Climate Change

Introduction (Urban Climate Processes, Trends, and Projections)

Cities play a multidimensional role in the climate change story. Urban climate effects, in particular the urban heat island effect, comprise some of the oldest observations in climatology, dating from the early nineteenth century work of meteorologist Luke Howard (Howard, 1820). This substantially predates the earliest scientific thought about human fossil fuel combustion and global […]

Natural variability of the climate system (Urban Climate Processes, Trends, and Projections)

Cities are vulnerable to modes of natural climate variability (that is, not caused by climate change), or preferred oscillations in atmospheric circulation. These preferred oscillations tend to recur at seasonal to multi-year timescales, have somewhat predictable impacts on temperature and precipitation in specific regions, and impact large portions of the planet. Modes of climate variability […]

Global climate change and its impact on urban areas (Urban Climate Processes, Trends, and Projections)

Along with all other planetary surfaces, urban climates are subject to global changes due to radiative forcing. The impact of global change on cities is the subject of this section. The climate system and global climate change The elements of the global climate system include the atmosphere, biosphere, hydrosphere, cryosphere, and lithosphere (Figure 3.9). The […]

Observed climate change in cities (Urban Climate Processes, Trends, and Projections) Part 1

We present observed long-term climate data for the 12 cities to evaluate whether there are long-term trends. The urban heat island effect that may exist in each case should in principle be captured by the urban weather stations used. The selected cities include a wide range of climate zones. Tropical cities such as Dakar are […]

Observed climate change in cities (Urban Climate Processes, Trends, and Projections) Part 2

Precipitation Observations of annual total precipitation reveal precipitation changes in cities on decadal timescales. Natural climate variability can greatly influence annual precipitation (more so than temperature). Changes in the inter-annual variability of precipitation can also provide insight into how the climate is changing. For example, in New York City, while annual precipitation has only increased […]

Future climate projections (Urban Climate Processes, Trends, and Projections) Part 1

This section describes climate change projection methods and results. The projections can be used by urban stakeholders to identify key sector-specific impacts of climate change, as a first step for developing adaptation strategies. The projection component is derived from the global climate models that focus on broad geographical scales, rather than urban climate processes. However, […]

Future climate projections (Urban Climate Processes, Trends, and Projections) Part 2

Temperature projections for Delhi, India Delhi, India, is one city where annual mean temperature is projected to increase over the next century. A slight upward, although not statistically significant, trend has been observed in the city from 1931 to 2005. This trend is consistent with trends from the region around Delhi in India. The region […]

Future climate projections (Urban Climate Processes, Trends, and Projections) Part 3

Precipitation There is greater variability in the direction of projections of percentage change in precipitation for these cities. Some cities are expected to see increases in precipitation while others are projected to experience sharp declines in precipitation by the 2080s. For cities in higher latitudes projected to see increased precipitation, such as Toronto and New […]

Future climate projections (Urban Climate Processes, Trends, and Projections) Part 4

Climate change adaptation in Kokkola, Finland Kokkola, a medium-sized town on the west coast of Finland, was one case study of the Developing Policies & Adaptation Strategies to Climate Change in the Baltic Sea Region (ASTRA) project. The award-winning ASTRA project was co-financed by the European Regional Development Fund (ERDF) under the INTERREG IIIB Programme. […]

Introduction (Climate Change and Urban Energy Systems)

The energy systems that provide the "life blood" to cities are as complex and diverse as cities themselves. Reflecting local natural resource and economic conditions, supply chains that may extend globally, historic investments in technology, and cultural and political preferences, urban energy systems serve as either a key accelerator or brake on the vitality and […]