BBC News By Matt McGrath For Nasa, last year is in a statistical dead heat with 2016 as the warmest year. Others, including the UK Met Office, believe it is second in the rankings dating back to the 19th Century. But all the agencies reporting on Thursday agree that last 12 months are part of the warmest decade on record. Thursday's reports, from five key agencies around the world, show some dissent from this view, but all agree 2020 is in the top three. image copyrightWales News Service image captionWildfires raged in many parts of the world as temperatures soared Nasa says 2020 is tied with 2016, while the US National Oceanic and Atmospheric Administration (Noaa) and the UK Met Office have it second.