Thirty years ago,

the international community understood the grave danger of ozone depletion and came together to sign the Montreal Protocol on Substances that Deplete the Ozone Layer. Through this multinational effort, nations showed the benefit of working together for the common good — and for the well-being of each nation in a globalized world.

As a result of this cooperation, the ozone layer over Antarctica has started to recover.

This spirit of cooperation was lost the moment Trump set our nation and the world on a backward course. Who would have imagined that 1987 would have been a more enlightened time than 2017? Linda Shahinian Culver City

Europe and China are taking the lead on climate change. Since when did either of those two deserve to be a standard of moral authority?

I love Europe and have been there at least 30 times. But over the last 100-plus years, that continent has given us two world wars and the toxic trilogy of fascism, communism, and socialism, causing governments around the world to kill millions of their own people and impoverish even more. China has a similar moral history.

To be fair, Africa and the Middle East have also produced horrific states, but I really don’t care if Uganda supports the Paris Accord. David Goodwin Los Angeles

In the early 1970s, when I was in college, a friend and I spent a summer traveling throughout Europe and Israel. Because the United States was viewed poorly in light of the Vietnam War, we were advised to downplay the fact that we were Americans and pretend that we were actually Canadian.

Now, because of Trump’s behavior (specifically his abysmal decision to withdraw the United States from the Paris Climate Accord), it is once again being suggested that while traveling abroad we would save ourselves a significant amount of ridicule if we laid low as Americans.

While most of us are unable to leave our current lives and become Canadians, it might be appropriate to, at least while abroad, pretend we are. David Esquith Northridge