Temperature stabilization, ocean heat uptake and radiative forcing overshoot profiles
Artikel i vetenskaplig tidskrift, 2011

Political leaders in numerous nations argue for an upper limit of the global average surface temperature of 2 K above the pre-industrial level, in order to attempt to avoid the most serious impacts of climate change. This paper analyzes what this limit implies in terms of radiative forcing, emissions pathways and abatement costs, for a range of assumptions on rate of ocean heat uptake and climate sensitivity. The primary aim is to analyze the importance of ocean heat uptake for radiative forcing pathways that temporarily overshoot the long-run stabilization forcing, yet keep the temperature increase at or below the 2 K limit. In order to generate such pathways, an integrated climate-economy model, MiMiC, is used, in which the emissions pathways generated represent the least-cost solution of stabilizing the global average surface temperature at 2 K above the pre-industrial level. We find that the level of overshoot can be substantial. For example, the level of overshoot in radiative forcing in 2100 ranges from about 0.2 to 1 W/m2, where the value depends strongly and positively on the effective diffusivity of heat in the oceans. Measured in relative terms, the level of radiative forcing overshoot above its longrun equilibrium level in 2100 is 20% to 60% for high values of climate sensitivity (i.e., about 4.5 K) and 8% to 30% for low values of climate sensitivity (i.e., about 2 K). In addition, for cases in which the radiative forcing level can be directly stabilized at the equilibrium level associated with a specific climate sensitivity and the 2 K limit, the net present value abatement cost is roughly cut by half if overshoot pathways are considered instead of stabilization of radiative forcing at the equilibrium level without an overshoot.

sea-level rise

trade-off

atmospheric co2

p1705

model

time scales

v33

rster p

rest ce

emissions

naka k

2007

2006

global mean temperature

transient climate response

greenhouse gases

targets

2001

ather m

2008

Författare

Daniel Johansson

Chalmers, Energi och miljö, Fysisk resursteori

Climatic Change

0165-0009 (ISSN) 1573-1480 (eISSN)

Vol. 108 107-134

Ämneskategorier

Annan naturresursteknik

DOI

10.1007/s10584-010-9969-4