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Climate change: demographics matter [Print to PDF] [Print to RTF]

Changes in population size, ageing and urbanisation could have a major influence on global carbon dioxide (CO2) emissions over the coming decades, new research reveals. Writing in the Proceedings of the National Academy of Sciences (PNAS) journal, scientists from Austria, Germ...
Climate change: demographics matter
Changes in population size, ageing and urbanisation could have a major influence on global carbon dioxide (CO2) emissions over the coming decades, new research reveals. Writing in the Proceedings of the National Academy of Sciences (PNAS) journal, scientists from Austria, Germany and the US write that curbing population growth could contribute up to 29% of the emissions reductions needed by 2050 to keep average global temperatures from rising to dangerous levels. If population growth remains low, by the end of the century it could account for up to 41% of the emissions reductions needed.

'If global population growth slows down, it is not going to solve the climate problem, but it can make a contribution, especially in the long term,' commented Brian O'Neill of the US National Center for Atmospheric Research (NCAR).

'A slowing of population growth in developing countries today will have a large impact on future global population size. However, slower population growth in developed countries will matter to emissions too, because of higher per capita energy use,' added Shonali Pachauri of the International Institute for Applied Systems Analysis (IIASA) in Austria.

The team also investigated the influence of rising urbanisation on carbon emissions. Their results suggest that the growth in urban populations could trigger a 25% rise in CO2 emissions in some developing countries. The researchers attribute this to the higher productivity and consumption preferences of the urban workforce.

On the other hand, ageing populations are likely to cut emissions levels by up to 20% in some industrialised countries, as older populations have a lower proportion of workers. This results in lower productivity and lower economic growth.

Summarising the findings, Dr O'Neill said: 'Demography will matter to greenhouse gas emissions over the next 40 years. Urbanisation will be particularly important in many developing countries, especially China and India, and ageing will be important in industrialised countries.

'Further analysis of these trends would improve our understanding of the potential range of future energy demand and emissions,' he added.

Meanwhile, the team suggests that those working on emissions scenarios pay greater attention to the impacts of urbanisation and ageing on emissions, particularly in key regions such as the China, the EU, India and the US.

Scientists have long been aware that population changes affect greenhouse gas emissions, but the scale of the impact has remained unclear. In this study, the researchers arrived at their conclusions using new computer model (the Population-Environment-Technology model, or 'PET') to develop a range of economic growth, energy use and emissions scenarios. The team distinguished between different household types, separating them out by age, size and whether they were in an urban or rural location. They also drew on data from national surveys providing information on changes in household characteristics, such as labour supply and the demand for consumer goods, over time.

Sarah Ruth of the US National Science Foundation (NSF), which co-funded the research, concluded: 'By examining the relationship between population dynamics and greenhouse gas emissions, this groundbreaking research increases our understanding of how human behaviours, decisions and groundbreaking research increases our understanding of how human behaviours, decisions and lifestyles will determine the path of future climate change.'
Source: PNAS; IIASA; NSF; NCAR

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Record Number: 32652 / Last updated on: 2010-10-14
Category: Miscellaneous
Provider: EC