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A seminal book by Milankovitch in 1941 proposed that the sequence of ice ages that has characterized long term changes in the Earth’s climate over the past hundreds of thousands of years was due to changes in the amount of solar radiation reaching the Earth as a result of small variations in the Earth’s orientation and orbit with respect to the sun. Since then research has shown that Milankovitch cycles by themselves do not determine the timing of glacial and interglacial cycles and that we still lack a unified mechanism that links changes in Earth’s orbit to ice ages.
In contrast to West Antarctica where several large glaciers have been losing ice for decades, East Antarctica glaciers have exhibited little evidence of ice loss but NASA’s latest detailed maps of East Antarctica ice velocity and elevation show that a number of glaciers have begun to lose ice over the past decade.
Between 2005 and 2017 the U.S. economy as measured by real GDP expanded by about 20 %. Over this same period, emissions from power generation dropped which is evidence of a decoupling between economic growth and power generation.
Atmospheric methane concentration plateaued leading up to 2006, but began to rise again in 2007. The source of the increase has been widely debated, but using satellite imagery a recent study has found that the increase can be ascribed to increased fossil fuels and livestock sources in roughly equal measure.
A reanalysis of the effect of black carbon emissions has found that it is second only to carbon dioxide emissions in its warming impact on the climate. Together carbon dioxide, black carbon, and methane emissions represent the anthropogenic sources with the largest impact on Earth’s climate.
During the last deglaciation there was several episodes of rapid and substantial sea level rise. A recent study has found that during one of these, sea level rose by about 17 meters over a period that does not exceed 350 years, but could be as low as a century.
June 5, 2017
Approximately 800,000 years ago something changed in the Earth’s climate system that led to the climate then following a series of approximately 100,000 year cycles. Small, predictable changes in the Earth’s orbit about the Sun act as triggers for the glacial and interglacial periods, but other factors such as ice sheet volume, CO2 concentration, and biological feedback mechanisms are also involved.
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During the last deglaciation there was several episodes of rapid and substantial sea level rise. A recent study has found that during one of these, sea level rose by about 17 meters over a period that does not exceed 350 years, but could be as low as a century.
A recent study of ice cores from Antarctica provides a climate record for the past 800,000 years. The analysis reveals that atmospheric carbon dioxide was strongly correlated with Antarctic temperature throughout eight glacial cycles.
Between 2005 and 2017 the U.S. economy as measured by real GDP expanded by about 20 %. Over this same period, emissions from power generation dropped which is evidence of a decoupling between economic growth and power generation.
In 1997 Raymo was the first to provide observations supporting the orbital forcing hypothesis for glacial/deglacial cycles that did not rely on orbital tuning. The research also suggested that ice sheet dynamics needed to be considered in addition to orbital forcing to explain the observed 100,000 year glacial/deglacial cycles.