- Summary- Companies- Greenhouse gas levels hit new record in 2021- Methane surge is highest since data began- Report comes less than two weeks before COP27LONDON, Oct 26 (Reuters) - Greenhouse gas concentrations climbed at above-average rates to new records last year, the U.N. weather agency said on Wednesday, warning that time is running out for people to make the transformational changes needed to cap global temperature rises.The annual report by the World Meteorological Organization is the first of several released ahead of a U.N. climate summit next month in Egypt and aims to spur leaders into action.Hikes in the atmospheric concentration of all three greenhouse gases - carbon dioxide, methane and nitrous oxide - outstripped the average increase over the past decade, it showed, meaning they are now all at new record levels.Concentrations of the main greenhouse gas carbon dioxide rose by 2.5 parts per million to 415.7 - a level not seen since at least 3 million years ago when the Earth was much warmer.Unlike emissions which can be cut, such as through reduced travel and industry during the pandemic, much of the carbon dioxide emitted decades ago remains in the atmosphere and activates slow processes like sea-level rises over millennia."