CCMA4: UHI mitigation strategies I : urban expansion & climate change links
Bamboo Structures: A perspective for Climate Change Mitigation
1GreenBam Solutions, New Delhi; 2Airef Engineers Pvt. Ltd, New Delhi, India; 3Department of Civil Engineering, Indus University, Ahmedabad, India; 4Haritha Ecological Institute, Andhra Pradesh, India
The exponentially growing population, fast expanding cities, depleting resources and accelerated pace of development has led to various unprecedented changes in the earth’s environment. The present rapid development of infrastructure in the form of buildings has heavily relied on brick, concrete and steel which are very energy intensive materials having high carbon footprint. If the unchecked growth of utilization of these materials continues for the target of achieving 26 million houses in India, it will be a sure recipe for an ecological disaster. Hence, it’s time to evolve the strategies for achieving sustainable growth, fulfilling the needs of the people in general and addressing the climate change concerns in particular.
The present paper brings out the potential of a ubiquitous grass, bamboo, for addressing the housing issues for the masses in the light of advancing climate change. A typical bamboo plant production potentials is around 2 – 20 t/ha/yr depending on the fertility of land; compressive strengths around 20 – 100 MPa and tensile strength around 100 – 300 MPa. This suggests great potential to produce annually equivalent renewable bamboo to replace steel, concrete, aluminum and plastics. India has over 120 species of bamboo with different potential applications, but Indian Standards with specific guidelines need to be developed for utilizing this material with confidence.
The paper presents the experimental results of the various load bearing elements like beams and columns made of bamboo composites which could be of great utility for the various upcoming housing projects. In the background of the high rate of urbanization, the proposed usage of bamboo as a constructional material would decisively infuse sustainability and would be of substantial use for mitigating the climate change
The Impact of future urbanization on summer climate of Israel
1Ben Gurion University of the Negev, Israel; 2Arizona State University, USA
Israel’s population is projected to increase significantly through the middle of the current century, requiring further expansion of the built environment. This study examines the impact of future urban expansion on local near-surface temperatures using a future land modification scenario based on the national development plan (TAMA35). The Weather Research and Forecast model was used to simulate the present (August 2010) and future (2050) climate at 1-km resolution. The future simulation incorporates the projected changes in the urban area of Israel to account for the expected urban expansion. Analysis of the temperature changes revealed that future urbanization will lead to nighttime warming of up to 3.5 °C across all Israel’s geo-climatic gradient, whereas no impact was detected for daytime temperatures. At the national scale, the averaged warming due to TAMA35 urban expansion is 0.4-0.8 °C; the same magnitude as the projected climate change for Israel. The reduction in albedo, increased heat storage capacity during the day, and the longwave emission of the stored energy during nighttime are the key mechanisms causing the warming over areas undergone urbanization. Spatially, temperatures differences show an evident north-south and east-west gradient, suggesting local conditions play a significant role in determining impact of future urban expansion. The results presented here illustrate the need to incorporate climate models as tool for quantifying the consequences of a specific land use strategy, and identifying the places where planning intervention is needed.
Urban Climate Adaptation Impacts: A multi-scale assessment to examine modeling robustness
Arizona State University, United States of America
Recent projections indicating the U.S. will add about 300 million inhabitants through the end of the current century emphasize the considerable conversion of existing land covers to new urban land uses. California, the most populated state in the U.S., is among the states where a significant portion of end of century urbanization is anticipated. To examine climatic impacts of projected urbanization, multi-year, multi-member, continental scale simulations at medium resolution (20km grid spacing) are conducted with the WRF model coupled to a single-layer urban canopy scheme. Guided by medium-range resolution results, additional high-resolution experiments (2km grid spacing), positioned to coincide with the California area projected to undergo greatest urban expansion (i.e., Central Valley region of the state), are performed for several summer seasons to identify result dependence on resolution, an essential determinant of modeling robustness. Results demonstrate qualitative resolution-independent agreement: greater near-surface temperature benefits due to cool compared to green roofs deployment. However, changes in simulated convective mixed layer characteristics, and consequently, a much shallower planetary boundary layer depth, illustrate a key concern associated with diminished daytime turbulence due to both adaptation strategies that extend to air quality concerns: identical emissions of pollutants (e.g., particulate matter [PM]) will be confined to a smaller volume, thereby decreasing daytime perceivable air quality. In addition to emphasizing the need for integrated assessment incorporating biophysically induced urban impacts, I argue in favor of examining scale dependency of simulated outcomes to comprehensively address tradeoff assessment of various urban adaptation approaches.