1 00:00:05,070 --> 00:00:09,070 2018 was the fourth hottest year on record. 2 00:00:13,000 --> 00:00:17,070 Earth has been warming up for decades. 3 00:00:25,000 --> 00:00:29,000 The last five years are the hottest five years on record… 4 00:00:33,070 --> 00:00:37,070 And the last four were all more than 1 degree Celsius 5 00:00:37,070 --> 00:00:41,000 warmer than the 19th Century average. 6 00:00:41,000 --> 00:00:45,000 A warmer climate contributes to… 7 00:00:45,000 --> 00:00:49,000 melting polar ice and mountain glaciers, 8 00:00:49,000 --> 00:00:53,000 rising sea levels, 9 00:00:53,000 --> 00:00:57,000 more severe droughts, 10 00:00:57,000 --> 00:01:01,000 longer fire seasons. 11 00:01:05,000 --> 00:01:09,070 NASA and NOAA work together to study the temperature from weather stations,