labs_title

Caldeira Lab Research:Energy, Global Carbon Cycle, and Climate

Carbon Sequestration via Direct Injection

H. Herzog, K. Caldeira & E. Adams

The impending danger of major climate change due to anthropogenic CO2 emission calls for a radical solution. As of now it appears unlikely that humans will stop using fossil fuels as a primary energy source for years to come, prompting the investigation into alternative solutions such as carbon sequestration. This is an investigation of the capacity, effectiveness, procedural requirements, and possible consequences of carbon sequestration in the deep ocean.


Herzog, H., K. Caldeira and E. Adams, Carbon Sequestration via Direct Injection. In J H Steele, S A Thorpe and K K Turekian (eds) Encyclopedia of Ocean Sciences Vol. 1, pp 408 - 414. London, UK: Academic Press, 2001.

How much CO2 will remain sequestered permanently? The percentage of sequestered CO2 that had not leaked in the model is graphed above as a function of various atmospheric CO2 concentrations. The percentage declines over time but in general stays fairly high.

Fraction of CO2 that is leaked: The relative amount of CO2 leaked at various depths shown as a function of time. These results indicate that for deep sea injection to be effective, it must be done at depths of greater than 1000m.

Abstract

The build-up of carbon dioxide (CO2) and other greenhouse gases in the Earth’s atmosphere has caused concern about possible global climate change. As a result, international negotiations have produced the Framework Convention on Climate Change (FCCC), completed during the 1992 Earth Summit in Rio de Janeiro. The treaty, which the United States has ratified, calls for the stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. The primary greenhouse gas is CO2, which is estimated to contribute to over two-thirds of any climate change. The primary source of CO2 is the burning of fossil fuels, specifically gas, oil, and coal. Therefore, efforts are being made to reduce our dependence on fossil fuels through improved efficiency and the introduction of nonfossil energy sources, such as solar and nuclear. However, it is becoming clear that although these strategies may slow the build-up of atmospheric CO2, they will not reduce emissions to the level required by the FCCC. In other words, the fossil fuels, which currently supply over 85% of the world’s energy needs, are likely to remain our primary energy source for the foreseeable future. This has led to increased interest in a new strategy termed carbon management and sequestration.