Climate impacts of shipping and petroleum
extraction in an unlocked Arctic ocean
B. H. Samset(1), T. Berntsen(1,2), S.B. Dalsøren(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) Norwegian Veritas, (4) Statistics Norway
Present day effects
The Arctic ocean is an attractive
arena for future shipping and
petroleum extraction
Effects in 2030-2050
• Petroleum: Warming from BC in air and on snow
• Shipping: Cooling from direct and 1st indirect
effects of sulphate
(In preparation)
Radiative forcing time series, petroleum
Radiative forcing
Reductions in sea ice extent are expected to open up the
Arctic region to increased volumes of ship traffic and
petroleum extraction activities.
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
Conclusions
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
sent 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).
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 changes in atmospheric
burden (NRF) or to emissions (GWP), suggest that the annual averaged sensitivities for
Arctic emissions, are similar to the global averages. BC on snow and ice is a notable
exception. The seasonal cycle in the sensitivities, and thus in the radiative forcings, is,
however much more pronounced than the global mean.
Seasonal radiative and normalized forcing
For future emissions the general results remain similar, but the total RFs develop with
changes in emission volume andcomposition.
Methodology
Ødemark et al., ACP, 2012
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.
The melting of Arctic sea ice will unlock the Arctic ocean
areas, leaving it increasingly open to human activity.
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 the impact
of the emissions of the intermediate and long-lived components methane and carbon dioxide
must also 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. (Dalsøren et al. (in prep.))
The estimate and analysis chain used for the present analyses is outlined below.
Emission estimates
Chemical transport w. OsloCTM2
Radiative transport v. DISORT
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 Norwegian Veritas 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.
Results
Present day: Ødemark et al., ACP, 2012
2030/2050: Dalsøren et al. (in prep.)