It was an "agreement" made by Barack Hussein Obama --- EVERYTHING that went before involving him is problematic, and that means it's quite DISPUTABLE --- That includes the so-called "Paris Agreement" on the environment.....
What is not at all in dispute, is that it's 2017 and Barack Hussein Obama is not now the President of the United States --- President Trump needs to show the world over, and over, and over again that there is a new "Sheriff in Town" --- and what the prior sheriff might have thought and said and done don't count for sh*t anymore.....
Picture the scene in "Blazing Saddles" when the new sheriff comes into town..... Only now, picture Trump as a new "new sheriff" --- and picture his holding the gun pointed at the head of the old "new sheriff," as played by Barack Hussein Obama..... The next line from one of the town folk --- "He says he's gonna shoot the... (a bell sounds loudly -- 'BONG')" --- takes on a whole new meaning, doesn't it .....
There are many good policy reasons for the President to announce that the USA is not part of the Paris Agreement; and show the world that the Trump Administration wants no part of the contemporary dogma on climate change and how to fix it..... (See e.g. "Report: Trump Planning to Exit Paris Agreement" by Kathryn Blackhurst, 5/28/17, LifeZette/ PoliZette [http://www.lifezette.com/polizette/report-trump-planning-exit-paris-agreement/]). The real reason on this and a lot of other stuff is politics, local, national and world-wide.....
Trump needs to show America and the rest of the world that he takes seriously his campaign promises to undo almost everything that Obama put into place.
President Trump will stay on top as long as he keeps undoing the various parts of the "Obama Legacy" in a visibly systematic fashion.....