Snowball Earth refers to the contention that in the distant past the Earth froze over from pole to pole. There is considerable evidence to support this contention and now believe this freezing occurred not just once but a number of times in perhaps more than one episode of freezing and thawing.
The explanation that has been developed to explain these cycles of freezing and thawing is that the weathering of rocks reduces the carbon dioxide in the atmosphere resulting in a cooling of the Earth.
Last week brought freezing temperatures brought the claims of climate change to the general public.
study in the journal Nature Climate Change finding that one of the largest glaciers in Antarctica has started melting irreversibly.
contributor to sea-level rise, could add as much as one centimeter to ocean levels within the next 20 years.
The glacier has started a phase of self-sustained recoil and will irreversibly continue its decline.
The team of researchers used state-of-the-art ice-flow models and field observations to help determine how the glacier’s ice flows will change in coming years.
told Planet Earth Magazine.
found that that glacier’s grounding line, which has already receded up to 10 kilometers this century, is “probably engaged in an unstable 40-kilometer retreat.”
see this rising to 100 billion tonnes a year in the coming decades.
Polar bears are listed as a threatened species under the United States Endangered Species Act and are classified as “vulnerable” with declining populations on the International Union for Conservation of Nature and Natural Resources’ Red List. Climate warming is reducing the availability of their ice habitat, especially in the spring when polar bears gain most of their annual fat reserves by consuming seal pups before coming ashore for the summer. The new work, led by Rockwell and Linda Gormezano, a postdoctoral researcher in the Museum’s Division of Vertebrate Zoology, examines how polar bears might compensate for energy shortage from decreasing seal-hunting opportunities.
As climate change has shortened the hunting season on sea ice, polar bears have shifted to eating more land-based foods such as geese, eggs and caribou. Some have even resorted to garbage!