wrapping up

So it has been 3 months since I started this blog and it is now time to give a brief summary of what I have said and some small conclusions and opinions that I have come to.

I set off talking about how the discourse on climate change has become more relevant to us and how we make decisions on climate change mitigation in the context of abrupt climate changes and the economic rationale behind such action (or inaction). I have also set out to identify some of the impacts of abrupt climate change events to economic development.

I was fortunate (or unfortunate) to have had the occurrence of adverse weather conditions (such as Hurricane Sandy) and key climate policy decisions (extension of the Kyoto Protocol) being made during this period of time and I have tried to incorporate these factors into the discussion on abrupt climate change.

As the discussion unfolded, I realized that the recurring theme among all the different aspects of mitigating climate change was how the uncertainties were managed and how people made decisions based on their perception of these uncertainties and the degree to reach people were risk averse. I have only mentioned the reasons and considerations behind making policy decisions and have not explicitly talked about the costs and benefits involved in the process of mitigating climate change but I recognize this as a way to bring this project forward. I rounded up the discussion with two case studies; one for mitigating climate change and the other for identifying possible correlations between human development and climate change.

This experience has shown me that we continue to tread the line between inaction and taking action to combat climate change. This situation is made worse by contrasting opinions on climate change. My view on this concurs with the recent Global Risk 2013 report by the World Economic Forum (the section on economic and environmental resilience). Delaying action on climate change is not justified as costs (both economic and social) are rising. The line is only getting thinner the further we walk away from positive action on climate change mitigation. 

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.

Case study: rise and fall of civilizations

After spending much of the time talking about the mechanisms of economic analysis in mitigating climate change (or abrupt climate change), I would like to give some examples of how environmental change has affected past human development. In particular, I would like to highlight the paper I recently read by Yancheva et. al 2007. 

Yancheva et. al 2007 presents 'the role of climate and environmental change in the success or failure of societies'. They propose that major changes in Chinese dynasties occurred when the East Asian winter monsoon was strong and that 'dynastic transitions tended to occur when the summer monsoon was weak and rainfall was reduced'. A reduction of rainfall led to phases of crop failure and famine which leads to uprisings and riots. They also link the phases in dynasties with the phases of collapse of the classic mayan civilisation (Fig. 1). 

Fig. 1: Paleoclimate records during the past 4,500 years in the context of major events in the cultural history of China (Yancheva et. al 2007).

The mechanism that they propose for abrupt climate change is the shifts in the inter-tropical convergence zone (ITCZ) which represents the band of rainfall in the tropics. When the ITCZ is displaced to the North, summer monsoons will strengthen and vice versa. On the topic of the ITCZ, Timmermann et. al. (2007) and Zhang and Delworth (2005) proposes that there is an intimate link between the strength of the thermohaline circulation in the Atlantic Ocean and the meridional position of the ITCZ. With a weakening of the thermohaline circulation, there will be less heat transported to the northern high latitudes and consequently, a southward flow of heat. This causes the ITCZ to migrate southwards.

A weakening of the thermohaline circulation might be due to several reasons but one widely cited cause of a slow down in the circulation is a massive and abrupt injection of freshwater into the Northern Atlantic. This mechanism has been widely accepted to be the cause of abrupt climate change events such as the Younger Dryas event and the 8.2 kyr cooling event. 

The Chinese and the Mayan were not the only civilizations affected by climate change. Other studies have shown that the Norse abruptly abandoned their settlements in Greenland during the little ice ages in the 14th and 19th century as well as the Akkadian empire in Mesopotamia 4,200 years ago. Putting this in the perspective of climate change today, it is highly likely that abrupt climate changes might occur as a weakening of the thermohaline circulation seems like a possibility in the future (e.g. due to the melting of ice sheets in Greenland). This might then have an impact on countries situated in the tropics and especially in countries where the people are heavily reliant on the patterns of precipitation for agricultural or farming purposes. For example, China is heavily dependent on the agricultural sector to support her growing population and economy and hence, will be subjected to the impacts of a migrating ITCZ. 

References:

Timmermann, A., Okumura, Y., An, S, I., Clement, A., Dong, B., Guilyardi, E., Hu, A., Jungclaus, J. H., Renold, M., Stocker, T. F., Stouffer, R J., Sutton, R., Xie, S. P. and Yin, J. (2007) ‘The influence of a weakening of the Atlantic meridional overturning circulation on ENSO’, Journal of Climate, 20, 4899-4919.

Yancheva, G., Nowaczyk, N. R., Mingram, J., Dulski, P., Schettler, G., Negendank, J. F. W., Liu, J., Sigman, D. M., Peterson, L.C. and Haug, G. H. (2007) ‘Influence of the intertropical convergence zone on the East Asian monsoon’, Nature, 445, 74-77.

Zhang, R. and Delworth, T. L. (2005) ‘Simulated Tropical Response to a substantial weakening of the Atlantic thermohaline Circulation’, Journal of Climate, 18, 1853-1860.

Review of a review

In my previous post I mentioned the Stern Review as a proponent for the kyoto protocol and an opponent to Bjørn Lomborg. However, this blog is aware of the many reviews of the review. One key factor that others have mentioned is that the review is 'not arbitrary and not balanced', as proposed by Zenghelis in the previous video.

Peter Lilley put forward that in general, the Stern Review accurately outlines the basic economic questions involved in global warming. Also, it makes an important contribution in selecting climate change policies with an eye to balancing economic priorities with environmental dangers. 

However, it is political in nature and has advocacy in purpose. For example, it emphasises studies and findings that are in support of its policy recommendations, while opposing views of the dangers of global warming are ignored. Furthermore, the Stern Review was published without an appraisal of methods and assumptions by independent outside experts.

On top of that, Lilley mentions that the Review proposes assumptions that produce very low discount rates relative to our global-warming analyses. If more conventional discount rates were used, the Review's dramatic results will no longer hold true. Hence, we see that we are back to a problem of using appropriate discount rates, and making hypotheses about the behaviour of human beings (i.e. risk aversion, patience etc.)

I believe that this problem of coming up with a solution for climate change is summed up nicely by the following video presentation by Gwyn Prins, a professor at the London School of Economics. He sums up problems faced by humans into two categories- 'tame' and 'wicked'. Tame problems are defined as problems which are bounded, where the more we learn about it, the more certain we are about its characteristics and potential solutions. Wicked problems on the other hand are open problems (such as climate change). Professor Prins is skeptical of human constructed policies to tackle climate change He believes that people are using a tame problem framework (where the more we learn, the more certain we are) to tackle a wicked problem. This is because 'we now know much more clearly about what we do not know'. The connections between human action and climate change are very complicated and he believes that there is a political hubris about climate change. Put in context, this suggests that people believe they can assign specific discount values in their analyses of climate change and proposals for policy solutions but these are often disputed, just as how Lilley has disputed with the Stern Review.