situation where the source is diffuse because the sub-
stances concerned have entered the environment all over the industrialized and agricultural
world, while the Arctic source has been minimal. However, for complex reasons that were
not recognized until quite recently, the most sensitive receptors are located in the Arctic.
Finally, in our evolutionary progression, we reach climate change. The sources of
greenhouse gas emissions (considered by the IPCC as being “very likely” to have caused
most of the global warming observed over the last 50 years) are also diffuse and global.
The receptor is the entire global environment. However, not all parts of the world are