Economic aspects of global warming in a post-Copenhagen environment

Abstract

The science of global warming has reached a consensus on the high likelihood of substantial warming over the coming century. Nations have taken only limited steps to reduce greenhouse gas emissions since the first agreement in Kyoto in 1997, and little progress was made at the Copenhagen meeting in December 2009. The present study examines alternative outcomes for emissions, climate change, and damages under different policy scenarios. It uses an updated version of the regional integrated model of climate and the economy (RICE model). Recent projections suggest that substantial future warming will occur if no abatement policies are implemented. The model also calculates the path of carbon prices necessary to keep the increase in global mean temperature to 2 degrees C or less in an efficient manner. The carbon price for 2010 associated with that goal is estimated to be $59 per ton (at 2005 prices), compared with an effective global average price today of around $5 per ton. However, it is unlikely that the Copenhagen temperature goal will be attained even if countries meet their ambitious stated objectives under the Copenhagen Accord.

Fig. 1.

Projected emissions of CO₂ under alternative policies. Copen, Copenhagen.

Fig. 2.

Atmospheric concentrations of CO₂ under alternative policies. Copen, Copenhagen.

Fig. 3.

Global temperature increase (°C from 1900) under alternative policies. Copen, Copenhagen.

Fig. 4.

Total costs of compliance as percent of national income. EU, European Union.