Plants Key in Regulating Ice Ages
06.07.2009 - Atmosphere & Space, Land & Geology, Ice & Snow, Other, Arctic, Antarctic
Until now leading models had not been able to explain what kept advancing glaciers from covering the whole planet during the last ice age, since over the past 24 million years geological conditions should have caused CO2 levels in the atmosphere to plummet, leading to a possible runaway icehouse effect. However new research published in the July 2 issue of Nature shows that plants have played an important role in keeping concentrations of atmospheric CO2 within such a relatively narrow range.
Plants perform important actions that can either increase or decrease carbon dioxide levels in the atmosphere. They hold soils in place, controlling erosion, breaking down minerals in the soil and increasing the amount of carbon dissolved in groundwater and sequestering minerals containing carbon in the Earth's crust by encouraging sedimentation. According to Ken Caldeira of the Carnegie Institution's Department of Global Ecology, if CO2 levels get too low, then the plants suffocate and weathering slows down.
However the important role plants play in regulating carbon does not give us free rein to spew as much CO2 into the atmosphere as we like. Dr. Caldiera mentioned that "while these weathering processes will eventually remove the CO2 we are adding to the atmosphere, they act too slowly to help us avoid dangerous climate change. It will take hundreds of thousands of years for these rock weathering processes to remove our fossil fuel emissions from the atmosphere."
