A rough deadline for today saw only 32 out of 195 countries submit pledges for tackling greenhouse gases under UN climate talks scheduled to conclude just over eight months from now.
Analysts, though, said the commitments were generally encouraging, even if the UN's aim to curb warming to two degrees Celsius (3.6 degrees Fahrenheit) remained worryingly distant.
Among major carbon emitters, the United States and the European Union put their positions on the table as expected, along with Mexico, the first emerging country to do so.
But developing giants China, India and Brazil were absent for now, which could further complicate an already tortured process, these observers added.
"While there has been some progress in what governments are proposing for the post-2020 period, with several countries moving from 'inadequate' to 'medium,' proposals are still a long way from being 2 C compatible," said Bill Hare of Climate Analytics, a monitoring group.
"The delay (in submitting pledges) is going to be a problem," cautioned Celia Gautier of the French branch of Climate Action Network (CAN), an umbrella group of NGOs.
"The more time that countries take, the less keen they will be to comparing their pledges with those of other countries and improving what they've put on the table."
End-March had been set as a loose date for parties to the UN Framework Convention on Climate Change (UNFCCC) to put their proposed measures on the table.
Voluntary but open to scrutiny, these "intended nationally determined contributions" (INDCs) are deemed to be the core of a post-2020 pact, to be agreed in Paris by December 11, to peg global warming to 2C over pre-industrial levels.
Today's deadline applied to countries "ready to do so" under an agreement in Lima last December, and several big players had already indicated they would make their announcements later.
Parties that had entered their commitments as of March 31 included the No. 2 emitter, the United States, and the No. 3, the EU, which represents 28 nations.
