New York Times: After two years of study, President Obama this week defined the criteria for what will be one of the signature decisions of his presidency: the proposed Keystone XL pipeline that would carry heavy crude from here to American refineries must not significantly worsen global warming. Anticipating that standard, Canadian oil companies have embarked on a race to develop cleaner technologies that will make their production less damaging to the environment. From improving valves to revamping giant boilers...