Readers respond to the rapidly developing events in the Middle East. Also: The virtues of coal; three hours with Velázquez.

The world generated more electricity from renewable energy than coal for the first time ever, a new report finds. The United States is lagging behind.

Domestic coal can’t compete with batteries, solar and gas much longer.

The burning of coal is the largest contributor to climate change worldwide. But the Trump administration sees United States coal as crucial.

The burning of coal is the largest contributor to climate change worldwide. But the Trump administration sees United States coal as crucial.

While the West is distracted and divided, China is focused and surging ahead.

President Xi Jinping told a U.N. climate summit that China will reduce emissions across its economy, expand renewables sixfold and make electric cars “mainstream.”

Its vast investment in solar, wind and batteries is on track to end an era of global growth in the use of coal, oil and gas, the researchers said.