The world is on track to see "terrifying" climate impacts as stepped-up emissions-cutting plans filed by countries so far fail to limit fast-accelerating global warming, analysts said Wednesday.

More than two-thirds of about 195 countries that signed the 2015 Paris Agreement on climate change had submitted a new or updated climate action plan by an extended U.N. deadline on Tuesday, a tracker by the U.S.-based World Resources Institute (WRI) shows.

That is an increase from the just over half of countries who had filed plans by the end of July. Nations that updated their pledges in recent days include South Africa and Japan, with the latter promising to halve its emissions from 2013 levels by 2030.