There are a number of general conclusions that can be easily drawn: (i) human-induced climate change is an important new stress, particularly on ecological and socio-economic systems that are already affected by pollution, increasing resource demands, and non-sustainable management practices; (ii) the most vulnerable systems are those with the greatest sensitivity to climate change and the least adaptability; (iii) most systems are sensitive to both the magnitude and rate of climate change; (iv) many of the impacts are difficult to quantify because existing studies are limited in scope; and (v) successful adaptation depends upon technological advances, institutional arrangements, availability of financing and information exchange, and that vulnerability increases as adaptation capacity decreases.
Therefore, developing countries are more vulnerable to climate change than developed countries.
The range of adaptation options for managed systems such as agriculture and water supply is generally increasing because of technological advances, thus reducing the vulnerability of these systems to climate change.
However, some regions of the world, i.e., developing countries, have limited access to these technologies and appropriate information.
The efficacy and cost-effectiveness of adaptation strategies will depend upon cultural, educational, managerial, institutional, legal and regulatory practices that are both domestic and international in scope.
Incorporation of climate change concerns into resource-use and development decisions and plans for regularly scheduled investments in infrastructure will facilitate adaptation.
The issues of climate variability and climate change need to be integrated into resource use and development decisions: Many sectors are currently not optimally managed with respect to today's natural climate variability because of the choice of policies, practices and technologies.
Decreasing the vulnerability of socio-economic sectors and ecological systems to natural climate variability through a more informed choice of policies, practices and technologies will, in many cases, reduce the long-term vulnerability of these systems to climate change.
For example, use of seasonal climate forecasts into management decisions can reduce the vulnerability of the water and agricultural sectors to floods and droughts caused by the ENSO phenomena.
Let me now briefly discuss the implications of climate change for a representative number of systems: water resources, agricultural productivity and food security, natural ecosystems (forests and coral reefs), human health and sea level rise.
Water Resources:
Climate change could exacerbate water stress in arid and semi-arid areas, and most regions will experience an increase in floods: Currently 1.3 billion people do not have access to adequate supplies of safe water, and 2 billion people do not have access to adequate sanitation.
Today, some nineteen countries, primarily in the Middle East and Africa, are classified as water-scarce or water-stressed.
Even in the absence of climate change, this number is expected to double by 2025, in large part because of increases in demand from population and economic growth.
Unfortunately in many regions of the world a significant fraction of water is wasted, largely through inefficient irrigation in the agricultural sector.
Hence, climate change could further exacerbate the frequency and magnitude of droughts in some places, in particular central Asia, northern and southern Africa, the Middle East, the Mediterranean and Australia where droughts are already a recurrent feature.
Developing countries are highly vulnerable to climate change and increased water stress because many are located in arid and semi-arid areas.
In addition, it should be recognized that the frequency and magnitude of floods in most regions of the world are expected to increase because of the projected increase in heavy precipitation events.
Agricultural Productivity and Food Security: Agricultural productivity is projected to decrease in many countries in the tropics and sub-tropics: Currently, 800 million people are malnourished; as the world’s population increases and incomes in some countries rise, food demand is expected to double over the next three to four decades.
Studies show that on the whole, global agricultural production might be relatively unaffected by small changes in climate, i.e., global mean surface temperature changes of less than 2 degrees Centigrade, but is projected to decrease with greater warming.
Crop yields and changes in productivity due to climate change will vary considerably across regions and among localities, thus changing the patterns of production.
In general, productivity is projected to increase in middle to high latitudes, depending on crop type, growing season, changes in temperature regime, and seasonality of precipitation.
However, in the tropics and subtropics, where some crops are near their maximum temperature tolerance and where dryland, non-irrigated agriculture dominates, yields are likely to decrease for even small changes in climate, especially in Africa and Latin America, where decreases in overall agricultural productivity of up to 30 percent are projected during the next century.
Therefore, there may be increased risk of hunger in some locations in the tropics and subtropics where many of the world's poorest people live.
Natural Ecosystems: Biological systems have already been affected by changes in climate during the last several decades: There are a number of instances where changes in biological systems, e.g., earlier flowering of trees and egg-laying in birds, lengthening of the growing season, and the pole-ward and altitudinal shifts in insect ranges, have been associated with regional changes in climate.
While these biological systems are subject to numerous stresses that can alter their behavior, it should be noted that in many cases these observed changes in biological systems are consistent with well-known biological responses to climate.
Climate change is projected to alter the structure and functioning of ecological systems and decrease biological diversity: The structure, composition and geographic distribution of many ecosystems will shift as individual species respond to changes in climate and disturbance regimes, but these ecological changes are likely to lag behind the changes in climate by decades to centuries.
There will likely be reductions in biological diversity and in the goods ecosystems provide society, e.g., sources of food, fiber, medicines, recreation and tourism, and ecological services such as controlling nutrient cycling, waste quality, water run-off, soil erosion, pollination services, detoxification and air quality.
Forests are vulnerable to projected changes in climate: The distribution of forests and forest species are projected to change in response to changes in temperature, precipitation, extreme events, pest outbreaks and fires, altering the ecosystem goods and services provided.
Boreal systems are most the vulnerable, primarily due to changes in fire regime and pest outbreaks, leading to forest die-back, a change in age structure and a decrease in carbon content.
The global terrestrial biosphere is currently sequestering about 0.7 Gt C per year, the difference between a global uptake of 2.3 Gt C per year and an emission of about 1.6 Gt C per year from tropical deforestation (IPCC Special Report on Land-Use, Land-Use Change and Forestry - LULUCF).
The majority of the uptake is estimated to occur in the temperate forests (about 1 - 2 Gt C per year, in response to management practices, carbon dioxide fertilization, nitrogen deposition and climate change), with little net uptake in Boreal regions.
This terrestrial uptake will likely diminish with time and forest ecosystems may even become a source of carbon emissions.
Net carbon emissions are very sensitive to the El-Nino Southern Oscillation phenomena, with the terrestrial biosphere being a net source during ENSO years to a net sink in non-ENSO years, albeit with large regional variations.
Coral reefs are threatened by increases in temperature: Coral reefs, which are the most biologically diverse marine ecosystems, are important for fisheries, coastal protection, erosion control and tourism.
Coral reef systems, which are already being threatened by pollution, unsustainable tourism and fishing practices, are very vulnerable to changes in climate.
While these systems may be able to adapt to the projected increases in sea level, sustained increases in water temperatures of 3-4 degrees Centigrade above long-term average seasonal maxima over a 6-month period can cause significant coral mortality; short-term increases on the order of only 1-2 degrees Centigrade can cause shorter-term "coral bleaching".
Human Health: Human health is sensitive to changes in climate because of its impact, in particular, on changes in food security, water supply and quality, and the functioning and range of ecological systems.
These impacts are likely to be mostly adverse, and in many cases would cause loss of life. Direct health effects would include increases in heat-related mortality and illness resulting from an anticipated increase in heatwaves, although offset to some degree in temperate regions by reductions in winter mortality.
Indirect effects would include extensions of the range and season for vector organisms (e.g., mosquito, water snails, black and tsetse flies), often increasing the likelihood of transmission of vector-borne infectious diseases (e.g., malaria, dengue, yellow fever and encephalitis).
Projected changes in climate could lead to an increase in the number of people at risk of malaria of the order of tens of millions annually, primarily in tropical, subtropical, and less well protected temperate-zone populations.
Some increases in non-vector-borne infectious diseases such as salmonellosis, cholera and other food- and water-related infections could also occur, particularly in tropical and subtropical regions, because of climatic impacts on water distribution and temperature, and on micro-organism proliferation.
The impacts of climate change on food production within food-insecure regions and the consequences of economic dislocation and demographic displacement (e.g., sea level rise) would have wide-ranging health impacts.
Sea Level Rise: Sea-level rise is projected to have negative impacts on human settlements, tourism, freshwater supplies, fisheries, exposed infrastructure, agricultural lands and wetlands, causing loss of land, economic losses and the displacement of tens of millions of people: It is currently estimated that about half of the world’s population lives in coastal zones.
Changes in climate will affect coastal systems through sea-level rise and an increase in storm-surge hazards and possible changes in the frequency and/or intensity of extreme events.
Impacts may vary across regions, and societal costs will greatly depend upon the vulnerability of the coastal system and the economic situation of the country.
Sea-level rise will increase the vulnerability of coastal populations to flooding. An average of about 50 million people per year currently experience flooding due to storm surges; a 50 cm sea-level rise could double this number.
The estimates will be substantially higher if one incorporates population growth projections. A number of studies have shown that small islands and deltaic areas are particularly vulnerable to a one-meter sea-level rise.
In the absence of mitigation actions (e.g., building sea walls), land losses are projected to range from 1.0 percent for Egypt, 6 percent for Netherlands, 17.5 percent for Bangladesh, to about 80 percent of the Marshall Islands, displacing tens of millions of people, and in the case of low-lying Small Island States, the possible loss of whole cultures.
Many nations face lost capital value in excess of 10 percent of GDP. While annual adaptation/protection costs for most of these nations would be relatively modest (about 0.1 percent GDP), average annual costs to many small island states could be as high as several percent of GDP, assuming adaptation is possible.
Part III: Approaches to Mitigate Climate Change by Reducing Emissions and Enhancing Sinks:Significant reductions in net greenhouse gas emissions are technically, and economically, feasible: Cost-effective reductions in greenhouse gases can be achieved by utilizing an extensive array of technologies:
energy supply -- more efficient conversion of fossil fuels; switching from high to low carbon fossil fuels; decarbonization of flue gases and fuels, coupled with carbon dioxide storage; increased use of modern renewable sources of energy (e.g., plantation biomass, micro-hydro, wind, and solar); and increasing the use of nuclear energy (subject to addressing safety, environmental and other concerns);
energy demand -- industry, transportation, and residential/commercial buildings;
agricultural and forestry -- afforestation, reforestation, slowing deforestation, improved forest, cropland and rangeland management, including restoration of degraded agricultural lands and rangelands, promoting agroforestry, and improving the quality of the diet of ruminants; and
waste management and reductions in halocarbon emissions.
Policy instruments can be used to facilitate the penetration of lower carbon intensive technologies and modified consumption patterns.
By the year 2100, the world's commercial energy system will be replaced at least twice because of the natural lifetime of energy systems offering opportunities to change the energy system without premature retirement of capital stock.
However, full technical potential is rarely achieved because of a lack of information and cultural, institutional, legal and economic barriers.
The optimum mix of policies to facilitate the penetration of lower carbon intensive technologies and encourage the efficient use of energy will vary from country to country as policies need to be tailored for local situations and developed through consultation with stakeholders.
Policies include: energy pricing strategies (e.g., carbon taxes and reduced energy subsidies); reducing or removing subsidies that increase greenhouse gas emissions (e.g., agricultural and transport subsidies); internalization of environmental extranalities (e.g., incorporating the health costs associated with particulates caused by the combustion of coal into the price of coal);
Incentives such as provisions for accelerated depreciation and reduced costs for the consumer; domestic and international tradable emissions permits and joint implementation; voluntary programs and negotiated agreements with industry; utility demand-side management programs; regulatory programs including minimum energy efficiency standards;
Market pull and demonstration programs that stimulate the development and application of advanced technologies; and product labeling.
Energy services are critical to poverty alleviation and economic development: It is quite clear that increased energy services in developing countries are critical in order to alleviate poverty and underdevelopment, where 1.3 billion people live on less than $1 per day, 3 billion people live on less than $2 per day, and 2 billion people are without electricity.
Hence the challenge is to assist developing countries expand their production and consumption of energy in the most efficient and environmentally benign manner.
Co-benefits can lower the cost of climate change mitigation: The long term challenge of stabilizing the atmospheric concentrations of greenhouse gas concentrations as required by Article 2 of the UNFCCC (Article 2) will eventually require global emissions of greenhouse gases to be significantly lower than today.
The figure clearly shows that for any of these stabilization levels emissions must be lower than IS92a (often called the business-as-usual scenario) within the next few decades.
Given the challenges of improving indoor and outdoor air quality in many parts of the world, and the goals to reduce acid deposition, land degradation and protect biodiversity, policies, practices and technologies that can simultaneously address these local and regional environmental issues, while reducing net greenhouse gas emissions are particularly attractive.
Estimates of the costs of mitigating climate change should take into account the co-benefits of switching from a fossil fuel based economy to a lower-carbon intensity energy system.
Co-benefits from energy sector interventions could include lower levels of local and regional pollution, including particulates, surface ozone and acid rain.
Such interventions would have both social and economic benefits. Co-benefits from the agricultural and forestry sector could include increased soil fertility and reduced loss of biodiversity.
Significant reductions in greenhouse gases can be accomplished by pursuing sustainable development goals. A future world with greenhouse gas emissions comparable to those of today can either be achieved through the adoption of specific polices, practices and technologies to limit greenhouse gas emissions, through the adoption of a range of policies, practices and technologies to achieve other sustainable development goals (SRES).
It should be noted that a major oil company, Shell, has suggested that the mix of energy sources could change radically during the next century.
Non-fossil energy sources (solar, wind, modern biomass, hydropower, geothermal and nuclear) could account for as much as half of all energy produced by the middle of this century.
Such a future would be consistent with the lower projections of greenhouse gas emissions and would clearly eliminate the highest projections of greenhouse gases from being realized.
However, an energy efficient and low-carbon energy world is considered by many to be unlikely to occur without significant policy reform, technology transfer, capacity-building and enhanced public and private sector energy R&D programs.
Technology transfer is a critical issue: The recent IPCC Special Report on Methodological and Technological Issues in Technology Transfer examined the flows of knowledge, experience and equipment among governments, private sector entities, financial institutions, NGOs, and research and education institutions, and the different roles that each of these stakeholders can play in facilitating the transfer of technologies to address climate change in the context of sustainable development.
The report concluded that the current efforts and established processes, i.e., business-as-usual, will not be sufficient to meet this challenge.
The report concluded that enhanced capacity is required in developing countries and that additional government actions can create the enabling environment for private sector technology transfers within and across national boundaries.
Government actions could include, inter-alia, reforming legal systems, protecting intellectual property rights and licenses, encouraging financial reforms, promoting competitive and open markets for environmentally sound technologies, and knowledge sharing.
Mechanisms for technology transfer include National Systems of Innovation, Official Development Assistance, the Global Environmental Facility, Multilateral Banks and the Kyoto Protocol Mechanisms (Clean Development Mechanism) and the UNFCCC.
Summary: Without action to limit greenhouse gas emissions the Earth’s climate will warm at a rate unprecedented in the last 10,000 years: If actions are not taken to reduce the projected increase in greenhouse gas emissions, the Earth’s climate is projected to change at a rate unprecedented in the last 10,000 years with adverse consequences for society, undermining the very foundation of sustainable development.
Policymakers are faced with responding to the risks posed by anthropogenic emissions of greenhouse gases in the face of significant scientific uncertainties.
They may want to consider these uncertainties in the context that climate-induced environmental changes cannot be reversed quickly, if at all, due to the long time scales (decades to millennia) associated with the climate system.
Decisions taken during the next few years may limit the range of possible policy options in the future because high near-term emissions would require deeper reductions in the future to meet any given target concentration.
Delaying action would increase both the rate and the eventual magnitude of climate change, and hence adaptation and damage costs.
Policymakers will have to decide to what degree they want to take precautionary measures to limit anthropogenic climate change by mitigating greenhouse gas emissions and enhancing the resilience of vulnerable systems by means of adaptation.
Uncertainty does not mean that a nation or the world community cannot position itself better to cope with the broad range of possible climate changes or protect against potentially costly future outcomes.
Delaying such measures may leave a nation or the world poorly prepared to deal with adverse changes and may increase the possibility of irreversible or very costly consequences.
Options for mitigating change or adapting to change that can be justified for other reasons today and make society more flexible or resilient to anticipated adverse effects of climate change appear particularly desirable.
By: Robert T. Watson
Sixth Conference of Parties - to the United Nations Framework Convention on Climate Change November 13, 2000
Source: www.ipcc.ch.
© 2001 Mena Report (www.menareport.com)
