Document ID: ./input/supremecourt_opinions/opinions/06pdf/05-1120.pdf
Page Number: 48

10 

MASSACHUSETTS v. EPA 

ROBERTS, C. J., dissenting 

standards,  greenhouse  gas  emissions—and  therefore 
global  warming  and  its  attendant  harms—have  been 
higher  than  they  otherwise  would  have  been;  once  EPA 
changes course, the trend will be reversed.

The  Court  ignores  the  complexities  of  global  warming,
and  does  so  by  now  disregarding  the  “particularized”
injury it relied on in step one, and using the dire nature of
global  warming  itself as  a  bootstrap  for  finding  causation
and redressability.  First, it is important to recognize the
extent  of  the  emissions  at  issue  here.    Because  local 
greenhouse gas emissions disperse throughout the atmos-
phere  and  remain  there  for  anywhere  from  50  to  200
years,  it  is  global  emissions  data  that  are  relevant.    See 
App.  to  Pet.  for  Cert.  A–73.    According  to  one  of  petition-
ers’ declarations, domestic motor vehicles contribute about 
6 percent of global carbon dioxide emissions and 4 percent 
of global greenhouse gas emissions.  Stdg. App. 232.  The 
amount  of  global  emissions  at  issue  here  is  smaller  still; 
§202(a)(1)  of  the  Clean  Air  Act  covers  only  new  motor 
vehicles  and  new  motor  vehicle  engines,  so  petitioners’ 
desired emission standards might reduce only a fraction of 
4 percent of global emissions. 

This  gets  us  only  to  the  relevant  greenhouse  gas  emis-
sions;  linking  them  to  global  warming  and  ultimately  to 
petitioners’ alleged injuries next requires consideration of 
further  complexities.    As  EPA  explained  in  its  denial  of 
petitioners’ request for rulemaking, 

“predicting future climate change necessarily involves 
a  complex  web  of  economic  and  physical  factors  in-
cluding:  our  ability  to  predict  future  global  anthropo-
genic  emissions  of  [greenhouse  gases]  and  aerosols;
the fate of these emissions once they enter the atmos-
phere  (e.g.,  what  percentage  are  absorbed  by  vegeta-
tion  or  are  taken  up  by  the  oceans);  the  impact  of
those emissions that remain in the atmosphere on the