Human Habitat

Sea-level rise will increase the vulnerability of coastal populations to flooding. Model estimates put about 46 million people per year currently at risk of flooding due to storm surges; a 50 cm sea-level rise would increase this number to about 92 million; a 1 meter sea-level rise would increase this number to 118 million. The estimates will be substantially higher if one incorporates population growth projections. A number of studies have shown that small islands and delta areas are particularly vulnerable to a one-meter sea-level rise. Land losses ranged from 0.05% in Uruguay, 1.0% for Egypt, 6% for Netherlands, 17.5% for Bangladesh, to about 80% of the Marshall Islands, displacing tens of millions of people.

PART III:

Technical Options Exist to Reduce Emissions and Enhance Sinks of
Greenhouse Gases

Significant reductions in greenhouse gas emissions are technically possible and can be economically feasible. These reductions can be achieved by utilizing an extensive array of technologies and policy measures that accelerate technology development, diffusion, and transfer in all sectors, including the energy, industry, transportation, residential/commercial, and agricultural/forestry sectors.

Energy Demand

Numerous studies have indicated that it is possible to reduce energy demand: that 10-30% energy efficiency gains above present levels are feasible at little or no net cost in many parts of the world through technical conservation measures and improved management practices over the next 2 to 3 decades. Using technologies that presently yield the highest output of energy services for a given input of energy, efficiency gains of 50-60% would be technically feasible in many countries over the same time period. Achieving these potentials will depend on future cost reductions, financing and technology transfer, as well as measures to overcome a variety of non-technical barriers.

Energy Supply

It is technically possible to realize deep emissions reductions in the energy supply sector in step with the normal timing of investments to replace infrastructure and equipment as it wears out or becomes obsolete. Promising approaches, not ordered according to priority, include: more-efficient conversion of fossil fuels; switching to low-carbon fossil fuels and suppressing emissions; decarbonization of flue gases and fuels and carbon dioxide storage; switching to non-fossil fuel sources of energy such as nuclear energy or renewable fuels. Technological advances offer new opportunities and declining costs for energy from these sources.

Agriculture and Forestry

Beyond the use of biomass fuels to displace fossil fuels, the management of forests, agricultural lands, and rangelands can play an important role in reducing current emissions of carbon dioxide, methane, and nitrous oxide and enhancing carbon sinks. A number of measures could conserve and sequester substantial amounts of carbon (approximately an additional 60-90 GtC in the forestry sector alone) over the next 50 years. In the forestry sector, costs for conserving and sequestering carbon in biomass and soil are estimated to range widely but can be competitive with other mitigation options.

Policy Instruments

Policies are available to governments that facilitate the penetration of less greenhouse gas-intensive technologies and modified consumption patterns. Many countries have extensive experience with a variety of policies that can accelerate the adoption of such technologies. This experience comes from efforts over the past 20 to 30 years to achieve improved energy efficiency, reduce the environmental impacts of agricultural policies, and meet conservation and environmental goals unrelated to climate change. Policies to reduce net greenhouse gas emissions appear more easily

implemented when they are designed to address other environmental concerns (e.g. air pollution, and soil erosion). These policies include: (i) voluntary programs and negotiated agreements with industry; (ii) utility demand-side management programs; (iii) tradable emissions permits; (iv) energy pricing strategies—for example, carbon or energy taxes, and reduced energy subsidies; (v) renewable energy incentives during market build-up; (vi) incentives such as provisions for accelerated depreciation and reduced costs for consumers; (vii) reducing or removing other subsidies, for example agricultural and transport subsidies, which increase greenhouse gas emissions; (viii) regulatory programs including minimum energy-efficiency standards, such as for appliances and fuel economy; (ix) stimulating research, development, and demonstration to make new technologies available.

Policymakers are faced with responding to the risks posed by anthropogenic emissions of
greenhouse gases in the face of significant scientific uncertainties. They should note though, that
uncertainties go in two directions, i.e., the models may be either over-estimating or under-
estimating the impact of human activities on the Earth's climate. In addition, policymakers should
consider these uncertainties in the context of information indicating 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 might reduce
the overall costs of mitigation because of potential technological advances but could increase both
the rate and the eventual magnitude of climate change, and hence the adaptation and damage costs.
Policymakers will have to decide to what degree they want to take precautionary measures 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.

While human-induced climate change is a serious environmental issue, it is also clear that improved
scientific knowledge and technological advances, coupled with strong policy measures, can allow
society to significantly reduce greenhouse gas emissions in a cost-effective manner. However, to
achieve this goal will require that a priority be placed on research and development in a number of
areas: (i) an improved understanding of how human activities change climate at the regional scale;
(ii) an improved understanding of how human health, ecological and socio-economic systems
respond to changes in climate; (iii) the development of cost-effective adaptation strategies; and (iv)
the development of improved energy efficiency technologies and low greenhouse gas emission
energy supply technologies. A coordinated effort to address the climate change issue by the
scientific community, industry, business, environmental organizations and governments, all
working towards the common goal of the cost-effective protection of human health and our vital
economic and ecological systems, is within our grasp.

Annex I

Background Information

on the

Intergovernmental Panel on Climate Change

The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO). Its purpose is to assess scientific and technical information about climate change.

Previous Reports

In the 7 years since its inception, the IPCC has prepared a series of reports and methodologies, including:

The 1990 comprehensive three-volume assessment of climate change, which evaluated anthropogenic alteration of the climate system, potential impacts, and available response measures (IPCC, 1990). This report became a standard reference, widely used by policymakers, scientists, and other experts.

A supplementary review of literature related to climate change, impacts, and response measures prepared for the U.N. Conference on Environment and Development (UNCED) (IPCC, 1992).

A special report on radiative forcing of climate and greenhouse gas emissions scenarios, produced for the first meeting of the Conference of Parties to the U.N. Framework Convention on Climate Change (UNFCCC) (IPCC, 1994a).

The IPCC methodology for assessing climate change impacts and adaptation measures (IPCC, 1994b).

The IPCC, Organisation for Economic Cooperation and Development (OECD), and International Energy Agency (IEA) methodology for conducting and reporting on national inventories of greenhouse gas emissions (IPCC, 1995).

These publications have established a common body of scientific information that has been used by governments in international negotiations and national decisionmaking.

New Reports

At the request of governments, the IPCC is currently preparing its Second Assessment Report (SAR), which will provide a comprehensive assessment of new and recent literature. To be completed at the end of 1995, the SAR will be published in three volumes, plus a special report. The common title for all of the volumes is Climate Change 1995: The IPCC Second Assessment Report. Titles of the separate volumes (to be contributed by Working Groups I through III) and the special report follow:

Volume 2: Scientific-Technical Analyses of Impacts, Adaptations, and Mitigation of
Climate Change

Volume 3: Economics and Social Dimensions

The IPCC Synthesis Report: An Assessment of Scientific-Technical Information Relevant to Interpreting Article 2 of the U.N. Framework Convention on Climate Change, and the Summaries for Policymakers.

The scientific and technical chapters of the SAR will contain detailed reviews of critical issues such as detection of climate change; assessment of model results; effects of aerosols on radiative forcing; potential impacts for many ecological systems, human activities, and human infrastructure; technical evaluations of measures for reducing greenhouse gas emissions; and analysis of the potential economic consequences and the applicability of such decisionmaking tools as cost-benefit analysis.

Each volume of the SAR will include a "Summary for Policymakers" that extracts critical information from the underlying technical reports of interest to the policy community. In addition, the Special Report on Article 2 of the Convention will synthesize material contained in the three volumes of the full report that is particularly relevant to governments' interpretation of the UNFCCC objective of stabilizing atmospheric concentrations of greenhouse gases at a level that would avoid "dangerous anthropogenic interference with the climate system." Of specific concern are the relationships between emissions and atmospheric concentrations of greenhouse gases, changes in concentrations and their effects on the rate and magnitude of climate change, and potential impacts of different levels of climate change on natural ecosystems, food security, and sustainable economic development.

Structure and Process

The IPCC operates at two overlapping but distinct levels—as a formal intergovernmental body and as a scientific and technical assessment body. Government representatives meet in formal plenary sessions to approve the topics for assessment and the overall workplans for preparation of the reports. They also review and accept the detailed scientific and technical reports, as well as approve on a line-by-line basis the Summaries for Policymakers that highlight the policy implications of the detailed reports. Scientific and technical experts from each chapter writing team participate in the final approval process to maintain consistency between the Summary and the underlying chapters of the assessment. It is through this intergovernmental review and approval mechanism that the work of the IPCC is connected to international and national policy concerns. The detailed scientific and technical reports themselves are prepared through the enthusiasm and cooperation of scientists and technical experts from around the world. Hundreds of experts are involved in preparing the different chapters of the reports; literally thousands are involved in providing expert peer review. These experts come from many countries and are trained in disciplines ranging from atmospheric chemistry to economics. They include university professors, researchers working in private industry and at national laboratories, and scientific experts affiliated with nongovernmental organizations. The teams of experts that draft the individual sections of the reports are structured to include the broadest possible range of scientific opinion.

IPCC reports are considered by virtually the entire scientific community to be balanced, unbiased assessments of the full range of scientific information on critical climate change issues. This is because the process of preparing the reports involves reviewing the most up-to-date scientific information, reconciling competing views where possible, and characterizing the disagreements when consensus is not achievable. IPCC reports have served another purpose as well: They have identified climate change issues that deserve the priority attention of the research community in the future.

The IPCC is divided into three working groups. Working Group I analyzes the functioning of the climate system and potential changes to it resulting from human activities; Working Group II assesses potential impacts of climate change, adaptation strategies, and measures that could be adopted to reduce greenhouse gas emissions; and Working Group III focuses on evaluating the

economic implications of climate change. This task involves assessing potential economic damages and the applicability of cost-benefit analysis to decisionmaking.