BP, Shell and Exxon all want the same thing: to make money while the use of their core products - oil and natural gas - is under attack as a likely cause of global warming. Burning oil and natural gas creates carbon dioxide, whether the purpose is to drive cars, power air conditioners, or illuminate rooms. Scientists label carbon dioxide a "greenhouse gas" because they believe its emission into the atmosphere contributes to the rise in the Earth's temperature known as global warming.
The initial response of the oil industry was to question this theory, which defines Exxon Mobil's approach to this day. The company says it views global warming and the "potential" for human-induced climate change seriously. But it opposes restrictions on greenhouse-gas emissions without further research on the causes of climate change.
BP struck out on a different path four years ago. Instead of continuing to battle the growing pressure for control of greenhouse-gas emissions, the company decided to join the effort. Shell made a similar decision.
The two companies have not joined the environmentalist camp. They have not diminished their efforts to find and develop sources of oil and natural gas. But they decided to counteract the threat to their business by convincing consumers that they are doing what they can to deal with greenhouse gases.
BP and Shell pulled out of the Global Climate Coalition, an oil industry lobbying group that argued against global-warming theories, and joined the Pew Center on Global Climate Change, a suburban Virginia group dedicated to addressing global warming.
Shell says it has reduced its greenhouse-gas emissions to 11 percent below 1990 levels, and BP pledges a 10 percent reduction by 2010. Both companies also have invested in alternative energy sources such as solar power.
Reducing greenhouse-gas emissions makes good business sense when it results from cutting energy use and, therefore, a company's costs. Exxon Mobil is reducing its greenhouse-gas emissions that way, too. "We haven't thrown a target out there," said Ken Cohen, vice president for public affairs at Exxon Mobil. "We're just doing it."