The 21st Century climate challenge

CHAPTER3Avoidingdangerous climate change:strategies for mitigationLiving within a sustainable21 st Century carbonbudget requires that richcountries cut emissions ofgreenhouse gases by at least80 percent by 2050, with30 percent cuts by 2020Climate change is an immense, long-term and global challenge that raises difficultquestions about justice and human rights, both within and across generations.Humanity’s ability to address these questions is a test of our capacity to managethe consequences of our own actions. Dangerous climate change is a threat, not apre-ordained fact of life. We can choose to confront and eliminate that threat, orwe can choose to let it evolve into a fully fledged crisis for poverty reduction and forfuture generations.Approaches to mitigation will determine theoutcome. The more we delay action, the moreatmospheric concentrations of greenhouse gaseswill rise, the more difficult it will be to stabilizebelow the 450 ppm CO 2e target—and the morelikely the 21 st Century will experience dangerousclimate change.On our sustainable emissions pathway setout in chapter 1, mitigation would start to makea difference after 2030 and world temperatureswould peak around 2050. These outcomeshighlight the lag between action and results intackling climate change. They also drawattention to the importance of thinking beyondthe time-horizon defined by political cycles.Dangerous climate change is not a short termemergency amenable to a quick fix. The currentgeneration of political leaders cannot solve theproblem. What they can do is to keep openand then widen the window of opportunity forfuture generations to take up the battle. The21 st Century carbon budget set out in chapter 1provides a roadmap for achieving this objective.Keeping the window open will requireearly and radical shifts in energy policy. Sincethe industrial revolution, economic growthand human prosperity have been fuelled bycarbon-based energy systems. Over the next fewdecades, the world needs an energy revolutionthat enables all countries to become low-carboneconomies. That revolution has to start in thedeveloped world. Living within a sustainable21 st Century carbon budget requires that richcountries cut emissions of greenhouse gases byat least 80 percent by 2050, with 30 percentcuts by 2020. If the targets are to be achieved,the collective emissions curve will have to peakand start bending in a downwards directionbetween 2012 and 2015. Developing countrieswill also have to chart a low-carbon transitionpathway, albeit at a pace that reflects their morelimited resources and the imperative of sustainingeconomic growth and cutting poverty.This chapter looks at the strategies neededto achieve a rapid transition to a low-carbonfuture. The 21 st Century carbon budget providesa roadmap for reaching the agreed destination—a world free of dangerous climate change. Buttargets and roadmaps are not a substitute forpolicies. They will only contribute to the battleagainst climate change if they are backed byeffective mitigation strategies.There are three foundations for success.The first is putting a price on carbon emissions.Market-based instruments have a critical role toplay in creating incentives that signal to businessand consumers that there is a value in reducingemissions—and that the Earth’s capacity for3Avoiding dangerous climate change: strategies for mitigationHUMAN DEVELOPMENT REPORT 2007/2008 111