DGwartney's TakeOnIt

Many other strategies should take precedence over climate engineering in regards to combating global warming. The first thing to note is that even if you are not worried about climate change, an abundance of surface carbon dioxide emissions within large cities coupled with stagnant air masses is definitely not good for you. That being said, and assuming humans play a tremendous role in excess atmospheric CO2 (I know that is a debate in itself), natural measures such as carpool lanes or extended metro systems would be better alternatives. Even if engineering my be cheaper or faster than reducing CO2 emissions, perhaps it is not the safest way. However, the argument remains that the CO2 levels in the atmosphere already exceed the numbers that emission reduction could tackle on its own. With this consideration, the ideal approach would be to start implementing reduced emissions and couple this practice with geo-engineering down the road. This way, emissions may start to reach a plateau while geo-engineering tackles the rest of the excess CO2.

The oceans and rain forests are primary carbon sinks in the world. Without them, and at the rate excess CO2 is pumped into the atmosphere via anthropogenic and biologic processes, the planet would likely see far more extreme temperatures than it currently does. The oceans are great sources for absorbing CO2 from the atmosphere which is beneficial to cooling the atmosphere. However, as air temperature increases (possibly from excess CO2 emissions) oceans will increase in temperature and will be less dense, thus losing their ability to absorb excess CO2 from the atmosphere. Due to this, increasing CO2 in the atmosphere will continue to increase air temperature, which in turn increases ocean surface temperature.

Positive and negative feedbacks on the climate are basically used to define the stability of a given climate. Positive feedbacks are those that directly impact the earth’s climate system which can cause a change in climate to occur, leading to even further change in the climate. A negative feedback is one that may cause a climate change, but effectively leads to further mechanisms that act as mitigation towards negative impacts that can emerge from environmental change.

A very strong example of a positive feedback mechanism is ocean warming. This is a very important topic that many researchers have been studying for quite some time. This is a positive feedback due to the ability of water to act as a sink for CO2. The oceans are great sources for absorbing CO2 from the atmosphere which is beneficial to cooling the atmosphere. However, as air temperature increases (possibly from excess CO2 emissions) oceans will increase in temperature and will be less dense, thus losing their ability to absorb excess CO2 from the atmosphere. Due to this, increasing CO2 in the atmosphere will continue to increase air temperature, which in turn increases ocean surface temperature.

A negative feedback would be if increasing temperature leads to increasing evapotranspiration. Effectively, this would have the possibility to increase cloud cover in the atmosphere. This may be advantageous in the ability of the clouds to reflect incident solar radiation, thus leading to cooler temperatures. There is a caveat to this though; if the increase in clouds are low they will indeed cool, but if the clouds produced act as cirrus (very high) they would have the ability to increase temperature. This falls in the category of possibly increasing the greenhouse effect with increasing cirrus formation.

Two major mechanisms for abrupt climate change will reside with changes in the atmosphere and oceans. Additional CFC’s in the atmosphere, including carbon dioxide and methane, have the potential of sharply raising the earth’s global temperature. The possible effects of climate forcing positive feedbacks is that as greenhouse gases increase, they can in turn cause increased heating. It is then assumed that the increased heating will continue along with even more increases in CFC’s. There are many other theories that carbon dioxide may have an irreversible change on our climate. The oceans have the ability to absorb the excess carbon dioxide, but if the numbers continue to rise the absorption may become saturated. This would lead to warming of the deep ocean warming as well as atmosphere. There is a possibility of increased frequency of El Niño events. This could even lead to a pole ward shift of the Hadley Atmospheric Circulation Cell. Such a drastic shift could force areas such as the American Southwest to become deserted wastelands. Essentially, if ocean and atmospheric oscillations are disturbed or updated due to increased heating, the global climate change has the potential of being disastrous.