In a December 12 special report, Business Week teamed up with the Climate Group, a British organization that serves as a clearing house for information on carbon reduction, and Innovest Strategic Value Advisors, a leading Wall Street green investment research firm. Together with a panel of expert judges drawn from academic institutions, these groups identified and ranked the companies that have shown the greatest initiative in cutting their greenhouse gas emissions, and also identified best practices, effective policies, and what kinds of results to expect.

Details about how the judges made their selections and a wealth of material on the companies and individuals in the rankings can be found at businessweek.com/go/carbon.

Business Week, the Climate Group, and a panel of judges compiled the ranking of top carbon cutters based on companies' total reduction of greenhouse gases, results relative to their size, and the leadership they have shown:

The magazine also named the following "Green Leaders," who stand out for their efforts to cut gases that cause global warming:

• Tony Blair, British Prime Minister
  Raised awareness of global warming at the G-8 – and tangled with the U.S. on its position. He was also the first leader to go beyond Kyoto's targets – which call for sub-10% cuts by 2012 – and pledge a 60% cut by 2050.
• John Browne, BP Chairman and CEO
  Shocked the oil industry in 1997 when he declared that by 2010 BP would reduce emissions 10% below 1990 levels. That was six months before negotiations on the Kyoto accord began in earnest. BP has since reaped huge profits while transforming its traditional big-oil culture.
• Zhao Hang, President of China Auto Tech & Research Center
  Believes China must grapple with global warming. Working with foreign advisers, he devised fuel-economy rules 20% tougher than those in the U.S. By 2030, 300 million cars will be on China's roads – 10 times today's number.
• Franzjosef Schafhausen, German Ministry of the Environment
  Helped Germany exceed its Kyoto obligation. Today greenhouse gas emissions are 19% lower than in 1990. In the process, he has helped to cut Germany's high jobless rate by creating 450,000 new jobs in renewable-energy industries.
• Arnold Schwarzenegger, Governor of California
  Issued an order that requires California to slash gases by 80% by 2050 – the toughest state target of all. He is also backing a plan to cut total tailpipe emissions by one-third by the 2016 model year.

Finally, it named these "best practices" for carbon cutting:

• CEOs Don't Just Delegate
  Pasquale Pistorio, former CEO of STMicroelectronics, believed environmental initiatives in making chips should come from the top – and he passed that commitment along to his successor, Carlo Bozotti. At BP, CEO John Browne works in the trenches with environmental specialists from all business segments. Iberdrola's top gun, Ignacio Sanchez Galan, oversees the Emission Allowances Working Group, which devises ways to fulfill the Kyoto Protocol's requirements.
  
• Green Achievements Count in Performance Reviews
  Achieving targets designed to thwart climate change is a major element in senior executives' performance scorecards at Novo Nordisk. Dow Chemical's new Climate Change & Energy Strategy Board is populated by senior executives, who coordinate the work of expert teams responsible for regional strategy, site emissions, and energy conservation.
  
• Operating Units Clean Up
  Each Scottish Power division has a senior manager accountable for complying with energy and environment objectives. BHP Billiton has developed greenhouse gas curtailment plans tailored to each of its business sites. BP's operating units field a small army of influential managers for environmental technology, product emissions, and energy efficiency.
  
• Financiers See Dividends
  HSBC, led by CEO Stephen Green (right), pledged to offset its entire carbon output by 2006 and hit its goal ahead of schedule. At ABN Amro, new businesses include climate risk management and trading emission allowances. In assessing mortgages, Citigroup rewards borrowers buying energy-saving homes. And JPMorgan Chase is evaluating the impact of carbon on loans to big emitters.