Climate change is the greatest existential threat to humanity. The New York Times’ David Wallace-Wells joins Katie Phang to discuss what needs to be done to attempt to blunt the impact of global warming.  » Subscribe to MSNBC: http://on.msnbc.com/SubscribeTomsnbc MSNBC delivers breaking news, in-depth analysis of politics headlines, as well as commentary and informed perspectives. Find video clips and segments from The Rachel Maddow Show, Morning Joe, Meet the Press Daily, The Beat with Ari Melber, Deadline: White House with Nicolle Wallace, The ReidOut, All In, Last Word, 11th Hour, and more. Connect with MSNBC Online Visit msnbc.com: http://on.msnbc.com/Readmsnbc Subscribe to MSNBC Newsletter: http://link.msnbc.com/join/5ck/msnbc-daily-signup-youtube Find MSNBC on Facebook: http://on.msnbc.com/Likemsnbc Follow MSNBC on Twitter: http://on.msnbc.com/Followmsnbc Follow MSNBC on Instagram: http://on.msnbc.com/Instamsnbc #Climate #ClimateChange #globalwarming