The Greenhouse Gas Bulletin said the annual rate of increase last year was above the annual average between 2011 and 2020 GENEVA: Greenhouse gas concentrations in the atmosphere reached new record levels last year, the United Nations said Monday in a stark warning to the COP26 summit about worsening global warming. The Greenhouse Gas Bulletin, from the UN’s World Meteorological Organization, said the annual rate of increase last year was above the annual average between 2011 and 2020 — and the trend continued in 2021.