Related Experiment Video
Updated: Apr 14, 2026
07:12
Façade-Level Monitoring of CO2 Variability under Urban Heat Island Conditions using Low-Cost Sensor Data Loggers
Published on: December 12, 2025
334
Energy and material flows of megacities
Christopher A Kennedy1, Iain Stewart2, Angelo Facchini3
1Department of Civil Engineering, University of Toronto, Toronto, ON M4J 3K1, Canada; christopher.kennedy@utoronto.ca.
Summary
Megacities
Area of Science:
- Urban Metabolism and Sustainability Science
- Environmental Science and Ecology
- Urban Planning and Development
Background:
- Global environmental challenges necessitate understanding urban resource flows.
- Megacities, with populations over 10 million, face significant resource management stresses.
- Efficient resource management is critical for the sustainability of large urban populations.
Purpose of the Study:
- To quantify energy and material flows within the world's 27 megacities.
- To analyze the relationship between resource consumption and urban characteristics.
- To identify megacities with high/low consumption and efficient resource utilization.
Main Methods:
- Quantitative analysis of energy and material flows in 27 megacities (2010 data).
- Correlation analysis linking resource use to factors like heating-degree-days, urban form, economic activity, and population growth.
- Examination of scaling laws in urban resource consumption.
Main Results:
- Megacity resource flows align with established urban scaling laws.
- Established correlations between resource consumption (electricity, fuel, water, waste, steel) and urban drivers.
- Identified megacities with varying levels of resource consumption and efficiency.
- Per capita electricity use correlates with urbanized area and gross building floor area, increasing in lower-density cities.
- Megacity GDP and energy use grew faster than population (2001-2011).
Conclusions:
- Urban scaling laws provide a framework for understanding megacity resource dynamics.
- Urban form and economic activity are key drivers of megacity resource consumption.
- Megacities show a trend of rapid economic and energy use growth relative to population growth, highlighting sustainability challenges.
Related Concept Videos
02:12Short-distance Transport of Resources
18.2K
Short-distance transport refers to transport that occurs over a distance of just 2-3 cells, crossing the plasma membrane in the process. Small uncharged molecules, such as oxygen, carbon dioxide, and water, can diffuse across the plasma membrane on their own. In contrast, ions and larger molecules require the assistance of transport proteins due to their charge or size. Transport across membranes also occurs within individual cells, playing a variety of essential roles for the plant as a whole.
18.2K
01:10Energy Diagrams - II
14.2K
Energy diagrams are important to understand the dynamics of a system. The topology of an energy diagram helps illustrate the equilibrium points of the system.
The point in the energy diagram at which the system’s potential energy is the lowest is known as the local minima. The system tends to stay in this position indefinitely unless acted upon by a net force. The slope of the potential energy diagram at the local minima is zero, indicating that zero net force is acting on the system. The...
The point in the energy diagram at which the system’s potential energy is the lowest is known as the local minima. The system tends to stay in this position indefinitely unless acted upon by a net force. The slope of the potential energy diagram at the local minima is zero, indicating that zero net force is acting on the system. The...
14.2K
01:14Energy Diagrams - I
5.9K
The dynamics of a mechanical system can be easily understood by interpreting a potential energy diagram. Since energy is a scalar quantity, the interpretation of the dynamics of the system becomes even simpler.
Take the example of a skater on a parabolic ramp. The potential energy at different points along the ramp will be proportional to the height of the ramp, which varies quadratically with the horizontal position on the ramp. As the skater moves down the ramp from the highest position,...
Take the example of a skater on a parabolic ramp. The potential energy at different points along the ramp will be proportional to the height of the ramp, which varies quadratically with the horizontal position on the ramp. As the skater moves down the ramp from the highest position,...
5.9K
00:51Energy Budgets
11.1K
Organisms must balance energy intake with the energy required for growth, maintenance and reproduction. These trade-offs result in a variety of survivorship and reproductive strategies, including semelparity and iteroparity. Semelparous species, like annual plants, have only one reproductive episode in their lifetimes and consequently have short lifespans. Iteroparous species, by contrast, have many reproductive events during their lifetimes but have relatively few offspring. These two...
11.1K
01:37Energy to Drive Translocation
3.0K
Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Generally, polypeptides are unfolded by two distinct...
3.0K
00:58Energy
17.7K
The universe is composed of matter in different forms, and all forms of matter contain energy. The different forms of energy on Earth originate from the Sun—the ultimate energy source. For instance, plants capture light energy from the Sun, and through the process of photosynthesis, convert it into chemical energy. This stored energy from plants can be harnessed in many ways. For example, eating plant products as food provides energy for our body to function, and burning wood or...
17.7K