A、It was the hottest year recorded since 1800s. B、It experienced the biggest El Nino weather. C、It saw the strongest global warm

Global warming and a powerful El Nino weather event combined to make 2015 the planet’s hottest year since modern records began in the 1800s, according to scientists, who warned this year could be even warmer.
    Heatwaves around the world, including one in India that led to more than 2,000 deaths and another in Iraq that saw the mercury top 50℃, helped push temperatures it above pre-industrial levels for the first time, US and UK researchers said.
    Temperatures in 2015 also shattered the previous record set in 2014 by 0.13℃, according to Nasa.
    "Only once before, in 1998, has the new record been greater than the old record by this much," the administration added.
    Last year was especially striking because global heat records were broken or tied in every month except January and April, researchers said.
    "That’s the first time we’ve seen that," said Thomas Karl, director of the US National Oceanic and Atmospheric Administration’s national centres for environmental information.
Questions 1 and 2 are based on the news report you have just heard.
1. According to scientists, what happened in the year 2015?
2. According to NASA, what was the temperature difference between 2015 and 2014?