World leaders have been adding their voices to those of scientists on climate change, following the latest warning that levels of greenhouse gases in the atmosphere reached a record high last year.br br The World Meteorological Organization (WMO) has produced evidence showing that carbon dioxide levels have climbed steadily each year since reliable records began in 1984.br br “We have broken a new record once again. Over the last 25 years between 1990 and 2014, there was a 36 percent increase in the radiative forcing of greenhouse gases,” said the World Meteorological Organisation’s Secretary-General Michel Jarraud.br br UN weatherclimate agency chief calls for urgent action on #greenhousegas #COP21 WMOnews pic.twitter.