Acidification and Arctic Haze - The Changing Arctic Environment: The Arctic Messenger - page 87

and all the other countries of the former Soviet Union, together with Canada and the Un-
ited States. It therefore embraces most of the heavily industrialized countries of the North-
ern Hemisphere, with the exception of China and India. Under the UNECE, a brand-new
treaty was established in 1979, called the Convention on Long-Range Transboundary Air
Pollution (CLRTAP), to enable countries to work cooperatively to reduce acid rain. At the
time, it was a unique and bold enterprise. Europe was divided between East and West and
the Cold War showed no symptoms of the thaw that was to dramatically arrive in the late
1980s. Cooperation between East and West was not something that happened easily. The
CLRTAP was (and still is) a framework convention. It basically sets out some general aims
and principles. On this mutually agreed foundation, it enables parties to “attach” legally
binding protocols that target specific pollution issues as they emerge.
Over the years since 1979, several protocols to address acidification have been nego-
tiated under the CLRTAP, with the latest and most ambitious being the 1999 Gothenburg
Protocol to Abate Acidification, Eutrophication and Ground-Level Ozone. As a general
rule, the early protocols have evolved from a flat-rate emission reduction philosophy to a
science-based approach in the Gothenburg Protocol. Under the Gothenburg approach, on
the basis of the acid rain sensitivity of the environment that will ultimately be the expected
area of deposition, geographically gridded emission ceilings are established for the source
regions. This description is mine and is not totally accurate, but I think you will understand
how it works.
The scientific basis for the development and operation of the Gothenburg Protocol
comes from the European Monitoring and Evaluation Programme (EMEP). It feeds the in-
tegrated emissions, atmospheric transportation and deposition assessments that lie at the
heart of the protocol's effects-based emissions-reduction strategy. Another core scientific
body is the Working Group on Effects (WGE), which looks at the sensitivity of the recept-
ors and monitors the impacts. Two key concepts that link it all together are known as critic-
al loads and critical levels . Critical loads are defined as a “quantified estimate of an expos-
ure to one or more pollutants below which significant harmful effects on specified sensitive
elements of the environment are not expected to occur”. Critical levels are defined as “con-