Document ID: ./input/supremecourt_opinions/opinions/06pdf/05-1120.pdf
Page Number: 11

Cite as:  549 U. S. ____ (2007) 

5 

Opinion of the Court 

long-term  and  substantial  increase  in  the  average  tem-
perature  on  Earth,”  §1102(1),  101  Stat.  1408,  Congress
directed  EPA  to  propose  to  Congress  a  “coordinated  na-
tional  policy  on  global  climate  change,”  §1103(b),  and 
ordered the Secretary of State to work “through the chan-
nels  of  multilateral  diplomacy”  and  coordinate  diplomatic 
efforts  to  combat  global  warming,  §1103(c).    Congress
emphasized that “ongoing pollution and deforestation may 
be  contributing  now  to  an  irreversible  process”  and  that 
“[n]ecessary  actions  must  be  identified  and  implemented 
in time to protect the climate.”  §1102(4).

Meanwhile,  the  scientific  understanding  of  climate 
change progressed.  In 1990, the Intergovernmental Panel 
on Climate Change (IPCC), a multinational scientific body 
organized under the auspices of the United Nations, pub-
lished  its  first  comprehensive  report  on  the  topic.    Draw-
ing  on  expert  opinions  from  across  the  globe,  the  IPCC
concluded that “emissions resulting from human activities
are  substantially  increasing  the  atmospheric  concentra-
tions  of  . . .  greenhouse  gases  [which]  will  enhance  the 
greenhouse  effect,  resulting  on  average  in  an  additional 
warming of the Earth’s surface.”12 

Responding  to  the  IPCC  report,  the  United  Nations
convened  the  “Earth  Summit”  in  1992  in  Rio  de  Janeiro. 
The  first  President  Bush  attended  and  signed  the  United
Nations  Framework  Convention  on  Climate  Change
(UNFCCC), a nonbinding agreement among 154 nations to 
reduce  atmospheric  concentrations  of  carbon  dioxide  and
other  greenhouse  gases  for  the  purpose  of  “prevent[ing] 
dangerous  anthropogenic  [i.e.,  human-induced]  interfer-
ence  with  the  [Earth’s]  climate  system.”13    S.  Treaty  Doc. 
—————— 

12 IPCC,  Climate  Change:  The  IPCC  Scientific  Assessment,  p. xi  (J. 

Houghton, G. Jenkins, & J. Ephraums eds. 1991). 

13 The industrialized countries listed in Annex I to the UNFCCC un-
dertook to reduce their emissions of greenhouse gases to 1990 levels by
the year 2000.  No immediate restrictions were imposed on developing