Climate change is one of the greatest challenges facing humanity in the 21st century. Most environmental problems, including those arising from climate change, are aggravated by population growth. Thus, the fact that the world's population has surpassed 6.7 billion and continues to grow by some 78 million additional people each year presents enormous challenges.
Making a clear and direct linkage between population change and climate change is complex because the effects of human activity on emissions are the product of a range of driving forces, including economic growth, technological changes, and population growth.
A growing body of evidence shows that recent climate change is primarily the result of human activity. Evidence suggests that the poorest countries and population groups are most vulnerable to climate change impacts. Population growth is occurring most rapidly in the developing world, increasing the scale of vulnerability to projected impacts of climate change. Other demographic trends, such as urbanization in coastal areas and encroachment of populations into ecologically marginal areas, can exacerbate climate risks. Population growth is already putting a strain on the world’s limited supply of fresh water. Without taking into account the projected impacts of climate change, five billion people more than half the world’s populations are expected to live in water stressed countries by 2050.
A growing body of evidence shows that recent climate change is primarily the result of human activity. Evidence suggests that the poorest countries and population groups are most vulnerable to climate change impacts. Population growth is occurring most rapidly in the developing world, increasing the scale of vulnerability to projected impacts of climate change. Other demographic trends, such as urbanization in coastal areas and encroachment of populations into ecologically marginal areas, can exacerbate climate risks. Population growth is already putting a strain on the world’s limited supply of fresh water. Without taking into account the projected impacts of climate change, five billion people more than half the world’s populations are expected to live in water stressed countries by 2050.
The impacts of extreme weather events and projected sea level rise are particularly significant due to high population density on and near coastlines and low-elevation zones. In Bangladesh and China, for example, populations living in low elevation coastal zones grew at almost twice the national population growth rate between 1990-2000 exposing disproportionately growing numbers of people to the negative effects of sea-level rise and extreme weather.
Under middle range projections of population growth, agricultural production loss and an increase in the prices of crops due to climate change will lead to an additional 90 to 125 million people at risk of hunger in the developing world by 2080. In Bangladesh, on more than 25,000 hectares of land in the south, agricultural production has dropped significantly in recent years. Most of the affected area is less than 1.5m above sea level and due to sea level rise, 13.74 percent of net cropped area and about 401,600 hectares of mangrove forest along with its wild life will be vanished.
In 2005, the average population density in developing countries was 66 people/km2, which is more than double in developed regions (27 people/km2). Under high population pressure, a large share of the population in the developing world is already living in marginalized areas, which are susceptible to climate variation and extreme weather events. For instance, around one-sixth of the world’s population is living in arid and semi-arid regions; more than 250 million people are directly affected by desertification, while another one billion are at risk. The world’s major arid regions are in the developing world, where the population growth rate is high, and socio-development levels are low.
Poor and vulnerable populations are those living in places exposed to climate risks, heavily dependent on climate for survival, and who have fewer resources to cope with the adverse impacts of climate change. For example, 70 percent of the African population relies on rain-fed agriculture for their livelihoods, and a slight shift in rainfall patterns or temperature can be disastrous.
It was found by Intergovernmental Panel on Climate Change (IPCC) that higher population growth projections generally result in more GHG emissions. The Population assumptions range widely, from a low population projection of 7.1 billion to a high of 15 billion in 2100. For example, the effects of highly carbon-intensive economic growth and technological change can be more substantial than population growth on future carbon emissions, at least for several decades.
A weakness of the IPCC’s current scenarios is that population size is the only demographic variable considered; no allowances are made for compositional changes within the population as it grows. Energy consumption patterns differ between rural and urban populations, between younger and older populations, and between households with many people versus households with fewer. The world is becoming increasingly urban and older, and household sizes are becoming smaller but these changes have not yet been accurately accounted for in climate change models. The majority of future population growth is likely to occur in areas of the world that are already beginning to experience climate change impacts, and this growth is likely to be concentrated in areas and among populations—poor, urban, and coastal—that are already highly vulnerable to climate change impacts.
Many of the policies that affect population trends, such as meeting the demand for family planning nd reproductive health services among the world’s women and families, can play an important role in climate change adaptation and mitigation, but have not yet been incorporated into comprehensive climate change solutions.
It was found by Intergovernmental Panel on Climate Change (IPCC) that higher population growth projections generally result in more GHG emissions. The Population assumptions range widely, from a low population projection of 7.1 billion to a high of 15 billion in 2100. For example, the effects of highly carbon-intensive economic growth and technological change can be more substantial than population growth on future carbon emissions, at least for several decades.
A weakness of the IPCC’s current scenarios is that population size is the only demographic variable considered; no allowances are made for compositional changes within the population as it grows. Energy consumption patterns differ between rural and urban populations, between younger and older populations, and between households with many people versus households with fewer. The world is becoming increasingly urban and older, and household sizes are becoming smaller but these changes have not yet been accurately accounted for in climate change models. The majority of future population growth is likely to occur in areas of the world that are already beginning to experience climate change impacts, and this growth is likely to be concentrated in areas and among populations—poor, urban, and coastal—that are already highly vulnerable to climate change impacts.
Many of the policies that affect population trends, such as meeting the demand for family planning nd reproductive health services among the world’s women and families, can play an important role in climate change adaptation and mitigation, but have not yet been incorporated into comprehensive climate change solutions.
Combating climate change calls for the spirit of environmental stewardship and international cooperation on a range of emissions reduction and adaptation approaches. These approaches will benefit from greater attention to population dynamics, including growth, household structure, urbanization and aging. Population policies and programs that promote universal access to voluntary contraception, when linked with broader efforts to address a range of demographic factors and meet development and poverty reduction objectives, such as the MDGs, will help lead to a more sustainable demographic future that will play a crucial role in climate change mitigation and adaptation.
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