On September 21 2009 I posted The Vulnerability Perspective. In it, I identified 5 major resource areas that should be the focus of assessments as to the spectrum of risks from climate variability and change, as well as from other environmental and social threats. I wrote
There are 5 broad areas that we can use to define the need for vulnerability assessments : water, food, energy, health and ecosystem function. Each area has societally critical resources. The vulnerability concept requires the determination of the major threats to these resources from climate, but also from other social and environmental issues. After these threats are identified for each resource, then the relative risk from natural- and human-caused climate change (estimated from the GCM projections, but also the historical, paleo-record and worst case sequences of events) can be compared with other risks in order to adopt the optimal mitigation/adaptation strategy.
In our my book chapter with Dev Niyogi
Pielke Sr. R.A., and D. Niyogi, 2009: The role of landscape processes within the climate system. In: Otto, J.C. and R. Dikaum, Eds., Landform – Structure, Evolution, Process Control: Proceedings of the International Symposium on Landforms organised by the Research Training Group 437. Lecture Notes in Earth Sciences, Springer, Vol. 115, in press
we presented a section that introduces a framework to investigate vulnerabilities. The section reads
“Within the climate system, the need to consider the broader role of land-surface feedback becomes important not only for assessing the impacts but also for developing regional vulnerability and mitigation strategies.
The IPCC fourth assessment second and third working groups deal with a range of issues targeted to these topics (Schneider et al. 2007). The IPCC identifies seven criteria for “key” vulnerabilities. They are: magnitude of impacts, timing of impacts, persistence and reversibility of impacts, likelihood (estimates of uncertainty) of impacts and vulnerabilities and confidence in those estimates, potential for adaptation, distributional aspects of impacts and vulnerabilities, and the importance of the system(s) at risk. While a number of potential vulnerabilities and uncertainties are considered (such as irreversible change in urbanization), the resulting feedback on the atmospheric processes due to such changes is still poorly understood or unaccounted for in these assessments. Indeed the UNFCCC Article 1 states: “‘Adverse effects of climate change’ means changes in the physical environment or biota resulting from climate change which have significant deleterious effects on the composition, resilience or productivity of natural and managed ecosystems or on the operation of socio-economic systems or on human health and welfare.” Thus, while the role of landscape is inherent within the UNFCCC framework, the corresponding translation for the assessments still remains largely greenhouse gas driven.
Further, while the climate change projections have largely been at coarser resolution, the impacts and potential mitigation policies are often at local to regional scales. For example, climate models often project increasing drought at a regional scale. The resilience to such increased occurrence as well as changes in the intensity of droughts is, however, dependent on the local scale environmental conditions (such as moisture storage, and convective rainfall), and farming approaches (access to irrigation, timing of rain or stress, etc). As summarized in Adger (1996), an important issue for IPCC-like global assessments is to assess if the top-down approach can incorporate the “aggregation of individual decision-making in a realistic way, so that results of the modelling are applicable and policy relevant”.
Therefore, as the community braces to develop resilience strategies it will becoming increasingly important to consider a bidirectional impact, i.e., not just the role of atmospheric changes (such as temperature and rainfall) on the physical environmental or biota, but also a feedback of the biota and other land-surface processes on further changes in the atmospheric processes – such as reviewed in this chapter.
Klein et al. (1999) sought to assess whether the IPCC guidelines for assessing climate change impacts as well as adapative strategies can be applied to one example of coastal adaptation. They recommend that a broader approach is needed which has more local-scale information and input for assessing as well as monitoring the options. Again the missing link between local-scale features with global scale projections become apparent. The expanded eight-step approach of Schroter et al. (2005), designed to assess vulnerability to climate change, states the need for considering multiple interacting stresses. They recognize that climate change can be a result of greenhouse gas changes which are coupled to socioeconomic developments, which in turn are coupled to land-use changes – and that all of these drivers are expected to interactively affect the human – environmental system (such as crop yields).
To extract the significance of the individual versus multiple stressors on crop yields, Mera et al. (2006) developed a crop modeling study with over 25 different climatic scenarios of temperature, rainfall, and radiation changes at a farm scale for both C3 and C4 types of crops (e.g., soybean and maize). As seen in many crop yield studies, the results suggested that yields were most sensitive to the amount of effective precipitation (estimated as rainfall minus physical evaporation/transpiration loss from the land surface). Changes in radiation had a nonlinear response with crops showing an increased productivity for some reduction in the radiation as a result of cloudiness and increased diffuse radiation and a decline in yield with further reduction in radiation amounts. The impact of temperature changes, which has been at the heart of many climate projections, however, was quite limited particularly if the soils did not have moisture stress. The analysis from the multiple climate change settings do not agree with those from individual changes, making a case for multivariable, ensemble approaches to identify the vulnerability and feedbacks in estimating climate-related impacts (cf. Turner et al. 2003).
Another issue is the coupled vulnerability of the land surface to socioeconomic and climate change processes. This question was addressed byMetzger et al. (2006). They concluded that most assessment studies cannot provide needed information on regions or on ecosystem goods that are vulnerable. To address this question, we can hypothesize that the vulnerability of landscape (V) change is a product of the probability of the landscape change (Lc) and the service (S) provided by the landscape:
V = prob (Lc) ∗S
The service provided is a broad term and could mean societal benefits (such as recreation), or economic benefits (such as timber and food), or physical feedback as in terms of the modulating impact a landscape may have on regional temperatures or precipitation. While a variety of studies on vulnerability have sought to look at the economic and the societal feedbacks, the physical feedback of the fine-scale land heterogeneities have been critically missing in the literature. It is however important that land heterogeneity and transformation potential be considered at a finer scale because the landscape changes will in turn affect the regional and local vulnerability.
Current economical assessment studies (Stern 2007) conclude that controlling land-use change such as from deforestation provides an opportunity cost in excess of $5 billion per annum. This estimate however appears to only consider the land transformation impact of deforestation and the resulting greenhouse emissions. As summarized in this chapter, the dynamical effects such as changes in rainfall, evaporation, convection, and temperature patterns due to landform changes can cause additional vulnerability (or resilience in some cases) and needs to be considered in such assessments (Marland et al. 2003). Similarly, the UNFCCC Article 3 also seeks afforestation (reforestation minus deforestation) since 1990 as a country’s commitment towards the green house gas emission controls. Not considering the dynamical feedbacks due to such forest land transformation can lead to additional vulnerabilities as described in Pielke et al. (2001a, 2002).”
I plan to have further posts on this topic, focusing on the 5 resource areas of water, food, energy, health and ecosystem function, in future weblogs.