As one of his very first official actions Dec. 3, Kevin Rudd, Australia’s newly sworn-in prime minister, signed the instrument of ratification for the Kyoto Protocol limiting greenhouse gas emissions. The ratification will come into force in 90 days.

Rudd was elected prime minister Nov. 24 as the candidate of Australia’s Labor Party. His election was a stunning defeat for Prime Minister John Howard, a right-wing ally of President Bush.

Australia’s ratification of the Kyoto accords is significant because the United States and Australia have the highest per capita emissions of any country. Until Rudd’s election upset, the refusal of both countries to ratify the Kyoto accords has limited their impact and effectiveness.

Rudd’s action puts additional pressure on the U.S. government to acknowledge the scientific consensus on global climate change and to participate in international negotiations for future climate change agreements. It also sets the stage for the negotiations in Bali, Indonesia, sponsored by the UN Framework Convention on Climate Change.

The Bali conference, which opened on the same day as Rudd’s action and runs through Dec. 14, is discussing the accumulating evidence of rapid climate change and the need for new negotiations on an international accord to become effective after the Kyoto Protocol expires in 2012.

The conference is set to hear remarks by Ban Ki-moon, the UN secretary-general, calling for a breakthrough leading to “a comprehensive agreement that tackles climate change on all fronts — including adaptation, mitigation, deforestation, clean technologies and resource mobilization.”

Many heads of state will be gathered in Bali, along with other government officials responsible for environmental policy and scientists. Though the conference is not expected to reach any definitive agreements, it will lay the groundwork for future negotiations.

Rajendra Pachauri, chair of the Intergovernmental Panel on Climate Change (IPCC), said, “We, the human race, have substantially altered the earth’s atmosphere. In 2005, the concentration of carbon dioxide exceeded the natural range that has existed over 650,000 years. Eleven of the warmest years since instrumental records have been kept occurred during the last twelve years. Therefore climate change is accelerating.”

The IPCC, a UN-sponsored scientific panel, along with Al Gore, recently won the Nobel Peace Prize for its work on global climate change.

Difficult issues face the negotiators — how to implement mandatory limits on carbon dioxide emissions, how severe those limits should be, how much to rely on so-called market solutions, how to reconcile the wide divergence of per capita emissions between developed and developing countries, and how rapidly action should be undertaken, among others.

But scientific evidence shows that climate change is real, is caused in large part by human activity and is accelerating rapidly. Climate change interacts with water shortages, desertification, escalating oil and natural gas prices, and poverty to cause escalating environmental problems all over the world.