What  do  scien-sts  do  with  the  models?  

Source:  h6ps://www.flickr.com/photos/climatesafety/4111829103/  

MR Allen et al. Nature 458, 1163-1166 (2009)

Which  Target?  Emissions Concentrations Temperature

1    Trillion  Tonnes    of  Carbon  

350  ppm    CO2e  

No  more  than  +2ºC  

No  more  than  +1.5ºC  

Emissions  by  Sector  Source:  U

N  Guide

 to  Clim

ate  Neu

trality

   

Source:  h6p://www3.epa.gov/climatechange/ghgemissions/global.html  

Where  do  GHG  emissions  come  from?  

Stabiliza-on  Wedges  

Source:  h6p://cmi.princeton.edu/wedges/intro.php  

Source:  h6p://cmi.princeton.edu/wedges/intro.php  

…is  a  strategy  to  reduce  carbon  emissions    It  starts  small  Grows  in  50  years  to  1.0  GtC/yr.    

Each  wedge  must  have  already  been  commercialized  at  scale  somewhere.  

             

1  GtC/yr  

50  years  

Total  =  25  Gigatons  carbon  

Each  Wedge  

Source:  h6p://cmi.princeton.edu/wedges/intro.php  

Delay  makes  the  problem  harder:  

Source:  h6p://www.climatecentral.org/blogs/wedges-­‐reaffirmed  

Reanalysis  of  the  Wedges  

Davis,  S.  J.,  Cao,  L.,  Caldeira,  K.,  &  Hoffert,  M.  I.  (2013).  Rethinking  wedges.  Environmental  Research  Le6ers,  8(1).  

Davis,  S.  J.,  Cao,  L.,  Caldeira,  K.,  &  Hoffert,  M.  I.  (2013).  Rethinking  wedges.  Environmental  Research  Le6ers,  8(1).  

Reanalysis  of  the  Wedges  

Re-­‐thinking  Wedges  

Davis,  S.  J.,  Cao,  L.,  Caldeira,  K.,  &  Hoffert,  M.  I.  (2013).  Rethinking  wedges.  Environmental  Research  Le6ers,  8(1).