CO2 in the world's constantly swirling and borderless air is currently at about 389 parts per million and rising steadily.
Many nations have agreed on 450 ppm as an acceptable limit to try for.
Other scientists, including NASA's James Hansen, say the world must get back down to 350 ppm soon to avoid catastrophic climate change.
The ambassador told ABC News that climate negotiations should not focus on economy-based emissions target numbers that help only some countries. Instead, he said, they should focus simply on how to stop global warming -- for all countries.
"To me, we are now dancing around the problem, not really spearing the problem in the heart!" he said.
Micronesia is one of 37 island nations around the world, comprising many thousands of islands.
"The way we are doing things now," said the ambassador, "we're going down the path of ultimate destruction."