A group of leading scientists urged decision-makers to bring about a successful international agreement to reduce the risk of dangerous climate change, according to the Earth Statement released by the Earth League.

The statement, released to coincide with Earth Day on Wednesday, was written by 17 world-leading scientists from various countries. It warned of the risk of crossing tipping points - climate thresholds in the Earth's system that are difficult to reverse once crossed.

The scientists listed eight essential elements in the statement to clarify what the international climate agreement in Paris this coming December should achieve in order to provide the world with a good chance of avoiding dangerous climate change.

The first essential element is a commitment to limit global warming to below two degrees Celsius, requiring a transition to a zero-carbon society by mid-century.

"The key to success is deep decarbonization by mid-century. Our studies show that this can be accomplished, at modest cost, and with a significant improvement in the quality of life. Success will require a shared global vision, strong national commitments, and global cooperation on technology pathways," said Professor Jeffrey Sachs, one of the authors of the Earth Statement.

Other elements listed in the statement included a global carbon budget, the development of low-carbon energy systems and sustainable land, safeguarding carbon sinks and vital ecosystems, etc.

"The scientific evidence shows that we can create a positive future, but only with bold action now," said Johan Rockstrom, Chair of the Earth League.

The Earth League is an international alliance of prominent scientists from world-class research institutions.