Average Temperature of the Northern Hemisphere based on
published research. The black line at the right is instrumental
data recorded since 1856; follow the link to see the other
sources. Figure created by Robert A. Rohde and distributed under
a Creative Commons License. Today representatives from numerous
countries and organizations are starting a conference in
Copenhagen to discuss the changing climate. The meeting was
intended to produce a new international treaty to replace the
Kyoto Protocols from 1998. Whether such a treaty will be signed
this month remains to be seen; some news reports have indicated
that negotiations might continue into early next year. Even if a
treaty is signed, it is likely to result in lower emissions
reductions than needed. The scientific consensus appears to be
that the highest atmospheric carbon levels that the climate can
tolerate without triggering catastrophic change is about 350
parts per million. Even that level would trigger some rather
uncomfortable effects. Since we are