Urban areas are expanding in all parts of the world, and are recognized as important atmospheric sources of greenhouse gases (GHG) and short-lived climate pollutants (SLCP). The SLCP refers to the gases and particulates that are also responsible for global warming not caused by CO2 and have an atmospheric lifetime of less than 20 years. The emissions, fate, and atmospheric concentrations of these species will be affected by climate change (expected modification of temperature and humidity), and specifically by the atmospheric temperature, and by extreme hydrometeorological events.

In December 2015, the Conference of the Parties at the Framework Convention on Climate Change of United Nations (COP21) recommended measures to keep the increase of the mean temperature of the Earth well below 2°C above pre-industrial levels. The adopted texts provided two statements that represent the motivation of the proposed research:

“Recognizing that climate change represents an urgent and potentially irreversible threat to human societies and the planet and thus requires the widest possible cooperation by all countries, and their participation in an effective and appropriate international response, with a view to accelerating the reduction of global greenhouse gas emissions”

“Also recognizing that deep reductions in global emissions will be required in order to achieve the ultimate objective of the Convention and emphasizing the need for urgency in addressing climate change”

A drastic reduction of greenhouse gas and other climate pollutants emissions is required to attain the objectives highlighted by the COP21 agreement. The impact on the climate of the megacities and urban conglomerates is well established since a large fraction of emissions takes place in these populated areas. In fact, urban areas constitute also a major source of air pollutants (related to energy production and consumption, transport, and waste disposal). One of the challenges is to find win-win strategies by which one improves air quality while limiting anthropogenic climate forcing.

Moreover, the world is becoming increasingly urban as more than 50% of the population worldwide lives in cities. This proportion reaches almost 80% in Latin America. São Paulo is the most important megacity in South America and can, therefore, be considered as a laboratory for an integrated assessment of the impact on the atmosphere of the sources of GHG (CO2, N2O, CH4) and of other radiative active species, the SLCP. Here, we will focus our attention on the black carbon, methane, and tropospheric ozone, constituents of the SLCP and on the feedback of the climate change on air quality. To evaluate the climate impacts of the São Paulo Megacity emissions, the first step is to assess the sources of GHG and SLCP.

All current information on GHG emissions is based on bottom-up estimates performed from the extrapolation of limited flux observations and economic information. These estimated emissions have never been verified or reconciled with surface observations of species concentrations and/or with remote sensing atmospheric data. Therefore, the overall objective of the proposed project is to examine the role of the São Paulo Megacity emissions as drivers for regional air quality degradation and climate change. The project aims to integrate multi-platform measurements and modeling tools to describe the atmospheric behavior of the GHG and SLCP, and the effects of climate change on the air quality in the Metropolitan Area of São Paulo.

This objective will be achieved through 6 specific goals:

• Development of an integrated framework to estimate the sources and sinks of GHG and SLCP in the metropolitan region of São Paulo and neighborhood (with regard to the sinks);
• Implementation of a network for GHG and SLCP continuous measurements: surface, fluxes, and integrated atmospheric vertical columns;
• Developing integrated tools of Chemistry Transport Models to describe the air quality and the GHG emissions, transport, and fate;
• Evaluation of the impacts of the GHG and SLCP emissions on regional climate;
• Assessment of the impact of climate change feedback on air quality in the Metropolitan Area of São Paulo;
• Dissemination of the results to governmental institutions and to a broader community.

An accurate characterization of pollutant emissions and quantification of their impacts on the climate are important challenges that have to be addressed and will complement ongoing initiatives on other urban areas all over the world. The emission inventory will be conciliated with surface measurements and satellite data, the atmospheric modeling will be performed with Chemistry Transport Models from local to regional scale, and the evaluation of the future climate will be conciliated with the IPCC AR5 proposed scenarios.

The availability of the data in this website does not constitute publication of the data or permission to use the data, or information contained in it, for publication or any commercial use. We reserve the right to make corrections to the data based on scientific grounds, e.g., recalibration of standard gases or discovery of operational issues not known at the time of the release. To discuss publication, presentation, and collaboration, please contact the Metroclima Project describing your plans for use.