Our world continues to become increasingly urban. From the 19th century growth of European and North American cities, to the explosive population increase during the 1950s in cities like Tokyo and Mexico City, to the current expansion of cities in China and Sub-Saharan Africa, cities have been –and continue to be– global engines for innovation and economic development. Cities occupy about two percent of the world’s landmass. Their impact however, is colossal; cities consume over two-thirds of the world’s energy and account for more than 70% of global CO2 emissions.
Cities are uniquely positioned to be at the forefront of climate change mitigation while continuing to foster economic development. They not only have influence over major GHG generation activities like land use regulations, transportation or building codes, they are also home to more than half of the world’s population. Policies implemented at the local level can be tailored to the specificities of each urban area, and benefit by having thousands of local governments acting on climate change often proves more effective, and innovative, than only national governments alone.
Towards a Successful Green Economy
To foster a green economy and make significant reductions in GHG emissions, cities must first understand and measure current baseline emissions. Without baseline numbers for total city emissions and a sectoral breakdown of their origin, the relative impact of climate mitigation policies cannot be determined. As cities’ climate change mitigation programs gain momentum, city officials will need data to prove that their spending both maximizes carbon emission reductions and fosters economic development. Without GHG inventories, public policies will not be able to address climate change and economic development effectively.
Urban areas’ carbon emissions can be grouped in three categories. In-boundary emissions are those released directly from sources within the city (e.g. emissions from vehicles). Trans-boundary emissions are those released outside city boundaries from processes that provide necessary services to people within a city (e.g. electricity generated from power plants outside of city limits). Embodied emissions are those associated with purchased material goods.
Accounting for each of these categories would enable cities to identify critical places for policy intervention. Depending on the specificities of each urban area, cities should prioritize policies that target the type of emissions most critical to them. A city like Los Angeles, for example, where personal vehicle use is a major driver of emissions, may implement policies to improve public transit. While a city like New York, where buildings produce over half of the emissions, could seek stricter building energy efficiency codes.
To increase the effectiveness of policies, from both a climate and economic development standpoint, city officials must gain a deep understanding of the emissions drivers native to each city. GHG inventories are the essential first step towards effective climate policies and low-carbon growth. They also present an opportunity to promote economic development by delivering savings to existing businesses and attracting new ones. Without reliable emissions data, cities may find themselves directing efforts to projects that are easy to implement but not necessarily effective.
Comprehensive, up-to-date emissions inventories inform policymakers of the success of implemented strategies, and enable them to take further action on existing policies or channel efforts to address emerging emissions sources. Complete accounting (of all emission types) will be particularly helpful for developed cities. As economic growth accelerates, embodied emissions will increase with income and purchasing power. Empowered by comprehensive, accurate data, cities will have the opportunity to stimulate a new green economy that leads the world in carbon mitigation and sustainable growth. Meeting high accounting standards and acting on that information can make cities bastions of low-carbon growth, and magnets for green jobs and sustainable enterprise.