2019/03/01 by John Bongaarts · 3 citations
Economics, Econometrics and Finance · Environmental Science · #Climate Change Policy and Economics #Atmospheric and Environmental Gas Dynamics #Climate Change and Environmental Impact
paper · pdf · doi:10.1111/padr.12234
The latest major effort of the international community to address global warming is the Paris Agreement reached in 2016 within the United Nations Framework Convention on Climate Change (UNFCCC). The Agreement aims to reduce the risks and effects of climate change by limiting the increase in global average temperature to 1.5°C above the pre-industrial level. Under the Agreement, each country must determine, plan, and regularly report on the contribution that it undertakes to mitigate global warming. At the invitation of UNFCCC, the International Panel on Climate Change (IPCC, the leading and international body for the scientific assessment of climate change) prepared the present report. Its goal is to assess the impact of global warming of 1.5° C and to identify associated greenhouse gas (GHG) emission pathways. Drawing on the expertise of hundreds of scientists, the report systematically and authoritatively examines the latest scientific evidence related to alternative GHG emission pathways compatible with 1.5°C of global warming. It also assesses the impacts of such warming on natural and human systems and options for implementing and strengthening the global response. A concise summary for policy makers is included. The main conclusion from this analysis is that limiting global warming to 1.5°C requires “unprecedented” and extremely steep cuts in global GHG emissions. To meet the Paris goal, emissions must be reduced by half in 2030 and reach “net zero” around 2050. Moreover, after 2050, GHG emissions have to become net negative (i.e. gases would have to be removed from the atmosphere) for some time to remain under the limit in the long run. The Paris goal seems unachievable because the commitments made by governments are insufficient to meet the goal and several countries (notably including the US) have either withdrawn from the agreement or are exceeding even their own limited objectives. It is therefore very likely that the world will exceed the 1.5°C limit in the next few decades and much higher temperatures could be reached by 2100. As a result, the world must prepare for the wide range of adverse effects on natural and man-made systems and on human society. There is an especially urgent need for more effective adaptation measures to protect vulnerable populations. Geoengineering options are not discussed in the report but will likely need to be considered eventually to avoid extreme warming. The report is densely written but rich in scientific content and includes many highly informative figures. However, readers of PDR may be disappointed that there is no discussion of the role of continued growth of the global population (expected to reach 11.2 billion by 2100) or of population policy options.