According to an article in the WSJ this morning, all authorities concerned have documented that 2017 was overall the second warmest year on record. The first was recent (within 5 years, but I forget which). There is a negligible cooling “trend”, not unexpected as El Ninyo fades away. Some experts think this is due to the progressive loss of foliage and use of cement/asphalt around the world.
IMO the cause is the continual hyperventilation and wailing from the dems ever since the election.