Greenhouse gases in the atmosphere, the main driver of climate change, hit record highs last year and have continued climbing this year, despite measures to halt the pandemic, the United Nations said Monday.

The World Meteorological Organization (WMO) said that while lockdowns and other measures had cut emissions, this had not curbed record concentrations of the greenhouse gases that are trapping heat in the atmosphere, raising temperatures, causing sea levels to rise and driving more extreme weather.

"The lockdown-related fall in emissions is just a tiny blip on the long-term graph. We need a sustained flattening of the curve," WMO Chief Petteri Taalas said in a statement.