Ch 1: Understanding Global Climate Change

PART I

The Science and Politics of

Global Warming

Chapter One

Understanding Global Climate Change

Given the same information about objective climate science, why is there such a great disparity between people’s opinions about what policies to adopt? Professor John Adams of University College London suggests it is about how each individual views risk and nature (1995). Adams developed four views of nature and Geographer Mark Maslin (2004) adapted this model to apply to how different people perceive global warming (see Figure 1).

Some view nature as predictable and stable and a non-interventionist approach can be taken because it is benign in the context of human scale. This is false because it ignores palaeoclimatic data about rapid shifts in the earth’s climate and six global mass extinctions.⁷ Dr. David Pimentel and a number of organizations suggest humans have overshot a sustainable carrying capacity by more than four and a half billion people. Opposite of this nature-benign view is a view of nature as ephemeral. This second view sees nature as fragile and unforgiving. It is in danger of catastrophic collapse thanks to human interference, and the guiding management rule is one of strict precaution. This is obviously false because the earth is remarkably regenerative and can absorb and process much of the energy humans are creating.⁸ The third view of nature, a combination of the first two, is that nature is both tolerant and perverse and can be relied upon within limits to behave predictably. Regulation is required to prevent major excesses and this view of risk results justifies an interventionist management. It is this view that most closely reflects reality. And the fourth view is that nature is capricious and unpredictable. This view results in an agnostic concern and fatalist outlook.

Views of Nature (from Maslin: 2004)

Based on people’s risk assessment it is reasonable that people have a variety of responses. Some people do not believe global climate change is a threat because these people do not have enough information, and this is a problem.⁹ People are fluid in their beliefs and opinions shift depending on the evidence put forward. The following section about global warming should convince people that nature is tolerant-perverse: care must be taken not to knock the ball out of the cup. Precaution is necessary to prevent a collapse (a drastic decrease in human population size and/or political, economic, or social complexity over a large area for an extended time) due to the instability of clathrate reservoirs, disease, or war (Diamond: 2005). These are the three primary non-linear effects of global warming that could trigger a tipping point. The following section should also convince people that the ball is at the edge of the cup, precariously balanced.

The earth’s ecosystem can look after itself in minor matters but burning such massive amount of fossil fuels has created a serious problem. The limiting of GHGs is about keeping the ball in the cup. And the current scientific consensus is that a concentration above 450-500 ppm CO₂ would be pushing the system beyond stability. The problem is that GHG concentrations are now about 460 ppm and rising fast—about 2 ppm per year (Metro: 2007).¹⁰

The following is a synopsis of the three Summary for Policymakers reports authored in 2007 by the United Nation’s Intergovernmental Panel on Climate Change’s (IPCC) Working Groups I, II and III. It includes “The Physical Science Basis”, “Impacts, Adaptation and Vulnerability”, and “Mitigation of Climate Change”. With more than two thousand scientists from one hundred countries, the IPCC is the largest and most rigorously peer-reviewed scientific collaboration in history.

The great majority of these next three sections of my thesis are directly taken from the IPCC reports: it is important, I believe, to respect the IPCC’s exposition.

The Physical Science Basis

The following is to help understand the physical science of climate change that the IPCC judged to be most relevant to policymakers.

Human and Natural Drivers of Climate Change

Global atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial values determined from ice cores spanning many thousands of years. The global increases in carbon dioxide concentration are due primarily to fossil fuel use and land use change, while those of methane and nitrous oxide are primarily due to agriculture.

Carbon dioxide, the most important anthropogenic greenhouse gas, has increased from a pre-industrial value of about 280 to 379 parts per million (ppm) in 2005. This level exceeds by far the natural range over the last 650,000 years (180 to 300 ppm) as determined from ice cores. During the last ten years (1995-2005 average), carbon dioxide concentration growth rate was 1.9 ppm per year.

Global atmospheric concentration of methane has increased from a pre-industrial value of about 715 to 1,774 parts per billion (ppb) in 2005. This level exceeds by far the natural range over the last 650,000 years (320 to 790 ppb) as determined from ice cores. Methane increases are due to anthropogenic activities, predominantly agriculture and fossil fuel use. Nitrous oxide concentrations have increased from a pre-industrial value of about 270 ppb to 319 ppb in 2005. Nitrous oxide emissions are more than one-third anthropogenic and primarily due to agriculture.

Anthropogenic contributions to aerosols (primarily sulphate, organic carbon, black carbon, nitrate, and dust) together produce a cooling effect. Other significant anthropogenic contributions come from ozone-forming chemicals and halocarbons.

Direct Observations of Recent Climate Change

The IPCC reports “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.” Eleven of the last twelve years (1995-2006) rank among the twelve warmest years in the instrumental record of global surface temperatures (since 1850). The average temperature of the global ocean has increased to depths of at least 3000 meters and the oceans have been absorbing more than 80 percent of the heat added to the climate system. Such warming causes seawater to expand, contributing to sea level rise.

Losses from the ice sheets of Greenland and Antarctica have very likely contributed to sea level rise. The global average sea level rose at an average of 1.8 [1.3 to 2.3] mm (0.07 inches) per year from 1961 to 2003. The rate was faster over 1993-2003: about 3.1 [2.4 to 3.8] mm (0.12 inches) per year.

At continental, regional and ocean basin scales, numerous long-term changes in climate have been observed. These include changes in arctic temperatures and ice, widespread changes in precipitation amounts, ocean salinity, wind patterns and aspects of extreme weather including droughts, heavy precipitation, heat waves and the intensity of tropical cyclones.

A Palaeoclimatic Perspective

Palaeoclimatic studies use changes in climatically sensitive indicators to infer past changes in global climate on time scales ranging from decades to millions of years. Palaeoclimatic information supports the interpretation that the warmth of the last half century is unusual in at least the previous 1,300 years. The last time the polar regions were significantly warmer than present for an extended period (about 125,000 years ago), reductions in polar ice volume led to 4 to 6 m (13 to 19.7 feet) of sea level rise.¹¹

Understanding and Attributing Climate Change

Most of the observed increase in global average temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. Discernible human influences now extend to other aspects of climate, including ocean warming, continental-average temperatures, temperature extremes, and wind patterns.

Analysis of climate models together with constraints from observations enables an assessed likely (>66%) range to be given for climate sensitivity for the first time and provides increased confidence in the understanding of the climate system response to radiative forcing.¹²

Projections of Future Changes in Climate

For the next two decades, a warming of about 0.2°C (0.36°F) per decade is projected for a range of emission scenarios. Even if the concentrations of all greenhouse gases and aerosols had been kept constant at year 2000 levels, a further warming of about 0.1°C (0.18°F) per decade would be expected, due mainly to the slow response of the oceans. Decadal average warming is very likely to be at least twice as large as the corresponding model-estimated natural variability during the twentieth century.

The best estimate for warming in the twenty-first century is a low scenario of 1.8 [1.1 to 2.9] °C (3.24°F, 1.98 to 5.22 °F) and the best estimate for the high scenario is 4.0 [2.4 to 6.4] °C (7.2°F, 4.32 to 11.52 °F).

There is now higher confidence in projected patterns of warming and other regional-scale features, including changes in wind patterns, precipitation and some aspects of extreme conditions. It is very likely that hot extremes, heat waves and heavy precipitation events will continue to become more frequent. It is likely that future typhoons and hurricanes will become more intense.

Anthropogenic warming and sea level rise would continue for centuries to the time scales associated with climate processes and feedbacks, even if greenhouse gas concentrations were to be stabilized.

Impacts, Adaptation and Vulnerability

Observed Impacts on the Natural and Human Environment

Observational evidence from all continents and most oceans shows that many natural systems are being affected by regional changes, particularly temperature increases. There is very high confidence that recent warming is strongly affecting terrestrial biological systems, including such changes as (1) earlier timing of spring events, such as leaf unfolding, bird migration and egg-laying and (2) pole-ward and upward shifts in ranges in plant and animal species. Forests are expected to be particularly damaged because of the ecosystem’s low adaptability.

There is high confidence, based on substantial new evidence, that observed changes in marine and freshwater biological systems are associated with rising water temperatures, as well as related changes in ice cover, salinity, oxygen levels, and circulation. This includes shifts in ranges and changes in algal, plankton and fish abundance in high-latitude oceans. The uptake of anthropogenic carbon since 1750 has led to the ocean becoming more acidic and is the primary threat to the stability of coral reefs and other species that rely on calcium shells (one-third of all ocean species).

Effects of temperature increase have been documented in the following: (1) effects on agricultural and forestry management at Northern Hemisphere higher latitudes, such as earlier spring planting of crops, and alterations in disturbance regimes of forests due to fires and pests; (2) some aspects of human health, such as heat-related mortality in Europe, infectious disease vectors in some areas, and allergenic pollen in Northern Hemisphere high and mid-latitudes; and (3) some human activities in the Arctic (e.g., hunting and travel over snow and ice) and in lower-elevation alpine areas (such as mountain sports).

For example, in the Sahelian region of Africa, warmer and drier conditions have led to a reduced length of growing season with detrimental effects on crops. In southern Africa, longer dry seasons and more uncertain rainfall are prompting adaptation measures.

Current Knowledge about Future Impacts

Drought-affected areas will likely increase in extent. Heavy precipitation events, which are likely to increase in frequency, will add to flood risk. In the course of the century, water supplies stored in glaciers and snow cover are projected to decline, reducing water availability in regions supplied by melt-water from major mountain ranges, where more than one-sixth of the world population lives.

The resilience of many ecosystems is likely to be exceeded this century by an unprecedented combination of climate change, associated disturbances (e.g., flooding, drought, wildfire, insects, ocean acidification), and other global change drivers (e.g., land-use change, pollution, over-exploitation of resources).

Approximately twenty to thirty percent of plant and animal species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5-2.5°C (2.7 to 4.5°F). For example, corals are vulnerable to thermal stress and have low adaptive capacity. Increases in sea surface temperature of about 1-3°C (1.8 to 5.4°F) are projected to result in more frequent coral bleaching events and widespread mortality.

Over the course of this century, net carbon uptake by terrestrial ecosystems is likely to peak before mid-century and then weaken or even reverse, thus amplifying climate change. At lower latitudes, especially seasonally dry and tropical regions, crop productivity is projected to decrease for even small local temperature increases (1-2°C, 1.8-3.6°F), which would increase the risk of hunger.

Coasts are projected to be exposed to increasing risks, including coastal erosion due to climate change and sea-level rise. The effect will be exacerbated by increasing human-induced pressures on coastal areas. Many millions more people are projected to be flooded every year due to sea-level rise by the 2080s. The numbers affected will be largest in the mega-deltas of Asia and Africa while small islands are especially vulnerable. Adaptation for coasts will be more challenging in developing countries than in developed countries, due to constraints on financial resources.

The most vulnerable industries, settlements, and societies are generally those in coastal and river flood plains, those whose economies are closely linked with climate-sensitive resources, and those in areas prone to extreme weather events, especially where rapid urbanization is occurring. Poor communities can be especially vulnerable, in particular those concentrated in high-risk areas. The poor tend to have more limited adaptive capacities, and are more dependent on climate-sensitive resources such as local water and food supplies.¹³

Where extreme weather events become more intense and/or more frequent, the economic and social costs of those events will increase. Climate change impacts spread from directly impacted areas and sectors to other areas and sectors through extensive and complex linkages.

Projected climate change-related exposures are likely to affect the health status of millions of people, particularly those with low adaptive capacity, through: (1) increases in malnutrition and consequent disorders, with implications for child growth and development; (2) increased deaths, disease and injury due to heatwaves, floods, storms, fires and droughts; (3) the increased burden of diarrhoeal disease; (4) the increased frequency of cardio-respiratory diseases due to higher concentrations of ground-level ozone related to climate change; and (5) the altered spatial distribution of some infectious disease vectors.

Critically important will be factors that directly shape the health of populations such as:

• education,

• health care,

• public health initiatives, and

• infrastructure and economic development.

In North America, warming in western mountains is projected to cause decreased snowpack, more winter flooding, and reduced summer flows, exacerbating competition for over-allocated water resources. Disturbances from pests, diseases and fire are projected to have increasing impacts on forests, with an extended period of high fire risk and large increases in area burned.

Moderate climate change in the early decades of the century is projected to increase aggregate yields of rain-fed agriculture by five to twenty percent but with important variability among regions.

Coastal communities and habitats will be increasingly stressed by climate change impacts interacting with development and pollution. Population growth and the rising value of infrastructure in coastal area increase vulnerability to climate variability and future climate change. Current adaptation is uneven and readiness for increased exposure is low.

Impacts due to altered frequencies and intensities of extreme weather, climate and sea-level events are very likely to change. Some large-scale climate events have the potential to cause very large impacts, especially after the twenty-first century. Impacts of climate change will vary regionally but, aggregated and discounted to the present, they are very likely to impose net annual costs which will increase over time as global temperatures increase.

The complete melting of the Greenland ice sheet and the West Antarctic ice sheet would lead to a contribution to sea-level rise of up to 7 m (23 feet) and about 5 m (16.4 feet), respectively. It is very unlikely that the Meridional Overturning Circulation (MOC) in the North Atlantic will undergo a large abrupt transition during the twenty-first century. But slowing of the MOC is very likely during this century. This change is likely to include changes to marine ecosystem productivity, fisheries, ocean carbon dioxide uptake, oceanic oxygen concentrations, and terrestrial vegetation.

Responding to Climate Change

Some adaptation is occurring now, to observed and projected future climate change, but on a limited basis. Adaptation will be necessary to address impacts resulting from the warming which is already unavoidable due to past emissions. Unavoidable warming is about 0.6°C (1.08°F) by the end of the century even if atmospheric greenhouse gas concentrations remain at 2000 levels. A wide array of adaptation options is available, but more extensive adaptation than is currently occurring is required to reduce vulnerability to future climate change. There are barriers, limits and costs, but these are not fully understood.

The array of potential adaptive responses available to human societies is very large, ranging from purely technological (e.g., sea defenses), through behavioral (e.g., altered food and recreational choices), to managerial (e.g., altered farm practices) and to policy (e.g., planning regulations). While most technologies and strategies are known and developed in some countries, the assessed literature does not indicate how effective various options are at fully reducing risks, particularly at higher levels of warming and related impacts, and for vulnerable groups. In addition, there are formidable barriers to the implementation of adaptation:

• environmental,

• economic,

• information,

• social,

• attitudinal, and

• behavioral

For developing countries, availability of resources and building adaptive capacity are particularly important.

Adaptation alone is not expected to cope with all the projected effects of climate change, and especially not over the long term as most impacts increase in magnitude.

Vulnerability to climate change can be exacerbated by the presence of other stresses. Future vulnerability depends not only on climate change but also on the development pathway. Sustainable development can reduce vulnerability to climate change, and climate change could impede nations’ abilities to achieve sustainable development pathways.

Many impacts can be avoided, reduced, or delayed by mitigation. A portfolio of adaption and mitigation measures can diminish the risks associated with climate change. Unmitigated climate change would, in the long run, be likely to exceed the capacity of natural, managed and human systems to adapt. Such portfolios should combine policies with incentive-based approaches, and actions are needed at all levels from the individual citizen through to national governments and international organizations.

“Mitigation of Climate Change”

Greenhouse Gas Emission Trends

Global greenhouse gas emissions (GHGs) have grown since pre-industrial times, with an increase of 70 percent between 1970 and 2004. In 2004 UNFCCC Annex I (developed) countries held a 20 percent share in world population, produced 57 percent of world Gross Domestic Product based on Purchasing Power Parity (GDP_PPP) and accounted for 46 percent of global GHG emissions. A range of policies, including those on climate change, energy security, and sustainable development, have been effective in reducing GHG emissions in different sectors and in many countries. The scale of such measures, however, has not yet been large enough to counteract the global growth in emissions.

With current climate change mitigation policies and related sustainable development practices, global GHG emissions will continue to grow over the next few decades. Non-mitigation scenarios project an increase of baseline global GHG emissions by a range of 9.7-36.7 GtCO₂-eq (25-90 percent) between 2000 and 2030. In this scenario, fossil fuels are projected to maintain their dominant position in the global energy mix to 2030 and beyond. Carbon dioxide emissions between 2000 and 2030 from energy use are projected to grow 40 to 110 percent over that period. Two-thirds to three-quarters of this increase in energy CO₂ emissions is projected to come from non-Annex I regions (developing countries).

Mitigation In the Short and Medium Term (Until 2030)

Both bottom-up and top-down studies indicate that there is substantial economic potential for mitigation of global GHGs over the coming decades, that could offset the projected growth of global emissions or reduce emissions below current levels.

In 2030 macro-economic costs for multi-gas mitigation, consistent with emissions trajectories towards stabilization between 445 and 710 ppm CO₂-eq, are estimated at a three percent decrease of global GDP. However, regional costs may differ significantly from global averages.

Depending on the existing tax system and spending of the revenues, modeling studies indicate that costs may be substantially lower under the assumption that revenues from carbon taxes or auctioned permits under an emission trading system are used to promote low-carbon technologies or reform of existing taxes. Studies that assume the possibility that climate change policy enhances technological change also give lower costs. However, this may require higher upfront investment in order to achieve cost reductions thereafter.

Although most models show GDP losses, some show GDP gains because they assume that baselines are non-optimal and mitigation policies improve market efficiencies, or they assume that more technological change may be induced by mitigation policies. Examples of market inefficiencies include:

• unemployed resources,

• distortionary taxes, and/or

• subsidies.

A multi-gas approach and inclusion of carbon sinks generally reduces costs substantially compared to CO₂ emission abatement only.

IPCC Table SPM.3: Key mitigation technologies and practices by sector. Sectors and technologies are listed in no particular order. Non-technological practices, such as lifestyle changes, which are cross-cutting, are not included in this table.

Changes in lifestyle and behavior patterns can contribute to climate change mitigation across all sectors. Changes in lifestyles and consumption patterns that emphasize resource conservation can contribute to developing a low-carbon economy that is both equitable and sustainable. Management practices can also have a positive role. Education and training programs can help overcome barriers to the market acceptance of energy efficiency, particularly in combination with other measures. Changes in occupant behavior, cultural patterns and consumer choice and use of technologies can result in considerable reductions in carbon dioxide emissions related to energy use in buildings.

Transport Demand Management includes urban planning (to reduce the demand for travel) and provision of information and educational techniques (to reduce car usage and lead to an efficient driving style) can support GHG mitigation. In industry, management tools that include staff training, reward systems, regular feedback, documentation of existing practices can help overcome industrial organization barriers, reduce energy use, and GHG emissions.

While studies use different methodologies, in all analyzed world regions near-term health co-benefits from reduced air pollution as a result of actions to reduce GHG emissions can be substantial and may offset a substantial fraction of mitigation costs.

Integrating air pollution abatement and climate change mitigation policies offers potentially large cost reductions compared to treating those policies in isolation. Co-benefits include:

• increased energy security,

• increased agricultural production, and

• reduced pressure on natural ecosystems due to decreased tropospheric ozone concentrations.

New energy infrastructure investments in developing countries, upgrades of energy infrastructure in industrialized countries, and policies that promote energy security, can, in many cases, create opportunities to achieve GHG emission reductions compared to baseline scenarios. Additional co-benefits are country-specific but often include air pollution abatement, balance of trade improvement, provision of modern energy services to rural areas and employment.

Future energy infrastructure investment decisions, expected to total over $20 trillion between now and 2030, will have long term impacts on GHG emissions because of the long life-times of energy plants and other infrastructure capital stock. The widespread diffusion of low-carbon technologies may take many decades, even if early investments in these technologies are made attractive.

It is often more cost-effective to invest in end-use energy efficient improvement than in increasing energy supply to satisfy demand for energy services. Efficiency improvement has a positive effect on energy security, local and regional air pollution abatement, and employment.

Renewable energy generally has a positive effect on energy security, employment and on air quality. Given costs relative to other supply options, renewable electricity, which accounted for eighteen percent of the global electricity supply in 2005, can have a thirty to thirty-five percent share of the total electricity supply in 2030 at carbon prices up to fifty dollars per ton of CO₂-eq.

The higher the market prices of fossil fuels, the more low-carbon alternatives will be competitive, although price volatility will be a disincentive for investors.¹⁴ Higher priced conventional oil resources, on the other hand, may be replaced by high carbon alternatives such as from oil sands, oil shales, heavy oils, and synthetic fuels from coal and gas, leading to increasing GHG emissions, unless production plants are equipped with carbon capture and sequestration/storage (CCS).

Given costs relative to other supply options, nuclear power, which accounted for sixteen percent of the electricity supply in 2005, can have an eighteen percent share of the total electricity supply in 2030 at carbon prices up to fifty dollars per ton of CO₂-eq but safety, weapons proliferation and waste remain as constraints.

CCS in underground geological formations is a new technology with the potential to make an important contribution to mitigation by 2030. Technical, economic and regulatory developments will affect the actual contribution.

There are multiple mitigation options in the transport sector, but their effect may be counteracted by growth in the sector. Mitigation options are faced with many barriers, such as consumer preferences and lack of policy frameworks. Realizing emissions reductions in the transport sector is often a co-benefit of addressing traffic congestion, air quality, and energy security.

Improved vehicle efficiency measures, leading to fuel savings, in many cases have net benefits (at least for light-duty vehicles), but the market potential is much lower than the economic potential due to the influence of other consumer considerations, such as performance and size. Market forces alone, including rising fuel costs, are therefore not expected to lead to significant emission reductions.

Biofuels might play an important role in addressing GHG emissions in the transport sector depending on their production pathway. Biofuels used as gasoline and diesel fuel additives/substitutes are projected to grow to three percent of total transport energy demand in the baseline in 2030. This could increase to about five to ten percent, depending on future oil and carbon prices, improvements in vehicle efficiency and the success of technologies to utilize cellulose biomass.

Modal shifts from road to rail and to inland and coastal shipping and from low-occupancy to high-occupancy passenger transportation, as well as land-use, urban planning and non-motorized transport offer opportunities for GHG mitigation, depending on local conditions and policies.

Medium term mitigation potential for carbon dioxide emissions from the aviation sector can come from improved fuel efficiency, which can be achieved through a variety of means, including technology, operations and air traffic management. However, such improvements are expected to only partially offset the growth of aviation emissions.

Energy efficiency options for new and existing buildings could considerably reduce carbon dioxide emissions with net economic benefit. Many barriers exist against tapping this potential, but there are also large co-benefits.

By 2030, about thirty percent of the projected GHG emissions in the building sector can be avoided with net economic benefit. Energy efficient buildings, while limiting the growth of CO₂ emissions, can also improve indoor and outdoor air quality, improve social welfare and enhance energy security. Opportunities for realizing GHG reductions in the building sector exist worldwide. However, multiple barriers make it difficult to realize this potential. These barriers include availability of technology, financing, poverty, higher costs of reliable information, limitations inherent in building designs and an appropriate portfolio of policies and programs.¹⁵ The magnitude of the above barriers is higher in the developing countries and this makes it more difficult for them to achieve the GHG reduction potential of the building sector.

The economic potential in the industrial sector is predominantly located in energy intensive industries. Full use of available mitigation options is not being made in either industrialized or developing nations. Many industrial facilities in developing countries are new and include the latest technology with the lowest specific emissions. However, many older, inefficient facilities remain in both industrialized and developing countries. Upgrading these facilities can deliver significant emission reductions.

Key barriers to full use of available mitigation options include:

• the slow rate of capital stock turnover,

• lack of financial and technical resources, and

• limitations in the ability of firms, particularly small and medium-sized enterprises, to access and absorb technological information.

Agricultural practices collectively can make a significant contribution at low cost by increasing soil carbon sinks and by contributing biomass feedstocks for energy use. A large proportion of the mitigation potential of agriculture (excluding bioenergy) arises from soil carbon sequestration, which has strong synergies with sustainable agriculture and generally reduces vulnerability to climate change. (Stored soil carbon may be vulnerable to loss through both land management change and climate change.) Considerable mitigation potential is also available from reductions in methane and nitrous oxide emissions in some agricultural systems.

Biomass from agricultural residues and dedicated energy crops can be an important bioenergy feedstock, but its contribution to mitigation depends on demand for bioenergy from transport and energy supply, on water availability, and on requirements of land for food and fiber production. Widespread use of agricultural land for biomass production for energy may compete with other land uses and can have positive and negative environmental impacts and implications for food security.

Forest-related mitigation activities can considerably reduce emissions from sources and increase carbon dioxide removals by sinks at low costs, and can be designed to create synergies with adaptation and sustainable development. About 65 percent of the total mitigation potential is located in the tropics and about 50 percent of the total could be achieved by reducing emissions from deforestation.

Climate change can affect the mitigation potential of the forest sector (i.e., native and planted forests) and is expected to be different for different regions and sub-regions, both in magnitude and direction. Forest-related mitigation options can be designed and implemented to be compatible with adaptation, and can have substantial co-benefits in terms of:

• employment,

• income generation,

• biodiversity,

• watershed conservation,

• renewable energy supply, and

• poverty alleviation.

Post-consumer waste is a small contributor to global GHG emissions (less than 5 percent), but the waste sector can positively contribute to GHG mitigation at low cost and promote sustainable development. Existing waste management practices can provide effective mitigation of GHG emissions from this sector: a wide range of mature, environmentally effective technologies are commercially available to mitigate emissions and provide co-benefits for improved public health and safety, soil protection and pollution prevention, and local energy supply. Waste minimization and recycling provide important indirect mitigation benefits through the conservation of energy and materials.

Lack of local capital is a key constraint for waste and wastewater management in developing countries and countries with economies in transition. Lack of expertise on sustainable technology is also an important barrier.

Geo-engineering options, such as ocean fertilization to remove CO₂ directly from the atmosphere, or blocking sunlight by bringing material into the upper atmosphere, remain largely speculative and unproven, and with the risk of unknown side-effects. Reliable cost estimates for these options have not been published.

Mitigation in the Long Term (After 2030)

In order to stabilize the concentration of GHGs in the atmosphere, emissions would need to peak and decline thereafter. The lower the stabilization level, the more quickly this peak and decline would need to occur. Mitigation efforts over the next two to three decades will have a large impact on opportunities to achieve lower stabilization levels.

The range of stabilization levels assessed can be achieved by the deployment of a portfolio of technologies that are currently available and those that are expected to be commercialized in coming decades. This assumes that appropriate and effective incentives are in place for development, acquisition, deployment and diffusion of technologies and for addressing related barriers. The contribution of different technologies to emission reductions required for stabilization will vary over time, region and stabilization level. Energy efficiency plays a key role across many scenarios for most regions and timescales. For lower stabilization levels, scenarios put more emphasis on the use of low-carbon energy sources, such as renewable energy and nuclear power, and the use of carbon dioxide capture and storage (CCS). In these scenarios improvements of GHG intensity of energy supply and the whole economy need to be much faster than in the past.

Including non-carbon dioxide and carbon dioxide land-use and forestry mitigation options provides greater flexibility and cost-effectiveness for achieving stabilization. Modern bioenergy could contribute substantially to the share of renewable energy in the mitigation portfolio.

IPCC Table SPM. 5: Characteristics of post-TAR stabilization scenarios.

Investments in world-wide deployment of low-GHG emission technologies as well as technology improvements through public and private research, development and demonstration (RD&D) would be required for achieving stabilization targets as well as cost reduction. The lower the stabilization levels, especially those of 550 ppm CO₂-eq or lower, the greater the need for more efficient RD&D efforts and investment in new technologies during the next few decades. This requires that barriers to development, acquisition, deployment and diffusion of technologies are effectively addressed.

In 2050 global average macro-economic costs for multi-gas mitigation towards stabilization between 445 and 710 ppm CO₂-eq, are between a one percent gain to a 5.5 percent decrease of global GDP. For specific countries and sectors, costs vary considerably from the global average.

Decision-making about the appropriate level of global GHG mitigation over time involves a risk management process that includes mitigation and adaptation, taking into account:

• actual and avoided climate change damages,

• co-benefits,

• sustainability,

• equity, and

• attitudes to risk.

Choices about the scale and timing of GHG mitigation involve balancing the economic costs of more rapid emission reductions now against the corresponding medium-term and long-term climate risks of delay.

Limited and early analytical results from integrated climate sensitivity are a key uncertainty for mitigation scenarios that aim to meet a specific temperature level. Studies show that if climate sensitivity is high then the timing and level of mitigation is earlier and more stringent than when it is low.

Delayed emission reductions lead to investments that lock in more emission-intensive infrastructure and development pathways. This significantly constrains the opportunities to achieve lower stabilization levels and increases the risk of more severe climate change impacts (Table SPM.5).

Policies, Measures and Instruments to Mitigate Climate Change

A wide variety of national policies and instruments are available to governments to create the incentives for mitigation action. Their applicability depends on national circumstances and an understanding of their interactions, but experience from implementation in various countries and sectors shows there are advantages and disadvantages for any given instrument.

Four main criteria are used to evaluate policies and instruments:

1. environmental effectiveness,

2. cost effectiveness,

3. distributional effects, including equity, and

4. institutional feasibility.

All instruments can be designed well or poorly, and be stringent or lax. In addition, monitoring to improve implementation is an important issue for all instruments. General findings about the performance of policies are:

• Integrating climate policies in broader development policies makes implementation and overcoming barriers easier.

• Regulations and standards generally provide some certainty about emission levels. They may be preferable to other instruments when information or other barriers prevent producers and consumers from responding to price signals. However, they may not induce innovations and more advanced technologies.

• Taxes and charges can set a price for carbon, but cannot guarantee a particular level of emissions. Literature identifies taxes as an efficient way of internalizing costs of GHG emissions.

• Tradable permits will establish a carbon price. The volume of allowed emissions determines their environmental effectiveness, while the allocation of permits has distributional consequences. Fluctuation in the price of carbon makes it difficult to estimate the total cost of complying with emission permits.

• Financial incentives (subsidies and tax credits) are frequently used by governments to stimulate the development and diffusion of new technologies. While economic costs are generally higher than for the instruments listed above, they are often critical to overcome barriers.

• Voluntary agreements between industry and governments are politically attractive, raise awareness among stakeholders, and have played a role in the evolution of many national policies. The majority of agreements have not achieved significant emissions reductions beyond business as usual. However, some recent agreements, in a few countries, have accelerated the application of best available technology and led to measurable emission reductions.

• Information instruments (e.g. awareness campaigns) may positively affect environmental quality by promoting informed choices and possibly contributing to behavioral change, however, their impact on emissions has not been measured yet.¹⁶

• RD&D can stimulate technological advances, reduce costs, and enable progress toward stabilization.

Some corporations, local and regional authorities, nongovernmental organizations (NGOs), and civil groups are adopting a wide variety of voluntary actions. These voluntary actions may limit GHG emissions, stimulate innovative policies, and encourage the deployment of new technologies. On their own, they generally have limited impact on the national or regional level emissions.

Policies that provide a real or implicit price of carbon could create incentives for producers and consumers to significantly invest in low-GHG products, technologies and processes. Such policies could include economic instruments, government funding and regulation. An effective carbon-price signal could realize significant mitigation potential in all sectors.

Modeling studies, consistent with stabilization at around 550 ppm CO2-eq by 2100 (see Box SPM.3), show carbon prices rising to twenty to eighty dollars per ton CO2-eq by 2030 and thirty to one-hundred fifty-fife dollars per tCO2-eq by 2050. For the same stabilization level, studies that take into account induced technological change lower these price ranges to five to sixty-five dollars per tCO2-eq in 2030 and fifteen to one-hundred thirty dollars per tCO2-eq in 2050.

Most top-down, as well as some 2050 bottom-up assessments, suggest that real or implicit carbon prices of twenty dollars to fifty dollars per tCO2-eq, sustained or increased over decades, could lead to a power generation sector with low-GHG emissions by 2050 and make many mitigation options in the end-use sectors economically attractive.

Barriers to the implementation of mitigation options are manifold and vary by country and sector. They can be related to:

• financial,

• technological,

• institutional,

• informational, and

• behavioral aspects.

Government support through financial contributions, tax credits, standard setting and market creation is important for effective technology development, innovation and deployment. Transfer of technology to developing countries depends on enabling conditions and financing. Public benefits of RD&D investments are bigger than the benefits captured by the private sector, justifying government support of RD&D.

Government funding in real absolute terms for most energy research programs has been flat or declining for nearly two decades (even after the UN Framework convention on Climate Change (UNFCCC) came into force) and is now about half of the 1980 level.

Governments have a crucial supportive role in providing appropriate enabling environment, such as, institutional, policy, legal and regulatory frameworks to sustain investment flows and for effective technology transfer – without which it may be difficult to achieve emission reductions at a significant scale. Mobilizing financing of incremental costs of low-carbon technologies is important. International technology agreements could strengthen the knowledge infrastructure.

The potential beneficial effect of technology transfer to developing countries brought about by Annex I (developed) countries action may be substantial. Financial flows to developing countries through Clean Development Mechanism (CDM) projects have the potential to reach levels of the order of several billions per year but are at least an order of magnitude lower than total foreign direct investment flows. The financial flows through CDM and development assistance for technology transfer have so far been limited and geographically unequally distributed.

Notable achievements of the UNFCCC and its Kyoto Protocol are the establishment of a global response to the climate problem, stimulation of an array of national policies, the creation of an international carbon market and the establishment of new institutional mechanisms that may provide the foundation for future mitigation efforts. However, the impact of the Protocol’s first commitment period relative to global emissions is projected to be limited.

The literature identifies many options for achieving reductions of global GHG emissions at the international level through cooperation. It also suggests that successful agreements are environmentally effective, cost-effective, incorporate distributional considerations and equity, and are institutionally feasible.

Greater cooperative efforts to reduce emissions will help to reduce global costs for achieving a given level of mitigation, or will improve environmental effectiveness. Improving and expanding the scope of market mechanisms (such as emission trading and CDM) could reduce overall mitigation costs.

Efforts to address climate change can include diverse elements such as:

• emissions targets,

• sectoral, local, sub-national and regional actions,

• RD&D programs,

• adopting common policies,

• implementing development oriented actions, or

• expanding financing instruments.

These elements can be implemented in an integrated fashion.

Actions that could be taken by participating countries can be differentiated both in terms of when such action is undertaken, who participates and what the action will be. Actions can be binding or non-binding, include fixed or dynamic targets, and participation can be static or vary over time.

IPCC Table SPM 7: Selected sectoral policies, measures and instruments that have shown to be environmentally effective in the respective sector in at least a number of national cases.

Sustainable Development and Climate Change Mitigation

Making development more sustainable by changing development paths can make a major contribution to climate change mitigation, but implementation may require resources to overcome multiple barriers. There is a growing understanding of the possibilities to choose and implement mitigation options in several sectors to realize synergies and avoid conflicts with other dimensions of sustainable development.

Irrespective of the scale of mitigation measures, adaptation measures are necessary.

Addressing climate change can be considered an integral element of sustainable development policies. National circumstances and the strengths of institutions determine how development policies impact GHG emissions. Changes in development paths emerge from the interactions of public and private decision processes involving government, business and civil society, many of which are not traditionally considered as influencing climate policy. This process is most effective when actors participate equitably and decentralized decision making processes are coordinated.

Climate change and other sustainable development policies are synergistic. There is growing evidence that decisions about macroeconomic policy, agricultural policy, multilateral development bank lending, insurance practices, electricity market reform, energy security and forest conservation, for example, which are often treated as being apart from climate policy, can significantly reduce emissions. On the other hand, decisions about improving rural access to modern energy sources for example may not have much influence on global GHG emissions.

Climate change policies related to energy efficiency and renewable energy are often economically beneficial, improve energy security and reduce local pollutant emissions. Other energy supply mitigation options can be designed to also achieve sustainable development benefits such as avoided displacement of local populations, job creation, and health benefits.

Preventing the loss of natural habitat and deforestation can have significant biodiversity, soil and water conservation benefits, and can be implemented in a socially and economically sustainable manner. Forestation and bioenergy plantations can lead to restoration of degraded land, manage water runoff, and retain soil carbon and benefit rural economies. The plantations could compete with land for food production and may be negative for biodiversity, if not properly designed.

Making development more sustainable can enhance both mitigative and adaptive capacity, and reduce emissions and vulnerability to climate change. Synergies between mitigation and adaptation can exist, for example properly designed biomass production, formation of protected areas, land management, energy use in buildings and forestry. In other situations, there may be trade-offs, such as increased GHG emissions due to increased consumption of energy related to adaptive responses.

Tipping Points

The most well known effects of climate change that have been studied and modeled involve linear relationships between greenhouse gas forcing and climate change. The IPCC expects impacts to increase in magnitude (exponential growth) and this concept deserves additional attention. There is increasing concern from scientists that climate change may occur abruptly. Recent scientific evidence point to many past changes occurring with startling speed. There is a need for the wider community of scientists and policy makers to recognize this new paradigm and act accordingly (Rial et.al: 2004).

America’s national security establishment is actively preparing for the kind of large-scale political destabilization that a non-linear environmental tipping point would unleash. Anticipating the possibility of a rapid “climate snap,” a 2004 Pentagon scenario envisions far more violent storms, more mega-droughts, and masses of refugees from Mexico, South America, and the Caribbean swarming U.S. boarders in search of food. All over the world, countries would be drawn into resource wars over dwindling amounts of arable land, shrinking supplies of potable water, and increasingly scarce parcels of climatically hospitable territory, according to Pentagon planners.

The Pentagon is basing these predictions on the National Research Council’s report on Abrupt Climate Change (Schwartz & Randall: 2002). There are several economic and political tipping points that are likely to result from resource wars, disease, malnutrition, and migration that represents nothing less than a collapse in civilization. It is these non-linear consequences of GHGs and temperature rise that are the real concern.

Clathrate Gun Hypothesis

Gas hydrates refer to both the methane hydrate (clathrate) reservoirs in ocean sediments and the carbon in permafrost zones on land where the mean annual soil surface temperature remain below -5°C (23°F). The methane comes from decaying organic matter. In the ocean, a slight increase in temperature or decrease in pressure can cause the release of huge amounts of methane into the atmosphere. There are ten-thousand gigatonnes of stored gas hydrates compared with only one-hundred eighty gigatonnes of carbon dioxide currently in the atmosphere. Methane is a powerful greenhouse gas, twenty-one to sixty-two times the greenhouse warming potential of CO₂ (Kennett et.al.: 2002; Maslin: 2004).

The Clathrate Gun Hypothesis is that the destabilization of methane reservoirs is the primary cause for historic abrupt global warmings (less than one human lifespan) (Kennett et al.: 2002). Evidence suggests one event fifty-five million years ago involving about twelve-hundred gigatonnes of gas hydrates caused an extra 5°C (23°F) of warming (Maslin: 2004). At this temperature, shutdowns in the circulations of the ocean (MOC) are very likely to occur (Rahmstorf: 2000). One model calculation by Peter Cox predicts the breakdown of these hydrates within the next one-hundred years (Maslin, 112).

The methane hydrate reservoirs are generally not considered for several reasons: it is remote and poorly studied, little was known about them until recently, and modern reservoirs appeared stable until recently. But now ocean temperatures are increasing and the ocean’s ecosystems are the most immediately impacted by climate change. Scientists such as Buffett and Archer (2004), Kennett et al. (2002), and Maslin (2004) all believe that methane hydrates may be the “dark horse” of climate change.

Oil War

Oil is the lifeblood of the global economy. It is the energy responsible for extraordinary advances in technology, world trade, and industrial agriculture. An extended shock in the oil market would be disastrous for civilization and could cause a collapse in itself.

Oil is too heavily subsidized and undervalued. Burning it causes significant externalities that represent a massive market failure, which is why the IPCC recommends a carbon tax to address this problem. The organization Resources of the Future suggests a ten dollars per barrel oil tax as soon as possible. To avoid this politically difficult policy, they also propose a forty dollars per barrel floor price and funding for debt reduction, tax relief or subsidizing new energy technologies (Darmstadter: 2007).

The New York Time’s economic pundit Thomas L. Friedman thinks that we are in the “pre-climate war era.” Unless we create a more carbon-free world, according to Friedman, we can not preserve the free world. “Green has to become part of America’s DNA” (Friedman: 2007).

Even if optimistic forecasts about being able to maintain GHGs below 550 ppm is accurate, the world is facing an historic change that is unprecedented in scope and depth of impact. Becoming independent of fossil fuel resources is the best thing a community can do to buffer themselves from an impending oil supply disruption and the serious humanitarian impacts that will certainly follow (Heinberg: 2005).

Amazon Forest

The Amazon forest is dependent on the monsoon which every year brings massive amounts of rain. There are many climate models that show the world moving to a more El Niño-like state. This change would result in a much longer South American dry season and before long, the rainforest would be replaced by savannah (dry grassland) (Fedorov & Philander: 2000).

The forest is a huge natural store of carbon estimated to be sequestering about five tones of atmospheric carbon dioxide per ha per year (equivalent to about three-quarters of the world’s car pollution) (Maslin: 2004). Extended dry periods would lead to forest fires and this would return the carbon stored in the forest back into the atmosphere, accelerating global warming. Additional carbon, upwards of eighty percent, would come from increased soil decomposition (Schwartz, Randall: 2002 & Maslin: 2004).

At this time there is not enough evidence to say for certainty if the world will or will not move into a more El Niño-like state (Fedorov & Philander: 2000). Projections are far from conclusive: some predict more instability, some less, and the uncertain consensus indicates little change (Cane: 2005).

Our limits to knowledge about things like El Niño suggest taking precautionary action that would necessitate early and stringent GHG reductions. The earth’s ecological balance, as the Amazonian example suggests, is quite precarious.

Conclusion

An important characteristic of global warming is that delayed lag effects mean that action to prevent further warming has to be taken well in advance: a policy of immediatism is essential. The climate system at this time is naturally unstable, unpredictable, and highly sensitive.

Climate science is a field with many uncertainties but there is a growing consensus that the urgency and seriousness of global warming has been understated (Pacala et al.: 2003; Hansen: 2006; Oppenheimer et al.: 2007). The primary reason for an understatement of climate impacts is because factors such as methane hydrates, ocean circulation, El Niño, and the oil market are very difficult to model.

Five months after the IPCC’s 2007 reports came out, the IPCC issued the report Climate Change 2007 telling the public that GHGs were actually 455 ppm in 2005 and not 379 ppm. This was not expected to happen for another decade. This means that GHG concentrations are already above the threshold that can cause dangerous climate change (Metro: 2007).

The reason climate change is a crisis is because our actions today are going to cause widespread suffering in the future. Global population is growing at an unsustainable rate and economic volatility will cause food scarcity. Every effort should be taken to adapt to the impending changes and to mitigate effects for future generations. The tendency for governments to react to crises ad hoc rather than actively prevent crises is not compatible with this situation.

Global climate change could cause a global collapse in civilization but it is still possible to avoid this. There are many great opportunities that are synergistic with economic benefits, health benefits, and environmental benefits. The major causes of climate change are pollution and over-exploitation of fossil fuels, the land, and agriculture. These changes necessitate an adaptation to drought, floods, and water scarcity. Likewise, the earth’s ecosystems less able to adapt are going to be destroyed by these problems as well as wildfires, insects, and ocean acidification. We are experiencing the second worst extinction in the earth’s 575 million year fossil record (Siegel: 2000). The IPCC projects a ninety percent increase in GHGs by 2030 and recommends that we reduce our global GHGs by sixty percent by 2060. This means that we have to reduce projected GHGs by about one-hundred and fifty percent. This two and a half percent rate of reduced energy consumption is unprecedented.

Humans are not adapting fast enough. We are not prepared. Barriers to this change include environmental, economic, informational, social, attitudinal, and behavioral issues. One of the major problems is that two-thirds to three-fourths of the GHG increase is going to be from developing countries.

The global climate change debate demands we focus on at least three things:

1. Market failures. The full costs of energy use and production need to be internalized. The government needs to stop subsidizing fossil energy and start taxing it.

2. Behavioral patterns need to embrace greater conservation and less consumption.

3. Co-benefits that include health and environmental factors need to be included in cost analyses.

At the top of the list of issues to focus on, the IPCC recommends increasing building efficiency and forest and soil conservation (a priority in conflict with bioenergy production).

Mitigation policies include: regulation and standards, taxes and charges, financial incentives (tax credits and subsidies), information campaigns, and voluntary actions. Policies should be evaluated based on environmental costs, distributional effects (equity), and institutional feasibility. Action differentiation involves variations in when, who, (non)binding, fixed/dynamic targets, and static/varied participation.

Government has a responsibility to play a crucial supportive role in this energy change. The government needs to provide incentives for Energy Service Companies (ESCOs) and public sector leadership programs. The government also needs to shift subsidies for fossil production to renewable energy production. The American government arguably has the most important job in the world. However, it has yet to live up to the challenge in the recent future.