Introducing Geoengineering

In past posts we have discussed the threat climate change presents to us, and the critical moment in which we are living. The future of planet Earth depends on the decisions politicians make today.

The report states that in order to stay beneath the 2ºC of temperature change, we have to cease CO2 emissions by 2100. It discusses various ways of mitigation for doing this. But, unfortunately, the possibility of the planet getting warmer than desired exists. In fact, as we discussed in previous posts when analysing different projected scenarios, the probability of exceeding 2ºC is really high.

That being said, I consider it is very important to discuss ways of mitigation, because it is the only way we can truly save the planet. But, additionally, why not prepare ourselves for the worst case scenario and discuss techniques of artificially cooling the planet and reducing global warming? These techniques exist under the name of geoengineering. However, they are very controversial, mainly because of two reasons.

• The first and more important in my opinion, is the amount of secondary effects they convey. 

• The second one is that people fear that if we get too involved with geoengineering, we are reducing politicians' responsibility for cutting fossil fuel emissions. This is what David Keith called the 'moral hazard,' in the video in my previous post.

We will discuss these techniques and their side effects in following posts.

Geoengineering techniques divide mainly into two categories (Geoengineering the Planet, The Royal Society): Solar Radiation Management (SRM) and Carbon Dioxide Removal (CDR). Both have, as a final objective, reduce global warming. However, they are completely different in other aspects:

Solar Radiation Management

The objective of SRM techniques is to reflect a small percentage of sunlight and heat into the atmosphere, therefore avoiding great temperature increases. It does not address the issue of the concentration of CO2 in the atmosphere, nor the issue of ocean acidification, amongst others. However, it is relatively cheap and the effects are very quick. It is therefore of great interest to the scientific community, because it could be used in an emergency, to avoid a possible point of no return in climate change. Some of the techniques studied are shown in the following picture.

How SRM can reduce absorption of radiation. The width of each arrow is proportional to the magnitude in question. 

Carbon Dioxide Removal

The objective of CDR is, clearly, to reduce the concentration of Carbon Dioxide and other GHG from the atmosphere. It is a great solution, given that it works upon the root of climate change, and would therefore improve all its consequences. However, it is a much slower and expensive process. Additionally, none of the considered techniques have been proved to work without any severe side effects. One of the techniques involves capturing and compressing CO2, and storing it in porous rocks or into deep sea. Another technique is adding iron into the sea. This way we stimulate the growth of algae, that consume CO2. When these die, they would bury this CO2 in the bottom of the ocean with them.

The following picture illustrates some of the techniques we are to discuss in following posts:

Source

In the next post we are going to explicitly discuss powerful SRM techniques, along with their side effects.

Keep in touch!