Increased Urbanisation: Understanding the Implications for Climate Change

Transcription

1 nd International Conference Responding to Climate Change: UK-Indian Perspectives Increased Urbanisation: Understanding the Implications for Climate Change Amit Dhorde, Ph.D. Assistant Professor, Department of Geography, University of Pune, Pune, INDIA

2 Urbanization Climate Change

3 Human activity in urban environments alters atmospheric composition impacts components of the water cycle modifies the carbon cycle and ecosystems.

4 Urbanization: Swelling Cities % of people worldwide live in cities 8 % of people in developed countries live in cities Cities use % of the world s land surface Cities use 8 % of global resources

5 Growth of Urban Population (9-)

6 Greenhouse Gas Emissions from Cities Cities and Climate Change: Global report on Human Settlements

7 Number of million plus cities in India (9-) Number of Million Plus Cities in India (9-) No. of million plus cities Census Year

8 6 Ajmer Bangalore Chennai Coimbatore Gorakhpur Indore Kodaikanal..... Mumbai Mangalore Cities Depicting Increase in Temperature with Increase in Population Population Temperature

9 6 Amravati Belgaum Chandrapur Warangal Surat Jabalpur Raipur Ratnagiri Shillong Population Temperature

10 Annual TM Annual TMAX Annual TMIN Level of Significance.... Level of Significance.... Level of Significance.... Number of Cities Summer TM Number of cities Summer TMAX Number of Cities Summer TMIN Level of Significance.... Level of Significance.... Level of Significance.... Number Of Citeies Monsoon TM Number of Cities Monsoon TMAX Number of Cities Monsoon TMIN Level Of Significance.... Level Of Significance.... Level Of Significance.... Number Of Cities Number Of Cities Number Of Cities Fig : Significant Trends according to Mann-Kendall Test (Annual, Summer and Monsoon)

11 Post-monsoon TM Post-monsoon TMAX Post-monsoon TMIN Level Of Significance.... Level Of Significance.... Level Of Significance.... Number Of Cities Number Of Cities Number Of Cities Wi ntertm Wi nter TMAX Wi nter TMIN... Level Of Significance.. Level of Significance.. Level Of Significance..... Number Of Cities Number Of Cities Number Of Cities Fig : Significant Trends according to Mann-Kendall Test (Post-monsoon and Winter)

12 Trends in Annual Temperature

13 Temperature Trends: Post-Monsoon

14 Temperature Trends: Winter

15 Source: Zhou et. al.

16 Classified images of Landsat TM 99 and ETM+ 8 (Summer) April 99 May 8 Kalas 8 '"N 8 '"N 8 '"N Nagar Rd Hadapsar 8 '"N 8 '"N 8 '"N 8 '"N km Sinhagad Rd Km 7 '"E 7 '"E 7 '"E Katraj Land use Classes Water Bodies Agricultural Fields Vegetation Built up Barren land Hill slopes 7 '"E Note: Horizontal stripes on the eastern margin of the May 8 image are due to missing data Apr 99 May 8 Year Overall accuracy Kappa Coefficient Built up.6.8 April 99 8.%.79 Agri + Veg.9. May8 8.7%.88 Barren.9.76 Hill slope..

17 LST derived from Landsat TM and ETM+ images (Summer) April 99 (TM) May 8 (ETM+) 8 '"N 8 '"N 8 '"N 8 '"N Km m Km 7 '"E 7 '"E 7 '"E 7 '"E LST classes for April 99 LST classes for May 8 < LST in o C > 6. < p y LST in o C >.

18 Urban Environment and Carbon Cycle Shepherd & Jin Urban land transformation in the U.S. has reduced the amount of carbon fixed through photosynthesis by.6 percent of pre-urban values. This reduction nearly offsets the.8 percent gain made by the conversion of land to agricultural use. This is a striking fact given that urbanization covers less than % of the land in the U.S., while agricultural lands approach 9%. Using satellite data and a terrestrial carbon model, the impact of urbanization on net primary productivity (NPP) and its consequences on carbon balance and food production has been quantified. Urbanization is taking place on the most fertile lands and has a disproportionately large overall negative impact on regional and even continental scale NPP. In terms of biologically available energy, the loss of NPP due to urbanization alone is equivalent to the caloric requirement of about 6 percent of the U.S. population annually.

19 Flooding Climate change has the potential to increase flooding risks in cities in three ways: from the sea (higher sea levels and storm surges); from rainfall for instance by heavier rainfall or rainfall that is more prolonged than in the past; and from changes that increase river flows for instance through increased glacial melt. The IPCC has noted that heavy precipitation events are very likely to increase in frequency and will augment flood risk and the growing evidence of increased runoff and earlier spring-peak discharges in many glacier- and snow-fed rivers (Adger, Aggarwal, Agrawala et al., 7). In addition to flood hazards, more extreme rainfall events associated with climate change will also generate increased hazard from landslides in many urban centres.

20 . Santacruz hour Rainfall recorded at 8IST on 7 July Colaba - 7cm Santacruz - 9cm. Colaba

21 Mumbai Floods

22 Low & Moderate events Heavy events (>cm) V. Heavy events (>cm) Source: Goswami et al., Science, Dec., 6

23 RUNOFF February, 989 February, ± (a) (b) Legend 'N (c) (d) February, 989 February, 8 '"N 8 '"N 8 'N 8 'N 8 '"N 8 'N 8 'N 8 9'N 8 8'"N 8 8'N 7 'E 7 'E 7 'E 7 6'E 7 7'E 7 8'E 7 9'E 7 '"E 7 '"E 7 'E 7 6'"E 7 7'"E 7 8'"E Legend

24 Sub Basin Wise Estimated Runoff for 989 and Ro Ro Runoff (inches) Sub-basin Id

25 Rainfall (in mm)

26 Temperature Extremes

27 Summer TMax >=. o C (9P) (Mumbai_Culaba) y =.86x R = Summer TMax >=. o C (9P) (Hyderabad) y =.8x R = Summer TMax >=. o C (9P) (Bhopal) y =.8x R = Summer TMax >=8.7 o C (9P) (Chennai) y =.8x R = E Summer TMax >=. o C (9P) (Bangalore) y =.66x R = Summer TMax >=7.8 o C (9P) (Kolkata) y = -.x R = E Summer TMax >=. o C (9P) (Trivandrum) y =.86x R = Summer TMax >=9. o C (9P) (Pune) y = -.7x +. R = Summer TMax >=. o C (9P) (Panji) y =.6x R =

28 Winter TMin <=7.7 o C (P) (Mumbai_Culaba) y = -.7x +.96 R = Winter TMin <=. o C (P) (Hyderabad) y = -.9x +. R = Winter TMin <=.7 o C (P) (Bhopal) y = -.66x R = Winter TMin <=9. o C (P) (Chennai) y = -.7x R = Winter TMin <=. o C (P) (Bangalore) y = -.89x R = Winter TMin <=.6 o C (P) (Kolkata) y = -.x R = Winter TMin <=.8 o C (P) (Trivandrum) y = -.9x +.9 R = Winter TMin <=8 o C (P) (Pune) y = -.x R = Winter TMin <=8. o C (P) (Panji) y = -.87x +.7 R =

29 Green & Brown Agendas The Green Agenda: it is about the natural systems of the local, bioregional and global ecosystems that cities and other settlements use as services for open space, biodiversity, water provision, waste dispersion, health air, and reliable climate, food and fibre. The Brown Agenda concerns the human environment. The agenda is essential for making a city work; for a healthy and liveable environment; and for creating the human and economic opportunities that have been driving cities. This agenda is about optimizing land use; engineering of waste systems; minimizing energy consumption and transport; reducing use of materials; and creating an efficient built environment. Brown functions of a city often degrade its green resources, unless city intervenes through processes such as urban planning and environmental management. This is no longer feasible and cities need to slash their impact on the natural environment, and ensure that bioregional and global ecosystems are shielded from degradation.

30 Urban-Climate System Linkage To understand the urban-climate system linkage, an interdisciplinary effort combining in-situ and remote sensing, modeling, and human dimension assessments is ultimately required. Modeling the Earth s climate system has been hampered by at least two reasons: (i) poor representation of the urban environment in global and regional climate models (GCMs and CMs), and (ii) the difficulty obtaining detailed information on urban characteristics.

31 The urban areas included in this figure have populations greater than one million. The hazard risk represents a cumulative score based on risk of cyclones, flooding, landslides and drought. denotes low risk and denotes high risk. Cities and Climate Change: Global report on Human Settlements

32 Concluding Remarks Since cities consume large proportion of global resources including fossil fuel they are now considered as primary agents of climate change. But cities are also primary victims of climate change. Huge population of cities make them vulnerable to climate change. Cities are at risk from all types of climate change related hazards: Extremes in temperature & rainfall, flooding, landslides, drought, sea level rise. Heat waves in urban areas will be felt more strongly due to urban heat island effect. We need to adopt climate-conscious urban planning and management which can help achieve national climate goals and minimise tradeoffs between environmental and economic priorities.

33 Thank You