VATICAN CITY, April 22 (Reuters) - Pope Francis made an impassioned plea for protection of the environment on Wednesday's 50th anniversary of the first Earth Day, saying the coronavirus pandemic had shown that some challenges had to be met with a global response. Francis praised the environmental movement, saying it was necessary for young people to "take to the streets to teach us what is obvious, that is, that there will be no future for us if we destroy the environment that sustains us". The pope, who wrote a major encyclical in 2015 on the defence of nature and the...