NATURE:
A
model of the four main outlet glaciers that drain the Greenland Ice Sheet
predicts that they will contribute 19 to 30 millimetres to sea-level rise by
2200 in a mid-range future warming scenario, and 29 to 49 millimetres in a more
extreme scenario.
2. Climate mitigation: An
open dialogue on solar engineering
John Shepherd, Berhanu Abegaz & Jane Long
Nature 497, 188, doi:10.1038/497188b
Solar
Radiation Management (SRM) Governance Initiative (www.srmgi.org) was created: to ensure
that any research undertaken is carefully considered, safe and transparent. It
is a non-governmental organization. It involves partner organizations from 16
countries, and has run meetings in Asia and Africa.
A
growing community of scientists and stakeholders are already taking into
consideration the serious implications of SRM technologies for governance,
ethics and politics.
3. Global warming: A call
for peace on climate and conflict
Andrew R. Solow
Nature 497, 179–180, doi:10.1038/497179a
Among
the most worrying of the mooted impacts of climate change is an increase in
civil conflict as people compete for diminishing resources, such as arable land
and water.
They
argue that the factors that underlie civil conflict are more complex than the
quants allow and that the reported correlations are statistical artefacts. In
my view, although the concern that climate change could increase conflict is
valid, the link remains unproven.
4. Three projects seek to track changes in Atlantic overturning
circulation currents.
Quirin Schiermeier
Nature 497, 167–168, doi:10.1038/497167a
Oceanographers are planning
two new large-scale projects to watch over Atlantic currents.
In
addition to the array of instruments between Florida and the Canary Islands an
international project will begin another set of continuous measurements of the
Atlantic Meridional Overturning Circulation (AMOC), using an array of sensors
strung between South Africa and Argentina. Supporting agencies will also decide
whether they will support a new surface-to-bottom monitoring array between Labrador
in Canada and Scotland. Expanding such monitoring is crucial if scientists are
to improve seasonal weather and climate forecasts.
GEOLOGY
1. Profiles of ocean island coral reefs
controlled by sea-level history and carbonate accumulation rates
Michael Toomey, Andrew D. Ashton, and J. Taylor Perron
Geology,
2013, doi:10.1130/G34109.1
Compiled data from
modern systems show that many islands do not follow Darwin's canonical model of
reef development sequence. The diversity of modern reef morphology arises from
the combined effects of island subsidence, coral growth, and glacial sea-level
cycles. A model for the evolution of a reef elevation profile over the past 400
k.y. driven by Pleistocene sea-level oscillations reveals that different
combinations of reef accretion rate and island vertical motion produce a
variety of forms that matches the observed distribution of modern reefs.
2. North
Atlantic versus Southern Ocean contributions to a deglacial surge in deep ocean
ventilation
Geology, doi:10.1130/G34133.1
Past
glacial-interglacial climate transitions were accompanied by millennial-scale
pulses in atmospheric CO2 that are widely thought to have resulted
from the release of CO2 via the Southern Ocean. Combined radiocarbon
and neodymium isotope measurements from the last deglaciation are used to
confirm greatly enhanced overturning and/or air-sea exchange rates relative to
today.
3. Reach-scale river dynamics moderate
the impact of rapid Holocene climate change on floodwater farming in the desert
Nile
Mark G.
Macklin, Jamie C. Woodward, Derek A. Welsby, Geoff A.T. Duller, Frances M.
Williams, and Martin A.J. Williams
Geology,
doi:10.1130/G34037.1
This paper presents
the most comprehensive and robustly dated archaeological and paleoenvironmental
data sets yet compiled for the desert Nile. We have studied the stratigraphy
and archaeological records of paleochannels of the Nile upstream of Kerma using
optically stimulated luminescence to date when channels flowed and when they
dried up. The dynamics of the local alluvial environment were critical in
determining whether climatic fluctuations and changes in river flow represented
an opportunity, a hazard that could be managed, or an environmental catastrophe
that resulted in settlement abandonment.
4. A new paleothermometer for forest
paleosols and its implications for Cenozoic climate
Timothy M.
Gallagher and Nathan D. Sheldon
Geology,
doi:10.1130/G34074.1
Climate is a primary
control on the chemical composition of paleosols. Soil chemistry data were
compiled for 158 modern soils in order to derive a new paleosol
paleothermometry relationship between mean annual temperature and a paleosol
weathering index that is based on the relative loss of major cations (Na, Mg,
K, Ca) from soil B horizons. The new paleothermometer can be applied to
clay-rich paleosols that originally formed under forest vegetation. A case
study using Cenozoic paleosols from Oregon (US) shows that paleotemperatures
produced with this new proxy compare favorably with paleobotanical and marine temperature
records.
