Kejun Jiang

Temperature increase of 21st century mitigation scenarios

Estimates of 21st Century global-mean surface temperature increase have generally been based on scenarios that do not include climate policies. Newly developed multigas mitigation scenarios, based on a wide range of modeling approaches and socioeconomic assumptions, now allow the assessment of possible impacts of climate policies on projected warming ranges. This article assesses the atmospheric CO2 concentrations, radiative forcing, and temperature increase for these new scenarios using two reduced-complexity climate models. These scenarios result in temperature increase of 0.5–4.4°C over 1990 levels or 0.3–3.4°C less than the no-policy cases. The range results from differences in the assumed stringency of climate policy and uncertainty in our understanding of the climate system. Notably, an average minimum warming of ≈1.4°C (with a full range of 0.5–2.8°C) remains for even the most stringent stabilization scenarios analyzed here. This value is substantially above previously estimated committed warming based on climate system inertia alone. The results show that, although ambitious mitigation efforts can significantly reduce global warming, adaptation measures will be needed in addition to mitigation to reduce the impact of the residual warming.

Will economic growth and fossil fuel scarcity help or hinder climate stabilization? Overview of the RoSE multi-model study

We investigate the extent to which future energy transformation pathways meeting ambitious climate change mitigation targets depend on assumptions about economic growth and fossil fuel availability. The analysis synthesizes results from the RoSE multi-model study aiming to identify robust and sensitive features of mitigation pathways under these inherently uncertain drivers of energy and emissions developments. Based on an integrated assessment model comparison exercise, we show that economic growth and fossil resource assumptions substantially affect baseline developments, but in no case they lead to the significant greenhouse gas emission reduction that would be needed to achieve long-term climate targets without dedicated climate policy. The influence of economic growth and fossil resource assumptions on climate mitigation pathways is relatively small due to overriding requirements imposed by long-term climate targets. While baseline assumptions can have substantial effects on mitigation costs and carbon prices, we find that the effects of model differences and the stringency of the climate target are larger compared to that of baseline assumptions. We conclude that inherent uncertainties about socio-economic determinants like economic growth and fossil resource availability can be effectively dealt with in the assessment of mitigation pathways.

An integrated assessment of the potential of agricultural and forestry residues for energy production in China

Biomass has been widely recognized as an important energy source with high potential to reduce greenhouse gas emissions while minimizing environmental pollution. In this study, we employ the Global Change Assessment Model to estimate the potential of agricultural and forestry residue biomass for energy production in China. Potential availability of residue biomass as an energy source was analyzed for the 21st century under different climate policy scenarios. Currently, the amount of total annual residue biomass, averaged over 2003–2007, is around 15 519 PJ in China, consisting of 10 818 PJ from agriculture residues (70%) and 4701 PJ forestry residues (30%). We estimate that 12 693 PJ of the total biomass is available for energy production, with 66% derived from agricultural residue and 34% from forestry residue. Most of the available residue is from south central China (3347 PJ), east China (2862 PJ) and south‐west China (2229 PJ), which combined exceeds 66% of the total national biomass. Under the reference scenario without carbon tax, the potential availability of residue biomass for energy production is projected to be 3380 PJ by 2050 and 4108 PJ by 2095, respectively. When carbon tax is imposed, biomass availability increases substantially. For the CCS 450 ppm scenario, availability of biomass increases to 9002 PJ (2050) and 11 524 PJ (2095), respectively. For the 450 ppm scenario without CCS, 9183 (2050) and 11 150 PJ (2095) residue biomass, respectively, is projected to be available. Moreover, the implementation of CCS will have a little impact on the supply of residue biomass after 2035. Our results suggest that residue biomass has the potential to be an important component in Chinas sustainable energy production portfolio. As a low carbon emission energy source, climate change policies that involve carbon tariff and CCS technology promote the use of residue biomass for energy production in a low carbon‐constrained world.

Climate and Sustainability

Projected change in climate in the coming decades adds a layer of complexity in the search for sustainability. Warming temperatures, rising sea levels, changing precipitation patterns and their impacts on natural and human systems could threaten the attainment of development goals. Many countries in Asia and the Pacific are among the most vulnerable to the impacts of climate change and there is growing recognition that climate change adaptation must be tackled as an integral part of the development process, for example in mainstreaming climate change adaptation into national plans and programmes. The aim of Chap. 6 is to explore linkages between sustainable development and efforts to address climate change in Asia and the Pacific, particularly focussing in two areas of low carbon development (LCD) pathways for the region, and the importance of natural ecosystems in sustaining the delivery of ecosystem services that are essential for climate change adaptation and mitigation. The challenges posed by climate change will be felt in the coming decades in Asia and the Pacific. In parallel, nations in the region will continue to aspire for sustainable development. Policy makers and development workers must find ways to ensure that both these concerns are addressed synergistically while avoiding negative outcomes. One way to mitigate climate change while pursuing sustainable development is through LCD, which will require negotiations across many stakeholders of governments, non-government agencies, industry and broader communities. In Asia and the Pacific natural ecosystems will continue to play a critical role in addressing climate change adaptation and mitigation. Nations in the region will have to find innovative ways to manage and rehabilitate natural ecosystems for a multiplicity of functions and services. This will involve greater collaboration and communication between scientists and policy makers as well as between natural and social scientists. In many developing countries, there is still very limited empirical information and research needs to be ramped up. North-South and South-South partnerships could help fill the gap.

Data on fossil fuel availability for Shared Socioeconomic Pathways

The data files contain the assumptions and results for the construction of cumulative availability curves for coal, oil and gas for the five Shared Socioeconomic Pathways. The files include the maximum availability (also known as cumulative extraction cost curves) and the assumptions that are applied to construct the SSPs. The data is differentiated into twenty regions. The resulting cumulative availability curves are plotted and the aggregate data as well as cumulative availability curves are compared across SSPs. The methodology, the data sources and the assumptions are documented in a related article (N. Bauer, J. Hilaire, R.J. Brecha, J. Edmonds, K. Jiang, E. Kriegler, H.-H. Rogner, F. Sferra, 2016) [1] under DOI: http://dx.doi.org/10.1016/j.energy.2016.05.088.