Chinese President Xi Jinping, accompanied by his wife Peng Liyuan, arrives in Paris, capital of France, to attend the opening ceremony of an international conference on climate change on November 29, 2015. [Photo/Xinhua]

Although the wounds and pain from the recent terrorist attack have yet to heal, and new threats hover over the proceedings, world leaders decided to gather in Paris today to show their unwavering support to Paris and to commit to unified leadership on climate change.

This is a historical moment in the global effort to address climate change, with the potential to reshape global climate governance.

The Paris conference marks the 21st meeting of the Parties of the UNFCCC. More than two decades have passed since the signing of the UNFCCC in Rio de Janeiro, Brazil in 1992.

While the Kyoto Protocol marks the height of the climate negotiations, most of the past two decades of negotiations have been tainted by disputes, distrust, stagnation and pessimism.

The Kyoto Protocol was a first attempt to shape global climate governance in a top-down manner, which set a global target of greenhouse gas mitigation and then disaggregated the effort among countries deemed to be responsible.

Meanwhile, the need for climate finance and technology transfer was identified with the coordination of the United Nations.

In 2001, President Bush withdrew the United States from the Kyoto Protocol, a major setback in efforts to coordinate an international solution since the US was then the world's largest carbon emitter.

A crisis of failure became imminent as several more developed countries followed suit. Although the Kyoto Protocol held together in the end, the climate regime proved unsuccessful in rallying a truly inclusive, global effort to address climate change.

Then, the Copenhagen Conference in 2009 was invested with overwhelming expectations, proclaimed by a broad selection of policymakers, scholars, and activists as the last chance to save the world.

With Denmark playing host, the European Union worked hard to achieve a new agreement in the style of Kyoto that the media and environmental NGOs demanded be ambitious, fair and legally binding.

However, these expectations were not met, with an eleventh hour deal struck without the EU on site. Disappointing to the EU and many other participants, the Copenhagen Conference was the last attempt at a top-down approach, a style of global coordination that was doomed to fail as most of the world was not prepared to follow.

Meanwhile, the meeting and its aftermath provoked a moment of reflection to determine an alternative approach.

The Copenhagen Accord is essentially a collection of pledges from individual countries based on their own social and economic circumstances, with a political commitment to limit an increase in global temperatures to no more than 2oC.