WASHINGTON, United States -- Lengthy pandemic school closures have cost students trillions of dollars in lifetime earnings, the World Bank and UN agencies said Monday, warning that the crisis has worsened since last year.

The Washington-based development lender, along with UNICEF and UNESCO, in a report said the current generation of students risk losing $17 trillion in lifetime earnings, amounting to about 14 percent of global GDP, due to classroom disruptions caused by Covid-19.

That was higher than a previous estimate made last year of a $10 trillion hit to students worldwide from the pandemic.

"The Covid-19 crisis brought education systems across the world to a halt. Now, 21 months later, schools remain closed for millions of children, and others may never return to school," said Jaime Saavedra, the World Bank's Global Director for Education.

"The loss of learning that many children are experiencing is morally unacceptable."

The disruptions are not being felt equally, with the study finding that poorer and disabled children have less access to remote learning, while younger students were overall more affected.

Girls had both less ability to shift to remote learning and more education loss overall, the report added.

While governments worldwide have unveiled stimulus measures to bolster their economies against the pandemic's disruptions, less than three percent of these funds have gone to education, and more than 200 million students live in countries that don't have the means to offer all lessons remotely.