Climate risks from CO2 and short-lived climate pollutants

Kolkata: Housing practices influence climate, which has an intimate relationship with health.The building sector (residential and commercial) accounted for approximately 32 per cent of global final energy consumption, 19 per cent of global greenhouse gas emissions and one-third of global black carbon emissions in 2010, according to the Intergovernmental Panel on Climate Change (2014).

Carbon dioxide is the long-lived greenhouse gas that is the dominant contributor to climate emissions worldwide, while black carbon is a short-lived climate pollutant, and the second largest contributor to climate change after CO2.

Black carbon persists in the environment from days to weeks but it has hundreds to thousands of times more warming potential than carbon dioxide. It is also a component of particulate matter, which is a major environmental cause of premature death from air pollution globally. In connection with housing, black carbon is produced by biomass, coal and diesel cookstoves or heating systems.

A significant proportion of housing-related climate emissions are attributed to the use of grid-electricity for electric cookstoves and heaters, lighting, air conditioning and other electric appliances. The remainder of household emissions are due to on-site burning of fuels, e.g. for fuel based cookstoves and heating systems.

Household-related climate pollutants include not only CO2 and black carbon, but also other short-lived pollutants such as methane (from incomplete coal combustion), and hydrofluorocarbons used in home cooling systems, contribute significantly to climate change.

Methane, produced by the burning of certain household fuels, has a global warming potential 25 times more potent than carbon dioxide.

It is a precursor to ground-level ozone, which is a risk factor in asthma and other lung diseases. Hydrofluorocarbons are released by household energy devices, such as refrigeration and air conditioning units, when they are damaged or leaking. These chemicals can remain in the atmosphere for 15 years and are powerful contributors to global warming.

Poor urban design, including residential neighborhood design, exacerbates the "urban heat island effect" from sunlight reflected onto extensive paved surfaces, which can raise temperatures in city environments by 5-12 degrees Celsius. 

More urban heat island impacts, in turn, increase heat-related mortality risks, air quality, and reliance on air conditioning ? further contributing to climate change.Climate change itself also exacerbates housing-related health risks.

 For instance, more frequent extreme weather events will increase the vulnerability of housing structures, particularly in coastal areas, to damp, flooding, extreme cold and heat. Increased flooding risks can affect the safety and security of household drinking water supplies, and increase spread of bacterial contamination and waterborne diseases linked to poor sanitation.

With climate change an increasingly critical issue, mitigation of the contributions of the housing sector is therefore needed to both reduce health risks and achieve health co-benefits from long-term environmental stability.(UNI)