The Border Wall and Climate Change

There is a humanitarian crisis going on at the U.S. Southern border, but there is also a humanitarian crisis along the shores of the Mediterranean Sea. There are humanitarian crises along the southern hemisphere borders between the temperate climate zones. When all is said and done about the southern border wall of the United States, how much difference will it make?

• VOX 01/30/2017: 9 maps and charts that explain the global refugee crisis 
• University of Richmond 09/27/2017: A World Ravaged by Global Warming 
• NASA Earth Observatory 01/03/2007: Defining Desertification 
• Invasive Notes 12/15/2008: Climate Change - Invasive Species 
• Climate Central 

I believe the biggest security threat of all is to our clean fresh water. If there's a chance that the U.S. will suddenly find itself in a national humanitarian crisis, would the rest of the world sympathize? Maybe some, but not likely most.