What is Geoengineering?

Whilst looking for a good video clip to summarise geoengineering, I stumbled upon a hornet’s nest of conspiracy theories and very intense campaigns. A simple YouTube search of ‘geoengineering’ sent me straight to the heart of it with very emotive titles such as ‘WARNING’, ‘COVER UP’ and ‘DEATH FROM ABOVE’ dominating the results. Far from the cute clip art inspired animation I was expecting. Undoubtedly, there is strong opposition to geoengineering because it raises a range of social, ethical and political issues. However, I can’t help feeling there is case of painting all types of geoengineering with the same brush as different methods will have different associated issues.  

Geoengineering is commonly defined as: 

A ‘deliberate large-scale manipulation of the planetary environment to counteract anthropogenic [human-induced] climate change’ (Royal Society, 2009).

A very broad definition which at first sounds quite radical. However, Heyward (2013) argues that mitigation techniques (reducing or preventing greenhouse gas emissions) would also fit into this extreme sounding definition. For example, cutting carbon emissions. This is a deliberate, large-scale change to the planetary environment with the aim to reduce the climate change caused by our consumerist lifestyles. Furthermore, I would also highlight that climate change itself is a large-scale manipulation of the planetary environment, deliberate or not. Due to these similarities between geoengineering and what we are already doing, personally, I do not have a problem with the idea of geoengineering. My uncertainty lies more with the specific methods.  

 

Geoengineering methods can be divided into two categories: Carbon Dioxide Removal (CDR) and Solar Radiation Management (SRM). I will use these to focus my blog.

 'It’s getting hot'...

 …‘Then take off your blanket!’ (Carbon Dioxide Removal)

 

The idea behind Carbon Dioxide Removal (CDR) is to remove the extra blanket of heat-trapping CO₂ we’ve put into the atmosphere. Years of burning fossil fuels and changing land use have converted stored carbon into atmospheric carbon dioxide. CDR proposes to reverse this process. Carbon in the atmosphere would be taken out and stored elsewhere, letting heat leave the planet more easily and therefore cool the planet. The carbon cycle below shows details of natural carbon stores that could be utilised by CDR. Many of these already hold much larger amounts of carbon than the atmosphere, but increasing these stores comes with risks even before the method is considered.  

  The carbon cycle (IPCC, 2013)

 

'It’s getting hot'...

 …‘Then turn the heating down!’ (Solar Radiation Management)

 Clearly Solar Radiation Management (SRM) methods do not propose reducing the heat of the sun. Rather they propose reducing the amount of heat and light from the sun reaching the surface of the Earth by reflecting more out to space. This would reduce the amount of heat getting in and counteract the fact that less heat is getting out. Therefore, cooling the planet. This is represented by the green path in the diagram below with the incoming shortwave radiation representing sunlight. SRM would not alter the amount of carbon dioxide in the atmosphere so tends to be the more controversial type of geoengineering. 

Incoming solar radiation budget (Netting, 2016)

To meet the 2°C target by the end of the century the question of timeframe also comes into play. CDR methods will take time to have an affect whereas SRM methods could be instantaneous, making both types worth exploring. I feel it is particularly relevant as the distinct lack of attention to climate change in the U.S presidential election (in the country with the world’s second largest CO₂ emissions) indicates geoengineering methods may become more necessary in the future.

 

Next week I will start looking at specific geoengineering methods and the associated benefits and risks. Until then http://www.scoop.it/t/cop21news is a great place to find the latest developments in climate news!