President Lee Myung-bak is urging North Korea to swiftly and unconditionally return to the six-way nuclear talks.

In a keynote speech at the U.N. General Assembly in New York on Thursday, Lee called on the North to abide by the 1992 South-North Joint Declaration on the Denuclearization of the Korean Peninsula. He also urged Pyongyang to join international efforts for denuclearization.

Lee then reiterated his proposal for a “grand bargain,” which centers on North Korea dismantling key aspects of its nuclear program while at the same time providing the North with a security guarantee and international aid.

Lee then touched on global environmental issues, stressing the need for the international community to set up a comprehensive system to manage water. He also introduced South Korea’s projects to develop its four key rivers, saying the projects are aimed at securing rain water, controlling floods and restoring rivers’ ecosystems.

He said South Korea has adopted “low-carbon, green growth” as a national development strategy and that he believes such a policy is the most effective way to tackle threats posed by climate change and the global financial crisis.