Includes natural processes within the climate system: orbital patterns, solar radiation, oceans, atmosphere, water cycle, the natural greenhouse effect, carbon cycle, regional climates and differences between climate and weather.
In October 2003, a little-known think tank in the Department of Defense quietly released a report warning that climate change could happen so suddenly it could pose a major threat to our country's national security. Why was the Pentagon worried about abrupt climate change? Because new evidence from Greenland showed it had happened before.
According to the 2009 National Climate Assessment, heavy downpours have increased in frequency and intensity during the last 50 years. Models predict that downpours will become still more more frequent and intense as greenhouse gas emissions and the planet’s temperature continue to rise.
The most likely explanation for the lack of significant warming at the Earth’s surface in the past decade or so is that natural climate cycles caused shifts in ocean circulation patterns that moved some excess heat into the deep ocean.
Following a brief interlude of “neutral” sea surface temperature conditions this summer, La Niña has returned to the tropical Pacific Ocean. The cool phase of the El Niño-Southern Oscillation climate pattern is expected to persist through winter.
Each summer, the seasonal unraveling of the Arctic’s blanket of ice exposes large areas of the ocean to solar heating. The smaller the ice extent, the larger the potential warming influence. Arctic sea ice extent in July 2011 was the lowest for that month in the satellite record.
The ocean is the largest solar energy collector on Earth. More than 90 percent of the warming that has happened on Earth over the past 50 years has occurred in the ocean. Not all of that heating is detectable at the surface because currents move some of the heat to deeper layers of water, where it can "hide" for years or decades.