Environmental Engineering Reference
In-Depth Information
best climate scientists in the United States to the relevant
panels, and the administration under President Barack
Obama has continued the practice. According to the panel
members that I know, there seems to have been little
politics in the selection of the scienti
c members of these
panels by any country.
Each of the three Working Groups produces what is
called a Summary for Policymakers. This summary is
non-technical and is gone over line by line with represen-
tatives of the signers of the UNFCCC at a meeting that
has political as well as technical overtones. Since the UN
operates by consensus on climate change there has to be
agreement on the exact wording of the report, and that
language evolves as the scienti
c evidence evolves. For
example, in the Third Assessment Report (AR
) the sum-
mary did not say that global warming was caused with
high probability by human activities (the main holdouts
were China and the United States). AR
said that global
warming was being caused by human activities, and AR
says it in even stronger terms.
After agreement is reached on the wording in the sum-
maries of the Assessment Reports, the scienti
c groups
have to go back and make the words in their technical
reports consistent with what is in the summary. They may
have to change their descriptive words but they do not
have to change their technical
findings or any of the
numbers in their analyses. Some would say that this pro-
cedure is overtly political. They would be correct, but
since only the countries that are the major emitters of
greenhouse gases can do anything about global warming,
a consensus on the issues is needed as a preface to global
action. Without that consensus the two largest emitters of
