Document ID: ./input/supremecourt_opinions/opinions/06pdf/05-1120.pdf
Page Number: 3.0

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

3 

Syllabus 

power  to  reduce  motor-vehicle  emissions  are  now  lodged  in  the  Fed-
eral Government.  Because congress has ordered EPA to protect Mas-
sachusetts  (among  others)  by  prescribing  applicable  standards,
§7521(a)(1),  and  has  given  Massachusetts  a  concomitant  procedural 
right to challenge the rejection of its rulemaking petition as arbitrary
and  capricious,  §7607(b)(1),  petitioners’  submissions  as  they  pertain
to Massachusetts have satisfied the most demanding standards of the 
adversarial  process.    EPA’s  steadfast  refusal  to  regulate  greenhouse 
gas emissions presents a risk of harm to Massachusetts that is both
“actual”  and  “imminent,”  Lujan,  504  U. S.,  at  560,  and  there  is  a 
“substantial likelihood that the judicial relief requested” will prompt
EPA  to  take  steps  to  reduce  that  risk,  Duke  Power  Co.  v.  Carolina 
Environmental Study Group, Inc., 438 U. S. 59, 79.  Pp. 12–17.

(b) The  harms  associated  with  climate  change  are  serious  and 
well  recognized.    The  Government’s  own  objective  assessment  of  the 
relevant  science  and  a  strong  consensus  among  qualified  experts  in-
dicate that global warming threatens, inter alia, a precipitate rise in
sea  levels,  severe  and  irreversible  changes  to  natural  ecosystems,  a 
significant  reduction  in  winter  snowpack  with  direct  and  important 
economic  consequences,  and  increases  in  the  spread  of  disease  and 
the ferocity of weather events.  That these changes are widely shared
does not minimize Massachusetts’ interest in the outcome of this liti-
gation.  See Federal Election Comm’n v. Akins, 524 U. S. 11, 24.  Ac-
cording  to  petitioners’  uncontested  affidavits,  global  sea  levels  rose
between  10  and  20  centimeters  over  the  20th  century  as  a  result  of 
global  warming  and  have  already  begun  to  swallow  Massachusetts’ 
coastal  land.    Remediation  costs  alone,  moreover,  could  reach  hun-
dreds of millions of dollars.  Pp. 17–19.  

(c) Given  EPA’s  failure  to  dispute  the  existence  of  a  causal  con-
nection  between  man-made  greenhouse  gas  emissions  and  global
warming, its refusal to regulate such emissions, at a minimum, “con-
tributes” to Massachusetts’ injuries.  EPA overstates its case in argu-
ing  that  its  decision  not  to  regulate  contributes  so  insignificantly  to
petitioners’  injuries  that  it  cannot  be  haled  into  federal  court,  and 
that there is no realistic possibility that the relief sought would miti-
gate  global  climate  change  and  remedy  petitioners’  injuries,  espe-
cially  since  predicted  increases  in  emissions  from  China,  India,  and 
other developing nations will likely offset any marginal domestic de-
crease EPA regulation could bring about.  Agencies, like legislatures,
do not generally resolve massive problems in one fell swoop, see Wil-
liamson v. Lee Optical of Okla., Inc., 348 U. S. 483, 489, but instead 
whittle  away  over  time,  refining  their  approach  as  circumstances
change and they develop a more nuanced understanding of how best
to proceed, cf. SEC v. Chenery Corp., 332 U. S. 194, 202–203.  That a