12 Months Ending April 30 2015 Tied For Warmest Year On Record - NOAA
April capped a 12-month period that tied the warmest such stretch on record, according to data released Tuesday. That period, going back to May 2014, tied the previous record holder, the 12 months from April 2014 to March 2015. Of the 10 warmest 12-month periods on record, nine occurred in the past two years, most of them in back-to-back stretches.
The clustering of such warm periods is a marker of how much global temperatures have risen thanks to the human-driven buildup of heat-trapping gases in the Earth’s atmosphere.
April’s heat also ensured that 2015 is still the warmest year-to-date on record. And with a healthy looking El Nino that could further intensify in the coming months, the chances that the year as a whole could best last year’s record-breaking temperature are boosted.
Data released Tuesday by the National Oceanic and Atmospheric Administration (NOAA) ranked this April as the fourth-warmest April in the past 136 years, with an average global temperature 1.33°F above the 20th century average. NASA’s similar database put the month tied for the third-warmest April; each agency treats global temperature data in slightly different ways, creating small differences, but overall broad agreement.
EDIT
http://www.climatecentral.org/news/12-months-warmest-on-record-19010
