Case study: Tipping points, boundaries and thresholds?

At the beginning of this blog I mentioned that the earth has experienced an unprecedented warm 'stable' climate since the start of the Holocene about 10,000 years ago. However, some scientists have proposed that we are now entering a new geological epoch called the Anthropocene, where human influence on the Earth's climate has overtaken its natural variability.

In particular, a group of researchers believe that 'human activities have reached a level that could damage the systems that keep Earth in the desirable Holocene state'. Some of these changes might have irreversible effects and might be detrimental to human development. Rockström et. al. (2009) propose a framework of 'planetary boundaries' to help us maintain the Holocene state and mitigate global environmental change and climate change.

Source: Rockström et. al. 2009

The planetary boundaries that they propose are nine earth-system processes that are critical to human development and maintaining the Holocene state- climate change, the rate of biodiversity loss (terrestrial and marine), interference with the nitrogen and phosphorus cycles, stratospheric ozone depletion, ocean acidification, global freshwater use, change in land use, chemical pollution and atmospheric aerosol loading (shown in the diagram above). Out of these nine boundaries, Rockström et. al. (2009) proposes that 3 of these thresholds have already been transgressed (climate change, biodiversity loss and interference with the nitrogen cycle) and thus, this calls for stronger mitigation efforts to be put in place.

Assessing climate change, or global environmental change, using such a method has many weaknesses and they are outlined by Rockström et. al. (2009). However, this approach paints climate change in a new light. It shows us that climate change could be abrupt and could have catastrophic impacts. This calls for a different approach to mitigating climate change and in turn, changes the economics behind climate change policies. 

Tipping points, boundaries and thresholds will call for more immediate action then what has been previously proposed (i.e. carbon caps, CDMs etc). In my conversation with Bjørn Lomborg, he believes that if tipping points or boundaries have been reached, this will require more focus in geoengineering efforts and I am in agreement with his point. By establishing an agreement on where tipping points (or boundaries) are, and if they have been crossed, economic analysis of the costs and benefits of climate change mitigation will have a smaller discount factor and potential benefits will greatly outweigh the costs of mitigation. Hence, it will be easier to justify immediate action and less procrastination and debates.

However, setting and agreeing on a common set of boundaries (such as the initial planetary boundaries proposed by Rockström et. al. (2009) is still subject to many gaps and uncertainties. Once again, it seems like the debate on climate change mitigation, regardless of whether there is imminent danger, hinges on uncertainties and risk perceptions. This has been the talking point for this blog and I believe it is the crux in the management of environmental change and abrupt climate change. 

References:

Rockström et. al. (2009) 'A safe operating safe for humanity', Nature, 461, 472-475.