[Note that the opening of Impeachment proceedings against United States (US) President Donald Trump will not be comprehensively covered here while the matter works it way through the appropriate phases. I'm not a fan of the divisive and isolationist US President, yet I believe some matters, even some relating to the Executive, are best left to due process and not opinion.]
With that said and onto a matter of immediate concern, I will therefore opine that nothing short of an international effort could combat Climate Change. The notion that each nation should be left unto itself to protect against Climate Change, is prosperous since the effects of the deepening urgency, will victimize the entire globe and not just a sole nation or region.
Even if some nations and regions are more victimized by Climate Change than others, then, all of humanity will still suffer. Barbados Prime Minister Mia Mottley, addressing the United Nations (UN) Climate Summit in New York City, New York, earlier this week, amply warned: "Make no mistake, there will be mass migration by climate refugees that will destabilize the countries of the world that are not on the frontline of this climate crisis."
Mottley, the first woman prime minister of my birth land, rightfully underscored the universal impacts that Climate Change will bring, and in doing so, she and other leaders, scientists and climate activists have affirmed that nothing short of an international effort could combat Climate Change.