Climate impacts of shipping and petroleum
extraction in an unlocked Arctic ocean
B. H. Samset(1), T. Berntsen(1,2), S.B. Dahlsøren(1), L.I. Eide(3), M.S. Eide(3), J. Fuglestvedt(1), S. Glomsrød(1), L. Lindholt(4), G. Myhre(1), T.B. Nilssen(3), G.P. Peters(1), and K. Ødemark(2)
(1) CICERO, Norway, (2) University of Oslo, Norway, (3) DNV (Norwegian Veritas), (4) SSB (Statistics Norway)
Present day effects
The Arctic ocean is an attractive
arena for future shipping and
petroleum extraction
Effects in 2030-2050
(In preparation)
Using 2004 emissions we find that the effects presently dominating are
• Shipping: Warming from BC in air and on snow
• Petroleum: Cooling from direct and 1st indirect effects of sulphate
Reductions in sea ice extent are expected to open up the
Arctic region to increased volumes of ship traffic and
petroleum extraction activities.
Radiative forcing time series, petroleum
Radiative forcing
Both of these potentially entail changes in concentrations of short-lived climate
forcers (SLCFs) such as aerosols and ozone, which may impact the future climate. The
response of the Arctic to SLCF emissions is however not well constrained, as the annual
cycle, solar irradiation, surface albedo and ambient temperature are special to this region.
The present study investigates the effects of SLCF
emissions in the Arctic in 2004, as well as in 2030 and
2050.
Global Warming Potentials
An emission inventory is used for present day activities, while future emissions are taken
from models of the global energy market and shipping fleet. Atmospheric concentrations are
input to the OsloCTM2 chemical transport model, and radiative forcings (RFs) are calculated
using a multi-stream radiation transport code. Climate impacts are quantified via RFs and
Global Warming Potentials of the various emitted components, in addition to estimates of the
first indirect aerosol effect and the snow albedo effect from black carbon (BC).
For present day emissions we calculate a net negative RF
from shipping, mainly driven by the indirect aerosol
effect, and a net positive RF from petroleum extraction,
mainly due to the BC snow albedo effect.
Conclusions
Seasonal radiative and normalized forcing
For future emissions the general results remain similar, but the total RFs develop with
changes in emission volume andcomposition.
The melting of Arctic sea ice will unlock the Arctic ocean areas, leaving it increasingly
open to human activity.
The physical conditions in the Arctic including, high solar angle, high surface albedo,
summer season with midnight sun and polar night during winter are very different from
other regions of the World. However, the normalized forcings, e.g. to change in atmospheric
burden (NRF), or to emissions as in the GWPs, suggest that the annual averaged
sensitivities for Arctic emissions, with BC on snow and ice as a notable exception, are similar
to the global averages. The seasonal cycle in the sensitivities and thus in the radiative
forcings is, however, much more pronounced.
We find that presently the effect of Arctic shipping emissions of SLCFs and
precursors is negative, while the net effect from Arctic petroleum emissions
of SLCFs is positive.
The regional radiative forcings north of 60 N are of the order of −20 mWm−2 and +20mWm−2,
respectively. To assess the overall effects of shipping and petroleum in the Arctic also the
impact of the emissions of the intermediate and long-lived components methane and carbon
dioxide must be taken into account. However, for these components the location of the
emissions is unimportant.
Future emissions could potentially have a significant effect on Arctic environment,
regional air pollution levels and radiative budget.
This will be addressed in upcoming studies.
Methodology
The estimate and analysis chain used for the present analyses is outlined below.
Emission estimates
Chemical transport w. OsloCTM2
Radiative transport v. DISORT
Results
Based on economical models and present day
inventories, see Peters et al. 2011
Emissions are input to a state-of-the-art chemical transport
model, running in 3D with T42 resolution and 3hour timesteps,
driven by ECMWF meteorology. Deposition of BC on snow is
included, Arctic ice extent estimates from DNV are used.
Radiative transport using four shortwave bands and 8
multiple scattering streams. Same resolution as the
chemical model. O3 forcing estimates also use longwave
scheme. 1st indirect effect estimated by parametrizing
droplet radius vs. aerosol optical depth.
Present day: Ødemark et al., ACP, 2012
2030/2050: Dahlsøren et al. (in prep.)