Background color for WARNING safety signs, labels, and tags. Marking hazardous parts of machines with may cut, crush, or otherwise injure. Emphasizing hazards when enclosure doors are open or when gear, belt, or other guards around moving equipment are opened or removed, exposing unguarded hazards. Marking exposed edges of
Bibcode:1995GBioC...9..377C. doi:10.1029/95GB01107. An ice age is a period of long-term reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers.
Ice Ages. Our current climate regime -â a regime weâve had for the past ~2 million years â- is characterized by long periods of ice ages and shorter warm periods. The last ice age ended about 12,000 years ago, and since then weâve been in a warm period. Some argue that global warming is no concern, since the Earth will naturally switch back to an ice age. This is very likely to be true: an ice age is almost certainly in our planetâs future. But itâs a question of when. Our current concerns about climate change focus on the coming decades to the next century â- the time period relevant to our childrenâs and grandchildrenâs experience.