Most scientist agree the main cause of the current global warming trend is human expansion of the "greenhouse effect" warming that results when the atmosphere traps heat radiating from earth toward space. Certain gases in the atmosphere block heat from escaping.
Carbon dioxide and other air pollution that is collecting in the atmosphere like thickening blanket, trapping the sun's heat and causing the planet to warm up.
Researcher Bill Fraser has tracked the decile of the Adelie penguins on Antarctica, where their numbers have fallen from 32,0000 breading pairs to 11,000 in 30 years