"In light of the ongoing, worldwide effects of Covid-19, holding an ambitious, inclusive COP26 in November 2020 is no longer possible," the government said in a statement, adding that dates for a rescheduled conference in 2021 would be announced later.
Some 30,000 people, including 200 world leaders, had been due to attend the 10-day conference for crucial talks to halt rising global temperatures.
A UN panel in 2018 concluded that avoiding global climate chaos needed a major shift in society and the world economy.
Global CO2 emissions needed to drop 45 percent by 2030 and reach "net zero" by 2050 to limit temperature rises at 1.5 degrees Celsius - the safe cap set as a goal in the Paris climate agreement.
UN Secretary General Antonio Guterres said he supported the decision to postpone as "the need to suppress the virus and safeguard lives is our foremost priority".
"This dramatic human crisis is also an example of how vulnerable countries, societies and economies are to existential threats," he said in a statement.
"Countries must work to protect the health of people and the planet has never been more at risk."
UN Climate Change Executive Secretary Patricia Espinosa said postponement was unavoidable but that the pandemic should not divert the world from the climate change challenge.
"Covid-19 is the most urgent threat facing humanity today, but we cannot forget that climate change is the biggest threat facing humanity over the long term," she said.
Climate activists recognised the need to delay the conference because of the global health crisis, but urged governments not to forget their climate commitments.
"While events can be postponed, climate change won't pause even for a pandemic of epic proportions," said Alden Meyer, a climate negotiations specialist.
(with AFP)
