The UN pledged to improve the lives of the world's most needy; enacting that plan is another matter

It's been two years since the United Nations adopted 17 goals aimed at fighting poverty and inequality, protecting the environment and fostering peace.

The target year for achieving those goals is 2030, but that's little time, given the scope of the agenda, and experts note formidable obstacles stand in the way of achieving these "sustainable development goals," or SDGs.

"We had the SDG agreements in 2015. Everybody felt very good," said Homi Kharas, co-director in the global economy and development program at the Brookings Institution.

But while there was progress in 2016 and 2017, there also was some regression, Kharas said. "The pace is not fast enough to achieve the SDGs. I