So What is Geoengineering Anyway?

I think that the logical starting point for this blog would be to address the question:

What is geoengineering?

"Geoengineering is deliberate intervention in the climate system to counteract man-made global warming. There are two main classes of geoengineering: direct carbon dioxide removal and solar radiation management."

(Shepherd, 2012 :4166)

Keith (2001) specifies the importance of scale and intent when defining geoengineering. Geoengineering should be of a large enough scale to have a global impact; so small-scale or localised environmental changes, regardless of the deliberate intentions to alter the environment, should not be considered geoengineering.

Conversely cases of large-scale (global) environmental change should not be considered as examples of geoengineering unless those changes were deliberately intended. So anthropogenic CO2 emissions, which have certainly impacted the global environmental system (see side note below), cannot be considered geoengineering as this was an unintended consequence of human energy consumption.

Side Note: The IPCC Summary for Policy Makers Report, which was released in September, uses the word "unequivocal" (page 2) to describe climate change. The report further states that "human influence on the climate system is clear" (page 13) and that "it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century" (page 15). For anyone unfamiliar with the report the link below provides a light summary of the most salient points:

Buzzfeed: 7 Stupid Things People Say About Climate Change That Aren't At All True

The issue of intent with regard to geoengineering is an important point that is relevant to the ethical concerns surrounding geoengineering - a topic for a future blog entry.

Geoengineering is only one proposed response to global environmental change. Steffen et al (2007) list it as one of three potential approaches. A brief description of the other two approaches is given below.

1. Business-as-usual

This is the least proactive of the three approaches and it places great faith in the ability of technology and economic systems to counter global environmental change. It makes assumptions that the time scales and the magnitude of environmental changes will be evenly matched with society's ability to respond.

2. Mitigation

This approach aims to recognise and address the anthropogenic stresses placed on the earth system. It ultimately seeks to curtail the human impact on the global environmental system through well-managed and sustainable interactions with the environment.

It seems likely that in reality some combination of all three approaches could be used to tackle global environmental change.

The IPCC summary report named geoengineering as a potential response to global environmental change. This places geoengineering firmly in the mainstream global environmental change debate, but nevertheless it remains a highly controversial and sometimes ill-defined approach.