The 21st Century climate challenge

1The 21 st Century climate challenge• While our sustainable emissionspathway points to an indicative targetof cuts in the range of at least 80percent for OECD countries, the IEAreference scenario indicates a 40 percentincrease—an aggregate expansion of 4.4Gt CO 2. The United States will accountfor around half the increase, takingemissions 48 percent above 1990 levels(figure 1.15).• According to the IEA, developing countrieswill account for three-quarters of theincrease in global CO 2emissions, whereasour sustainable emissions pathway pointsto the need for cuts of around 20 percentby 2050 against 1990 levels. The projectedexpansion would represent a fourfoldincrease over 1990 levels.• While per capita emissions will increasemost rapidly in developing countries,convergence will be limited. By 2030,OECD emissions are projected at 12tonnes of CO 2per capita, compared with5 tonnes CO 2for developing countries.In 2015, per capita emissions from Chinaand India are projected at 5.2 and 1.1tonnes, compared with 19.3 tonnes forthe United States.• IPCC scenarios are more comprehensivethan those developed by the IEA becausethey incorporate other sources of emissions,Figure 1.15 Business-as-usual CO 2emissions on a rising trendEnergy-related CO 2emissions (Mt CO 2)12,00010,0008,0006,0004,0002,0000United StatesRussian FederationChinaEuropean UnionJapan1990 1995 2000 2005 2010 2015 2020 2025 2030Source: IEA 2006c.Indiaincluding agriculture, changes in land use,and waste, and a wider range of greenhousegases. These scenarios point to emissionlevels of 60–79 Gt CO 2e by 2030, on asharply rising trend. The lower end of thisrange is 50 percent above the 1990 baseline.One of the IPCC’s non-mitigationscenarios has emissions doubling in thethree decades to 2030. 77Drivers for increased emissionsAs with any future scenario, these figureshave to be treated with caution. Theyrepresent a best-estimate based onunderlying assumptions about economicgrowth, population change, energy markets,technology and current policies. The scenariosdo not chart a predetermined trajectory.What they draw attention to is the hard factthat the world is currently on an emissionstrajectory that guarantees a collision betweenpeople and planet.Changing trajectories will be difficult. Thereare three powerful drivers of rising emissionsthat will interact with technology, changes inenergy markets and public policy choices.• Demographic trends. Current projectionspoint to an increase in world populationfrom 6.5 billion today to 8.5 billion by2030. At a global level, just standingstill in terms of overall emissions willrequire 30 percent reductions in averageper capita emissions—and standing stillwill not be enough to avoid dangerousclimate change. Almost all the increase inpopulation will take place in developingcountries, where there are currently largeunmet energy needs and lower levels ofenergy efficiency.• Economic growth. Economic growthand the carbon intensity of growth—afunction of energy mix and sectoralcomposition—are two of the mostpowerful drivers of emission trends. Anyprojections in this area are subject touncertainty. Climate change itself couldact as a brake on future growth, especiallyin the event of catastrophic sea-level56 HUMAN DEVELOPMENT REPORT 2007/2008