40 Emissions projections edit further information: Climate change scenario projected total carbon dioxide emissions between using the six illustrative "sres" marker scenarios. 41 Changes in future greenhouse gas emission levels movie are highly uncertain, and a wide range of quantitative emission projections have been produced. 42 Rogner. (2007) 43 assessed these projections. Some of these projections aggregate anthropogenic emissions into a single figure as a " carbon dioxide equivalent " (CO2-eq). By 2030, baseline scenarios projected an increase in greenhouse emissions (the f-gases, nitrous oxide, methane, and CO2, measured in CO2-eq) 44 of between 25 and 90, relative to the 2000 level. 43 For CO2 only, two-thirds to three-quarters of the increase in emissions was projected to come from developing countries, although the average per capita co2 emissions in developing country regions were projected to remain substantially lower than those in developed country regions. 43 by 2100, co2-eq projections ranged from a 40 reduction to an increase in emissions of 250 above their levels in 2000.
35 developed countries' past contributions to climate change were in the process of economically developing to their current level of prosperity; developing countries are attempting to rise to this level, this being one cause of their increasing greenhouse strange gas emissions. 36 Equity is an issue in ghg emissions scenarios, sonali. Chitre argues, and Emerging markets countries, such as India and China, often would rather analyze per capita emissions instead of committing to aggregate Emissions reduction because of historical contributions by the Industrialized nations to the climate change crisis, under the principle of Common But Differentiated. 37 For example, the scenarios used in the Intergovernmental Panel on Climate Change's (ipcc) First Assessment Report of 1990 were criticized by parikh (1992). 38 Parikh (1992) 38 argued that the stabilization scenarios contained in the report "stabilize the lifestyles of the rich and adversely affect the development of the poor". The ipcc's later " sres " scenarios, published in 2000, explicitly explore scenarios with a narrowing income gap ( convergence ) between the developed and developing countries. 39 Projections of convergence in the sres scenarios have been criticized for lacking objectivity ( Defra / hm treasury, 2005).
Over this time period, reductions in energy intensity of gdp and carbon intensity of energy use have been unable to offset increases in population and gdp per capita. Consequently, energy-related co 2 emissions have increased. Between 19, energy-related co 2 emissions grew on average by about.8 per year. 30 Population grew on average by about.1 per year and gdp per capita.6 per year. 30 Energy intensity of gdp on average fell by about.1 per year, and carbon intensity of energy fell by about.2 per year. 30 Trends and projections edit see also: greenhouse gas Greenhouse gas emissions, and global climate model Projections of future climate change Emissions edit Equity and ghg emissions edit see also: Greenhouse gas Regional and national attribution of emissions, and Climate change mitigation Sharing In considering. In common language equity means "the quality of being impartial" or "something that is fair and just." 33 One example of the relevance of equity to ghg emissions are the different ways in which emissions can be measured. 34 These include the total annual emissions of one country, cumulative emissions measured over long time periods (sometimes measured over more than 100 years average emissions per person in a country ( per capita emissions as well as measurements of energy intensity of gdp, carbon. 34 Different indicators of emissions provide different insights relevant to climate change policy, and have been an important issue in international climate change negotiations (e.g., see kyoto ProtocolNegotiations ).
Quantifying the consensus on global warming in the
30 Historically, growth in ghg emissions have been driven by economic development. 31 :169 summary One way of understanding trends in ghg emissions is to use the kaya identity. 16 The kaya identity breaks down emissions growth into the effects of changes in human population, economic affluence, and technology: 16 31 :177 co 2 emissions from energy Population ( gross domestic product (GDP) per essay head of population) (energy use / gdp) (CO 2 emissions. These two terms are often referred to as " energy intensity of gdp" and " carbon intensity of energy respectively. 32 Note that the abbreviated term "carbon intensity" may also refer to the carbon intensity of gdp,.
E., (energy-related co 2 emissions / gdp). 32 Reductions in the energy intensity of gdp and/or carbon intensity of energy will tend to reduce energy-related co 2 emissions. 31 :177 Increases in population and/or gdp per capita will tend to increase energy-related co 2 emissions. If, however, energy intensity of gdp or carbon intensity of energy were reduced to zero (i.e., complete decarbonization of the energy system increases in population or gdp per capita would not lead to an increase in energy-related co 2 emissions. The graph on the right shows changes in global energy-related co 2 emissions between 19Also plotted are changes in world population, world gdp per capita, energy intensity of world gdp, and carbon intensity of world energy use.
These scenarios project a wide range of possible futures. Some are pessimistic, for example, 5 scenarios project the future breakdown of human society. 27 Others are optimistic, for example, in 5 other scenarios, future advances in technology solve most or all of humanity's problems. Most scenarios project increasing damage to the natural environment, but many scenarios also project this trend to reverse in the long-term. 28 In the scenarios, morita.
(2001) 29 found no strong patterns in the relationship between economic activity and ghg emissions. By itself, this relationship is not proof of causation, and is only reflective of the scenarios that were assessed. In the assessed scenarios, economic growth is compatible with increasing or decreasing ghg emissions. 29 In the latter case, emissions growth is mediated by increased energy efficiency, shifts to non-fossil energy sources, and/or shifts to a post-industrial (service-based) economy. Most scenarios projecting rising ghgs also project low levels of government intervention in the economy. Scenarios projecting falling ghgs generally have high levels of government intervention in the economy. 29 Factors affecting emissions growth edit see also: i pat changes in components of the kaya identity between 19Includes global energy-related co 2 emissions, world population, world gdp per capita, energy intensity of world gdp and carbon intensity of world energy use.
Why Obamas big global warming push
Some analysts have developed scenarios that project a continuation of current policies into the future. These scenarios are sometimes called "business-as-usual" scenarios. 22 Experts who work on scenarios tend to prefer the term "projections" to "forecasts" or "predictions". 23 This distinction is made to emphasize twist the point that probabilities are not assigned to the scenarios, 23 and that future emissions depend on decisions made both now and into the future. 24 :75 Another approach is that of uncertainty analysis, evernote 4 where analysts attempt to estimate the probability of future changes in emission levels. Global futures scenarios edit see also: Global Scenario group "Global futures" scenarios can be thought of as stories of possible futures. 25 They allow for the description of factors which are difficult to quantify but are important in affecting future ghg emissions. The ipcc third Assessment Report (Morita., 2001) 26 includes an assessment of 124 global futures scenarios.
4 In scenario analysis, scenarios are developed that are based on differing assumptions of future development patterns. An example of this are the "sres" emissions scenarios produced by the Intergovernmental Panel on Climate Change (ipcc). The sres scenarios project a wide range of possible future emissions levels. 17 The sres scenarios are "baseline" or "non-intervention" scenarios, in that they assume no specific policy measures to control future ghg emissions. 18 The different sres scenarios contain widely differing assumptions of future social and economic changes. For example, the sres "A2" emissions scenario projects a future population level of 15 billion people in the year 2100, but the sres "B1" scenario projects a lower online population level of 7 billion people. 19 The sres scenarios were not assigned probabilities by the ipcc, but some authors 20 21 have argued that particular sres scenarios are more likely to occur than others.
other development objectives. 12 13 In other areas, the cost of global warming policies may divert resources away from other socially and environmentally beneficial investments (the opportunity costs of climate change policy). 12 13 Contents Scenarios edit see also: Climate change scenario and Climate change mitigation scenarios One of the economic aspects of climate change is producing scenarios of future economic development. Future economic developments can, for example, affect how vulnerable society is to future climate change, 14 what the future impacts of climate change might be, as well as the level of future ghg emissions. 15 Emissions scenarios edit In scenarios designed to project future ghg emissions, economic projections,. G., changes in future income levels, will often necessarily be combined with other projections that affect emissions,. G., future population levels. 16 Since these future changes are highly uncertain, one approach is that of scenario analysis.
5 Economists have attempted to quantify these impacts in monetary terms, but these assessments can be controversial. 6 7 The two main policy responses to global warming are to reduce greenhouse gas emissions ( climate change mitigation ) and to adapt to the impacts of global warming (e.g., by building hippie levees in response to sea level rise). Another policy response which has recently received greater attention is geoengineering of the climate system (e.g. Injecting aerosols into the atmosphere to reflect sunlight away from the earth's surface). 8 One of the responses to the uncertainties of global warming is to adopt a strategy of sequential decision making. 9 This strategy recognizes that decisions on global warming need to be made with incomplete information, and that decisions in the near term will have potentially long-term impacts. Governments might choose to use risk management as part of their policy response to global warming. 10 For instance, a risk-based approach can be applied to climate impacts which are difficult to quantify in economic terms,. G., the impacts of global warming on indigenous peoples.
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The economics of global warming concerns the economic aspects of global warming ; this can inform policies that governments resume might consider in response. A number of factors make this a difficult problem from both economic and political perspectives: it is a long-term, intergenerational problem; 1 benefits and costs are distributed unequally both within and across countries; and scientific and public opinions may diverge. One of the most important greenhouse gases is carbon dioxide cO2 ). 2, around 20 of carbon dioxide which is emitted due to human activities can remain in the atmosphere for many thousands of years. The long time scales and uncertainty associated with global warming have led analysts to develop " scenarios " of future environmental, social and economic changes. 4, these scenarios can help governments understand the potential consequences of their decisions. The impacts of climate change include the loss of biodiversity, sea level rise, increased frequency and severity of some extreme weather events, and acidification of the oceans.