Earth heads for a top 5 warmest year as the Arctic heats up

Continued freak warmth in the Arctic helped propel global average temperatures to the second-warmest level on record for the month of April, NASA reported on Monday. 

Separately, on Thursday the National Oceanic and Atmospheric Administration (NOAA) reported the same rank for the month, and also said the year-to-date currently ranks as the 2nd-warmest January through April period, behind the same timeframe last year.

The new findings illustrate how the planet is still setting climate milestones even in the absence of other factors that tend to elevate global air and sea temperatures, such as an El Niño event. 

This makes clear the growing influence of human-caused global warming on the planet's climate, month after month, year after year, as the amounts of planet-warming greenhouse gases in the atmosphere continue to rise to levels unseen during all of human history.