The first nine months of 2017 are the second-warmest in records that date back to the late 1800s, according to the latest monthly National Oceanic and Atmospheric Administration report Wednesday.

Why it matters: The data underscore how this year is part of a long-term warming trend that scientists say is largely due to human influences.

The gritty details: The January-September period was 0.87°C (1.57°F) above the 20th-century average.

• "Nine of the 10 warmest January-September global land and ocean temperatures occurred during the 21st century (since 2005), with only one year from the 20th century (1998) among the top 10. Based on three simple scenarios, 2017 will likely end up among the top three warmest years on record," NOAA said.