Turn down the heat: regional climate change impacts on development
The Paris Agreement, a landmark in international climate policy, advocates “holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels”. Achieving the Paris agreement is ambitious, because time for bringing humanity on a sustainable development pathway is short. Warming in 2016 has reached 1.1 °C as compared to the pre-industrial (1880–1900) average (WMO 2017) and current emission reduction pledges presented for the COP21 in Paris will lead with 50% probability to a global warming of about 2–3 °C, and with 34% probability to about 3–4 °C until 2100 compared to pre-industrial levels (Fawcett et al. 2015). Climate change impacts in a broad range of physical, biological and human systems have already been attributed to the observed warming for most regions of the World and are projected to further intensify (IPCC 2014). Particular risk is being attributed to climate change impacts that interact across sectors and spatio-temporal scales and lead to a cascade of impacts threatening development endeavours (Schellnhuber et al. 2012; Piontek et al. 2014).
However, currently, there is still a lack of detailed knowledge about the progression of climate change impacts from environmental systems to human systems in different world regions as the world moves from current warming towards a 1.5 °C, 2 °C or even a 4 °C world. This pertains not only to the frequency, intensity and magnitude of impacts but also to their mutual interaction and reversibility. Impacts may for example be non-linearly related to temperature increase and/or may result in a cascade of impacts where biophysical impacts trigger crucial impacts in human systems across different sectors that may turn out to be irreversible at least on human timescales. Henceforth, assessing the vulnerability of social systems towards climate change is a crucial knowledge gap that may threaten current and future development initiatives.
What are the key biophysical climate change impacts in different world regions under different degrees of warming (1, 1.5, 2 and 4 °C)?
What are the crucial development impacts triggered by biophysical climate change impacts within and across sectors in these regions?
What are the implications of climate change impacts (physical, biophysical and social) for the (differential) social vulnerability within these regions?
In the following, we briefly introduce the common methodology underlying the regional impact papers and discuss how the Development Narratives contribute to piecing together the often non-systematic evidence from individual climate impact studies.
Five diverse regions—one common methodology
The five regional impact papers presented in this special feature were all based on a common methodology combing (1) an in-depth literature review of regional climate impact studies with (2) an original analysis of climate and sea-level rise projections and (3) a co-production of knowledge process to develop the Development Narratives.
We reviewed the peer-reviewed scientific literature on climate change impacts in each region. We focussed on the English literature; very few references were also taken from national languages. The climate impacts identified in the literature review were in most cases not referring to global warming levels but usually based on regional warming levels specific to each individual study. While the latter makes sense when considering an impact study in its regional context, relating the regional impacts to global warming levels is required for global climate policy. Therefore, wherever possible, we derived global warming levels for the impact studies analysed in the regional impact papers based on models and scenarios from the CMIP3 or CMIP5 database (Schleußner and Mengel 2017). This allowed us to attribute climate changes on a regional scale to their respective global warming level.
The climate data were based on two Representative Concentration Pathways (RCPs 2.6 and RCP8.5) from five General Circulation Models (GCMs, namely GFDL-ESM2M, HadGEM2-ES, IPSL-CM5A-LR, MIROC-ESM-CHEM, NorESM1-M). The GCM data were interpolated to a 0.5 °C resolution and bias-corrected as part of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP, Warszawski et al. 2014). Please see Schellnhuber et al. (2014) for a detailed description of the climate data.
Sea-level rise projections
The sea-level rise projections in the SSA and SA regions were based on a semi-empirical approach (Rahmstorf 2007; Schaeffer et al. 2012), while for LAC and MENA a process-based approach has been used (based on Hinkel et al. 2014; Church et al. 2013). The latter reflects increases in knowledge as presented in the IPCC AR5 (IPCC 2013) and leads to slightly more conservative sea-level rise estimates. However, the upper bounds are comparable under RCP8.5 and they are the most relevant from a risk assessment perspective (c.f. Schellnhuber et al. 2014 for a detailed discussion of the two approaches).
Co-production of knowledge
Piecing things together: on the value of the Development Narratives
The Development Narratives take a special position within the analysis of climate impacts on development presented in this special feature. They present the outcome of applied transdisciplinarity. Through the iterative writing process, authors were forced to engage in concepts foreign to their own disciplines. Within the small writing teams, the misunderstandings that come with such engagement could be clarified and overcome. It was our experience that the tacit associations that come with each term according to its embeddedness in different world-views needed to be made explicit and clear without settling for a particular definition or interpretation. This reflects the suggestion that linguistic inconsistency can be a major obstacle to interdisciplinary work (Newell et al. 2005; Füssel 2007). However, at this fundamental stage of cross-disciplinary integration, the appreciation of multiple perspectives was what was aimed for rather than a homogenization of views.
The narrative style of assessment sensitizes different research communities to the value-dimensions that come with applying indicators representing human well-being. In a world of finite resources and necessary trade-offs, aggregation of indicators to allow for comparability is often sought for. However, aggregation comes at a high price. As the notion of multi-dimensional poverty indicates, poverty is a human experience and is highly context-dependent (Leichenko and Silva 2014). Critical reflection is thus required as to which scale and metric is most appropriate for assessing the risks that climate change poses for development. Global aggregates, for example, often mask important regional differences in vulnerability and consequently the degree of impact (Tschakert 2015) and yield no insights into the distributive effects of climate impacts. Further, what counts as valuable might often be a matter of perspective (Morrissey and Oliver-Smith 2013). For example, the perceived value of territory lost to sea-level rise will differ across regions depending on cultural assets and emotional attachment to place (Albrecht et al. 2007; Tschakert et al. 2013). Working on a common narrative in a trans- and interdisciplinary setting can promote an appreciation of such culturally specific value judgements, which, combined with the sober quantification of impacts, will ultimately yield important insights for decision-making particularly at the regional scale.
Summary of the regional Development Narratives
In the following, we provide brief highlights of the regional Development Narratives (see also Fig. 1). The full storylines can be found in the respective regional impact papers. In Latin America and the Caribbean (Reyer et al. 2017b), climate change endangers small and large-scale agricultural production, freshwater supplies and ecosystem services. Stronger extreme events are projected to affect both rural and urban communities, particularly living on steep slopes and in coastal regions. In Middle East and Northern Africa (Waha et al. 2017), climate change threatens agricultural production, food security, water availability and public health and acts as a threat multiplier for the security situation in the region. Within Sub-Saharan Africa (Serdeczny et al. 2017), East Africa is strongly affected by flooding while West Africa might face agricultural production losses combined with declining oceanic productivity and densely populated coastal cities in the whole region face increasing risk from sea-level rise. In East Africa, climate change will affect public health and damage infrastructures while in West Africa food security and employment are at risk. In Central Asia (Reyer et al. 2017a), water resources might increase during the first half of the century leading to higher flood risk and decline thereafter, amplifying the competition for water between hydropower generation and irrigation to avoid declining agricultural production. In South Asia (Vinke et al. 2017), changes in tropical cyclones, precipitation patterns and river flows would affect the population through changes in floodings, droughts and agricultural yield losses. The ensuing food price shocks and health risks such as childhood stunting, transmission of waterborne diseases and disorders associated with excess salinity would particularly affect the poor.
The papers presented in this special feature relate regional climate impacts and their implications for human development to global warming levels (1.5, 2, 3 and 4 °C). Thus, they allow to assess the relevance of global climate policy for key development regions of the world. Moreover, they provide crucial input for the upcoming IPCC Special Report on 1.5 °C warming and ensuing climate risk assessments (e.g. O’Neill et al. 2017) as well as adaptation planning (Kilroy 2015).
The papers show that all regions covered in the regional impact papers are facing climate impacts even if climate warming is limited to 1.5 or 2 °C above pre-industrial levels. Warming of around 4 °C in many cases has disastrous consequences and natural and human systems and would seriously challenge promoting human development and ending poverty. These findings are compounded by a review of social vulnerability showing that the poor, elderly and children are often hit hardest by climate change.
The work presented in this special feature is the product of a 3-year inter- and transdisciplinary interaction between researchers and development practitioners of the World Bank. This interaction amalgamates hard scientific evidence with findings from a semi-structured stakeholder consultation with leading regional development experts leading to plausible Development Narratives of how climate change may impair development and poverty reduction efforts. The Development Narratives presented in each of the regional impact papers highlight the value of this co-production of knowledge to integrate climate change impacts across sectors and carve out their relevance for human development. This knowledge should help to gain a better understanding of the relationship between climate and development, bring up novel research questions and ultimately contribute to sustainable development under changing climatic conditions.
The research presented in this special feature has been funded through the World Bank Project “Turn Down the Heat” and we are grateful to everybody involved in this activity for making it a success. Moreover, we would like to thank Wolfgang Cramer and Gabriele Götz making this Special Feature possible and for their valuable guidance throughout this process. CPOR acknowledges funding from the German Federal Ministry of Education and Research (BMBF, grant no. 01LS1201A1). We are grateful to the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) for providing the climate data.