A study conducted by Nasa’s Goddard Institute for Space Studies has revealed that motor vehicles are the largest form of pollutants in the world and they will remain so till 2020. However, by 2100 power sector will overtake motor vehicles in polluting the air.
The study — “Attribution of Climate Forcing to Economic Sectors” by Nadine Unger — was based on the calculations on real world inventories of emissions collected by scientists around the world, and they assumed that those emissions would stay relatively constant in the future. The study has estimated the impact of 13 sectors of the economy from the year 2000 to 2100.
For each sector of the economy, the team analysed the effects of a wide range of chemical species, including carbon dioxide, nitrous oxide, methane, organic carbon, black carbon, nitrate, sulphate and ozone.
In their analysis, motor vehicles emerged as the greatest contributor to atmospheric warming now and in the near term. Cars, buses and trucks release pollutants and greenhouse gases that promote warming, while emitting few aerosols that counteract it.
The researchers found that the burning of household biofuels — primarily wood and animal dung for home heating and cooking — contribute the second most to global warming. And raising livestock, particularly methane-producing cattle, contribute the third most.
While household fossil fuels come fourth in their contribution to global warming, it is followed by landfill, agriculture and power.
By the year 2100, the projections suggest that the impact of the various sectors will change significantly. By 2050, electric power generation would overtake road transportation as the biggest promoter of global warming. The industrial sector likewise jumps from the smallest contribution in 2020 to the third largest by the year 2100.
The difference is because of the impacts of greenhouse gases that would accumulate and intensify over time and because they persist in the atmosphere for such long periods.
In contrast, aerosols rain out after a few days and can only have a short-term impact.