Climate Change Challenge: Why Population is Important

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.

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.

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.

Wetlands, Climate Change Impact and Adaptation

The term global climate change conjures up different images to each of us, depending on a variety of factors such as our geographic location and our lifestyle. Based on its research, the IPCC concludes that "human activities, including the burning of fossil fuels, land-use change and agriculture, are increasing the atmospheric concentrations of greenhouse gases (which tend to warm the atmosphere) and, in some regions, aerosols (microscopic airborne particles, which tend to cool the atmosphere), are projected to change regional and global climate and climate elated parameters such as temperature, precipitation, soil moisture and sea level."

While currently the number one driver of wetland loss and degradation is habitat change as a result of human development, climate change effects are already being felt across the world. As our understanding of climate change increases, there is a new sense of urgency about the state of wetland species and ecosystems: clearly, climate change will become one of the major drivers of ecosystem loss during this century and will intensify the impacts of the other drivers.

In general, wetlands found in prairies, tropical and boreal forests, arctic and alpine ecosystems, and coral reefs and mangroves are thought to be especially vulnerable to climate change because they have a limited capacity to adapt to change - damage to these ecosystems may be irreversible.

Expected increases in sea surface temperature of about 1-3°C are likely to result in more frequent coral bleaching events and widespread mortality of corals.  Coastal wetlands including salt marshes and mangroves are likely to be negatively affected by sea-level rise, especially where there are physical barriers on their landward side; increased damage from coastal flooding through storms and tidal surges will take place in many areas.

Changes in the timing and volume of fresh water run-off from inland wetlands will affect salinity, nutrient availability, and moisture regimes in coastal ecosystems – all of which will have an impact on coastal ecosystem functions. Many low-lying islands, particularly those in the Pacific, Indian and Atlantic Oceans and the Caribbean Sea, are likely to be at risk of being submerged.

Changes in rainfall intensity and variability are expected to increase flooding and drought in many areas. In general, precipitation increases are expected in high latitudes and parts of the tropics and decreases in some sub-tropical and lower mid-latitude regions (some of these latter areas are already water stressed). Some climate models predict that by 2050, annual average river runoff and water availability are projected to increase by 10-40% at high latitudes and in some wet tropical areas, and decrease by 10-30% over some dry regions at mid-latitudes and in the dry tropics. Higher water temperatures and extreme weather events (such as floods and droughts) are projected to affect water quality and to intensify many forms of water pollution – pollutants such as high nutrient levels, pathogens, pesticides, salt, etc.

Nearly 2 billion people already live in areas of high flood risk, often as a result of destruction of floodplain wetlands and reclamation for agriculture and urban development; further losses of wetlands in these areas, along with the impact of climate change in certain latitudes, increases this vulnerability. The impacts of floods are many – quite aside from the immediate effects of human mortality there is the risk of infectious diseases, and there is evidence of equally negative impacts of climate-related effects on mental health, resulting in long-term depression and anxiety.

Around 50% of the world’s people live along the coast and the density of populations in coastal area is three times higher than the global average. Many of the world’s poorest communities are coastal dwellers and rely on mangrove and reef-based fisheries for food security.

In developing countries, coral reefs contribute about a quarter of the annual fish catch, providing food for about one billion people in Asia alone; in Indonesia, for example, some 60% of the population is dependent on marine and coastal fishing resources for food and livelihoods. The Great Barrier Reef contributes a total of US$ 4.5 billion to the Australian economy, with US$3.9 billion from tourism, US$469 million from recreation, and US$115 million from commercial fishing, collectively generating 63,000 jobs.

Broadly there are a number of key responses that can be made to resolve the loss of wetland biodiversity and the additional impacts of climate change on those losses:

·         Maintain the health of our intact wetlands;

·          Redouble efforts to address the key drivers of wetland loss and degradation (habitat loss, pollution, excessive water withdrawals, invasive species, overexploitation, etc.);

·         Continue to identify vulnerable species and ecosystems, and plan and implement species and ecosystem action plans for recovery;

·         Priorities and plan wetland management and restoration programmes for a changing and more variable climate; managers will have to adapt their planning to take account of these changes with the aim of maintaining as far as possible the delivery of ecosystem services;

·         Continue to restore degraded wetlands, since healthier wetlands are more resilient than degraded ones; and  urgently address the additional impact of climate change on wetland species and ecosystems through:

·         Climate change mitigation actions;

·         Appropriate climate change adaptation strategies.

Mitigation requires us to reduce greenhouse gas emissions and to encourage the removal of such gases already in the atmosphere, ‘trapping’ them in soils and vegetation. There is no question that the key culprit globally in CO2 emissions is our use of fossil fuels. But we can also have a real impact on emissions by the way we manage our environment. Especially significant are the continuing rapid rates of deforestation of wetland and other forests and the draining of peat lands. Peat lands, though covering only 3% of global land area, have long been recognized as an important carbon sink, and their drainage and conversion for other uses as an important source of emissions. There is also increasing evidence of the role of mangroves, salt marshes and other wetlands as carbon sinks, and thus there is an urgent need to restore and secure the management of these wetlands as well.

For this Ecosystem-based adaptation is the best to climate change delivers this holistic approach. For inland wetlands, it requires actions to:

·         Reduce the degradation of river basins by deforestation;

·         Increase afforestation;

·         Maintain and restore riparian wetlands and floodplains along rivers so that they can provide better protection from flooding;

·         Improve management of wetlands and water at the basin level;

·         Restore “green infrastructure” wherever possible: the natural flood defense system provided by inland wetlands will help to ensure that the other ecosystem services provided by wetlands are maintained.

Ecosystem-based adaptation in coastal ecosystems requires actions to:

·         Reduce the loss and degradation of, mangroves, salt marshes, sand dunes, coral and shellfish reefs and other coastal wetlands, and restore them where possible, to produce ecosystems more resilient against sea level rise;

·         Minimize “hard” infrastructure developments against coastal floods in favor of green infrastructure wherever possible;

·         Remove artificial barriers on the landward side of mangroves and salt marshes so that they may be able to migrate landwards as sea levels rise.

Agriculture: A Most Vulnerable Sector due to Climate Change

Environment is constantly changing. With increased technical capabilities man changes his surrounding faster than ever before. However, mankind is aware that fast climate changes (anthropogenic and/or natural) have impacts on many aspects of life. The most direct economical influence of global climate change is due to its direct impact on agriculture and crop yields.  Increased intensity and frequency of storms, drought and flooding, altered hydrological cycles and precipitation variance have implications for future food availability, some coastal food-producing areas will be inundated by the seas, and food production will fall in some places in the interior.

In developing countries, 11 percent of arable land could be affected by climate change, including a reduction of cereal production in up to 65 countries, about 16 percent of agricultural GDP (FAO Committee on Food Security, Report of 31st Session, 2005).

A study published in Science suggest that, due to climate change, "Southern Africa could lose more than 30% of its main crop, maize, by 2030. In South Asia losses of many regional staples, such as rice, millet and maize could top 10%".

The 2001 IPCC Third Assessment Report concluded that the poorest countries would be hardest hit, with reductions in crop yields in most tropical and sub-tropical regions due to decreased water availability, and new or changed insect pest incidence.

In the long run, the climatic change could affect agriculture in several ways:

·         Productivity in terms of quantity and quality of crops

·         Agricultural practices, through changes of water use (irrigation) and agricultural inputs such as herbicides, insecticides and fertilizers.

·         Environmental effects, in particular in relation of frequency and intensity of soil drainage (leading to nitrogen leaching), soil erosion, reduction of crop diversity.

·         Rural space, through the loss and gain of cultivated lands, land speculation, land renunciation, and hydraulic amenities.

·         Adaptation, organisms may become more or less competitive, as well as humans may develop urgency to develop more competitive organisms, such as flood resistant or salt resistant varieties of rice.

The earth's average temperature has been rising since the late 1970s, with nine of the 10 warmest years on record occurring since 1995. In 2002, India and the United States suffered sharp harvest reductions because of record temperatures and drought. Similarly, because of higher temperatures and humidity, there could be an increased pressure from insects, fungal diseases and disease vectors. Studies have shown that higher CO₂ levels lead to reduced plant uptake of nitrogen resulting in crops with lower nutritional value. This would primarily impact on populations in poorer countries less able to compensate by eating more food, more varied diets, or possibly taking supplements.

Climate change could have a particularly severe impact on South Asia, where a large proportion of the region’s population depends on subsistence agriculture for their livelihoods.

Agricultural crop of Bangladesh is influenced by seasonal characteristics and different variables of climate such as temperature, rainfall, humidity, day-length etc. It is also often constrained by different disasters such as floods, droughts, soil and water salinity, cyclone and storm surges. Several studies indicated that climate is changing and becoming more unpredictable every year in Bangladesh. Flood and water logging in the central region, flash-flood in the northeast region, drought in the northwest and southwest region, and salinity intrusion and coastal inundation in the coastal regional would be a more acute problem in future. All of these will have an extra bearing on the agriculture sector.  

Different models predict different level of impacts for yield reduction under different climate change scenarios. The GFDL model predicted about 17 % decline in overall rice production for Bangladesh and as high as 61% decline in wheat production under 4 degree changes in temperature. The highest impact would be on wheat followed by rice (Aus variety). Of the three varieties of rice grown in Bangladesh, the Aus rice (grown during the summer, monsoon period under rain-fed conditions) seems to be the most vulnerable. The temperature impact already seen in this season in different region of Bangladesh. It is predicated that rice production will decrease in this year and people will face serious food crisis and economic loss. “We need more extensive climate research in different agroeconomic zone in Bangladesh to get actual adaptation in the context of local environment” stated Dr. Syed Hafizur Rahman, Chairman, Department of Environmental Sciences, Jahangirnagar University. 

Climate change is obvious thing, so adaption is very much important in Bangladesh to overcome the food crisis and economic loss by cost-effective ways to help poor farmers, Provide funds for infrastructure and institutional innovations, Provide funds for agricultural science and technology, allow funding mechanisms that recognize the connection between pro-poor development policies for sustainable growth and sound climate change policies, allow funding mechanisms that recognize and support synergies between adaptation and mitigation etc.