Science envoy resigns over Trump – with a letter spelling out 'impeach'

State department's Daniel Kammen quits with note calling out Charlottesville and Paris accord - and a hidden message in the first letters of each paragraph

One of the US state department's three science envoys resigned on Wednesday, the latest in a wave of defections over Donald Trump's response to a white nationalist rally in Charlottesville, Virginia.

Daniel Kammen, a professor at the University of California, Berkeley, said in a letter posted on his Twitter account that Trump had failed to condemn white supremacists and neo-Nazis, part of "a broader pattern of behavior that enables sexism and racism, and disregards the welfare of all Americans, the global community and the planet".