More than 150 companies including Airbus, Coca-Cola and IKEA pledged on Friday to reduce the carbon burden of their operations in a voluntary pact urging governments to do more to confront climate change.

Drugmakers Novartis and Pfizer, mining giants Anglo American and Rio Tinto, and the luxury goods specialist LVMH were among the 153 firms who committed themselves to greater energy efficiency.

Top environment officials welcomed the companies' promise to undertake practical actions to reduce their contribution to global warming, despite the lack of binding targets.

Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change, said he hoped more of the 3,000 businesses which have signed up to a United Nations corporate responsibility drive would also adopt the measure.

You need a group of pioneers who get things going, he told a news conference in Geneva, where more than 1,000 corporate and government leaders met this week for a summit of the U.N. Global Compact. These are some of the leaders who would inspire several others in the business.

Achim Steiner, head of the U.N. Environment Programme, said companies may take time to accede to the Caring for Climate initiative, which was distributed to all Global Compact members a few months ago for review.

A company which signs this is making some fairly far-reaching commitments vis-a-vis its shareholders, vis-a-vis the public, and vis-a-vis consumers, never mind governments also, Steiner said.

Among big members of the U.N. Global Compact that did not sign the climate initiative are banks UBS and Credit Suisse; clothing retailers Nike, Hennes & Mauritz and Gap; oil company Royal Dutch Shell; mining group BHP Billiton; and coffee company Starbucks.

Bjorn Stigson, president of the Geneva-based World Business Council for Sustainable Development, said it was important that such initiatives remain voluntary to draw more companies into discussions on climate change and other issues.

He said regulations on environmental taxes and fees and other measures could help reinforce a shift towards the greener practices espoused by those participating in the Global Compact meetings at the U.N.'s European headquarters.

The Caring for Climate statement also urged governments to agree as soon as possible on longer-term environmental policies to succeed the Kyoto Protocol in 2012, including efforts to set up a stable carbon-trading market.

Separately, the chief executives of Coca-Cola, Levi Strauss, Lackeby Water Group, Nestle, SABMiller and Suez launched a CEO Water Mandate project to help companies better manage water use throughout their supply chains and help avoid a global water crisis.