| Details1: | 1
Meeting the Challenge of Global Warming
William R Cline
Center for Global Development and Institute for International Economics
Introduction
This chapter compares the costs and benefits of three alternative policy strategies to
reduce Mankind’s emissions of greenhouse gases and limit damage due to global
warming.
It is particularly difficult to analyse the economics of policies to limit such emissions
because expected benefits to be generated from such policy actions will materialise only
in the distant future, whereas many of the costs will be incurred much sooner. Therefore
the way in which future benefits are discounted to give a present value is crucial: how
much is the prospect of $100 earned in 50 or 100 years worth to us today? This is
discussed in more detail below before the model used for evaluating the three policy
options is described.
The State of Global Warming Science and Policy
The Intergovernmental Panel on Climate Change (IPCC) provides a framework for
scientists from across the world to share and evaluate the data generated by a range of
computer models projecting future changes to atmospheric composition, average
temperatures and climate patterns. The IPCC periodically reviews this situation, most
recently in the Third Assessment Report (TAR) published in 2001. This report compiles
a vast amount of detailed scientific information, which is distilled into a “Summary for
Policymakers”, agreed to by all participating governments. This summary is the basis for
planning future action.
The TAR projects an increase in average temperatures by 2100 in the range 1.4-5.8 °C
(above the 1990 baseline). It is also estimated that global average surface temperature
rose by 0.6 °C from 1861 to 2000, and the panel concluded that “most of the observed
warming over the last 50 years is likely to have been due to the increase in greenhouse
gas concentrations”. Of the six recognised greenhouse gases, carbon dioxide (CO2) plays
the greatest role because it is emitted in the greatest quantities and persists for long
periods in the atmosphere.
When projecting future temperature rises, the climate models use a range of six
benchmark scenarios, which give rise to very different patterns of man-made carbon
dioxide emissions. It is implicitly assumed in the TAR that all these scenarios have equal
weight, and therefore that the future temperature rise is equally likely to be anywhere
within the projected range. However, the analysis in this chapter assumes that some
scenarios which predict low emissions are extremely unlikely without economic
incentives, which means that future temperature rise would be towards the upper end of
the range.
International policy on mitigation of climate change is focused on the Kyoto protocol,
negotiated in 1997. This treaty sets limits on emissions of carbon dioxide allowed from
industrialised and transition economies, without making any demands on the developing
world. This agreement was seen as the first, relatively small, step by the international
Summary of Copenhagen Consensus Challenge Paper
Not to be released before 30 April 2004
Fortsetzung: Bitte auf obigen Link clicken ! |
