US government scientists are widely expected to announce Wednesday that 2015 was the planet's hottest year in modern times, amid mounting concerns over the pace of climate change worldwide.

Last year was the second hottest on record in the contiguous United States, and included 10 major weather and climate events, such as droughts and storms, that each led to over $1 billion in damages, the National Oceanic and Atmospheric Administration said on Thursday.

Thirty large whales have died in the western Gulf of Alaska since May, an unusually high number for the region, and scientists aren't sure what's causing the die-off.

July was the hottest month in history, and the first seven months of the year were also the warmest since modern record-keeping began.

The car-tire-size opah is striking enough thanks to its rotund,silver body. But now, researchers have discovered something surprising about this deep-sea dweller:It's got warm blood.