Many believe these impacts are already being felt. Last year in the United States, extreme heat caused massive wildfires in Florida and crop damage throughout the South. Guyana experienced severe drought, Indonesia devastating fires, China record floods that left over three thousand dead. Off the coast of southern California, zooplankton, a key link in the aquatic food chain, have declined a stunning seventy percent in the last two decades. In the course of the last century, Alpine glaciers have lost almost fifty percent of their ice.
Spring now arrives a full week earlier to the Northern Hemisphere than it did just twenty years ago.
Consider these possible feedback loops. As global warming melts the permafrost, stored methane is released. But methane is a greenhouse gas, so global warming accelerates, releasing still more methane. As temperatures rise, entire forests die off, releasing as they decay staggering amounts of carbon dioxide, further warming the atmosphere. Meanwhile, as the ozone layer depletes, ultraviolet radiation decimates the phytoplankton that absorb carbon dioxide, speeding global warming while triggering a crash in fish populations that feed on the plankton.