Geoengineering involves the artificial manipulation of the Earth's climate in order to mitigate the negative effects of increased greenhouse gases in the atmosphere. Two major categories of geoengineering have been proposed and discussed: Carbon Dioxide Removal (CDR) and Solar Radiation Management (SRM). A more in-depth description of each of these strategies is described in the tabs above.
Why are some people considering geoengineering strategies? It is known that certain gasses, like carbon dioxide and methane, prevent some solar radiation from leaving the atmosphere and returning back to space. Generally, this is a good thing, because without a certain amount of these gasses, the Earth would be too cold to be inhabitable. However, the amount of these gases in the atmosphere has been steadily increasing, in large part due to the burning of fossil fuels like oil and coal. The increase in the concentration of greenhouse gasses has already lead to an increase in global temperatures. Several models recreating global temperatures over time have been published. In 2001, the Intergovernmental Panel on Climate Change released the now well known 'hockey stick' graph showing the rapid increase in global temperatures within the last century.
In addition to this graph, many different models have been developed to predict the future trend in average global temperature. Even though these models start with different assumptions, all of them predict a significant increase in temperature.
Although it is known that the Earth is warming, what is not fully known are what the effects of a warmer planet could be. The climate is a very complex system that involves the interaction of many aspects, and it is not completely certain what repercussions could be caused by changes to this system. It is generally thought that we need to reduce greenhouse gas emissions in order to prevent climate change from becoming a severe problem. Those who advocate for geoengineering believe that it is too late to rely on reducing emissions alone and think that we should have some sort of alternative plan to implement in addition to lowering emissions. In this, some think that we should try to remove some amount greenhouse gases from the atmosphere, either directly or indirectly. Still others want to prevent some incoming solar radiation from reaching Earth as a way to prevent increased warming.