Background: Carbon dioxide is the most significant greenhouse gas, but methane is a close second. It makes up nearly 10 percent of U.S. greenhouse gas emissions, a significant portion of which comes from the oil and gas sector.

Another angle: The growing intensity of wildfires and their spread to regions that have rarely burned have raised fears that climate change is exacerbating the dangers.

American cyberattack targeted Iran

A secret operation in June wiped out a database used by Tehran to plan attacks on shipping traffic in the Persian Gulf, according to senior American officials.

The cyberattack came on the same day that President Trump called off a strike after Iran shot down an American drone. The U.S. has blamed Iran for attacks on oil tankers in the Gulf.