Natural Causes of Climate Change

This page discusses natural causes of climate change.

The Greenland ice sheet is melting from below, caused by a high heat flow from the mantle into the lithosphere. This influence is very variable spatially and has its origin in an exceptionally thin lithosphere. Consequently, there is an increased heat flow from the mantle and a complex interplay between this geothermal heating and the Greenland ice sheet. The international research initiative IceGeoHeat led by the GFZ German Research Centre for Geosciences establishes in the current online issue of Nature Geoscience that this effect cannot be neglected when modeling the ice sheet as part of a climate study.

Natural swings in the climate have significantly intensified Northern Hemisphere monsoon rainfall, showing that these swings must be taken into account for climate predictions in the coming decades, a new study finds.

One important factor in climate change is natural causes, that is, aspects of our earth, other than effects of people, that affect our climate. Natural causes of climate change include the earth itself, winds, volcanoes, and ocean currents. Most of these factors are discussed in other posts. This post contains links to factors affecting climate changes that are not discussed in other places.
Ancient rises in sea levels and global warming are partially attributable to cyclical activity below Earth's surface, researchers from New York University and Ottawa's Carleton University have concluded in an analysis of geological studies.

However, the article's authors, NYU's Michael Rampino and Carleton University's Andreas Prokoph, note that changes spurred by Earth's interior are gradual, taking place in periods ranging from 60 million to 140 million years -- far less rapidly than those brought on by human activity.

A team led by the University of Colorado Boulder looking for clues about why Earth did not warm as much as scientists expected between 2000 and 2010 now thinks the culprits are hiding in plain sight -- dozens of volcanoes spewing sulfur dioxide.

"We have shown that adding polar storms into computer-generated models of the ocean results in significant changes in ocean circulation -- including an increase in heat traveling north in the Atlantic Ocean and more overturning in the Sub-polar seas.

Lead author, Dr Paul Holland of BAS says: "Until now these changes in ice drift were only speculated upon, using computer models of Antarctic winds. This study of direct satellite observations shows the complexity of climate change. The total Antarctic sea-ice cover is increasing slowly, but individual regions are actually experiencing much larger gains and losses that are almost offsetting each other overall. We now know that these regional changes are caused by changes in the winds, which in turn affect the ice cover through changes in both ice drift and air temperature. The changes in ice drift also suggest large changes in the ocean surrounding Antarctica, which is very sensitive to the cold and salty water produced by sea-ice growth.

"In the temperature curves from the ice cores we can see that there is no general global cooling as a result of the eruption. There is certainly a cooling and large fluctuations in temperature in the northern hemisphere, but it becomes warmer in the southern hemisphere, so the global cooling has been short," says Anders Svensson.

Reports of declining ice coverage and drowning polar bears in the Arctic illustrate dramatic ecosystem responses to global climate change in Earth's polar regions. But in this first-ever account of a long-term project in the southern Caribbean, a Stony Brook professor and his colleagues report in this week's Proceedings of the National Academy of Sciences that tropical ecosystems are also affected by global climatic trends -- and with accompanying economic impacts.

Lead author Dr Stewart Jamieson, a glaciologist at the Department of Geography, Durham University, said: "Our research shows that the physical shape of the channels is a more important factor in controlling ice stability than was previously realised. Channel width can have a major effect on ice flow, and determines how fast retreat, and therefore sea-level rise, can happen.