United Nations Secretary-General Ban Ki-moon has praised U.S. President Barack Obama Tuesday for his visionary and bold leadership in moving forward a plan to cut carbon pollution produced by American power centers.

Mr. Obama's plan aims to cut carbon emissions by 32 percent below 2005 levels by 2030. Opponents are calling the plan too costly and possibly illegal.

After meeting with Mr. Obama at the White House, the U.N. leader said, "On climate change, I highly commend President Obama's strong commitment since day one in his office up to now."

Mr. Obama said the environmental threat posed by climate change is perhaps the critical issue facing the world. The American leader said the Paris conference on global environmental standards this December needs to be a success.

The two leaders said they also discussed crises in Syria, Yemen, Libya and South Sudan.