doctors in the united states have carried out the first successful transplant of a pig's heart into a human patient. the animal was genetically modified to reduce the chance of the tranplanted organ being rejected. surgeons at the university of maryland medical centre said the 57—year—old patient, david bennett, was doing well and the heart appeared to be working normally. the past seven years have been the hottest on record, according to the eu's copernicus climate change service, which said they were the warmest by a clear margin since 1850. last year was the fifth—warmest year, with record—breaking heat in some regions and levels of carbon dioxide and methane hit new heights. our climate editor, justin rowlatt, examines the data. what a way to see in the new year. almost 1,000 homes were destroyed